Noninvasive single-beat determination of left ventricular end-systolic elastance in humans

Ventricular-arterial coupling is associated with clinical outcomes in patients with systemic right ventricle

BACKGROUND

Adults with transposition of the great arteries (TGA) and systemic right ventricle (SRV) are at risk for heart failure (HF) and decreased survival. Ventricular-arterial coupling (VAC) quantifies the interaction between myocardial contractile function and the load imposed by the arterial circulation and may be valuable in identifying subclinical SRV dysfunction. The purpose of our study is to determine the association of VAC with adverse clinical outcomes in adults with TGA and SRV.

METHODS

A single center, retrospective cohort study of subjects ≥16 years of age with TGA and SRV who underwent a cardiac magnetic resonance (CMR) examination. VAC was calculated as the ratio between CMR-derived SRV end-systolic volume and stroke volume. Cox proportional hazards regression analysis was performed to assess the association of VAC with clinical outcomes.

RESULTS

One hundred sixty-seven subjects (mean age 32 ± 10 years, 59% males) were evaluated. VAC predicted the composite outcome of death, cardiac arrest and HF hospitalizations (hazard ratio (HR) 2.09; 95% CI, 1.12-3.92, P = .02), as well as other cardiovascular hospitalizations including device implantation and percutaneous or surgical structural intervention (HR 1.65, 95% CI, 1.09-2.49, P = .02) after adjustment for age, sex, and the presence of significant tricuspid regurgitation.

CONCLUSIONS

VAC is associated with major clinical adverse outcomes in patients with TGA and SRV, and may improve risk stratification of this complex population.

Point of View: A Holistic Four-Interface Conceptual Model for Personalizing Shock Resuscitation

The resuscitation of a patient in shock is a highly complex endeavor that should go beyond normalizing mean arterial pressure and protocolized fluid loading. We propose a holistic, four-interface conceptual model of shock that we believe can benefit both clinicians at the bedside and researchers. The four circulatory interfaces whose uncoupling results in shock are as follows: the left ventricle to arterial, the arterial to capillary, the capillary to venular, and finally the right ventricle to pulmonary artery. We review the pathophysiology and clinical consequences behind the uncoupling of these interfaces, as well as how to assess them, and propose a strategy for approaching a patient in shock. Bedside assessment of shock may include these critical interfaces in order to avoid hemodynamic incoherence and to focus on microcirculatory restoration rather than simply mean arterial pressure. The purpose of this model is to serve as a mental model for learners as well as a framework for further resuscitation research that incorporates these concepts.

Science of left ventricular unloading

The concept of left ventricular unloading has its foundation in heart physiology. In fact, the left ventricular mechanics and energetics represent the cornerstone of this approach. The novel sophisticated therapies for acute heart failure, particularly mechanical circulatory supports, strongly impact on the mechanical functioning and energy consuption of the heart, ultimately affecting left ventricle loading. Notably, extracorporeal circulatory life support which is implemented for life-threatening conditions, may even overload the left heart, requiring additional unloading strategies. As a consequence, the understanding of ventricular overload, and the associated potential unloading strategies, founds its utility in several aspects of day-by-day clinical practice. Emerging clinical and pre-clinical research on left ventricular unloading and its benefits in heart failure and recovery has been conducted, providing meaningful insights for therapeutical interventions. Here, we review the current knowledge on left ventricular unloading, from physiology and molecular biology to its application in heart failure and recovery.

Differential impact of ventricular-arterial coupling on left ventricular function in patients with acute myocardial infarction: a comparison between preserved and reduced ejection fraction

BACKGROUND

Ventricular-arterial coupling (VAC) plays a crucial role in the initiation and progression of heart failure in patients with coronary artery disease. The influence of VAC on left ventricular (LV) function may vary depending on LV systolic function. This study investigated the relationship between VAC and LV function in patients with acute myocardial infarction (AMI), stratified by ejection fraction (EF).

METHODS

Echocardiographic indices of LV volumes, systolic function, and diastolic function were measured using standard techniques. Effective arterial elastance (EA) was calculated based on stroke volume derived from the LV outflow waveform. Effective LV end-systolic elastance was determined using the single-beat method. The central aortic pressure waveform was recorded via applanation tonometry. Characteristic impedance (Zc) of the aortic root was calculated using Fourier transformation of both aortic pressure and flow waveforms.

RESULTS

A total of 85 patients (mean age, 58.5 ± 10.6 years) with AMI were enrolled. They were classified into two groups: those with reduced EF (< 50%, 27 patients) and those with preserved EF (≥ 50%, 58 PATIENTS). In the adjusted linear regression analysis, E' velocity was significantly associated with VAC (β = -0.310, P = 0.008) in the preserved EF group but not in the reduced EF group. LV global longitudinal strain showed significant positive associations with VAC (β = 0.505, P < 0.001), EA index (β = 0.536, P < 0.001), and Zc (β = 0.344, P = 0.018) exclusively in the preserved EF group.

CONCLUSIONS

The distinct influence of EF status on the relationships between hemodynamic parameters and LV diastolic and systolic functions suggests a differential interplay between arterial and ventricular dynamics depending on LV systolic function.

Hemodynamic Patterns and Left Ventricular Function Recovery in Peripartum Cardiomyopathy: A Comprehensive Echocardiographic Analysis

BACKGROUND

The influence of hemodynamic changes at presentation on the recovery of left ventricular (LV) function in peripartum cardiomyopathy (PPCM) patients remains uncertain.

OBJECTIVES

This study aims to identify hemodynamic patterns in individuals with PPCM.

METHODS

This study included women with PPCM from 2 databases in Israel and Indonesia. Conventional echocardiography, 2-dimensional strain, myocardial work, and noninvasive pressure-volume loop analysis were performed with subsequent data clustering.

RESULTS

Among 89 women (median age 32 years, IQR: 8.7 years; LV ejection fraction [EF] 36.0%, IQR: 11.5%), 63 (70.8%) experienced LV function recovery (LVEF ≥50%) during 6 months of follow-up. Gestation hypertension/pre-eclampsia and LVEF >35% and LVDD ≤55 mm at presentation were associated with LV recovery. Significant hemodynamic variability was observed, indicating a nonuniform PPCM pattern. Cluster analysis of 43 patients identified 3 hemodynamic subtypes. In cluster 1, patients exhibited the lowest rate of LV recovery (12.5%), profound contractility impairment, severe LV remodeling, and reduced cardiac output (CO). Cluster 2 showed a high LV recovery rate of 78.6%, prevalent in Southeast Asian patients with gestational hypertension. These patients displayed decreased CO and extremely elevated afterload. Load-dependent contractility indexes, like LVEF and global longitudinal strain, were markedly reduced, while load-independent end-systolic elastance remained unaffected, indicating afterload-dependent contractility impairment. All patients in cluster 3 recovered LVEF, presenting mildly reduced contractility indexes, mild ventricular dilatation, slightly increased afterload, and preserved CO.

CONCLUSIONS

PPCM exhibits heterogeneous hemodynamic patterns, with 3 distinct phenotypes displaying varying rates of LV recovery. Understanding the heterogeneity in PPCM hemodynamic phenotypes can guide optimal treatment.

Structural and functional remodeling for elite cyclists during exercise; pressure-volume loops and hemodynamic forces analysis

The study was designed to investigate the pattern of intraventricular hemodynamic forces (HDFs) and myocardial performance during exercise in elite cyclists (ECs). Transthoracic stress echocardiography was performed on 19 ECs and 13 age-matched sedentary controls (SCs) at three incremental exercise intensities based on heart rate reserve (HRR). Left ventricular (LV) HDFs were computed from echocardiography long-axis datasets using a novel technique based on endocardial boundary tracking, both in apex-base and latero-septal directions. Pressure volume (PV) loops were noninvasively investigated using the single-beat approach. Differences between groups were investigated using mixed model analysis. At PV loops, EC showed a steeper increase in stroke work compared with SC, without acute changes in ventricular capacity (EDVI20). Contractility, measured as ventricular elastance (Ees), increased during exercise with no difference between groups (P = 0.625). At rest, EC had significantly lower heart rates and generated lower HDF than SC. However, during exercise, the pressure gradient developed by EC in systole, and therefore systolic HDF, was significantly higher than that developed by SC (P < 0.009), also showing a greater elastic rebound in late systole compared with SC (P < 0.032). Importantly, during early diastolic filling, EC showed lower HDF deceleration than SC (P < 0.043), indicating a facilitated relaxation of the left ventricle. Analysis of the HDF pattern during exercise shows the functional changes that occur in EC, characterized by increased HDF generation in systole, and facilitated relaxation in early diastole. This is the first time LV structural and functional remodeling is reported for elite cyclists during exercise.NEW & NOTEWORTHY Analysis of the hemodynamic forces shows that the functional changes that occur in elite cyclists during exercise are characterized by increased hemodynamic forces generation in systole, and facilitated relaxation in early diastole.

The Right Ventricle and Exercise Capacity in Adults with Repaired Tetralogy of Fallot: Passive Bystander or Active Participant?

Exercise intolerance is a hallmark symptom in adults with tetralogy of Fallot (TOF). This may be attributed to impairments in right ventricular (RV) function, augmentation in RV load, and their effect on left ventricular (LV) hemodynamics. To elucidate these mechanisms, we examined oxygen uptake (VO2) and cardiac hemodynamics in TOF and healthy controls at rest and during exercise. At peak exercise, VO2 was lower in TOF. This was partially attributed to lower heart rate in conjunction with a blunted exercise-induced change in LV stroke volume from rest to compensate for the chronotropic incompetence. Additionally, at peak exercise, pulmonary-RV was higher in TOF. Additionally, at peak exercise, in TOF, pulmonary-RV coupling negatively correlated with VO2 , changes in LV end-diastolic volume, and changes in LV SV from rest. These findings reveal the reliance of LV hemodynamics on the interplay between RV systolic load and function during exercise in TOF.

Increased Afterload in Patients With Acute Reduction in Left Ventricular Ejection Fraction Following Mitral Valve Transcatheter Edge-to-Edge Repair

AIM

The mechanisms and clinical importance of acute reduction (ARD) in left ventricular (LV) function following transcatheter edge-to-edge repair (TEER) for mitral regurgitation (MR) remains unclear. This study aimed to non-invasively evaluate the cardio-mechanical parameters, including end-systolic elastance (Ees) and arterial elastance (Ea), to explore their association with ARD following mitral TEER.

