Strain and strain rate by speckle-tracking echocardiography correlate with pressure-volume loop-derived contractility indices in a rat model of athlete's heart

The effect of sustained-release CARvedilol in patients with hypErtension and heart failure with preserved ejection fraction: a study protocol for a pilot randomized controlled trial (CARE-preserved HF)

Background

Although beta-blockers improve clinical outcomes in heart failure with reduced ejection fraction, the benefit of beta-blockers in heart failure with preserved ejection fraction (HFpEF) is uncertain. Global longitudinal strain (GLS) is a robust predictor of heart failure outcomes, and recent studies have shown that beta-blockers are associated with improved survival in those with low GLS (GLS <14%) but not in those with GLS ≥14% among patients with LVEF ≥40%. Therefore, the objective of this trial is to evaluate the effect of sustained-release carvedilol (carvedilol-SR) on the outcome [N-terminal pro-B-natriuretic peptide (NT-proBNP) concentration] in patients with hypertension and HFpEF and will assess the differential effects of these drugs on the outcome, according to the GLS categories.

Methods

This prospective randomized double-blind multicenter trial (CARE-preserved HF) will include 100 patients with HFpEF from three tertiary hospitals in South Korea. Patients with HFpEF and hypertension aged ≥20 years who have evidence of functional and structural heart disease on echocardiography and elevated natriuretic peptide will be enrolled. Eligible participants will be randomized 1:1 to either the carvedilol-SR group (n = 50) or the placebo group (n = 50). Patients in the carvedilol-SR group will receive 8, 16, 32, or 64 mg carvedilol-SR once daily for 6 months, and the dose of carvedilol will be up-titrated at the discretion of the treating physicians. The primary efficacy outcome was the time-averaged proportional change in N-terminal pro-B-natriuretic peptide concentration from baseline to months 3 and 6. We will also evaluate the differential effects of carvedilol-SR on primary outcomes according to GLS, using a cut-off of 14% or the median value.

Discussion

This randomized controlled trial will investigate the efficacy and safety of carvedilol-SR in patients with HFpEF and hypertension.

Clinical Trial Registration

ClinicalTrial.gov, identifier NCT05553314.

Right Ventricular Structure and Function in Adolescent Athletes: A 3D Echocardiographic Study

The aim of this study was to characterize the right ventricular (RV) contraction pattern and its associations with exercise capacity in a large cohort of adolescent athletes using resting three-dimensional echocardiography (3DE). We enrolled 215 adolescent athletes (16±1 years, 169 males, 12±6 hours of training/week) and compared them to 38 age and sex-matched healthy, sedentary adolescents. We measured the 3DE-derived biventricular ejection fractions (EF). We also determined the relative contributions of longitudinal EF (LEF/RVEF) and radial EF (REF/RVEF) to the RVEF. Same-day cardiopulmonary exercise testing was performed to calculate VO2/kg. Both LV and RVEFs were significantly lower (athletes vs. controls; LVEF: 57±4 vs 61±3, RVEF: 55±5 vs 60±5%, p<0.001). Interestingly, while the relative contribution of radial shortening to the global RV EF was also reduced (REF/RVEF: 0.40±0.10 vs 0.49±0.06, p<0.001), the contribution of the longitudinal contraction was significantly higher in athletes (LEF/RVEF: 0.45±0.08 vs 0.40±0.07, p<0.01). The supernormal longitudinal shortening correlated weakly with a higher VO2/kg (r=0.138, P=0.044). Similarly to the adult athlete's heart, the cardiac adaptation of adolescent athletes comprises higher biventricular volumes and lower resting functional measures with supernormal RV longitudinal shortening. Characteristic exercise-induced structural and functional cardiac changes are already present in adolescence.

Left atrial strain associated with interatrial block in patients with ST-segment elevation myocardial infarction

Both interatrial block (IAB) and left atrium (LA) strain are associated with atrial arrhythmias in ST-segment elevation myocardial infarction (STEMI) patients, but the relationship between IAB and LA strain has not yet been reported. This study was to investigate the correlation between LA strain and IAB in STEMI patients. This is a single-center retrospective clinical observational study. The STEMI patients with primary percutaneous coronary intervention (pPCI) were enrolled, and all patients completed cardiac magnetic resonance (CMR). A standard 12-lead electrocardiogram (ECG) was recorded on the same day as CMR. IAB was measured by p duration on ECG at follow-up. 302 patients were enrolled, including 91 (30.1%) with IAB. The reservoir strain, conduit strain and booster strain were included in model 1, model 2 and model 3, respectively. In model 1, age (OR 1.025; 95%CI 1.003-1.047; p = 0.026), hypertension (OR 2.188; 95%CI 1.288-3.719; p = 0.004), and reservoir strain (OR 0.947; 95%CI 0.920-0.974; p < 0.001) were independent factors for IAB. In model 2, age (OR 1.031; 95%CI 1.009-1.053; p = 0.006), hypertension (OR 2.058; 95%CI 1.202-3.522; p = 0.008), RCA lesions (OR 1.797; 95%CI 1.036-3.113; p = 0.037), and conduit strain (OR 0.910; 95%CI 0.868-0.953; p < 0.001) were independent factors for IAB. In model 3, age (OR 1.022; 95%CI 1.001-1.045; p = 0.044), hypertension (OR 2.239; 95%CI 1.329-3.773; p = 0.002), and booster strain (OR 0.948; 95%CI 0.908-0.991; p = 0.019) were independent factors for IAB. With the lowest AIC and BIC values, model 2 was the best-fit model. LA strain associated with IAB in STEMI patients. The model including conduit strain was the best-fit one.

Diagnostic and Prognostic Role of Left Ventricular Strain Imaging in Adults with Coarctation of aorta

The relative diagnostic and prognostic performance of left ventricular (LV) global longitudinal strain (LVGLS) compared with LV ejection fraction (LVEF) and the role of LVGLS for detecting the early stages of LV systolic dysfunction in adults with repaired coarctation of the aorta are unknown. This study aimed to address these knowledge gaps. We used a retrospective cohort study of adults with repaired coarctation of the aorta who underwent transthoracic echocardiogram (2003 to 2020). LV systolic function was assessed using LVEF (derived from volumetric analysis) and LVGLS (derived from speckle-tracking echocardiography). Of the 795 patients (age 36 ± 14 years), the mean LVEF and LVGLS were 62 ± 11% and 21 ± 4%, respectively. The prevalence of LV systolic dysfunction was higher when assessed using LVGLS than using LVEF (20% vs 6%, p <0.001). Of 795 patients, 94 (12%) patients died, of which 75 (9%) died from cardiovascular causes. LVGLS provided more robust prognostic power in predicting the all-cause mortality than LVEF, as evidenced by a higher C-statistic (0.743, 95% confidence interval 0.730 to 0.755 vs 0.782, 95% confidence interval 0.771 to 0.792, p <0.001). Furthermore, patients with normal LVEF in the setting of reduced LVGLS had a higher risk of all-cause mortality (than patients with normal LVGLS and LVEF) and were at risk for a temporal decrease in LVEF during follow-up. These findings suggest that the use of LVGLS for risk stratification can help identify high-risk patients and provide opportunities for interventions, which would, in turn, improve clinical outcomes. Further studies are required to empirically test these postulates.

Echocardiography to Assess Cardiac Structure and Function in Genetic Cardiomyopathies

Rodents are the most common experimental models used in cardiovascular research including studies of genetic cardiomyopathies. Genetic cardiomyopathies are characterized by changes in cardiac structure and function. Echocardiography allows for relatively inexpensive, non-invasive, reliable, and reproducible assessment of these changes. However, the fast heart and small size present unique challenges for investigators. To ensure accuracy and reproducibility of these measurements, investigators need to be familiar with standard practices in the field, normal values, and potential pitfalls. The goal of this chapter is to describe steps needed for reliable acquisition and analysis of echocardiography in rodent models. Additionally, we discuss some common pitfalls and challenges.

Effect of experimental periodontitis on cardiac functions: a comprehensive study using echocardiography, hemodynamic analysis, and histopathological evaluation in a rat model

Introduction

Periodontitis is a prevalent and severe dental condition characterized by the gradual degradation of the bone surrounding the teeth. Over the past two decades, numerous epidemiological investigations have suggested a potential link between periodontitis and cardiovascular disease. However, the complex mechanistic relationship between oral health issues and cardiovascular disorders remains unclear.

Aim

This study aimed to explore comprehensively the cardiac function through various methods, including conventional echocardiography, intraventricular pressure gradient (IVPG) analysis, speckle tracking echocardiography (STE), and hemodynamics analysis.

Methods

Ligature-induced periodontitis was established in a group of rats while the second group served as sham. The successful establishment of the periodontitis model was confirmed through staining and radiographic examination of the affected mandibles.

