Left ventricular global longitudinal strain and cardiorespiratory fitness in patients with heart failure: Systematic review and meta-analysis

BACKGROUND

There is no definition for strain deformation values in relation to cardiorespiratory fitness (CRF) in different heart failure (HF) phenotypes.

AIM

To identify the relationship between echocardiographic systolic function measurements and CRF in HF patients.

METHODS

Systematic review and meta-analysis following the PRISMA recommendations. Studies reporting echocardiographic assessments of left ventricular global longitudinal strain (LVGLS), left ventricular ejection fraction (LVEF), and direct measurement of peak oxygen uptake (VO2peak) in HF patients with reduced or preserved LVEF (HFrEF, HFpEF) were included. The patients were divided into Weber classes according to VO2peak.

RESULTS

A total of 25 studies involving of 2,136 patients (70.5% with HFpEF) were included. Mean LVEF and LVGLS were similar in HFpEF patients in Weber Class A/B and Class C/D. In HFrEF patients, a non-significant difference was found in LVEF between Weber Class A/B (30.2% [95%CI: 29.6 to 30.9%]) and Class C/D (25.2% [95%CI: 20.5 to 29.9%]). In HFrEF patients, mean LVGLS was significantly lower in Class C/D compared to Class A/B (6.5% [95%CI: 6.0 to 7.1%] and 10.3% [95%CI: 9.0 to 11.5%], respectively). The correlation between VO2peak and LVGLS (r2 = 0.245) was nearly twofold stronger than that between VO2peak and LVEF (r2 = 0.137).

CONCLUSIONS

Low LVGLS values were associated with low CRF in HFrEF patients. Although a weak correlation was found between systolic function at rest and CRF, the correlation between VO2peak and LVGLS was nearly twofold stronger than that with LVEF, indicating that LVGLS may be a better predictor of CRF in patients with HFrEF.

Exercise Intolerance Is Associated with Cardiovascular Dysfunction in Long COVID-19 Syndrome

Background/Objectives: Cardiorespiratory complications are commonly reported among patients with long COVID-19 syndrome. However, their effects on exercise capacity remain inconclusive. We investigated the impact of long COVID-19 on exercise tolerance combining cardiopulmonary exercise testing (CPET) with resting echocardiographic data. Methods: Forty-two patients (55 ± 13 years), 149 ± 92 days post-hospital discharge, and ten healthy age-matched participants underwent resting echocardiography and an incremental CPET to the limit of tolerance. Left ventricular global longitudinal strain (LV-GLS) and the left ventricular ejection fraction (LVEF) were calculated to assess left ventricular systolic function. The E/e' ratio was estimated as a surrogate of left ventricular end-diastolic filling pressures. Tricuspid annular systolic velocity (SRV) was used to assess right ventricular systolic performance. Through tricuspid regurgitation velocity and inferior vena cava diameter, end-respiratory variations in systolic pulmonary artery pressure (PASP) were estimated. Peak work rate (WRpeak) and peak oxygen uptake (VO2peak) were measured via a ramp incremental symptom-limited CPET. Results: Compared to healthy participants, patients had a significantly (p < 0.05) lower LVEF (59 ± 4% versus 49 ± 5%) and greater left ventricular end-diastolic diameter (48 ± 2 versus 54 ± 5 cm). In patients, there was a significant association of E/e' with WRpeak (r = -0.325) and VO2peak (r = -0.341). SRV was significantly associated with WRpeak (r = 0.432) and VO2peak (r = 0.556). LV-GLS and PASP were significantly correlated with VO2peak (r = -0.358 and r = -0.345, respectively). Conclusions: In patients with long COVID-19 syndrome, exercise intolerance is associated with left ventricular diastolic performance, left ventricular end-diastolic pressure, PASP and SRV. These findings highlight the interrelationship of exercise intolerance with left and right ventricular performance in long COVID-19 syndrome.

Peak exercise myocardial deformation indices during cardiopulmonary exercise testing are associated with exercise capacity and ventilatory efficiency in patients with dilated cardiomyopathy

OBJECTIVE

Little is known about the exercise-induced changes in the multidimensional mechanical properties of the heart. We aimed to evaluate the myocardial deformation indices (MDI) at rest and their response at peak exercise during the same cardiopulmonary exercise testing (CPET) session, investigating their relationship to exercise capacity and ventilatory sufficiency in dilated cardiomyopathy (DCM) patients.

METHODS

We evaluated left ventricular (LV) function using speckle tracking imaging (STI) at rest and peak exercise during the same CPET session in 57 idiopathic DCM patients in New York Heart Association (NYHA) I-II class [54 ± 12 years, 42 males, ejection fraction (EF) 33 ± 9%]. We measured global longitudinal strain (GLS), longitudinal strain rate at systole (LSRS) and diastole (LSRD), and circumferential strain rate (CircS).

RESULTS

Resting GLS, LSRS, and LSRD were impaired compared with the predicted values but were improved at peak exercise (p < 0.001). All MDI at rest and/or at peak exercise were related to several CPET-derived parameters, including peak VO₂, load, O₂ pulse, and VE/VCO₂ slope. Peak exercise LSRS > -1.10 sec^-1 (AUC = 0.80, p < 0.001) and GLS > -13% (AUC = 0.81, p = 0.002) predicted impaired exercise capacity (peak VO₂ < 20 ml/min/kg) and ventilatory inefficiency (VE/VCO₂ slope>34). In multiple regression analysis, peak exercise LSRS and GLS were independently related to the peak VO₂ (Beta = -0.39, p = 0.003) and VE/VCO₂ slope (Beta = 0.35, p = 0.02), respectively.