METHODS AND RESULTS

We performed a retrospective analysis of serial transthoracic echocardiography (TTE) studies before and after mitral TEER. Cardio-mechanical parameters were evaluated non-invasively using a modified single-beat method. After the exclusion of nine patients requiring intravenous catecholamine infusion, the study cohort comprised 49 consecutive patients (25 men; mean age: 81 ± 9 years) with successful mitral TEER. ARD in LV function was defined as a decrease in LV ejection fraction (LVEF) of ≥5 points following the procedure by TTE, which was reported in 18 patients. The hospitalization period was longer in patients with ARD in LVEF than in those without ARD (5.5 days vs. 4 days, p = 0.031). Following improvement in MR, Ea increased (1.54 ± 0.49 mmHg/mL vs. 1.84 ± 0.55 mmHg/mL, p = 0.004). Linear regression analysis revealed a correlation between Δtotal stroke volume (SV) and ΔEa (r = 0.614, p < 0.0001). Notably, ΔEa was higher in patients with ARD in LVEF than in those without ARD in LVEF (0.60 ± 0.73 mmHg/mL vs. 0.14 ± 0.39 mmHg/mL, p = 0.006).

CONCLUSION

ARD in LVEF after mitral TEER was reported in a substantial proportion of patients and may have prognostic implications. Evaluating cardio-mechanical parameters may aid in understanding complex hemodynamics and guiding treatment strategies for patients with MR undergoing TEER.

Cardiovascular effects of lactate in healthy adults

BACKGROUND

Low-volume hypertonic solutions, such as half-molar lactate (LAC), may be a potential treatment used for fluid resuscitation. This study aimed to evaluate the underlying cardiovascular effects and mechanisms of LAC infusion compared to sodium-matched hypertonic sodium chloride (SAL).

METHODS

Eight healthy male participants were randomized in a controlled, single-blinded, crossover study. Each participant received a four-hour infusion of LAC and SAL in a randomized order. Assessor-blinded echocardiography and blood samples were performed. The primary endpoint was cardiac output (CO) measured by echocardiography.

RESULTS

During LAC infusion, circulating lactate levels increased by 1.9 mmol/L (95% CI 1.8-2.0 mmol/L, P < 0.001) compared with SAL. CO increased by 1.0 L/min (95% CI 0.5-1.4 L/min, P < 0.001), driven primarily by a significant increase in stroke volume of 11 mL (95% CI 4-17 mL, P = 0.002), with no significant change in heart rate. Additionally, left ventricular ejection fraction improved by 5 percentage points (P < 0.001) and global longitudinal strain by 1.5 percentage points (P < 0.001). Preload indicators were elevated during SAL infusion compared with LAC infusion. Concomitantly, afterload parameters, including systemic vascular resistance and effective arterial elastance, were significantly decreased with LAC infusion compared with SAL, while mean arterial pressure remained similar. Indicators of contractility improved during LAC infusion.

CONCLUSIONS

In healthy participants, LAC infusion enhanced cardiac function, evidenced by increases in CO, stroke volume, and left ventricular ejection fraction compared with SAL. Indicators of contractility improved, afterload decreased, and preload remained stable. Therefore, LAC infusion may be an advantageous resuscitation fluid, particularly in patients with cardiac dysfunction.

CLINICAL TRIAL REGISTRATIONS

https://clinicaltrials.gov/ct2/show/NCT04710875 . Registered 1 December 2020.

Echocardiographic Assessment in Patients with Vascular Ehlers-Danlos Syndrome: Insights from an Unexplored Field

INTRODUCTION

Vascular Ehlers-Danlos syndrome (vEDS) is an inherited connective tissue disorder characterized by arterial fragility. Celiprolol is a β1-adrenoceptor antagonist with partial β2 agonist activity that has been shown to reduce rates of vascular events in this setting, though the underlying mechanisms are not yet fully understood. Moreover, very few echocardiographic data are available in patients with vEDS.

AIM

To perform a comprehensive echocardiographic assessment of a cohort of patients with vEDS with or without celiprolol therapy compared with healthy subjects.

METHODS

Twenty patients with genetically confirmed diagnosis of vEDS followed at our Institution (University Hospital of Brescia, Italy) were divided into two groups according to whether or not they were on celiprolol therapy at the maximum recommended dose (400 mg daily) for at least 12 months. Both groups were compared to 10 healthy individuals matched for sex, age, body mass index (BMI), and office blood pressure (BP) values. Each participant underwent transthoracic echocardiography with tissue Doppler analysis (TDI) for a comprehensive evaluation of cardiac structure and function.

RESULTS

Mean age was 35 years and mean BMI was 21.6 kg/m2. Female sex was prevalent (60%). Left ventricular (LV) internal diameter values tended to be lower in patients with untreated vEDS than in healthy controls (4.33 vs 4.74 cm, respectively), though this difference was not statistically significant. Similar data were observed for LV mass index (56.9 vs 68.6 g/m2), stroke volume (56.6 vs 71.6 mL), and E/A ratio (1.26 vs 1.66), whereas an opposite trend was observed for e' lateral (13.2 vs 12.2 cm/s). No statistically significant difference was found between groups in terms of other parameters of LV mass, systolic and diastolic function. A normal LV geometry was found in all the cases. Indices of mechano-energetic efficiency and ventricular-arterial coupling were also similar between groups. No patient presented with aortic root dilation, mitral valve prolapse, valve insufficiency of more than mild degree, or valve stenosis of any degree.

CONCLUSION

Our study suggests that patients with vEDS have normal cardiac mass and geometry, as well as normal systolic and diastolic function. Celiprolol therapy does not seem to significantly influence such aspects. Compared with vascular imaging, less stringent follow-up with echocardiography seems reasonable in this setting. Future studies with prospective design should confirm these aspects.

Acute Effects of Cannabis Inhalation on Arterial Stiffness, Vascular Endothelial Function, and Cardiac Function

BACKGROUND

The cardiovascular impact of cannabis use is incompletely understood. Although evidence links chronic use to an increased risk of disease and adverse cardiovascular events, few studies have investigated the acute effects of cannabis inhalation on subclinical dysfunction. Furthermore, it remains unknown how method of inhalation and cannabinoid profile modify risk. While controlling for inhalation method and the effects of either Δ-9-tetrahydrocannabinol (THC) or cannabidiol (CBD), we examined the acute cardiovascular effects of cannabis use on arterial stiffness, vascular endothelial responsiveness, and cardiac function, as markers of cardiovascular impairment.

METHODS AND RESULTS

Twenty-two young, healthy, cannabis users were assessed for arterial stiffness via pulse wave velocity, vascular endothelial function via brachial artery flow mediated dilation, and cardiac function via echocardiography, before and after (1) smoking THC-predominant cannabis (S-THC), (2) vaporizing THC-predominant THC (V-THC), and (3) vaporizing cannabidiol-predominant cannabis (V-CBD). S-THC and V-THC increased heart rate (S-THC: ∆17±15 bpm, V-THC: ∆16±16 bpm;both P<0.0001) and mean arterial pressure (S-THC: ∆7±6 mm Hg, V-THC: ∆5±5 mm Hg;both P<0.0001) whereas V-CBD did not (∆1±4 bpm, ∆3±4 mm Hg;both P>0.05). After inhalation, pulse wave velocity increased (S-THC: ∆0.29±0.75 m/s, V-THC: ∆0.42±0.74 m/s, V-CBD: ∆0.10±0.44 m/s; P=0.002) and diastolic function was reduced ([early/late ratio] S-THC: ∆-0.2±0.53, V-THC: ∆-0.33±58, V-CBD: ∆0.01±66; P=0.03). Differences in heart rate were related to changes in pulse wave velocity (r2=0.2; P=0.0002) and diastolic function (r2=0.26; P<0.0001). Inhalation method did not alter these cannabinoid-dependent responses.

CONCLUSIONS

THC predominant, but not cannabidiol predominant, cannabis elicits increases in heart rate and blood pressure irrespective of inhalation method, which may increase arterial stiffness and reduce diastolic function. These findings implicate THC as a relevant factor for cannabis-related subclinical cardiovascular dysfunction.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT04693884.

Echocardiographic Predictors of Readiness for Double Switch Operation and Postoperative Ejection Fraction in Patients With Congenitally Corrected Transposition of the Great Arteries Undergoing Left Ventricular Retraining

BACKGROUND

In patients with congenitally corrected transposition of the great arteries (ccTGA), assessment of readiness for the double switch operation (DSO) after pulmonary arterial band (PAB) placement involves cardiac magnetic resonance imaging (cMRI) to measure left ventricular ejection fraction (LVEF) and mass and cardiac catheterization (catheterization) to assess the ratio of left ventricular to right ventricular pressure (LV:RVp). The aims of this study were to describe the relationships between echocardiographic and catheterization and cMRI measures of readiness for DSO and to develop risk factors for left ventricular (LV) dysfunction after DSO on the basis of echocardiographic measures of ventricular-arterial coupling (VAC).

METHODS

Patients with ccTGA undergoing LV retraining at a DSO referral center were reviewed. LVEF measured by echocardiography was compared with that measured by cMRI, and LV:RVp measured by echocardiography was compared with that measured by catheterization using Bland-Altman analysis. The relationship between preoperative VAC markers and postoperative echocardiography was analyzed using ventricular end-systolic elastance (EES) and a novel marker consisting of the product of LVEF and LV:RVp (EFPR).