Results

X-ray films and methylene blue staining revealed alveolar bone resorption in the affected first molar in the model rats, confirming the successful induction of periodontitis. The rats with periodontitis displayed a decrease in ejection fraction compared to the sham group, accompanied by a decrease in mid-to-apical IVPG and mid IVPG. Lower values of strain rate were recorded in the apical segment of the septum, the middle segment of the septum, and the basal segment of the lateral free wall in the periodontitis group, which was associated with histopathological examination showing some degree of myocardial tissue damage. Conversely, rats with periodontitis showed an increase in heart rate, end-systolic volume, and arterial elastance when compared to the sham rats. However, they also exhibited a decrease in stroke work, stroke volume, cardiac output, and end-systolic pressure.

Conclusion

This study suggests that experimental periodontitis may lead to cardiac dysfunction especially compromised systolic function and myocardial relaxation, potentially indicating an increased risk of cardiovascular events in clinical periodontitis cases. The comprehensive assessment of cardiac function, hemodynamics, and histopathological evaluation underscores the profound impact of periodontitis on heart functions within this specific experimental model.

Prognostic Relevance of Global Myocardial Work Index in Patients with Moderate Aortic Valve Stenosis

BACKGROUND

A reduced global myocardial work index (GWI) ≤ 1951 mmHg% is associated with increased mortality in patients with severe aortic valve stenosis (AS). However, parameters predicting the outcome in patients with moderate AS are limited. Therefore, the aim of this study was to evaluate the prognostic value of the GWI in patients with moderate AS.

METHODS AND RESULTS

In this prospective study, 103 patients with moderate AS (mean age 72 ± 10 years; male: 69%) underwent standardized transthoracic echocardiography. The primary endpoint was survival without an aortic valve replacement (AVR). After a median follow-up of 30 ± 5 months, 37 patients (36%) were referred for an AVR. Survival without an AVR was 96% at 12 months and 80% at 30 months (>1951 mmHg%) versus 96% and 68% (≤1951 mmHg%). A GWI ≤ 1951 mmHg% did not predict the need for an AVR (hazard ratio 1.31 (95% CI, 0.63-2.72), p = 0.49). Furthermore, there was no significant correlation between the mean GWI (1644 ± 448 mmHg%) and mean aortic valve pressure gradient (24.2 mmHg ± 6.2, p = 0.615) or effective aortic orifice area (1.24 cm2 ± 0.11, p = 0.678). There was no difference between the AVR and non-AVR groups in the occurrence of clinical symptoms.

CONCLUSION

In contrast to patients with severe AS, a GWI ≤ 1951 mmHg% did not predict the need for an AVR. Further research is needed to improve the risk stratification in patients with moderate AS.

Subclinical and latent cardiac dysfunction in obstructive sleep apnea and effectiveness of continuous positive airway pressure

PURPOSE

Obstructive sleep apnea (OSA) is associated with various cardiovascular disorders. This study aimed to investigate the effects of OSA on left ventricular (LV) function in patients with OSA who were at risk for heart failure but who had not yet developed structural heart changes. The study also sought to determine the effects of continuous positive airway pressure (CPAP) in these patients.

METHODS

In a retrospective study, consecutive patients with polysomnographic OSA (apnea-hypopnea index [AHI] >5) were categorized into mild (AHI < 15), moderate (15 ≤ AHI < 30), and severe OSA (AHI ≥ 30) groups. The subjects were patients with OSA and at risk for heart failure who had not yet developed structural heart changes. All study participants underwent echocardiography and two-dimensional speckle tracking analysis, and their global longitudinal strain (GLS) was calculated.

RESULTS

Of 275 patients, there were 31 with mild, 92 with moderate, and 152 with severe OSA. Of patients with moderate to severe OSA (AHI ≥ 20), 206 started CPAP and 92 patients underwent follow-up echocardiogram and speckle tracking echo analysis (median period of CPAP use: 283 days [258 to 391]). GLS was significantly reduced in patients with moderate and severe OSA compared with mild OSA (-17.8±3.1 vs. -18.0±2.6 vs. -19.3±2.8%, p=0.038). The proportion of patients with GLS ≥ -18% was significantly higher among the patients with moderate to severe OSA than among those with mild OSA. GLS improved after CPAP therapy in patients with moderate to severe OSA (GLS: -18.1±2.7% to -19.0±2.8%, p=0.004). Significant improvement in GLS was confirmed, particularly among patients with good CPAP adherence.

CONCLUSION

Moderate to severe OSA is associated with LV dysfunction and can be significantly improved by CPAP therapy.

Comparative effects of nebivolol and carvedilol on left ventricular diastolic function in older patients with heart failure and preserved ejection fraction

Background

Although many studies have compared carvedilol and nebivolol in heart failure (HF) patients with reduced left ventricular ejection fraction (LVEF), such comparative studies for the elderly have not been reported yet. Nebivolol is known to be effective for improving diastolic function of elderly patients with HF. Thus, this study aimed to determine whether nebivolol could improve LV diastolic function to a greater extent than carvedilol in older patients aged over 70 years.

Methods

This trial was a prospective, randomized, open-label, single-center, active-controlled study that enrolled 62 patients with class II or III HF over 70 years of age with an LVEF ≥40%. Patients were randomized into a carvedilol group or a nebivolol group. Transthoracic echocardiography was performed at baseline and 12 months by the same investigator who was blinded to clinical data. The primary endpoint was E/e' measured by echocardiographic evaluation 12 months after treatment.

Results

The median duration of follow-up was 24 months. Baseline clinical characteristics and echocardiographic parameters, such as LV diastolic function indices, did not differ significantly between carvedilol and nebivolol groups. Twelve-month follow-up echocardiography data showed no significant difference in E/e' or other LV diastolic function indices between the two groups. There were no significant changes in echocardiographic parameters over 12 months in either group.

Conclusions

There was no difference between carvedilol and nebivolol for improving diastolic function of elderly HF patients with LVEF ≥40%. This study showed no superiority of nebivolol over carvedilol in elderly patients with HF.

Evaluation of Left Ventricular Systolic Function Using Layer-Specific Strain in Rats Performing Endurance Exercise: A Pilot Study

OBJECTIVE

The functional characteristics of exercise-induced myocardial hypertrophy were studied in a rat model in conjunction with ultrasound layered strain technique to investigate the hidden changes in the heart brought about by exercise.

METHODS

Forty specific pathogen free (SPF) adult Sprague-Dawley rats were selected and randomly divided into two groups of 20 exercise and 20 control rats. The longitudinal and circumferential strain parameters were measured using the ultrasonic stratified strain technique. The differences between the two groups and the predictive effect of stratified strain parameters on left ventricular systolic function were analyzed.

RESULTS

The exercise group had significantly higher global endocardial myocardial longitudinal strain (GLSendo), global mid-myocardial global longitudinal strain (GLSmid) and global endocardial myocardial global longitudinal strain (GCSendo) values than the control group (p < 0.05). Even though global mid-myocardial circumferential strain (GCSmid) and global epicardial myocardial circumferential strain (GCSepi) were higher in the exercise group than in the control group, statistical significance was not reached (p > 0.05). Conventional echocardiography parameters were well correlated with GLSendo, GLSmid, and GCSendo (p < 0.05). GLSendo was the best predictor of left ventricular myocardial contractile performance in athletes determined using the receiver operating characteristic curve, with an area under the curve of 0.97, sensitivity of 95% and specificity of 90%.

CONCLUSION

Rats performing endurance exercise exhibited subclinical changes in the heart after prolonged high-intensity exercise. A stratified strain parameter, GLSendo, played an important role in the evaluation of LV systolic performance in exercising rats.

Shifting from Left Ventricular Ejection Fraction to Strain Imaging in Aortic Stenosis

Adverse ventricular remodeling is an inflexion point of disease progression in aortic stenosis (AS) and a major determinant of prognosis. Intervention before irreversible myocardial damage is of paramount importance to sustain favorable post-operative outcomes. Current guidelines recommend a left ventricular ejection fraction (LVEF)-based strategy to determine the threshold for intervention in AS. However, LVEF has several pitfalls: it denotes the left ventricular cavity volumetric changes and it is not suited to detecting subtle signs of myocardial damage. Strain has emerged as a contemporary imaging biomarker that describes intramyocardial contractile force, providing information on subclinical myocardial dysfunction due to fibrosis. A large body of evidence advocates its use to determine the switch from adaptive to maladaptive myocardial changes in AS, and to refine thresholds for intervention. Although mainly studied in echocardiography, studies exploring the role of strain in multi-detector row computed tomography and cardiac magnetic resonance are emerging. This review, therefore, summarizes contemporary evidence on the role of LVEF and strain imaging in AS prognosis, aiming to move from an LVEF-based to a strain-based approach for risk stratification and therapeutic decision-making in AS.

Prognostic Value of Left Ventricular Global Longitudinal Strain in Patients With Congenital Heart Disease

BACKGROUND

Left ventricular global longitudinal strain (LVGLS) has been shown to improve risk stratification in patients with LV systolic dysfunction and subsequent recovery of LV ejection fraction (LVEF) in the acquired heart disease population. The purpose of this study was to assess the relationship between LVGLS and cardiovascular events (heart failure hospitalization, sustained ventricular tachycardia/appropriate shock, heart transplant, or cardiovascular death) and deterioration in LVEF (absolute decrease in LVEF ≥10% to LVEF <50%) in adults with congenital heart disease.

METHODS

Retrospective cohort study of congenital heart disease patients with previous diagnosis of LV systolic dysfunction (LVEF <50%) and subsequent recovery of LVEF (absolute increase in LVEF of ≥10% to LVEF ≥50%) on subsequent echocardiogram (index echocardiogram). Based on the index echocardiogram, patients were divided into normal LVGLS (absolute LVGLS >18%) versus abnormal LVGLS (absolute LVGLS ≤18%) groups.

RESULTS

Of 193 patients with recovered LVEF, 86 (45%) had normalization of LVGLS at index echocardiogram. A higher absolute LVGLS and use of renin angiotensin aldosterone system antagonist was associated with a lower risk of cardiovascular events and subsequent deterioration in LVEF, while hypertension was associated with higher risk of cardiovascular events and deterioration in LVEF.

CONCLUSIONS

These results suggest that patients with congenital heart disease with recovered LVEF remained at risk for adverse outcomes, and LVGLS can be used to identify patients at risk for adverse outcomes. Medical therapy for heart failure and treatment of hypertension may reduce the risk of adverse outcome, but these findings require empirical validation, hence the need for a clinical trial.

Intraventricular pressure gradient: A novel tool to assess the post-infarction chronic congestive heart failure

Congestive heart failure (CHF), the leading cause of death, is deemed a grave sequel of myocardial infarction (MI). The employment of left ventricular end-diastolic pressure (LVEDP), as a primary indication of CHF, becomes restricted owing to the potential impairment of heart function and caused injury to the aortic valve during its measurement. Echocardiography is the standard technique to detect cardiac dysfunction. However, it exhibits a low capacity to predict the progression of CHF post chronic MI. Being extremely sensitive, noninvasive, and preload-independent, intraventricular pressure gradient (IVPG) was lately introduced to evaluate cardiac function, specifically during cardiomyopathy. Yet, the utility of its use to assess the CHF progression after chronic MI was not investigated. Herein, in the current research, we aimed to study the efficacy of a novel echocardiographic-derived index as IVPG in the assessment of cardiac function in a chronic MI rat model with CHF. Fifty healthy male rats were involved, and MI was surgically induced in 35 of them. Six months post-surgery, all animals were examined using transthoracic conventional and color M-mode echocardiography (CMME) for IVPG. Animals were euthanized the following day after hemodynamics recording. Gross pathological and histological evaluations were performed. J-tree cluster analysis was conducted relying on ten echocardiographic parameters suggestive of CHF. Animals were merged into two main clusters: CHF+ (MI/HF + group, n = 22) and CHF– (n = 28) that was joined from Sham (n = 15), and MI/HF– (n = 13) groups. MI/HF+ group showed the most severe echocardiographic, hemodynamic, anatomic, and histologic alterations. There was no significant change in the total IVPG among various groups. However, the basal IVPG was significantly increased in MI/HF+ group compared to the other groups. The remaining IVPG measures were considerably increased in the MI/HF+ group than in the Sham one. The segmental IVPG measures were significantly correlated with the anatomical, histological, echocardiographic, and hemodynamic findings except for the heart rate. Moreover, they were significant predictors of CHF following a long-standing MI. Conclusively, IVPG obtained from CMME is a substantially promising noninvasive tool with a high ability to detect and predict the progression of CHF following chronic MI compared to conventional echocardiography.

Prognostic Implications of Biventricular Global Longitudinal Strain in Patients With Severe Isolated Tricuspid Regurgitation

Background

Isolated TV surgery can be performed in patients with symptoms caused by severe isolated tricuspid regurgitation (TR), preferably before the onset of significant right ventricular (RV) dysfunction. In patients with severe TR, intrinsic RV dysfunction tends to be masked and promotes left ventricular (LV) mechanical dysfunction. This study investigated the prognostic implications of biventricular global longitudinal strain (GLS) in patients receiving isolated tricuspid valve (TV) surgery.

Methods

Among 1,670 patients who underwent TV surgery between January 2000 and December 2020, 111 patients with severe isolated TR who underwent echocardiography before and after TV surgery were analyzed. We assessed LV, RV, and biventricular GLS using speckle tracking echocardiography. Biventricular GLS was defined as the sum of LV-GLS and RV free-wall strain. The primary outcomes were cardiovascular death, heart failure hospitalization, re-done TV surgery, and heart transplantation.

Results

During 3.9 ± 3.8 years of follow-up after the postoperative echocardiography, 24 (21.6%) patients experienced a primary outcome. Those patients had more comorbidities and more impaired preoperative RV-GLS and biventricular GLS than those who did not experience a primary outcome, although the two groups did not differ in preoperative LV-GLS. Patients with a primary outcome also showed significantly impaired postoperative RV-GLS, biventricular GLS, and LV-GLS compared those without a primary outcome. In multivariate analyses, both pre- and postoperatively assessed RV-GLS [preoperative; hazard ratio (HR) 0.86, confidence interval (CI) 0.79–0.93, p < 0.001, postoperative; HR 0.89, CI 0.82–0.96, p = 0.004] and biventricular GLS [preoperative; HR 0.96, CI 0.91–1.00, p = 0.048, postoperative; HR 0.94, CI 0.89–0.99, p = 0.023] were independently associated with the primary outcomes.

Conclusion

In patients with severe isolated TR undergoing TV surgery, the absolute value of RV-GLS under 17.2% is closely associated with a poor prognosis, and that of biventricular GLS under 34.0%, mainly depending on the RV-GLS, is related to the poor prognosis. Further prospective multicenter studies are warranted to establish the risk stratification of isolated TV surgery.

Prevalence and Prognostic Implications of Left Ventricular Systolic Dysfunction in Adults With Congenital Heart Disease

BACKGROUND

Although the prevalence and prognostic implications of left ventricular systolic dysfunction (LVSD), and the effect of cardiac therapies on LVSD are well described in patients with acquired heart disease, such data are sparse in adults with congenital heart disease (CHD).

OBJECTIVES

The purpose of this study was to determine the prevalence, risk factors, and prognostic implications of LVSD, and the effect of cardiac therapies (guideline-directed medical therapy [GDMT] and cardiac resynchronization therapy [CRT]) on LVSD in adults with CHD.

METHODS

This was a retrospective study of adults with CHD with systemic LV (2003-2019). LVSD was defined as left ventricular ejection fraction (LVEF) <52%/<54% (men/women). Cardiovascular event was defined as heart failure hospitalization, heart transplant, and cardiovascular death.

RESULTS

Of 4,358 patients, 554 (12%) had LVSD, and the prevalence of LVSD was higher in right-sided lesions compared with left-sided lesions (15% vs 10%; P < 0.001). Cardiovascular events occurred in 312 (7%) patients. LVEF was independently associated with cardiovascular events (HR: 0.95; 95% CI: 0.93-0.97; P = 0.009). Of 544 patients with LVSD, 311 received GDMT and 48 patients received CRT. LVEF increased by 6% (95% CI: 2%-10%) and 11% (95% CI: 8%-14%), and N-terminal pro-hormone brain natriuretic peptide decreased by 151 pg/mL (95% CI: 62-289 pg/mL) and 201 pg/mL (95% CI: 119-321 pg/mL) in patients who received GDMT and CRT, respectively.

CONCLUSIONS

LVSD was present in 12% of adults with CHD, was more common in patients with right-sided lesions, and was associated with cardiovascular events. GDMT and CRT were associated with improvement in LVEF. These results provide a foundation for clinical trials to rigorously test the benefits of these therapies in CHD patients.

Myocardial strain to identify benefit from beta-blockers in patients with heart failure with reduced ejection fraction

Aims

Not all patients with heart failure with reduced ejection fraction (HFrEF) benefit equally from beta‐blockers. Previous studies suggest that myocardial strain that reflects myocardial deformation may have a better prognostic value than the left ventricular ejection fraction. We aimed to evaluate the differential effect of beta‐blockers according to the global longitudinal strain (GLS) in patients with HFrEF.

Methods and results

Of the 4312 patients in the Strain for Risk Assessment and Therapeutic Strategies in Patients with Acute Heart Failure registry, we included 2126 HFrEF patients whose data on beta‐blocker use and GLS were available. Patients were categorized into two groups: one group of patients had GLS ≥ 10%, and the other group had GLS < 10%. The primary outcome was 5 year all‐cause mortality according to beta‐blocker use. Of the 2126 patients with HFrEF, 526 (24.7%) and 1600 (75.3%) patients had GLS ≥ 10% and <10%, respectively. Overall, 1399 patients (65.8%) received beta‐blockers, and 864 (40.6%) patients died during the 5 year follow‐up. Beta‐blocker use was associated with improved survival in patients with GLS < 10% in both the inverse probability treatment‐weighted (hazard ratio 0.70, 95% confidence interval 0.59–0.83, P < 0.001) and Cox regression analyses (hazard ratio 0.69, 95% confidence interval 0.59–0.81; P < 0.001). However, beta‐blocker use was not associated with better survival in patients with GLS ≥ 10% in the inverse probability treatment‐weighted and Cox regression analyses (both P > 0.05).