RESULTS

Thirty-one patients with 56 evaluations for DSO were included, 24 of whom underwent DSO. Echocardiographic LVEF correlated well with cMRI LVEF (r = 0.79), and Bland-Altman analysis slightly overestimated cMRI LVEF (mean difference, +3%). Echocardiographic LVEF had a moderate ability to identify normal cMRI LVEF (area under the curve, 0.80) and at an optimal cut point of echocardiographic LVEF threshold of 61%, there was 71% sensitivity and 76% specificity to detect cMRI LVEF ≥ 55%. Echocardiographic LV:RVp correlated well with LV/RVp by catheterization (r = 0.77) and slightly underestimated the catheterization value (mean difference, -0.11). Echocardiographic LV:RVp had a good ability to identify adequate LV:RVp by catheterization (area under the curve, 0.95) and at an optimal echocardiography cut point of 0.75 had 100% sensitivity and 85% specificity to detect a catheterization LV:RVp >0.9. Echocardiography-based criteria for DSO readiness (echocardiographic LVEF of 61% and LV:RVp of 0.75) demonstrated specificity of 97% and positive predictive value of 96% for published criteria of DSO readiness (cMRI LVEF of 55% and catheterization LV:RVp of 0.9). EES and EFPR correlated with post-DSO LVEF (ρ = 0.72 and ρ = 0.60, respectively). EFPR of 0.51 demonstrated 78% sensitivity and 100% specificity for post-DSO LV dysfunction (LVEF < 55%). Age at first PAB also strongly correlated with post-DSO LVEF (ρ = 0.75). No patient with first PAB at <1 year of age exhibited post-DSO LV dysfunction.

CONCLUSIONS

Echocardiographic measures of LVEF and LV:RVp are reliable indicators of reference standard modalities and can guide management during retraining. The preoperative VAC markers EES and EFPR may be useful markers of post-DSO LV dysfunction. Values of echocardiographic LV:RVp >0.75 are likely to meet pressure-generation criteria for DSO and should be considered for referral to catheterization and cMRI evaluation for DSO. PAB placement before 1 year of life may optimize LV outcomes in patients considered for DSO.

Clinical impact of novel cardiovascular magnetic resonance technology on patients with congenital heart disease: a scientific statement of the Association for European Pediatric and Congenital Cardiology and the European Association of Cardiovascular Imaging of the European Society of Cardiology

Cardiovascular magnetic resonance (CMR) imaging is recommended in patients with congenital heart disease (CHD) in clinical practice guidelines as the imaging standard for a large variety of diseases. As CMR is evolving, novel techniques are becoming available. Some of them are already used clinically, whereas others still need further evaluation. In this statement, the authors give an overview of relevant new CMR techniques for the assessment of CHD. Studies with reference values for these new techniques are listed in the Supplementary data online, supplement.

Sex differences in the impact of ventricular-arterial coupling on left ventricular function in patients with hypertension

Increased arterial stiffness elevates aortic load, which can have adverse impacts on left ventricular (LV) function and contribute to the onset of heart failure. This impact is known to be more pronounced in women. Optimal coordination between ventricular contraction and the arterial system is required to maintain efficient cardiac function. This study aimed to investigate sex differences in the impact of ventricular-arterial coupling (VAC) on LV function in patients with hypertension at rest and after handgrip exercise. Echocardiographic indexes of LV volumes, systolic function, and diastolic function were obtained in the usual way. Effective arterial elastance (EA) and index (EAI) were calculated from stroke volume measured using LV outflow waveform. Effective LV end-systolic elastance (ELV) and index (ELVI) were obtained using the single-beat method. Central aortic pressure waveform was recorded using the applanation tonometry. Characteristic impedance (Zc) of aortic root and reflection magnitude (RM) was calculated after Fourier transformation of both aortic pressure and flow waveforms. Sixty-four patients (31 women and 33 men) with hypertension were enrolled. Women showed higher ELVI (1.33±0.34 vs. 1.10±0.29 mmHg/ml∙m2, P = 0.004) and EAI (1.14±0.25 vs. 0.93±0.26 mmHg/ml∙m2, P = 0.001), but VAC was not different (women: 0.88±0.17 vs. men: 0.85±0.11, P = 0.431). Zc and RM were not different between women and men. After handgrip exercise, an increase in ELVI (P = 0.021) and a decrease in VAC (P = 0.035) were observed specifically in men, with no corresponding changes noted in women. In women, VAC was significantly associated with E' velocity (beta -0.344, P = 0.029) and left ventricular global longitudinal strain (beta 0.470, P = 0.012) after adjustment, but in men, no association was found. Hypertensive women demonstrated greater stiffness in both the left ventricle and arterial systems, along with impaired LV contractile reserve in response to handgrip exercise, as compared to men. The ventricular-arterial mismatch had a notable impact on LV diastolic and systolic dysfunction only in women, but not in men.

Association of prior tuberculosis with cardiovascular status in perinatally HIV-1-infected adolescents

BACKGROUND

Whether, and how, co-occurring HIV-1 infection (HIV) and tuberculosis (TB) impact cardiovascular status, especially in adolescents with perinatally acquired HIV (APHIV), have not been examined. We hypothesised that APHIV with previous TB disease have worse cardiac efficiency than APHIV without TB, which is mediated by increased inflammation and disordered cardiometabolism.

METHODS

APHIV in Cape Town, South Africa, completed 3T cardiovascular magnetic resonance examination and high sensitivity C reactive protein (hsCRP), fasting plasma glucose (FPG), low-density lipoprotein (LDL) and triglyceride measurement. Ventriculoarterial coupling (VAC) was estimated as the ratio of arterial elastance (Ea) to ventricular end-systolic elastance (Ees). Regression models were applied to estimate cross-sectional associations between Ea/Ees ratio and TB status, with decomposition of these associations into direct and mediated effects of hsCRP, FPG and dyslipidaemia, if any, attempted.

RESULTS

We enrolled 43 APHIV with prior TB and 23 without TB of mean (SD) age 15.0 (1.5) and 15.4 (1.7) years, respectively. Prior TB was associated with lower Ea/Ees ratio (0.59 (0.56 to 0.64)) than no TB (0.66 (0.62 to 0.70)), which corresponded to an adjusted mean difference -0.06 (-0.12 to 0.01) (p=0.048). However, previous TB was not associated with increased hsCRP, FPG, LDL or triglycerides nor were hsCRP, FPG, LDL and triglycerides associated with Ea/Ees ruling out their mediated effects in the association between TB and cardiac efficiency.

CONCLUSIONS

Previous TB in APHIV is associated with comparatively reduced cardiac efficiency, related to altered VAC. The clinical significance of these findings requires further study, including a wider range of biomarkers of specific immune pathways.

Rapid estimation of left ventricular contractility with a physics-informed neural network inverse modeling approach

Physics-based computer models based on numerical solutions of the governing equations generally cannot make rapid predictions, which in turn limits their applications in the clinic. To address this issue, we developed a physics-informed neural network (PINN) model that encodes the physics of a closed-loop blood circulation system embedding a left ventricle (LV). The PINN model is trained to satisfy a system of ordinary differential equations (ODEs) associated with a lumped parameter description of the circulatory system. The model predictions have a maximum error of less than 5% when compared to those obtained by solving the ODEs numerically. An inverse modeling approach using the PINN model is also developed to rapidly estimate model parameters (in ∼ 3 min) from single-beat LV pressure and volume waveforms. Using synthetic LV pressure and volume waveforms generated by the PINN model with different model parameter values, we show that the inverse modeling approach can recover the corresponding ground truth values for LV contractility indexed by the end-systolic elastance Ees with a 1% error, which suggests that this parameter is unique. The estimated Ees is about 58% to 284% higher for the data associated with dobutamine compared to those without, which implies that this approach can be used to estimate LV contractility using single-beat measurements. The PINN inverse modeling can potentially be used in the clinic to simultaneously estimate LV contractility and other physiological parameters from single-beat measurements.

Evaluation of potential links between phenotypic features and genetic variants in left ventricular outflow tract obstruction in hypertrophic cardiomyopathy using cardiovascular magnetic resonance imaging

This study aimed to identify the phenotypic features contributing to the development of left ventricular outflow tract obstruction (LVOTO) in patients with hypertrophic cardiomyopathy (HCM) and to evaluate the genotype‒phenotype relationship. This cross-sectional study included 96 patients diagnosed with HCM (mean age: 56.9 ± 13.5 years, 32.3% female). The patients were divided into hypertrophic nonobstructive cardiomyopathy (HNCM; n = 60) and hypertrophic obstructive cardiomyopathy (HOCM; n = 36) groups. All patients underwent CMR. Patients (n = 77) who had previously provided formal approval underwent a genetic examination that included 18 genes. The anterior mitral leaflet (AML) length/LVOT diameter ratio, posterior mitral leaflet (PML) length/LVOT diameter ratio, and anterolateral papillary muscle (AL-PM) mobility were associated with LVOTO, independent of the basal IVS thickness, abnormal chordal attachment, and bifid PM. An AML length/LVOT diameter ratio of ≥ 2.30, a PML length/LVOT diameter ratio of ≥ 1.83, and an AL-PM mobility of ≥ 57.7% were predictors of LVOTO, with good sensitivity and specificity. Positive variants (VUS, LP, and P) were detected in 37.7% (29 of 77) of the patients who underwent genetic testing. The LP/P variant was detected in 20.8% (16 of 77) of patients. Three groups (variant-negative, VUS, and LP/P groups) had significant differences in the LVOT diameter (median 14, 12, and 10 mm, respectively; p = 0.021), AML length (mean 25.3, 26.5, and 27.5 mm, respectively; p = 0.029), AML length/LVOT diameter ratio (median 1.74, 2.33, and 2.85, respectively; p = 0.006), PML length/LVOT diameter ratio (median 1.29, 1.82, and 2.10, respectively; p = 0.045), and abnormal chordal attachment (6.3%, not observed, and 31.3%, respectively; p = 0.009). The AML length/LVOT diameter ratio, PML length/LVOT diameter ratio, and AL-PM mobility were associated with LVOTO. In addition, genetic testing results may provide information regarding the phenotypic expression of patients with HCM.

Analysis of ventricular-vascular properties during preeclampsia: an echocardiography study

The aim of the study is to analyze ventricular-vascular properties with different ventricular-arterial coupling (VAC) ratio in the preeclamptic women. Seventy-seven pregnant women with preeclampsia and eighty-nine with normal pregnancy were performed echocardiography. VAC was defined as the ratio between aortic elastance (Ea) and left ventricular (LV) end-systolic elastance (Ees). Using the VAC value of 0.8 as the cut-off near uncoupling, the preeclampsia cases were divided into two subgroups: VAC ratio ≥ 0.8 and <0.8. Cardiac structure and function, VAC properties, as well as four components of the LV pressure-strain loop, including global myocardial work index (GWI), constructive work (GCW), wasted work (GWW), and work efficiency (GWE) were determined. The preeclampsia with VAC ≥ 0.8 had an enlarger indexed ventricular volume and a thicker relative ventricular wall than the VAC < 0.8. The Ees significantly increased in the subgroup with VAC < 0.8 and decreased in the VAC ≥ 0.8, while the Ea increased in both of them. The preeclampsia with VAC ≥ 0.8 showed an obvious augmentation in GWI, GCW and GWE, along with a similar GWW compared to those with VAC < 0.8. There were variable relationships between the LV pressure-strain components and VAC properties. Thus, the preeclampsia with VAC ≥ 0.8 undergoes a more adverse remodeling and a greater impact on cardiac contractility. The increased stiffness of the heart and arterial system, and increased resistance of peripheral vessels net lead to the deteriorative ventricular efficiency with elevated myocardial oxygen consumption during a preeclampsia pregnancy.