Conclusions

Beta‐blocker use appears to be associated with improved survival in patients with HFrEF and GLS < 10%, but this is not the case in patients with GLS ≥ 10%. Therefore, GLS may be used to identify patients who have attenuated benefits from beta‐blockers in HFrEF.

Clinical Trial Registration: ClinicalTrials.gov: NCT03513653 (https://clinicaltrials.gov/ct2/show/NCT03513653).

Sex differences in rat renal arterial responses following exercise training

During aerobic exercise, hemodynamic alterations occure; while blood flow in skeletal muscle arteries increases, it decreases in visceral vessels due to mesenterial vasoconstriction. However, maintaining renal blood flow during intensive sport is also a priority. Our aim was to investigate the changes of vascular reactivity and histology of isolated renal artery of male and female rats in response to swim-training. Wistar rats were distributed into four groups: male sedentary (MSed), male trained (MTr), female sedentary (FSed), and female trained (FTr). Trained animals underwent a 12-week-long intensive swimming program. Vascular function of isolated renal artery segments was examined by wire myography. Phenylephrine-induced contraction was lower in FSed compared to MSed animals, and it was decreased by training in male but not in female animals. Inhibition of cyclooxygenases by indomethacin reduced contraction in both sedentary groups, and in MTr but not in FTr animals. Inhibition of nitric oxide production increased contraction in both trained groups. Acetylcholine induced relaxation was similar in all experimental groups showing predominant NO-dependency. Elastin and smooth muscle cell actin density was reduced in female rats after aerobic training. This study shows that, as a result of 12-weeks-long training, there are sex differences in renal arterial responses following exercise training. Swimming moderates renal artery vasoconstriction in male animals, while it depresses elastic fiber and smooth muscle actin density in females.

Effectiveness of therapy with low-dosage masitinib on pulmonary hypertension in dogs: a pilot study

The purpose of this pilot study was to assess the efficacy of long-term masitinib therapy at low doses on echocardiographic, cardiovascular, haematological, and blood biochemical indicators, as well as clinical symptoms in dogs with pulmonary hypertension (PH) caused by advanced chronic degenerative mitral valve disease or heartworm disease. Seven client-owned dogs with severe PH were recruited prospectively and given low-dose masitinib orally, 3 mg/kg body weight (approximately one-fourth of the recommended antineoplastic dosage), q24h, for 123–928 days. Examinations were performed prior to masitinib administration, as well as 1, 2, 3, 6, and 12 months later. At 1–12 months, low-dose masitinib significantly reduced systolic pulmonary arterial pressure (P < 0.05 or 0.01) and dramatically improved clinical symptoms. Low-dose masitinib treatment improved right ventricular function indicators such as right atrium/aorta ratio, maximum tricuspid regurgitation velocity, right ventricular Tei index, and tricuspid annular plane systolic excursion, without worsening left ventricular function indicators. These findings suggest that low-dose masitinib may be effective as an adjunctive therapeutic for chronic heart failure in dogs with PH and may increase the survival of PH dogs.

Increased Expression of N2BA Titin Corresponds to More Compliant Myofibrils in Athlete's Heart

Long-term exercise induces physiological cardiac adaptation, a condition referred to as athlete’s heart. Exercise tolerance is known to be associated with decreased cardiac passive stiffness. Passive stiffness of the heart muscle is determined by the giant elastic protein titin. The adult cardiac muscle contains two titin isoforms: the more compliant N2BA and the stiffer N2B. Titin-based passive stiffness may be controlled by altering the expression of the different isoforms or via post-translational modifications such as phosphorylation. Currently, there is very limited knowledge about titin’s role in cardiac adaptation during long-term exercise. Our aim was to determine the N2BA/N2B ratio and post-translational phosphorylation of titin in the left ventricle and to correlate the changes with the structure and transverse stiffness of cardiac sarcomeres in a rat model of an athlete’s heart. The athlete’s heart was induced by a 12-week-long swim-based training. In the exercised myocardium the N2BA/N2B ratio was significantly increased, Ser11878 of the PEVK domain was hypophosphorlyated, and the sarcomeric transverse elastic modulus was reduced. Thus, the reduced passive stiffness in the athlete’s heart is likely caused by a shift towards the expression of the longer cardiac titin isoform and a phosphorylation-induced softening of the PEVK domain which is manifested in a mechanical rearrangement locally, within the cardiac sarcomere.

The mitochondrial signaling peptide MOTS-c improves myocardial performance during exercise training in rats

Cardiac remodeling is a physiological adaptation to aerobic exercise and which is characterized by increases in ventricular volume and the number of cardiomyocytes. The mitochondrial derived peptide MOTS-c functions as an important regulator in physical capacity and performance. Exercise elevates levels of endogenous MOTS-c in circulation and in myocardium, while MOTS-c can significantly enhance exercise capacity. However, the effects of aerobic exercise combined with MOTS-c on cardiac structure and function are unclear. We used pressure–volume conductance catheter technique to examine cardiac function in exercised rats with and without treatment with MOTS-c. Surprisingly, MOTS-c improved myocardial mechanical efficiency, enhanced cardiac systolic function, and had a tendency to improve the diastolic function. The findings suggest that using exercise supplements could be used to modulate the cardiovascular benefits of athletic training.

Right ventricular function as assessed by cardiac magnetic resonance imaging-derived strain parameters compared to high-fidelity micromanometer catheter measurements

Right ventricular function has prognostic significance in patients with pulmonary hypertension. We evaluated whether cardiac magnetic resonance-derived strain and strain rate parameters could reliably reflect right ventricular systolic and diastolic function in precapillary pulmonary hypertension. End-systolic elastance and the time constant of right ventricular relaxation tau, both derived from invasive high-fidelity micromanometer catheter measurements, were used as gold standards for assessing systolic and diastolic right ventricular function, respectively. Nineteen consecutive precapillary pulmonary hypertension patients underwent cardiac magnetic resonance and right heart catheterization prospectively. Cardiac magnetic resonance data were compared with those of 19 control subjects. In pulmonary hypertension patients, associations between strain- and strain rate-related parameters and invasive hemodynamic parameters were evaluated. Longitudinal peak systolic strain, strain rate, and early diastolic strain rate were lower in PAH patients than in controls; peak atrial-diastolic strain rate was higher in pulmonary hypertension patients. Similarly, circumferential peak systolic strain rate was lower and peak atrial-diastolic strain rate was higher in pulmonary hypertension. In pulmonary hypertension, no correlations existed between cardiac magnetic resonance-derived and hemodynamically derived measures of systolic right ventricular function. Regarding diastolic parameters, tau was significantly correlated with peak longitudinal atrial-diastolic strain rate (r = -0.61), deceleration time (r = 0.75), longitudinal systolic to diastolic time ratio (r = 0.59), early diastolic strain rate (r = -0.5), circumferential peak atrial-diastolic strain rate (r = -0.52), and deceleration time (r = 0.62). Strain analysis of the right ventricular diastolic phase is a reliable non-invasive method for detecting right ventricular diastolic dysfunction in PAH.

Novel insights into the athlete's heart: is myocardial work the new champion of systolic function?

Aims

We sought to investigate the correlation between speckle-tracking echocardiography (STE)-derived myocardial work (MW) and invasively measured contractility in a rat model of athlete's heart. We also assessed MW in elite athletes and explored its association with cardiopulmonary exercise test (CPET)-derived aerobic capacity.

Methods and results

Sixteen rats underwent a 12-week swim training program and were compared to controls (n = 16). STE was performed to assess global longitudinal strain (GLS), which was followed by invasive pressure-volume analysis to measure contractility [slope of end-systolic pressure–volume relationship (ESPVR)]. Global MW index (GMWI) was calculated from GLS curves and left ventricular (LV) pressure recordings. In the human investigations, 20 elite swimmers and 20 healthy sedentary controls were enrolled. GMWI was calculated through the simultaneous evaluation of GLS and non-invasively approximated LV pressure curves at rest. All subjects underwent CPET to determine peak oxygen uptake (VO₂/kg). Exercised rats exhibited higher values of GLS, GMWI, and ESPVR than controls (−20.9 ± 1.7 vs. −17.6 ± 1.9%, 2745 ± 280 vs. 2119 ± 272 mmHg·%, 3.72 ± 0.72 vs. 2.61 ± 0.40 mmHg/μL, all P_Exercise < 0.001). GMWI correlated robustly with ESPVR (r = 0.764, P < 0.001). In humans, regular exercise training was associated with decreased GLS (−17.6 ± 1.5 vs. −18.8 ± 0.9%, P_Exercise = 0.002) but increased values of GMWI at rest (1899 ± 136 vs. 1755 ± 234 mmHg·%, P_Exercise = 0.025). GMWI exhibited a positive correlation with VO₂/kg (r = 0.527, P < 0.001).