Right Ventricular Pressure Waveform Analysis-Clinical Relevance and Future Directions

Continuous measurement of pressure in the right atrium and pulmonary artery has commonly been used to monitor right ventricular function in critically ill and surgical patients. This approach is largely based upon the assumption that right atrial and pulmonary arterial pressures provide accurate surrogates for diastolic filling and peak right ventricular pressures, respectively. However, due to both technical and physiologic factors, this assumption is not always true. Accordingly, recent studies have begun to emphasize the potential clinical value of also measuring right ventricular pressure at the bedside. This has highlighted both past and emerging research demonstrating the utility of analyzing not only the amplitude of right ventricular pressure but also the shape of the pressure waveform. This brief review summarizes data demonstrating that combining conventional measurements of right ventricular pressure with variables derived from waveform shape allows for more comprehensive and ideally continuous bedside assessment of right ventricular function, particularly when combined with stroke volume measurement or 3D echocardiography, and discusses the potential use of right ventricular pressure analysis in computational models for evaluating cardiac function.

Critical Care Ultrasound in Shock: A Comprehensive Review of Ultrasound Protocol for Hemodynamic Assessment in the Intensive Care Unit

Shock is a life-threatening condition that requires prompt recognition and treatment to prevent organ failure. In the intensive care unit, shock is a common presentation, and its management is challenging. Critical care ultrasound has emerged as a reliable and reproducible tool in diagnosing and classifying shock. This comprehensive review proposes an ultrasound-based protocol for the hemodynamic assessment of shock to guide its management in the ICU. The protocol classifies shock as either low or high cardiac index and differentiates obstructive, hypovolemic, cardiogenic, and distributive etiologies. In distributive shock, the protocol proposes a hemodynamic-based approach that considers the presence of dynamic obstruction, fluid responsiveness, fluid tolerance, and ventriculo-arterial coupling. The protocol gives value to quantitative measures based on critical care ultrasound to guide hemodynamic management. Using critical care ultrasound for a comprehensive hemodynamic assessment can help clinicians diagnose the etiology of shock and define the appropriate treatment while monitoring the response. The protocol's use in the ICU can facilitate prompt recognition, diagnosis, and management of shock, ultimately improving patient outcomes.

U-shaped prognostic value of left ventricular-arterial coupling in septic patients: a prospective study

BACKGROUND

Ventricular-arterial coupling (VAC) has garnered increasing interest in critical care. The prognostic significance of left ventricular-arterial coupling (LVAC) in this context remains a topic of debate.

OBJECTIVE

This study aimed to explore the association between LVAC and patient outcomes in sepsis.

METHODS

Patients with sepsis or septic shock admitted to the intensive care unit (ICU) were included. LVAC was evaluated using the arterial elastance (Ea)/left ventricular end-systolic elastance (Ees) ratio. Prognostic indicators, including 30-day mortality, length of ICU stay, mechanical ventilation (MV), changes in delta lactate levels, and oxygen index were also collected.

RESULTS

A total of 388 patients were enrolled in this study. A U-shaped relationship was observed between LVAC and 30-day mortality, with an optimal LVAC value of 1.19 identified. For LVAC values above 1.19, the odds ratio (OR) for 30-day mortality was 1.07 (95% confidence interval [CI] 1.01-1.14). Below this threshold, OR was 0.85 (95% CI 0.73, 0.99). Similarly, in the curve for ICU-free days, a β value of - 8.64 (95% CI - 16.53, - 0.76) was noted for LVAC values over 1.26. For ventilator-free time, the kink point was 1.24, with significant β values on both sides of this threshold [- 226.49 (95% CI - 411.59, - 41.38) and 147.67 (95% CI 12.40, 282.93), respectively].

CONCLUSIONS

This study established U-shaped associations between LVAC and various clinical outcomes in septic patients. Optimizing LVAC could potentially enhance patient prognosis. Given the slight variations in optimal LVAC values across different patient populations, individualized LVAC titration may be beneficial in improving clinical outcomes.

Ventriculo-arterial (VA) coupling and fQRS as new selection criteria for primary prevention ICD placement

For decades, left ventricular ejection fraction (LVEF < 35%) has been a mainstay for identifying heart failure (HF) patients most likely to benefit from an implantable cardioverter defibrillator (ICD). However, LVEF is a poor predictor of sudden cardiac death (SCD) and ignores 50% of HF patients with mildly reduced and preserved LVEF. The current international guidelines for primary prophylaxis ICD therapy are inadequate. Instead of LVEF, which is not a good measure of LV contractility or hemodynamic characterization, we hypothesize ventriculo-arterial (VA) coupling combined with fragmented QRS (fQRS) will improve risk stratification and patient suitability for an ICD. Quantifying cardiac and aortic mechanics, and predicting active arrhythmogenic substrate, from varying fQRS morphologies, may help to stratify ischemic and non-ischemic patients with different functional capacities and predisposition for lethal arrhythmias. We propose HF patients with a low physiological reserve may not benefit from ICD therapy, whereas those patients with higher reserves and extensive arrhythmogenic substrate may benefit. Our hypothesis combining VA coupling with fQRS changes has the potential to widen HF patient participation (low and high LVEF) and advance personalized medicine for HF patients at high risk of SCD.

Left and Right Ventricular Hemodynamic Response After Transcatheter Mitral Valve Replacement

Background

Transcatheter mitral valve replacement (TMVR) represents a novel treatment option for patients with mitral regurgitation (MR), but little is known about the hemodynamic impact of MR elimination following TMVR. We sought to investigate the hemodynamic impact of TMVR on left ventricular (LV) and right ventricular (RV) function using noninvasive pressure-volume loops.

Methods

All consecutive patients undergoing TMVR with dedicated devices between May 2016 and August 2022 were enrolled. The end-diastolic and end-systolic pressure-volume relationships were estimated from 26 patients using single-beat echocardiographic measurements at baseline and after TMVR at discharge. RV function was assessed by RV-pulmonary artery (PA) coupling and RV fractional area change. One-year follow-up was available for 19 patients. The prognostic impact of calculated end-diastolic volume at an end-diastolic pressure of 20 mmHg (VPed20) reduction was assessed by Cox regression.

Results

A total of 26 patients (77.0 years [interquartile range 73.9-80.1], N = 17 [65.4%] male) with successful TMVR were included (secondary MR [N = 21, 80.8%]; median LV ejection fraction was 37.0% [interquartile range 30.7-50.7]). At discharge, a decrease in VPed20 (p < 0.001) indicating leftward shift of end-diastolic pressure-volume relationship, and an increase of the end-systolic elastance slope (p = 0.007) were observed after TMVR. No changes were observed for RV-PA coupling (p = 0.19) and RV fractional area change (p = 0.22). At 1-year follow-up, LV contractility (end-systolic elastance) and RV-PA coupling remained stable. Vped20 reduction at discharge was significantly associated with 1-year all-cause mortality or heart failure hospitalization (hazard ratio 0.16, 95% CI 0.04-0.71, p = 0.016).

Conclusions

Noninvasive assessment of pressure-volume loops demonstrated early LV reverse remodeling and improved LV contractility, while RV performance was preserved. These results indicate the potential prognostic impact of complete MR elimination after TMVR.

Left Atrial Mechanics Following Preeclamptic Pregnancy

BACKGROUND

Preterm preeclampsia is a pregnancy complication associated with myocardial dysfunction and premature cardiovascular disease morbidity and mortality. Left atrial (LA) strain is a noninvasive index of left ventricular end diastolic pressure and an early marker of heart failure risk. This study aimed to evaluate LA strain during the postpartum period in participants with and without preterm preeclampsia and to assess whether this varied in the presence of hypertension, cardiac dysfunction or both.

METHODS

In this longitudinal cohort study, 321 women from 28 hospitals with preterm preeclampsia (cases) underwent cardiovascular assessment 6 months postpartum. This is a secondary analysis of the PHOEBE study (ISRCTN01879376). An uncomplicated pregnancy control group (n=30) was recruited from a single center for comparison. A full cross-sectional transthoracic echocardiogram was performed, and from these images, the myocardial strain of the left atrium, including reservoir, conduit, and contractile strain, as well as LA stiffness, were calculated.

RESULTS

At 6 months postpartum, compared with controls, prior preeclampsia was associated with a significantly attenuated LA reservoir, conduit, and contractile strain, as well as increased LA stiffness (all P<0.001). LA strain was further reduced in preeclamptic women who had and had not developed hypertension, systolic, or diastolic dysfunction at 6 months postpartum (all P<0.05).

CONCLUSIONS

LA mechanics were significantly attenuated at 6 months postpartum in participants with preterm preeclampsia, whether or not they remained hypertensive or had evidence of ventricular dysfunction. Further studies are needed to determine whether postnatal LA strain may identify women at greater risk for future cardiovascular disease.