Conclusions

GMWI precisely reflected LV contractility in a rat model of exercise-induced LV hypertrophy and captured the supernormal systolic performance in human athletes even at rest. Our findings endorse the utilization of MW analysis in the evaluation of the athlete’s heart.

Reduced left ventricular contractility, increased diastolic operant stiffness and high energetic expenditure in patients with severe aortic regurgitation without indication for surgery

OBJECTIVES

Recent mortality studies showed worse prognosis in patients (ARNS) with severe aortic regurgitation and preserved ejection fraction (EF) not fulfilling the criteria of current guidelines for surgery. The aim of our study was to analyse left ventricular (LV) systolic and diastolic function and mechanical energetics to find haemodynamic explanations for the reduced prognosis of these patients and to seek a new concept for surgery.

METHODS

Global longitudinal strain (GLS) and echo-based single-beat pressure-volume analyses were performed in patients with ARNS (LV end-diastolic diameter <70 mm, EF >50%, GLS > -19% n = 41), with indication for surgery (ARS; n = 19) and in mild hypertensive controls (C; n = 20). Additionally, end-systolic elastance (LV contractility), stroke work and total energy (pressure-volume area) were calculated.

RESULTS

ARNS demonstrated significantly depressed LV contractility versus C: end-systolic elastance (1.58 ± 0.7 vs 2.54 ± 0.8 mmHg/ml; P < 0.001), despite identical EF (EF: 59 ± 6% vs 59 ± 7%). Accordingly, GLS was decreased [-15.7 ± 2.7% (n = 31) vs -21.2 ± 2.4%; P < 0.001], end-diastolic volume (236 ± 90 vs 136 ± 30 ml; P < 0.001) and diastolic operant stiffness were markedly enlarged, as were pressure-volume area and stroke work, indicating waste of energy. The correlation of GLS versus end-systolic elastance was good (r = -0.66; P < 0.001). ARNS and ARS patients demonstrated similar haemodynamic disorders, whereas only GLS was worse in ARS.

CONCLUSIONS

ARNS patients almost matched the ARS patients in their haemodynamic and energetic deterioration, thereby explaining poor prognosis reported in literature. GLS has been shown to be a reliable surrogate for LV contractility, possibly overestimating contractility due to exhausted preload reserve in aortic regurgitation patients. GLS may outperform conventional echo parameters to predict more precisely the timing of surgery.

Sex Differences in Exercise-Training-Related Functional and Morphological Adaptation of Rat Gracilis Muscle Arterioles

Background

The cardiovascular effects of training have been widely investigated; however, few studies have addressed sex differences in arteriolar adaptation. In the current study, we examined the adaptation of the gracilis arterioles of male and female rats in response to intensive training.

Methods

Wistar rats were divided into four groups: male exercise (ME) and female exercise (FE) animals that underwent a 12-week intensive swim-training program (5 days/week, 200 min/day); and male control (MC) and female control (FC) animals that were placed in water for 5 min daily. Exercise-induced cardiac hypertrophy was confirmed by echocardiography. Following the training, the gracilis muscle arterioles were prepared, and their biomechanical properties and functional reactivity were tested, using pressure arteriography. Collagen and smooth muscle remodeling were observed in the histological sections.

Results

Left ventricular mass was elevated in both sexes in response to chronic training. In the gracilis arterioles, the inner radius and wall tension increased in female animals, and the wall thickness and elastic modulus were reduced in males. Myogenic tone was reduced in the ME group, whereas norepinephrine-induced vasoconstriction was elevated in the FE group. More pronounced collagen staining was observed in the ME group than in the MC group. Relative hypertrophy and tangential stress of the gracilis arterioles were higher in females than in males. The direct vasoconstriction induced by testosterone was lower in females and was reduced as an effect of exercise in males.

Conclusion

The gracilis muscle arteriole was remodeled as a result of swim training, and this adaptation was sex dependent.

Left ventricular longitudinal strain is a major determinant of CT-derived three-dimensional maximum principal strain: comparison with two-dimensional speckle tracking echocardiography

Computed tomography (CT)-derived three-dimensional maximum principal strain (MP-strain) can provide incremental value to coronary CT angiography for cardiac dysfunction assessment with high diagnostic performance in patients with myocardial infarction. Global longitudinal strain (GLS) measured using two-dimensional speckle tracking echocardiography (2D-STE) is more sensitive than left ventricular ejection fraction (LVEF) for detecting early myocardial dysfunction. We aimed to compare CT-derived MP-strain with each of 2D-STE-derived strains (i.e., longitudinal, circumferential, and radial strains), and identify the major determinants of CT-derived MP-strain among 2D-STE-derived strains. We studied 51 patients who underwent cardiac CT and echocardiography. CT images were reconstructed at every 5% (0-95%) of the RR interval. A dedicated workstation was used to analyze CT-derived MP-strain on the 16-segment model. We calculated CT-derived global MP-strain with all the 16 segments on a per patient basis. Pearson's test was used to assess correlations between CT-derived MP-strain and STE-strain at global and segmental levels. The intra-class correlation coefficient for interobserver agreement for CT-derived global MP-strain was 0.98 (95% confidence interval 0.96-0.99). The low-CT-derived global MP-strain group (≤ 0.43) had more patients with LV dysfunction than the high-CT-derived global MP-strain group (> 0.43). CT-derived global MP-strain was associated with STE-GLS (r = 0.738, P < 0.001), global circumferential strain (r = 0.646, P < 0.001), and global radial strain (r = 0.432, P = 0.001). In multivariate analysis, STE-GLS had the strongest association to CT-derived global MP-strain among three directional STE-strains and LVEF by echocardiography (standardized coefficient =  - 0.527, P < 0.001). STE-GLS is a major determinant of CT-derived global MP-strain. CT-derived MP-strain may enhance the value of coronary CT angiography by adding functional information to CT-derived LVEF.

Global longitudinal strain and long-term outcome in patients presenting to the emergency department with suspected acute coronary syndrome

AIMS

We have previously shown that 2-dimentional strain is not a useful tool for ruling out acute coronary syndrome (ACS) in the emergency department (ED). The aim of the present study was to determine whether in patients with suspected ACS, global longitudinal strain (GLS), measured in the ED using 2-dimensional strain imaging, can predict long-term outcome.

METHODS

Long-term (median 7.7 years [IQR 6.7-8.2]) major adverse cardiac events (MACE; cardiac death, ACS, revascularization, hospitalization for heart failure, or atrial fibrillation) and all-cause mortality data were available in 525/605 patients (87%) enrolled in the Two-Dimensional Strain for Diagnosing Chest Pain in the Emergency Room (2DSPER) study. The study prospectively enrolled patients presenting to the ED with chest pain and suspected ACS but without a diagnostic ECG or elevated troponin. GLS was computed using echocardiograms performed within 24 hours of chest pain. MACE of patients with worse GLS (>median GLS) were compared to patients with better GLS (≤ median GLS).

RESULTS

Median GLS was -18.7%. MACE occurred in 47/261 (18%) of patients with worse GLS as compared with 45/264 (17%) with better GLS, adjusted HR 0.87 (95% CI 0.57-1.33, P = .57). There was no significant difference in all-cause mortality or individual endpoints between groups. GLS did not predict MACE even in patients with optimal 2-dimensional image quality (n = 164, adjusted HR=1.51, 95% CI 0.76-3.0).

CONCLUSIONS

Global longitudinal strain did not predict long-term outcome in patients presenting to the ED with chest pain and suspected ACS, supporting our findings in the 2DSPER study.

Network analysis of the left anterior descending coronary arteries in swim-trained rats by an in situ video microscopic technique

BACKGROUND

We aimed to identify sex differences in the network properties and to recognize the geometric alteration effects of long-term swim training in a rat model of exercise-induced left ventricular (LV) hypertrophy.

METHODS

Thirty-eight Wistar rats were divided into four groups: male sedentary, female sedentary, male exercised and female exercised. After training sessions, LV morphology and function were checked by echocardiography. The geometry of the left coronary artery system was analysed on pressure-perfused, microsurgically prepared resistance artery networks using in situ video microscopy. All segments over > 80 μm in diameter were studied using divided 50-μm-long cylindrical ring units of the networks. Oxidative-nitrative (O-N) stress markers, adenosine A2A and estrogen receptor (ER) were investigated by immunohistochemistry.

RESULTS

The LV mass index, ejection fraction and fractional shortening significantly increased in exercised animals. We found substantial sex differences in the coronary network in the control groups and in the swim-trained animals. Ring frequency spectra were significantly different between male and female animals in both the sedentary and trained groups. The thickness of the wall was higher in males as a result of training. There were elevations in the populations of 200- and 400-μm vessel units in males; the thinner ones developed farther and the thicker ones closer to the orifice. In females, a new population of 200- to 250-μm vessels appeared unusually close to the orifice.

CONCLUSIONS

Physical activity and LV hypertrophy were accompanied by a remodelling of coronary resistance artery network geometry that was different in both sexes.

The relationship between miRNA-26b and connective tissue growth factor in rat models of aortic banding and debanding

BACKGROUND/AIMS

Connective tissue growth factor (CTGF) is a profibrotic factor implicated in pressure overload-mediated myocardial fibrosis. In this study, we determined the role of predicted CTGF-targeting microRNAs (miRNAs) in rat models of aortic stenosis and reverse cardiac remodeling.

METHODS

Minimally invasive ascending aortic banding was performed in 24 7-week-old male Sprague-Dawley rats, which were divided into three groups. The banding group consisted of eight rats that were sacrificed immediately after 6 weeks of aortic constriction. The debanding group underwent aortic constriction for 4 weeks and was sacrificed 2 weeks after band removal. The third group underwent sham surgery. We investigated the expression of CTGF, transforming growth factor-β1 (TGFβ1), and matrix metalloproteinase-2 using ELISA and examined miRNA-26b, miRNA-133a, and miRNA-19b as predicted CTGF-targeting miRNAs based on miRNA databases in 24-hour TGFβ-stimulated and TGFβ- washed fibroblasts and myocardial tissues from all subjects.

RESULTS

CTGF was elevated in 24-hour TGFβ-stimulated fibroblasts and decreased in 24-hour TGFβ-washed fibroblasts. miRNA-26b was significantly increased in TGFβ-washed fibroblasts compared with control and TGFβ-stimulated fibroblasts (p < 0.05). CTGF expression was significantly higher in the banding group than that in the sham and debanding groups. The relative expression levels of miRNA-26b were higher in the debanding group than in the banding group.

CONCLUSION

The results of our study using models of aortic banding and debanding suggested that miRNA-26b was significantly increased after aortic debanding. The in vitro model yielded the same results: miRNA-26b was upregulated after removal of TGFβ from fibroblasts.

Myocardial work index: a marker of left ventricular contractility in pressure- or volume overload-induced heart failure

Aims

While global longitudinal strain (GLS) is considered to be a sensitive marker of left ventricular (LV) function, it is significantly influenced by loading conditions. We hypothesized that global myocardial work index (GMWI), a novel marker of LV function, may show better correlation with load‐independent markers of LV contractility in rat models of pressure‐induced or volume overload‐induced heart failure.

Methods and results

Male Wistar rats underwent either transverse aortic constriction (TAC; n = 12) or aortocaval fistula creation (ACF; n = 12), inducing LV pressure or volume overload, respectively. Sham procedures were performed to establish control groups (n = 12/12). Echocardiographic loops were obtained to determine GLS and GMWI. Pressure‐volume analysis with transient occlusion of the inferior caval vein was carried out to calculate preload recruitable stroke work (PRSW), a load‐independent ‘gold‐standard’ parameter of LV contractility. Myocardial samples were collected to assess interstitial and perivascular fibrosis area and also myocardial atrial‐type natriuretic peptide (ANP) and brain‐type natriuretic peptide (BNP) relative mRNA expression. Compared with controls, GLS was substantially lower in the TAC group (−7.0 ± 2.8 vs. −14.5 ± 2.5%; P < 0.001) and was only mildly reduced in the ACF group (−13.2 ± 2.4 vs. −15.4 ± 2.0%, P < 0.05). In contrast with these findings, PRSW and GMWI were comparable with sham in TAC (110 ± 26 vs. 116 ± 68 mmHg; 1687 ± 275 mmHg% vs. 1537 ± 662 mmHg%; both P = NS), while it was found to be significantly reduced in ACF (58 ± 14 vs. 111 ± 40 mmHg; 1328 ± 411 vs. 1934 ± 308 mmHg%, both P < 0.01). In the pooled population, GMWI (r = 0.70; P < 0.001) but not GLS (r = −0.23; P = 0.12) showed a strong correlation with PRSW. GLS correlated with interstitial (r = 0.61; P < 0.001) and perivascular fibrosis area (r = 0.54; P < 0.001), and also with myocardial ANP (r = 0.85; P < 0.001) and BNP relative mRNA expression (r = 0.75; P < 0.001), while GMWI demonstrated no or only marginal correlation with these parameters.

Conclusions

Being significantly influenced by loading conditions, GLS may not be a reliable marker of LV contractility in heart failure induced by pressure or volume overload. GMWI better reflects contractility in haemodynamic overload states, making it a more robust marker of systolic function, while GLS should be considered as an integrative marker, incorporating systolic function, haemodynamic loading state, and adverse tissue remodelling of the LV.

Hemodynamics and Clinical Implications of Occult Left Ventricular Dysfunction in Adults Undergoing Ebstein Anomaly Repair

BACKGROUND

Left ventricular global longitudinal strain (LVGLS) can detect early phases of LV systolic dysfunction, but its application has not been studied in Ebstein anomaly. We hypothesized that LVGLS can detect early phases of LV systolic dysfunction and that patients with occult LV systolic dysfunction will have worse hemodynamics, end-organ dysfunction, and suboptimal postoperative LV reverse remodeling after tricuspid valve surgery in comparison to patients with normal LV systolic function.

METHODS

In this retrospective cohort study, 371 Ebstein patients that underwent tricuspid valve surgery were divided into 3 groups: normal LV systolic function (normal LVGLS and LV ejection fraction; n=244, 77%), occult LV systolic dysfunction (abnormal LVGLS with normal LV ejection fraction; n=44, 14%), and overt LV systolic dysfunction (abnormal LVGLS and LV ejection fraction; n=27, 9%).

RESULTS

Compared with the normal LV function group, the occult group had smaller LV volume and cardiac output (2.1±0.4 versus 2.9±0.6 L/min per m2, P<0.001), worse end-organ dysfunction (glomerular filtration rate, 78±14 versus 91±18 mL/min per 1.73 m2, P=0.01), and suboptimal postoperative LV reverse remodeling. Although both the occult and overt groups had a similar degree of end-organ dysfunction (glomerular filtration rate, 78±14 versus 82±16 mL/min per 1.73 m2, P=0.3), the occult group was less likely to be on heart failure therapy (48% versus 96%, P<0.001).

CONCLUSIONS

Abnormal LVGLS was associated with suboptimal postoperative LV reverse remodeling. These data suggest that LVGLS can potentially be used for risk stratification and provides a foundation for further studies to determine whether optimal heart failure therapy or tricuspid valve intervention can improve outcomes for LV systolic dysfunction in patients with Ebstein anomaly.

Experimental Research on the Evaluation of Left Ventricular Function by Layered Speckle Tracking in a Constrictive Pericarditis Rat Model

OBJECTIVES

In animal models with constrictive pericarditis (CP), detecting the function of cardiac systole by conventional noninvasive ultrasound is a challenge. We aimed to detect cardiac dysfunction in rat models with CP in the early stage by layered speckle tracking.

METHODS

We compared a rat CP model (n = 23, injected with a solution of 1-mg/mL lipopolysaccharides [0.5 mL] and a 10% talc suspension [0.5 mL]) with a control group (n = 20, no injection). After 8 weeks, conventional echocardiography and layered speckle tracking were used to assess the left ventricular structures and functions in the groups.

RESULTS

The global circumferential strain (CS) and longitudinal strain (LS) were decreased in the CP group (P < .05). The CS of the epicardial and middle layers in the CP group was decreased (P < .05), but the endocardial layer was not statistically different. The LS of the epicardial layer was decreased (P < .05), but the middle and endocardial layers were not statistically different. The global free-wall and septal-wall CS of the CP group was decreased (P < .05), mainly due to the decrease of CS of the epicardial and middle layers. The global free-wall LS of the CP group was decreased (P < .05), mainly due to the decrease of LS of the epicardial and middle layers. There were no significant differences between the groups in global LS of the septal wall.

CONCLUSIONS

In the early stage of CP, subepicardial myocardial damage precedes that of the subendocardial myocardium, and free-wall damage precedes that of the septal wall.

Characterisation of LV myocardial exercise function by 2-D strain deformation imaging in elite adolescent footballers

Purpose

Few data exist on the descriptions of LV myocardial mechanics and reserve during dynamic exercise of adolescent athletes. The aim of this study was to describe the LV myocardial and cardiopulmonary changes during exercise using 2-D strain deformation imaging.

Methods

Elite adolescent male football players (n = 42) completed simultaneous cardiopulmonary exercise testing (CPET) and exercise echocardiography measurement of LV myocardial deformation by 2-D strain imaging. LV longitudinal and circumferential 2-D strain and strain rates were analyzed at each stage during incremental exercise to a work rate of 150 W. Additionally, exercise LV myocardial deformation and its relation to metabolic exercise parameters were evaluated at each exercise stage and in recovery using repeated measures ANOVA, linear regression and paired t tests.