Reducing Left Ventricular Wall Stress through Aortic Valve Enlargement via Transcatheter Aortic Valve Implantation in Severe Aortic Stenosis

Background: In aortic stenosis, the left ventricle exerts additional force to pump blood through the narrowed aortic valve into the downstream arterial vasculature. Adaptive hypertrophy helps to maintain wall stress homeostasis but at the expense of impaired compliance. Advanced ventricular deformation impacts the extent of functional recovery benefits achieved through transcatheter aortic valve implantation. Methods and Results: Subgroups were stratified based on output, with low-flow severe aortic stenosis defined as stroke volume index <35 mL· m-2. Before intervention, the low-flow subgroup exhibited worse effective orifice area index and arterial and global impedance, along with thinner wall thickness and larger chamber volume marginally. LV performance, including stroke volume index, ventricular elastance, and ventricular-arterial coupling, were notably inferior, consistent with worse adverse remodeling. Although the effective orifice area index was similarly augmented after TAVI, inferior recovery benefits were noted. Persistently higher wall stress and energy consumption were observed, along with poorer ventricular-arterial coupling. These changes in wall stress showed an inverse relationship with alterations in wall thickness and were proportional to changes in dimension and volume. Additionally, they were proportional to changes in left ventricular end-systolic pressure, pressure-volume area, and ventricular-arterial coupling but inversely related to ventricular end-systolic elastance. Conclusions: The study revealed that aortic valve enlargement through transcatheter aortic valve implantation reduces left ventricular wall stress in severe aortic stenosis. The reduced recovery benefits in the low-flow subgroup were evident. Wall stress could serve as a marker of mechanical benefit after the intervention.

Correlation of Noninvasive Cardiac MRI Measures of Left Ventricular Myocardial Function and Invasive Pressure-Volume Parameters in a Porcine Ischemia-Reperfusion Model

Purpose To assess the correlation between noninvasive cardiac MRI-derived parameters with pressure-volume (PV) loop data and evaluate changes in left ventricular function after myocardial infarction (MI). Materials and Methods Sixteen adult female swine were induced with MI, with six swine used as controls and 10 receiving platelet-derived growth factor-AB (PDGF-AB). Load-independent measures of cardiac function, including slopes of end-systolic pressure-volume relationship (ESPVR) and preload recruitable stroke work (PRSW), were obtained on day 28 after MI. Cardiac MRI was performed on day 2 and day 28 after infarct. Global longitudinal strain (GLS) and global circumferential strain (GCS) were measured. Ventriculo-arterial coupling (VAC) was derived from PV loop and cardiac MRI data. Pearson correlation analysis was performed. Results GCS (r = 0.60, P = .01), left ventricular ejection fraction (LVEF) (r = 0.60, P = .01), and cardiac MRI-derived VAC (r = 0.61, P = .01) had a significant linear relationship with ESPVR. GCS (r = 0.75, P < .001) had the strongest significant linear relationship with PRSW, followed by LVEF (r = 0.67, P = .005) and cardiac MRI-derived VAC (r = 0.60, P = .01). GLS was not significantly correlated with ESPVR or PRSW. There was a linear correlation (r = 0.82, P < .001) between VAC derived from cardiac MRI and from PV loop data. GCS (-3.5% ± 2.3 vs 0.5% ± 1.4, P = .007) and cardiac MRI-derived VAC (-0.6 ± 0.6 vs 0.3 ± 0.3, P = .001) significantly improved in the animals treated with PDGF-AB 28 days after MI compared with controls. Conclusion Cardiac MRI-derived parameters of MI correlated with invasive PV measures, with GCS showing the strongest correlation. Cardiac MRI-derived measures also demonstrated utility in assessing therapeutic benefit using PDGF-AB. Keywords: Cardiac MRI, Myocardial Infarction, Pressure Volume Loop, Strain Imaging, Ventriculo-arterial Coupling Supplemental material is available for this article. © RSNA, 2024.

The additive prognostic value of end-systolic pressure-volume relation by stress CMR in patients with known or suspected coronary artery disease

PURPOSE

The difference between rest and peak stress end-systolic pressure-volume relation (ΔESPVR) is an afterload-independent index of left ventricular (LV) contractility. We assessed the independent prognostic value of ΔESPVR index by dipyridamole stress-cardiovascular magnetic resonance (CMR) in patients with known/suspected coronary artery disease (CAD).

METHODS

We considered 196 consecutive patients (62.74 ± 10.66 years, 49 females). Wall motion and perfusion abnormalities at rest and peak stress were analysed. Replacement myocardial fibrosis was detected by late gadolinium enhancement (LGE) technique. The ESPVR was evaluated at rest and peak stress from raw measurement of systolic arterial pressure and end-systolic volume by biplane Simpson's method.

RESULTS

A reduced ΔESPVR index (≤ 0.02 mmHg/mL/m2) was found in 88 (44.9%) patients and it was associated with a lower LV ejection fraction (EF) and with a higher frequency of abnormal stress CMR and myocardial fibrosis. During a mean follow-up of 53.17 ± 28.21 months, 50 (25.5%) cardiac events were recorded: 5 cardiac deaths, 17 revascularizations, one myocardial infarction, 23 hospitalisations for heart failure or unstable angina, and 4 ventricular arrhythmias. According to Cox regression analysis, diabetes, family history, LVEF, abnormal stress CMR, myocardial fibrosis, and reduced ΔESPVR were significant univariate prognosticators. In the multivariate analysis the independent predictors were ΔESPVR index ≤ 0.02 mmHg/mL/m2 (hazard ratio-HR = 2.58, P = 0.007), myocardial fibrosis (HR = 2.13, P = 0.036), and diabetes (HR = 2.33, P = 0.012).

CONCLUSION

ΔESPVR index by stress-CMR was independently associated with cardiac outcomes in patients with known/suspected CAD, in addition to replacement myocardial fibrosis and diabetes. Thus, the assessment of ΔESPVR index may be included into the standard stress-CMR exam to further stratify the patients.

Hemodynamic profile of cirrhotic patients with sepsis and septic shock: A propensity score matched case-control study

PURPOSE

Our understanding of hemodynamics in cirrhotic patients with sepsis remains limited. Our study aims to investigate differences in hemodynamic profiles using echocardiography between septic patients with and without cirrhosis.

MATERIALS AND METHODS

This is a single-center, retrospective study of septic patients with echocardiogram within 3 days of ICU admission. We compared baseline characteristics, echocardiographic markers of LV systolic function arterial load between patients with and without cirrhosis. A propensity score-matched case-control model was developed to describe the differences in those echocardiography derived parameters between the groups.

RESULTS

3151 patients with sepsis were included of which 422 (13%) had cirrhosis. In the propensity score matched group with 828 patients, cirrhotic patients had significantly higher left ventricular ejection fraction (64 vs.56%, p < 0.001) and stroke volume (72 vs.48 ml, p < 0.001) along with lower arterial elastance (Ea) (1.35 1vs.20.3, p < 0.001) and systemic vascular resistance (SVR) (851 vs.1209 dynes/s/m-5, p = 0.001). The left ventricular elastance (Ees) (2.83 vs 2.45, p = 0.002) was higher and ventricular-arterial coupling (Ea/Ees) (0.48 vs. 0.86, p < 0.001) lower in cirrhotic compared to non-cirrhotic.

CONCLUSIONS

Septic patients with cirrhosis had higher LVEF with lower Ea and SVR with higher Ees and significantly lower Ea/Ees suggesting vasodilation as the principal driver of the hyperdynamic profile in cirrhosis.

Cardiovascular Effects of Oral Ketone Ester Treatment in Patients With Heart Failure With Reduced Ejection Fraction: A Randomized, Controlled, Double-Blind Trial

BACKGROUND

Heart failure triggers a shift in myocardial metabolic substrate utilization, favoring the ketone body 3-hydroxybutyrate as energy source. We hypothesized that 14-day treatment with ketone ester (KE) would improve resting and exercise hemodynamics and exercise capacity in patients with heart failure with reduced ejection fraction.

METHODS

In a randomized, double-blind cross-over study, nondiabetic patients with heart failure with reduced ejection fraction received 14-day KE and 14-day isocaloric non-KE comparator regimens of 4 daily doses separated by a 14-day washout period. After each treatment period, participants underwent right heart catheterization, echocardiography, and blood sampling at plasma trough levels and after dosing. Participants underwent an exercise hemodynamic assessment after a second dosing. The primary end point was resting cardiac output (CO). Secondary end points included resting and exercise pulmonary capillary wedge pressure and peak exercise CO and metabolic equivalents.

RESULTS

We included 24 patients with heart failure with reduced ejection fraction (17 men; 65±9 years of age; all White). Resting CO at trough levels was higher after KE compared with isocaloric comparator (5.2±1.1 L/min versus 5.0±1.1 L/min; difference, 0.3 L/min [95% CI, 0.1-0.5), and pulmonary capillary wedge pressure was lower (8±3 mm Hg versus 11±3 mm Hg; difference, -2 mm Hg [95% CI, -4 to -1]). These changes were amplified after KE dosing. Across all exercise intensities, KE treatment was associated with lower mean exercise pulmonary capillary wedge pressure (-3 mm Hg [95% CI, -5 to -1] ) and higher mean CO (0.5 L/min [95% CI, 0.1-0.8]), significantly different at low to moderate steady-state exercise but not at peak. Metabolic equivalents remained similar between treatments. In exploratory analyses, KE treatment was associated with 18% lower NT-proBNP (N-terminal pro-B-type natriuretic peptide; difference, -98 ng/L [95% CI, -185 to -23]), higher left ventricular ejection fraction (37±5 versus 34±5%; P=0.01), and lower left atrial and ventricular volumes.

CONCLUSIONS

KE treatment for 14 days was associated with higher CO at rest and lower filling pressures, cardiac volumes, and NT-proBNP levels compared with isocaloric comparator. These changes persisted during exercise and were achieved on top of optimal medical therapy. Sustained modulation of circulating ketone bodies is a potential treatment principle in patients with heart failure with reduced ejection fraction.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT05161650.

Effects of a Transoceanic Rowing Challenge on Cardiorespiratory Function and Muscle Fitness

Ultra-endurance sports and exercise events are becoming increasingly popular for older age groups. We aimed to evaluate changes in cardiac function and physical fitness in males aged 50-60 years who completed a 50-day transoceanic rowing challenge. This case account of four self-selected males included electro- and echo-cardiography (ECG, echo), cardiorespiratory and muscular fitness measures recorded nine months prior to and three weeks after a transatlantic team-rowing challenge. No clinically significant changes to myocardial function were found over the course of the study. The training and race created expected functional changes to left ventricular and atrial function; the former associated with training, the latter likely due to dehydration, both resolving towards baseline within three weeks post-event. From race-start to finish all rowers lost 8.4-15.6 kg of body mass. Absolute cardiorespiratory power and muscular strength were lower three weeks post-race compared to pre-race, but cardiorespiratory exercise economy improved in this same period. A structured program of moderate-vigorous aerobic endurance and muscular training for>6 months, followed by 50-days of transoceanic rowing in older males proved not to cause any observable acute or potential long-term risks to cardiovascular health. Pre-event screening, fitness testing, and appropriate training is recommended, especially in older participants where age itself is an increasingly significant risk factor.