Results

LV peak systolic baseline 2-D strain (longitudinal: − 15.4 ± 2.5%, circumferential: − 22.5 ± 3.1%) increased with each exercise stage, but longitudinal strain plateaued at 50 W (mean strain reserve − 7.8 ± 3.0) and did not significantly increase compared to subsequent exercise stages (P > 0.05), whilst circumferential strain (mean strain reserve − 11.6 ± 3.3) significantly increased (P < 0.05) throughout exercise up to 150 W as the dominant mechanism of exercise LV contractility increase. Regression analyses showed LV myocardial strain increased linearly relative to HR, VO₂ and O₂ pulse (P < 0.05) for circumferential deformation, but showed attenuation for longitudinal deformation.

Conclusion

This study describes LV myocardial deformation dynamics by 2-D strain and provides reference values for LV myocardial strain and strain rate during exercise in adolescent footballers. It found important differences between LV longitudinal and circumferential myocardial mechanics during exercise and introduces a methodology that can be used to quantify LV function and cardiac reserve during exercise in adolescent athletes.

Chronic swimming training resulted in more relaxed coronary arterioles in male and enhanced vasoconstrictor ability in female rats

BACKGROUND

Exercise training is associated with hypertrophy of left ventricle (LV). The aim of the present study is to evaluate sex differences in the adaptation of the coronary contractile function in physiological left ventricular hypertrophy induced by long-term swim training.

METHODS

Thirty-two Wistar rats were randomly divided into 4 groups: exercised male (ExM), exercised female (ExF), untrained control male (CoM), and untrained control female (CoF). The trained animals underwent a 12-week-long swim training program. After finishing the training program, LV morphology and function were checked by echocardiography. The spontaneous tone, thromboxane (TxA<inf>2</inf>) agonist-induced vascular contractility and non-endothelial dilatation of the isolated intramural coronary resistance artery were examined by pressure microangiometry. The thromboxane receptor (TxA<inf>2</inf>R) protein expression in the wall of coronary arteries was examined using immunohistochemistry.

RESULTS

The LV mass index was significantly higher in the ExM and ExF groups, furthermore the LV mass index was significantly higher in female than in male animals. ExM animals had lower spontaneous tone than ExF. TxA<inf>2</inf> agonist-induced tone was raised only in ExF animals. The resistance coronary artery of exercised male animals had a significantly lower level of TxA<inf>2</inf>R positivity compared to exercised females.

CONCLUSIONS

Both sexes broaden their range of contractility following chronic swimming, but the vessel tone shifted toward contraction in exercised female rats, while these values shifted toward relaxation in males. These observations underline the significance of identifying potential gender differences in the chronic exercise-induced coronary vascular remodeling in human athletes.

Phenotyping Heart Failure According to the Longitudinal Ejection Fraction Change: Myocardial Strain, Predictors, and Outcomes

Background

Many patients with heart failure (HF) experience changes in left ventricular ejection fraction (LVEF) during follow‐up. We sought to evaluate the predictors and outcomes of different HF phenotypes according to longitudinal changes in EF.

Methods and Results

A total of 2104 patients with acute HF underwent echocardiography at baseline and follow‐up. Global longitudinal strain was measured at index admission. HF phenotypes were defined as persistent HF with reduced EF (persistent HFrEF, LVEF ≤40% at baseline and follow‐up), heart failure with improved ejection fraction (LVEF≤40% at baseline and improved to >40% at follow‐up), heart failure with declined ejection fraction (LVEF>40% at baseline and declined to ≤40% at follow up), and persistent HF with preserved EF (persistent HFpEF, LVEF>40% at baseline and follow‐up). Overall, 1130 patients had HFrEF at baseline; during follow‐up, 54.2% and 46.8% had persistent HFrEF and heart failure with improved ejection fraction, respectively. Among 975 patients with HFpEF at baseline, 89.5% and 10.5% had persistent HFpEF and heart failure with declined ejection fraction at follow‐up, respectively. The 5‐year all‐cause mortality rates were 43.1%, 33.1%, 24%, and 17% for heart failure with declined ejection fraction, persistent HFrEF, persistent HFpEF, and heart failure with improved ejection fraction, respectively (global log‐rank P<0.001). In multivariable analyses, each 1% increase in global longitudinal strain (greater contractility) was associated with 10% increased odds for heart failure with improved ejection fraction among patients with HFrEF at baseline and 7% reduced odds for heart failure with declined ejection fraction among patients with HFpEF at baseline.

Conclusions

LVEF changed during follow‐up. Each HF phenotype according to longitudinal LVEF changes has a distinct prognosis. Global longitudinal strain can be used to predict the HF phenotype.

REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03513653.

Long-term exercise results in morphological and biomechanical changes in coronary resistance arterioles in male and female rats

Background

Biomechanical remodeling of coronary resistance arteries in physiological left ventricular hypertrophy has not yet been analyzed, and the possible sex differences are unknown.

Methods

Wistar rats were divided into four groups: male and female sedentary controls (MSe and FSe) and male and female animals undergoing a 12-week intensive swim training program (MEx and FEx). On the last day, the in vitro contractility, endothelium-dependent dilatation, and biomechanical properties of the intramural coronary resistance arteries were investigated by pressure microarteriography. Elastica and collagen remodeling were studied in histological sections.

Results

A similar outer radius and reduced inner radius resulted in an elevated wall to lumen ratio in the MEx and FEx animals compared to that in the sedentary controls. The wall elastic moduli increased in the MEx and FEx rats. Spontaneous and TxA₂ agonist-induced tone was increased in the FEx animals, whereas endothelium-dependent relaxation became more effective in MEx rats. Arteries of FEx rats had stronger contraction, while arteries of MEx animals had improved dilation.

Conclusions

According to our results, the coronary arterioles adapted to an elevated load during long-term exercise, and this adaptation depended on sex. It is important to emphasize that in addition to differences, we also found many similarities between the sexes in the adaptive response to exercise. The observed sport adaptation in the coronary resistance arteries of rats may contribute to a better understanding of the physiological and pathological function of these arteries in active and retired athletes of different sexes.

Prognostic Value of Biventricular Strain in Risk Stratifying in Patients With Acute Heart Failure

Background Few studies have shown that right ventricular ( RV ) function is independently related to adverse events regardless of left ventricular ( LV ) function in heart failure. We evaluated the prognostic value of global longitudinal strain ( GLS ) of both ventricles in patients with acute heart failure. Methods and Results We measured biventricular strains in 1824 randomly selected patients (973 men, aged 70±14 years) from a strain registry. A total of 799 patients (43.8%) died during the median follow-up duration of 31.7 months. In univariate analysis, LVGLS and RVGLS were significantly associated with all-cause mortality. We classified them into 4 strain groups according to LVGLS (≥9%) and RVGLS (≥12%). On Cox proportional hazards analysis, group 4 (<9% LVGLS and <12% RVGLS ) had the worst prognosis, with a hazard ratio ( HR ) of 1.755 (95% confidence interval [ CI ], 1.473-2.091; P<0.001) compared with that of group 1 (≥9% LVGLS and ≥12% RVGLS ). After multivariate analysis, both LVGLS (per 1% decrease; HR : 1.057; 95% CI , 1.029-1.086; P<0.001) and RVGLS (per 1% decrease; HR : 1.022; 95% CI , 1.004-1.040; P=0.014) were also significant. The HR of RVGLS <12% was higher in patients without pulmonary hypertension (assessed by maximal tricuspid regurgitation ≤2.8 m/s) after the adjustment of LVGLS ( HR : 1.40 [95% CI , 1.11-1.77] versus 1.07 [95% CI , 0.88-1.30] with pulmonary hypertension; interaction, P=0.043). Conclusions In the patients with acute heart failure, RVGLS was significantly associated with all-cause mortality regardless of LVGLS , and those with decreased biventricular GLS showed the worst prognosis. The predictive power of RVGLS was more prominent in the absence of pulmonary hypertension.

Sex Differences in Morphological and Functional Aspects of Exercise-Induced Cardiac Hypertrophy in a Rat Model

Background: Recent evidences suggest that sex hormones may be involved in the regulation of exercise-induced left ventricular (LV) hypertrophy. However, the sex-specific functional consequences of exercise-induced myocardial hypertrophy is still not investigated in detail. We aimed at understanding the sex-specific functional and morphological alterations in the LV and the underlying molecular changes in a rat model of athlete’s heart.

Methods: We divided our young, adult male and female rats into control and exercised groups. Athlete’s heart was induced by a 12-week long swim training. Following the training period, we assessed LV hypertrophy with echocardiography, while pressure-volume analysis was performed to investigate in vivo LV function. After in vivo experiments, molecular biological studies and histological investigations were performed.