Feasibility and prognostic significance of ventricular-arterial coupling after myocardial infarction: the RIGID-MI cohort

AIMS

The clinical significance and feasibility of the recently described non-invasive parameters exploring ventricular-arterial coupling (VAC) remain uncertain. This study aimed to assess VAC parameters for prognostic stratification in stable patients with left ventricular ejection fraction (LVEF) ≥40% following myocardial infarction (MI).

METHODS AND RESULTS

Between 2018 and 2021, patients with LVEF ≥40% were evaluated 1 month following MI using transthoracic echocardiography (TTE) and arterial tonometry at rest and after a handgrip test. VAC was studied via the ratio between arterial elastance (Ea) and end-systolic LV elastance (Ees) and between pulse wave velocity (PWV) and global longitudinal strain (GLS). Patients were followed for major adverse cardiovascular events (MACE): all-cause death, acute heart failure, stroke, AMI, and urgent cardiovascular hospitalization. Among the 374 patients included, Ea/Ees and PWV/GLS were obtained at rest for 354 (95%) and 253 patients (68%), respectively. Isometric exercise was workable in 335 patients (85%). During a median follow-up of 32 months (interquartile range: 16-42), 41 (11%) MACE occurred. Patients presenting MACE were significantly older and had a higher prevalence of peripheral arterial disease, lower GLS, higher Ea, PWV, and PWV/GLS ratio. The Ea/Ees ratio and standard TTE parameters during isometric exercise were not associated with MACE. After adjustment, the PWV/GLS ratio was the only VAC parameter independently associated with outcome. Receiver operating characteristic curve analysis identified a PWV/GLS ratio >0.70 (Youden's index = 0.37) as the best threshold to identify patients developing MACE: hazard ratio (95% confidence interval) = 2.2 (1.14-4.27), P = 0.02.

CONCLUSION

The PWV/GLS ratio, assessed 1 month after MI, identifies a group of patients at higher risk of MACE providing additional value on top of conventional non-invasive parameters.

Development and Clinical Application of Left Ventricular-Arterial Coupling Non-Invasive Assessment Methods

The constant and dynamic interaction between ventricular function and arterial afterload, known as ventricular-arterial coupling, is key to understanding cardiovascular pathophysiology. Ventricular-arterial coupling has traditionally been assessed invasively as the ratio of effective arterial elastance over end-systolic elastance (Ea/Ees), calculated from information derived from pressure-volume loops. Over the past few decades, numerous invasive and non-invasive simplified methods to estimate the elastance ratio have been developed and applied in clinical investigation and practice. The echocardiographic assessment of left ventricular Ea/Ees, as proposed by Chen and colleagues, is the most widely used method, but novel echocardiographic approaches for ventricular-arterial evaluation such as left ventricle outflow acceleration, pulse-wave velocity, and the global longitudinal strain or global work index have arisen since the former was first published. Moreover, multimodal imaging or artificial intelligence also seems to be useful in this matter. This review depicts the progressive development of these methods along with their academic and clinical application. The left ventricular-arterial coupling assessment may help both identify patients at risk and tailor specific pharmacological or interventional treatments.

Impact of cardiac rehabilitation on ventricular-arterial coupling and left ventricular function in patients with acute myocardial infarction

To maintain efficient myocardial function, optimal coordination between ventricular contraction and the arterial system is required. Exercise-based cardiac rehabilitation (CR) has been demonstrated to improve left ventricular (LV) function. This study aimed to investigate the impact of CR on ventricular-arterial coupling (VAC) and its components, as well as their associations with changes in LV function in patients with acute myocardial infarction (AMI) and preserved or mildly reduced ejection fraction (EF). Effective arterial elastance (EA) and index (EAI) were calculated from the stroke volume and brachial systolic blood pressure. Effective LV end-systolic elastance (ELV) and index (ELVI) were obtained using the single-beat method. The characteristic impedance (Zc) of the aortic root was calculated after Fourier transformation of both aortic pressure and flow waveforms. Pulse wave separation analysis was performed to obtain the reflection magnitude (RM). An exercise-based, outpatient cardiac rehabilitation (CR) program was administered for up to 6 months. Twenty-nine patients were studied. However, eight patients declined to participate in the CR program and were subsequently classified as the non-CR group. At baseline, E' velocity showed significant associations with EAI (beta -0.393; P = 0.027) and VAC (beta -0.375; P = 0.037). There were also significant associations of LV global longitudinal strain (LV GLS) with EAI (beta 0.467; P = 0.011). Follow-up studies after a minimum of 6 months demonstrated a significant increase in E' velocity (P = 0.035), improved EF (P = 0.010), and LV GLS (P = 0.001), and a decreased EAI (P = 0.025) only in the CR group. Changes in E' velocity were significantly associated with changes in EAI (beta -0.424; P = 0.033). Increased aortic afterload and VA mismatch were associated with a negative impact on both LV diastolic and systolic function. The outpatient CR program effectively decreased aortic afterload and improved LV diastolic and systolic dysfunction in patients with AMI and preserved or mildly reduced EF.

Postoperative alterations in ventriculoarterial coupling are an indicator of cardiovascular outcomes in liver transplant recipients

BACKGROUND

Liver transplantation (LT) increases the heart and vessel workload in patients with cirrhotic cardiomyopathy. While the interaction of the left ventricle (LV) with the arterial system (ventriculoarterial coupling, VAC) is a key determinant of cardiovascular performance, little is known about changes in VAC after LT. Therefore, we evaluated the relationship between VAC after LT and cardiovascular outcomes.

METHODS

344 consecutive patients underwent echocardiographic assessments before and within 30 days after LT. Non-invasive arterial elastance (Ea), LV end-systolic elastance (Ees), and LV end-diastolic elastance (Eed) were calculated. The postoperative outcomes included the development of major adverse cardiovascular events (MACE) and the length of stay in the intensive care unit and hospital.

RESULTS

A total of 240 patients were included in the analyses. After LT, Ea increased by 16% (P < 0.001), and Ees and contractility index of systolic velocity (S') increased by 18% (P < 0.001) and 7% (P < 0.001), respectively. The Eed increased by 6% (P < 0.001). The VAC remained unchanged (0.56 to 0.56, P = 0.912). Of these patients, 29 had MACE, and those with MACE had significantly higher postoperative VAC. Additionally, a higher postoperative VAC was an independent risk factor for a longer postoperative hospital stay (P = 0.038).

CONCLUSIONS

These data suggest that ventriculoarterial decoupling is associated with poor postoperative outcomes after LT.

Effect of age and gender on ventricular-arterial coupling estimated using a non-invasive technique

BACKGROUND

Left ventricular-arterial coupling is assessed as the ratio of left ventricular end-systolic elastance (Ees) to arterial elastance (Ea). Previous studies have introduced non-invasive estimations of Ees/Ea. It requires only four variables, namely pre-ejection period, ejection time, end-systolic pressure and diastolic pressure. The aims of the present study were to clarify the reference values of Ees/Ea estimated using the noninvasive technique, and to investigate the effects of age and gender on Ees/Ea in healthy subjects.

METHODS

This retrospective study utilized data from healthy, 30-79-year-old subjects. We recorded electrocardiogram, phonocardiogram, and brachial arterial pulse waves simultaneously using the vascular screening system, and used the observed variables to calculate Ees/Ea. We separated subjects into five groups according to their age and compared Ees/Ea among the different age groups.

RESULTS

The study included 2114 males and 2292 females. Ees/Ea ranged from 1.87 to 2.04 in males, and 1.98 to 2.32 in females. We observed no age-related differences in Ees/Ea in males (p = 0.10), and significant differences in females (p < 0.001). Ees/Ea in males was not different compared to those in females in 60-69-year-old group (p = 0.92). Whereas Ees/Ea was higher in females compared to those in males in the other age groups. The differences between medians of Ees/Ea in males and those in females were 0.45 (p < 0.001), 0.24 (p < 0.001), 0.13 (p = 0.01), and 0.13 (p = 0.03) in 30-39, 40-49, 50-59, and 70-79-year-old age groups, respectively.

CONCLUSIONS

We clarified the reference values of Ees/Ea in healthy subjects. The effect of age on Ees/Ea is different in males and females, although Ees/Ea is maintained within a relatively narrow range in all subjects.

Echocardiography Assessment of Left Ventricular Function in Extremely Preterm Infants, Born at Less Than 28 Weeks' Gestation, With Bronchopulmonary Dysplasia and Systemic Hypertension

BACKGROUND

The survival of smaller and more immature premature infants has been associated with lifelong cardiorespiratory comorbidities. Infants with bronchopulmonary dysplasia (BPD) undergo routine screening echocardiography to evaluate for development of chronic pulmonary hypertension, a late manifestation of pulmonary vascular disease.

METHODS

Our aim was to evaluate left ventricular (LV) performance in infants with BPD and pulmonary vascular disease who developed systemic hypertension. We hypothesized that infants with hypertension were more likely to have impaired LV performance. We present a single-center cross-sectional study of premature infants born at less than 28 0/7 weeks' gestational age with a clinical diagnosis of BPD. Infants were categorized by the systolic arterial pressure (SAP) at time of echocardiography as hypertensive (SAP ≥90 mm Hg) or normotensive (SAP <90 mm Hg). Sixty-four patients were included.

RESULTS

Infants with hypertension showed altered LV diastolic function with prolonged tissue Doppler imaging-derived isovolumic relaxation time (54.2 ± 5.1 vs 42.9 ± 8.2, P < .001), lower E:A, and higher E:e'. Indices of left heart volume/pressure loading (left atrium:aorta and LV end-diastolic volume [6.1 ± 2 vs 4.2 ± 1.2, P < .001]) were also higher in the hypertensive group. Finally, infants in the hypertensive group had higher pulmonary vascular resistance index (4.42 ± 1.1 vs 3.69 ± 0.8, P = .004).

CONCLUSIONS

We conclude that extremely preterm infants with BPD who develop systemic hypertension are at risk of abnormal LV diastolic dysfunction. Increased pulmonary vascular resistance index in the hypertensive group may relate to pulmonary venous hypertension secondary to LV dysfunction. This is an important consideration in this cohort when selecting the physiologically most appropriate treatment.

An In Silico Model for Predicting the Efficacy of Edge-to-Edge Repair for Mitral Regurgitation

In recent years, transcatheter edge-to-edge repair (TEER) has been widely adopted as an effective treatment for mitral regurgitation (MR). The aim of this study is to develop a personalized in silico model to predict the effect of edge-to-edge repair in advance to the procedure for each individual patient. For this purpose, we propose a combination of a valve deformation model for computing the mitral valve (MV) orifice area (MVOA) and a lumped parameter model for the hemodynamics, specifically mitral regurgitation volume (RVol). Although we cannot obtain detailed information on the three-dimensional flow field near the mitral valve, we can rapidly simulate the important medical parameters for the clinical decision support. In the present method, we construct the patient-specific pre-operative models by using the parameter optimization and then simulate the postoperative state by applying the additional clipping condition. The computed preclip MVOAs show good agreement with the clinical measurements, and the correlation coefficient takes 0.998. In addition, the MR grade in terms of RVol also has good correlation with the grade by ground truth MVOA. Finally, we try to investigate the applicability for the predicting the postclip state. The simulated valve shapes clearly show the well-known double orifice and the improvement of the MVOA, compared with the preclip state. Similarly, we confirmed the improved reverse flow and MR grade in terms of RVol. A total computational time is approximately 8 h by using general-purpose PC. These results obviously indicate that the present in silico model has good capability for the assessment of edge-to-edge repair.

Left ventricular remodeling in twin pregnancy, noninvasively assessed using hemodynamic forces and pressure-volume relation analysis: prospective, cohort study

This study was designed to prospectively investigate the pattern of intraventricular hemodynamic forces (HDFs) associated with left ventricular (LV) function and remodeling in women with uncomplicated twin pregnancy. Transthoracic echocardiography was performed on 35 women (aged 35.9 ± 4.7-yr old) during gestation (T1, <14 wk; T2, 14-27 wk; T3, >28 wk) and 6-7 mo after delivery (T0). LV HDFs were computed from echocardiography long-axis data sets using a novel technique based on endocardial boundary tracking, both in apex-base (A-B) and latero-septal (L-S) directions. HDF distribution was evaluated by L-S over A-B HDF ratio (L-S:A-B HDF ratio). At T1, L-S:A-B HDF ratio was higher than in T0 (P < 0.05) indicating HDF misalignment. At T2, a slight impairment of cardiac function was then recorded with a reduction of global longitudinal strain (GLS) and left ventricular end-systolic elastance (Ees) at pressure-volume relationship analysis versus T1 (both P < 0.05). Finally, at T3, when HDF misalignment and LV contractility reduction (GLS and Ees) were all restored, a rightward shift of the end-diastolic pressure-volume relationship (EDPVR) with an increase of ventricular capacitance was documented. In twin pregnancy, HDF misalignment in the first trimester precedes the slight temporary decrease in left ventricular systolic function in the second trimester; at the third trimester, a rightward shift of the EDPVR was associated with a realignment of HDF and normalization of ventricular contractility indexes. These coordinated changes that occur in the maternal heart during twin pregnancy suggest the role of HDFs in cardiac remodeling.NEW & NOTEWORTHY These changes indicate that 1) the misalignment of hemodynamic forces (HDFs) precedes a mild reduction in systolic function in twin pregnancy and 2) the positive left ventricular (LV) response to hemodynamic stress is mainly due to an improved diastolic function with enhanced LV cavity compliance.

Exploring the Connection Between Relaxed Myosin States and the Anrep Effect

The Anrep effect is an adaptive response that increases left ventricular contractility following an acute rise in afterload. Although the mechanistic origin remains undefined, recent findings suggest a two-phase activation of resting myosin for contraction, involving strain-sensitive and posttranslational phases. We propose that this mobilization represents a transition among the relaxed states of myosin-specifically, from the super-relaxed (SRX) to the disordered-relaxed (DRX)-with DRX myosin ready to participate in force generation. This hypothesis offers a unified explanation that connects myosin's SRX-DRX equilibrium and the Anrep effect as parts of a singular phenomenon. We underscore the significance of this equilibrium in modulating contractility, primarily studied in the context of hypertrophic cardiomyopathy, the most common inherited cardiomyopathy associated with diastolic dysfunction, hypercontractility, and left ventricular hypertrophy. As we posit that the cellular basis of the Anrep effect relies on a two-phased transition of myosin from the SRX to the contraction-ready DRX configuration, any dysregulation in this equilibrium may result in the pathological manifestation of the Anrep phenomenon. For instance, in hypertrophic cardiomyopathy, hypercontractility is linked to a considerable shift of myosin to the DRX state, implying a persistent activation of the Anrep effect. These valuable insights call for additional research to uncover a clinical Anrep fingerprint in pathological states. Here, we demonstrate through noninvasive echocardiographic pressure-volume measurements that this fingerprint is evident in 12 patients with hypertrophic obstructive cardiomyopathy before septal myocardial ablation. This unique signature is characterized by enhanced contractility, indicated by a leftward shift and steepening of the end-systolic pressure-volume relationship, and a prolonged systolic ejection time adjusted for heart rate, which reverses post-procedure. The clinical application of this concept has potential implications beyond hypertrophic cardiomyopathy, extending to other genetic cardiomyopathies and even noncongenital heart diseases with complex etiologies across a broad spectrum of left ventricular ejection fractions.

Left Ventricular-Arterial Coupling as an Independent Predictor of Adverse Events in Young Patients with ST Elevation Myocardial Infarction-A 3D Echocardiographic Study

Left ventricular-arterial coupling (VAC) is a key determinant of global cardiovascular performance, calculated as the ratio between arterial elastance (EA) and left ventricular end-systolic elastance (EES). Over the years, acute myocardial infarction (STEMI) has remained an important cause of morbidity and mortality worldwide. Although, until recently, it was considered a disease occurring mostly in older patients, its prevalence in the young population is continuously rising. In this study, we aimed to investigate the role of 3D VAC and its derived indices in predicting adverse outcomes in young patients with STEMI. We prospectively enrolled 84 young patients (18-51 years) with STEMI who underwent primary PCI and 28 healthy age and sex-matched controls. A 3D echocardiography was used for non-invasive measurements of end-systolic elastance (EES), arterial elastance (EA), and VAC (EA/EES). The occurrence of major adverse cardiac events (MACE) was assessed one year after the index STEMI. Out of 84 patients, 15.4% had adverse events at 12 months follow-up. Patients were divided into two groups according to the presence or absence of MACE. There were no significant differences in arterial elastance between the two groups. EA was higher in the MACE group but without statistical significance (2.65 vs. 2.33; p = 0.09). EES was significantly lower in the MACE group (1.25 ± 0.34 vs. 1.91 ± 0.56. p < 0.0001) and VAC was higher (2.2 ± 0.62 vs. 1.24 ± 0.29, p < 0.0001). ROC analysis showed that VAC has a better predictive value for MACE (AUC 0.927) compared with EA or EEA but also compared with a classical determinant of LV function (LVEF and LVGLS). A VAC value over 1.71 predicts unfavourable outcome with 83.3% sensitivity and 97.1% specificity. In both univariate and multivariate COX regression analysis, VAC remained an independent predictor for MACE and demonstrated incremental prognostic value over LVEF and LVGLS in the proposed statistical models. In conclusion, 3D VAC is an independent predictor of adverse events in young patients with STEMI at a 12 month follow-ups and could be used for a more accurate risk stratification in the acute phase.

Effects of Continuous Accelerated Pacing on Cardiac Structure and Function in Patients With Heart Failure With Preserved Ejection Fraction: Insights From the myPACE Randomized Clinical Trial

BACKGROUND

Heart failure with preserved ejection fraction ≥50% is prevalent with few evidence-based therapies. In a trial of patients with heart failure with preserved ejection fraction with specialized pacemakers, treatment with accelerated personalized pacing averaging 75 bpm (myPACE) markedly improved quality of life, NT-proBNP (N-terminal pro-brain natriuretic peptide), physical activity, and atrial fibrillation burden compared with the standard lower rate setting of 60 bpm (usual care).

METHODS AND RESULTS

In this exploratory study, provider-initiated echocardiographic studies obtained before and after the trial were assessed for changes in left ventricular (LV) structure and function among participants who continued their pacing assignment. The analytic approach aimed to detect differences in standard and advanced echocardiographic parameters within and between study arms. Of the 100 participants, 16 myPACE and 20 usual care arm had a qualifying set of echocardiograms performed a mean (SD) 3 (2.0) years apart. Despite similar baseline echocardiogram measures, sustained exposure to moderately accelerated pacing resulted in reduced septal wall thickness (in cm: myPACE 1.1 [0.2] versus usual care 1.2 [0.2], P=0.008) and lower LV mass to systolic volume ratio (in g/mL: myPACE 4.8 [1.9] versus usual care 6.8 [3.1], P=0.038) accompanied by a minor reduction in LV ejection fraction (in %: myPACE 55 [5] versus usual care 60 [5], P=0.015). These changes were paralleled by improvements in heart failure-related quality of life (myPACE Minnesota Living with Heart Failure Questionnaire improved by 16.1 [13.9] points, whereas usual care worsened by 6.9 [11.6] points, P<0.001). Markers of diastolic function and LV performance were not affected.

CONCLUSIONS

Exposure to continuous accelerated pacing in heart failure with preserved ejection fraction is associated with a reduced LV wall thickness and a small amount of LV dilation with small reduction in ejection fraction.

Contractility, ventriculoarterial coupling, and stroke work after acute myocardial infarction using CMR-derived pressure-volume loop data

BACKGROUND

Noninvasive left ventricular (LV) pressure-volume (PV) loops derived by cardiac magnetic resonance (CMR) have recently been shown to enable characterization of cardiac hemodynamics. Thus, such PV loops could potentially provide additional diagnostic information such as contractility, arterial elastance (Ea ) and stroke work (SW) currently not available in clinical routine. This study sought to investigate to what extent PV-loop variables derived with a novel noninvasive method can provide incremental physiological information over cardiac dimensions and blood pressure in patients with acute myocardial infarction (MI).