Results: Echocardiography and post-mortem measured heart weight data indicated LV hypertrophy in both genders, nevertheless it was more pronounced in females. Despite the more significant relative hypertrophy in females, characteristic functional parameters did not show notable differences between the genders. LV pressure-volume analysis showed increased stroke volume, improved contractility and stroke work and unaltered LV stiffness in both male and female exercised rats, while active relaxation was ameliorated solely in male animals. The induction of Akt signaling was more significant in females compared to males. There was also a characteristic difference in the mitogen-activated protein kinase pathway as suppressed phosphorylation of p44/42 MAPK (Erk) and mTOR was observed in female exercised rats, but not in male ones. Myosin heavy chain α (MHC)/β-MHC ratio did not differ in males, but increased markedly in females.

Conclusion: Our results confirm that there is a more pronounced exercise-induced LV hypertrophy in females as compared to the males, however, there are only minor differences regarding LV function. There are characteristic molecular differences between male and female animals, that can explain different degrees of LV hypertrophy.

Left Ventricular Torsion in Hypertension and Hypertensive Heart Failure ― 3-Dimensional Speckle Tracking Echocardiography Assessment ―

Background: Left ventricular (LV) torsion by contraction of inner and outer oblique muscles contributes to EF. Outer muscle plays a predominant role in torsion. We evaluated the impact of LV remodeling by hypertension (HTN) on torsion using 3-dimensional speckle tracking echocardiography (3D-STE).

Methods and Results: LV strain, strain rate during systole (SR-S) and torsion at endocardium, mid-wall and epicardium were assessed on 3D-STE in 53 controls and 186 HTN patients. Torsion was defined as the difference between apical and basal rotation divided by long axis length. LVEF and strain, SR-S and torsion in all 3 layers in HTN without LV hypertrophy (LVH) were similar to those in controls. LV longitudinal strain at endocardium in HTN with LVH decreased, whereas LVEF was similar to that in controls and, which was associated with increased torsion at epicardium. Reduced LVEF in hypertensive HF was associated with reduced strain, SR-S and torsion in all layers and with LV dilation. On multivariate analysis, epicardial torsion was an independent determinant of LVEF. At epicardial torsion cut-off 0.41, the sensitivity and specificity for the identification of HFrEF were 88% and 68%.

Conclusions: Torsion on 3D-STE may represent a compensatory mechanism to maintain LVEF despite reduced endocardial function, suggesting that the deterioration of torsion caused by insult to outer muscle and dilation may lead to HFrEF.

Imaging of Myocardial Fibrosis and Its Functional Correlates in Aortic Stenosis: A Review and Clinical Potential

Patients with severe aortic stenosis (AS) show progressive fibrotic changes in the myocardium, which may impair cardiac function and patient outcomes even after successful aortic valve replacement. Detection of patients who need an early operation remains a diagnostic challenge as myocardial functional changes may be subtle. In recent years, speckle tracking echocardiography (STE) and cardiac magnetic resonance mapping have been shown to provide complementary information for the assessment of left ventricular mechanics and identification of subtle damage by focal or diffuse myocardial fibrosis, respectively. Little is known, however, about how focal and diffuse myocardial fibrosis occurring in severe AS are related to measurable functional changes by echocardiography and to which extent both parameters have prognostic and diagnostic value. The aims of this review are to discuss the occurrence of focal and diffuse myocardial fibrosis in patients with severe AS and to explore their relation with myocardial function, determined by STE, as well as the prognostic and diagnostic potential of both parameters.

In Vivo Imaging With Confirmation by Histopathology for Increased Rigor and Reproducibility in Translational Research: A Review of Examples, Options, and Resources

Preclinical noninvasive imaging can be an indispensable tool for studying animal models of disease. In vivo imaging to assess anatomical, functional, and molecular features requires verification by a comparison to the macroscopic and microscopic morphological features, since all noninvasive in vivo imaging methods have much lower resolution than standard histopathology. Comprehensive pathological evaluation of the animal model is underutilized; yet, many institutions have veterinary or human pathologists with necessary comparative pathology expertise. By performing a rigorous comparison to gross or histopathology for image interpretation, these trained individuals can assist scientists with the development of the animal model, experimental design, and evaluation of the in vivo imaging data. These imaging and pathology corroboration studies undoubtedly increase scientific rigor and reproducibility in descriptive and hypothesis-driven research. A review of case examples including ultrasound, nuclear, optical, and MRI is provided to illustrate how a wide range of imaging modalities data can be confirmed by gross or microscopic pathology. This image confirmation and authentication will improve characterization of the model and may contribute to decreasing costs and number of animals used and to more rapid translation from preclinical animal model to the clinic.

Characterization of the dynamic changes in left ventricular morphology and function induced by exercise training and detraining

BACKGROUND

Although exercise-induced cardiac hypertrophy has been intensively investigated, its development and regression dynamics have not been comprehensively described. In the current study, we aimed to characterize the effects of regular exercise training and detraining on left ventricular (LV) morphology and function.

METHODS

Rats were divided into exercised (n = 12) and control (n = 12) groups. Exercised rats swam 200 min/day for 12 weeks. After completion of the training protocol, rats remained sedentary for 8 weeks (detraining period). Echocardiographic follow-up was performed regularly to obtain LV long- and short-axis recordings for speckle-tracking echocardiography analysis. Global longitudinal and circumferential strain and systolic strain rate were measured. LV pressure-volume analysis was performed using additional groups of rats to obtain haemodynamic data.

RESULTS

Echocardiographic examinations showed the development of LV hypertrophy in the exercised group. These differences disappeared during the detraining period. Strain and strain rate values were all increased after the training period, whereas supernormal values rapidly reversed to the control level after training cessation. Load-independent haemodynamic indices, e.g., preload recruitable stroke work, confirmed the exercise-induced systolic improvement and complete regression after detraining.

CONCLUSIONS AND TRANSLATIONAL ASPECT

Our results provide the first comprehensive data to describe the development and regression dynamics of morphological and functional aspects of physiological hypertrophy in detail. Speckle-tracking echocardiography has been proven to be feasible to follow-up changes induced by exercise training and detraining and might provide an early possibility to differentiate between physiological and pathological conditions.

The Female Athlete's Heart: Comparison of Cardiac Changes Induced by Different Types of Exercise Training Using 3D Echocardiography

We aimed to characterize female athlete's heart in elite competitors in the International Federation of Bodybuilding and Fitness (IFBB) Bikini Fitness category and compare them to athletes of a more dynamic sport discipline and healthy, sedentary volunteers using 3D echocardiography. Fifteen elite female fitness athletes were recruited and compared to 15 elite, age-matched female water polo athletes and 15 age-matched healthy, nontrained controls. Using 3D echocardiography, left ventricular (LV) and right ventricular (RV) end-diastolic volume index (EDVi) and LV mass index (LVMi) were measured. Fitness athletes presented similar LV and RV EDVi compared to healthy, sedentary volunteers. Water polo athletes, however, had higher LV and also RV EDVi (fitness versus water polo versus control; LVEDVi: 76 ± 13 versus 84 ± 8 versus 73 ± 8 ml/m², ANOVA p = 0.045; RVEDVi: 61 ± 12 versus 86 ± 14 versus 55 ± 9 ml/m², p < 0.0001). LVMi was significantly higher in the athlete groups; the hypertrophy, however, was even more prominent in water polo athletes (78 ± 13 versus 91 ± 10 versus 57 ± 10 g/m², p < 0.0001). To the best of our knowledge, this is the first study to characterize female athlete's heart of IFBB Bikini Fitness competitors. The predominantly static exercise regime induced a mild, concentric-type LV hypertrophy, while in water polo athletes higher ventricular volumes and eccentric LV hypertrophy developed.

Longitudinal measures of deformation are associated with a composite measure of contractility derived from pressure-volume loop analysis in children

Aims

The relationship between echocardiographic measures of left ventricular (LV) systolic function and reference-standard measures have not been assessed in children. The objective of this study was to assess the validity of echocardiographic indices of LV systolic function via direct comparison to a novel composite measure of contractility derived from pressure-volume loop (PVL) analysis.

Methods and results

Children with normal loading conditions undergoing routine left heart catheterization were prospectively enrolled. PVLs were obtained via conductance catheters. A composite invasive composite contractility index (ICCI) was developed using data reduction strategies to combine four measures of contractility derived from PVL analysis. Echocardiograms were performed immediately after PVL analysis under the same anesthetic conditions. Conventional and speckle-tracking echocardiographic measures of systolic function were measured. Of 24 patients, 18 patients were heart transplant recipients, 6 patients had a small patent ductus arteriosus or small coronary fistula. Mean age was 9.1 ± 5.6 years. Upon multivariable regression, longitudinal strain was associated with ICCI (β = -0.54, P = 0.02) while controlling for indices of preload, afterload, heart rate, and LV mass under baseline conditions. Ejection fraction and shortening fraction were associated with LV mass and load indices, but not contractility.

Conclusion

Speckle-tracking derived longitudinal strain is associated ICCI in children with normal loading conditions. Longitudinal measures of deformation appear to accurately assess LV contractility in children.