METHODS

A total of 100 patients with acute MI and 75 controls were included in the study. All patients underwent CMR 2-6 days after MI including assessment of myocardium at risk (MaR) and infarct size (IS). Noninvasive PV loops were generated from CMR derived LV volumes and brachial blood pressure measurements. The following variables were quantified: Maximal elastance (Emax ) reflecting contractility, Ea , ventriculoarterial coupling (Ea /Emax ), SW, potential energy, external power, energy per ejected volume, and efficiency.

RESULTS

All PV-loop variables were significantly different in MI patients compared to healthy volunteers, including contractility (Emax : 1.34 ± 0.48 versus 1.50 ± 0.41 mmHg/mL, p = .024), ventriculoarterial coupling (Ea /Emax : 1.27 ± 0.61 versus 0.73 ± 0.17, p < .001) and SW (0.96 ± 0.32 versus 1.38 ± 0.32 J, p < .001). These variables correlated to both MaR and IS (Emax : r2  = 0.25 and r2  = 0.29; Ea /Emax : r2  = 0.36 and r2  = 0.41; SW: r2  = 0.21 and r2  = 0.25).

CONCLUSIONS

Noninvasive PV-loops provide physiological information beyond conventional diagnostic variables, such as ejection fraction, early after MI, including measures of contractility, ventriculoarterial coupling, and SW.

Obesity-Related Differences in Pathomechanism and Outcomes in Patients With HFpEF: A CMR Study

Background

Clinical significance of an integrated evaluation of epicardial adipose tissue (EAT) and the right ventricle (RV) in heart failure with preserved ejection fraction (HFpEF) is unknown.

Objectives

The authors investigated the potential of EAT and RV quantification for obesity-related pathophysiology and risk stratification in obese HFpEF patients using cardiovascular magnetic resonance (CMR).

Methods

A total of 150 patients (obese, body mass index ≥30 kg/m2; n = 73, nonobese, body mass index <30 kg/m2; n = 77) with a clinical diagnosis of HFpEF undergoing CMR were retrospectively identified. EAT volume surrounding both ventricles were quantified with manual delineation on cine images. Total RV volume (TRVV) was calculated as the sum of RV cavity and mass at end-diastole. The endpoint was the composite of all-cause mortality and first HF hospitalization.

Results

During a median follow-up of 46 months, 39 nonobese patients (51%) and 32 obese patients (44%) experienced the endpoint. EAT was a prognostic biomarker regardless of obesity and was independently correlated with TRVV. In obese HFpEF, EAT correlated with RV longitudinal strain (r = 0.32, P = 0.006), and increased amount of EAT and TRVV was associated with greater left ventricular end-diastolic eccentric index (r = 0.36, P = 0.002). The integration of RV quantification into EAT provided improved risk stratification with a C-statistic increase from 0.70 to 0.79 in obese HFpEF. Obese patients with EAT<130 ml and TRVV<180 ml had low risk (annual event rate 3.2%), while those with increased EAT ≥130 ml and TRVV ≥180 ml had significantly higher risk (annual event rate 11.8%; P < 0.001).

Conclusions

CMR quantification of EAT and RV structure provides additive risk stratification for adverse outcomes in obese HFpEF.

Use and Implications of Echocardiography in the Hemodynamic Assessment of Cardiogenic Shock

Cardiogenic shock (CS) is a complex multisystem syndrome due to pump failure, associated with high mortality and morbidity. Its hemodynamic characterization is key to the diagnostic algorithm and management. Pulmonary artery catheterization is the gold standard for the left and right hemodynamic evaluation, but some concerns exist for invasivity and untoward mechanical and infective complications. Transthoracic echocardiography is a robust noninvasive diagnostic tool for hemodynamic multiparametric assessment that well applies to the management of CS. Its applications expand from etiology definition to the choice of therapeutic intervention and their monitoring. The present review aims at detailing the role of ultrasounds in CS emphasizing the clinical implications of combining cardiac and non-cardiac ultrasounds examinations that may correlate with prognosis.

Mild hypothermia attenuates ischaemia/reperfusion injury: insights from serial non-invasive pressure-volume loops

AIMS

Mild hypothermia, 32-35°C, reduces infarct size in experimental studies, potentially mediating reperfusion injuries, but human trials have been ambiguous. To elucidate the cardioprotective mechanisms of mild hypothermia, we analysed cardiac performance in a porcine model of ischaemia/reperfusion, with serial cardiovascular magnetic resonance (CMR) imaging throughout 1 week using non-invasive pressure-volume (PV) loops.

METHODS AND RESULTS

Normothermia and Hypothermia group sessions (n = 7 + 7 pigs, non-random allocation) were imaged with Cardiovascular magnetic resonance (CMR) at baseline and subjected to 40 min of normothermic ischaemia by catheter intervention. Thereafter, the Hypothermia group was rapidly cooled (mean 34.5°C) for 5 min before reperfusion. Additional CMR sessions at 2 h, 24 h, and 7 days acquired ventricular volumes and ischaemic injuries (unblinded analysis). Stroke volume (SV: -24%; P = 0.029; Friedmans test) and ejection fraction (EF: -20%; P = 0.068) were notably reduced at 24 h in the Normothermia group compared with baseline. In contrast, the decreases were ameliorated in the Hypothermia group (SV: -6%; P = 0.77; EF: -6%; P = 0.13). Mean arterial pressure remained stable in Normothermic animals (-3%, P = 0.77) but dropped 2 h post-reperfusion in hypothermic animals (-18%, P = 0.007). Both groups experienced a decrease and partial recovery pattern for PV loop-derived variables over 1 week, but the adverse effects tended to attenuate in the Hypothermia group. Infarct sizes were 10 ± 8% in Hypothermic and 15 ± 8% in Normothermic animals (P = 0.32). Analysis of covariance at 24 h indicated that hypothermia has cardioprotective properties incremental to reducing infarct size, such as higher external power (P = 0.061) and lower arterial elastance (P = 0.015).

CONCLUSION

Using non-invasive PV loops by CMR, we observed that mild hypothermia at reperfusion alleviates the heart's work after ischaemia/reperfusion injuries during the first week and preserves short-term cardiac performance. This hypothesis-generating study suggests hypothermia to have cardioprotective properties, incremental to reducing infarct size. The primary cardioprotective mechanism was likely an afterload reduction acutely unloading the left ventricle.

Integrating Right Ventricular Pressure Waveform Analysis With Two-Point Volume Measurement for Quantification of Systolic and Diastolic Function: Experimental Validation and Clinical Application

OBJECTIVE

To define in an experimental model the variance, accuracy, precision, and concordance of single-beat measures of right ventricular (RV) contractility and diastolic capacitance relative to conventional reference standards, and apply the methods to a clinical data set.

DESIGN

A retrospective, observational analysis of recorded pressure waveforms and RV volume measurements.

SETTING

At a university laboratory.

PARTICIPANTS

Archived data from previous studies of anesthetized swine and awake patients undergoing clinically-indicated right-heart catheterization.

INTERVENTIONS

Recording of RV pressure with simultaneous measurement of RV volume by conductance (swine) or 3-dimensional (3D) echocardiography (humans) during changes in contractility and/or loading conditions.

MEASUREMENTS AND MAIN RESULTS

Using experimental data, single-beat measures of RV contractility quantified as end-systolic elastance, and diastolic capacitance quantified as the predicted volume at an end-diastolic pressure of 15 mmHg (V15), were compared to multi-beat, preload- variant, reference standards using correlation, Bland-Altman analysis, and 4-quadrant concordance testing. This analysis indicated that the methods were not directly interchangeable with reference standards, but were sufficiently robust to suggest potential clinical utility. Clinical application supported this potential by demonstrating enhanced assessment of the response to inhaled nitric oxide in patients undergoing diagnostic right-heart catheterization.

CONCLUSIONS

Study results supported the possibility of integrating automated RV pressure analysis with RV volume measured by 3D echocardiography to create a comprehensive assessment of RV systolic and diastolic function at the bedside.

Antagonism of contractile forces in left ventricular hypertrophy: a diagnostic challenge for better pathophysiological and clinical understanding

Cardiac function is characterised by haemodynamic parameters in the clinical scenario. Due to recent development in imaging techniques, the clinicians focus on the quantitative assessment of left ventricular size, shape and motion patterns mostly analysed by echocardiography and cardiac magnetic resonance. Because of the physiologically known antagonistic structure and function of the heart muscle, the effective performance of the heart remains hidden behind haemodynamic parameters. In fact, a smaller component of oblique transmural netting of cardiac muscle fibres simultaneously engenders contracting and dilating force vectors, while the predominant mass of the tangentially aligned fibres only acts in one direction. In case of hypertrophy, an increased influence of the dilating transmural fibre component might counteract systolic wall thickening, thereby counteract cardiac output. A further important aspect is the response to inotropic stimulation that is different for the tangentially aligned fibre component in comparison to the transmural component. Both aspects highlight the importance to integrate the analysis of intramural fibre architecture into the clinical cardiac diagnostics.

Ventriculo-arterial coupling for predicting cardiac index increase in infants after heart surgery

OBJECTIVES

The aim of this study was to test the ability of ventriculo-arterial coupling (VAC) to predict cardiac index (CI) response after milrinone infusion.

METHODS

This was a retrospective, observational study. We measured arterial blood pressure and echocardiography-derived variables, including CI, systemic vascular resistance index, arterial elastance (Ea) and end-systolic ventricular elastance before and after 18-24 h of milrinone infusion. VAC was calculated as the ratio of Ea to end-systolic elastance. Infants with over 15% increase in the CI were defined as CI responders. Logistical regression was used to evaluate predictors of CI responders.

RESULTS

We enrolled 92 infants who underwent cardiac surgery and received milrinone infusion, of whom 45 infants were CI responders. High VAC (odds ratio = 5.534, 95% confidence interval 2.339-13.090) and high Ea (odds ratio = 3.035, 95% confidence interval 1.459-6.310) were independently associated with cardiac index responders. Pre-milrinone VAC predicted CI responsiveness with a cut-off value of 1.12 (area under the curve = 0.900, 95% confidence interval 0.819-0.953, P < 0.0001). Furthermore, we observed a decrease in the infant's VAC, Ea and systemic vascular resistance index after milrinone infusion.

CONCLUSIONS

In infants with congenital heart disease after surgery, a pre-milrinone VAC >1.12 can predict the increase in the CI following milrinone infusion.