CONCLUSIONS

Peak exercise LSRS and GLS in NYHA I-II DCM patients subjected to CPET were associated with aerobic exercise capacity and ventilatory efficiency. Consequently, LSRS and GLS at peak exercise, through their association with CPET-derived CV risk indices, may underline the severity of heart failure and predict future CV events in this DCM population.

The impact of medical therapy on left ventricular strain: Current state and future perspectives

The speckle tracking strain is becoming a frequently used marker of subclinical left ventricular systolic dysfunction. Despite the wide range of data concerning left ventricular strain variability in the general population and its changes in various pathologic conditions, the information about the impact of medical therapy on left ventricle strain is limited. This article provides an analysis of published studies of left ventricle strain changes in response to different agents and combinations of medical therapies used for hypertension and congestive heart failure.

Echocardiography in Advanced Heart Failure for Diagnosis, Management, and Prognosis

Advanced heart failure, an end-stage disease characterized by high mortality and morbidity despite standard medical therapy, requires various therapeutic strategies like heart transplant and long-term mechanical circulatory support. Echocardiography is the main imaging technique to identify transitions to advanced stages of disease and guide risk stratification and therapeutic decision-making processes. Progressive development of advanced echocardiographic techniques allows more comprehensive assessment of the hemodynamic and structural profiles of patients with advanced heart failure, and its use in clinical practice continues to expand. This article provides an overview of basic and emerging echocardiographic tools to assess patients with advanced heart failure.

Prognostic Value of Right Ventricular 3D Speckle-Tracking Strain and Ejection Fraction in Patients With HFpEF

Background: Right ventricular longitudinal strain of free wall (RV FWLS) assessed by two-dimensional speckle-tracking echocardiography (2D-STE) is recognized as an independent predictor of poor prognosis in patients with heart failure with preserved ejection fraction (HFpEF). However, the prognostic implications of three-dimensional STE (3D-STE) parameters in patients with HFpEF have not been well-established. The purpose of our study was to determine whether 3D-STE parameters were the more powerful predictors of poor outcomes in HFpEF patients compared with 2D-STE indices.

Methods: Eighty-one consecutive patients with HFpEF were studied by 2D-STE and 3D-STE. RV volumes, ejection fraction (EF) and 3D-RVFWLS were measured by 3D-STE. 2D-RVFWLS was determined by 2D-STE. Patients were followed for the primary end point of heart failure (HF)-related hospitalization and death for HF.

Results: After a median follow-up period of 17 months, 39 (48%) patients reached the end point of cardiovascular events. Compared with HFpEF patients without end-point events, those with end-point events had lower RVEF and 3D-RVFWLS (P < 0.05). Separate multivariate Cox regression analyses revealed that 3D-RVFWLS (HR 5.73; 95% CI 2.77–11.85; P < 0.001), RVEF (HR 3.47; 95% CI 1.47–8.21; P = 0.005), and 2D-RVFWLS (HR 3.17; 95% CI 1.54–6.53; P = 0.002) were independent predictors of adverse outcomes. The models with 3D-RVFWLS (AIC = 246, C-index = 0.75) and RVEF (AIC = 247, C-index = 0.76) had similar predictive performance for future clinical events as with 2D-RVFWLS (AIC = 248, C-index = 0.74).

Conclusions: 3D-STE parameters are powerful predictors of poor outcomes, providing a similar predictive value as 2D-STE indices in patients with HFpEF. These findings support the potential of RV 3D-STE to identify HFpEF patients at higher risk for adverse cardiac events.

Traditional and Novel Imaging of Right Ventricular Function in Patients with Heart Failure and Reduced Ejection Fraction

PURPOSE OF REVIEW

This review attempts to summarize the role of standard and advanced echocardiographic techniques together with CMR in the evaluation of the RV in HF, providing an outlook on the recent evidence.

RECENT FINDINGS

In the last decade, there has been growing interest in the study of the RV, and it is now widely established that RV function is a strong predictor of mortality, in several cardiovascular diseases, in particular in the setting of heart failure (HF). The evaluation of RV function might be particularly challenging, which justifies the necessity of multi-modality imaging. The echocardiographic assessment remains the mainstay technique even though it might be complex, due to RV crescent shape and its position in the chest, requiring both qualitative and quantitative parameters. Cardiac magnetic resonance (CMR) represents a complementary exam which is particularly useful when precise structural and functional assessment are needed, considering the most recently developed sequences. Despite the technological improvement attested over the last years, there is still no universally accepted parameter that univocally defines RV function, hence the necessity to evaluate several parameters, combining different imaging techniques.

Left Ventricular Longitudinal Strain as a Marker for Point of No Return in Hypertensive Heart Failure Treatment

BACKGROUND

There are currently no therapies that can improve prognosis in cases of heart failure (HF) with preserved ejection fraction (EF). We hypothesized that there is a point of no return after which no response to treatment is noted and that for the prevention of hypertensive HF this point may be determined by left ventricle (LV) strain, in the prevention of hypertensive HF. Here an angiotensin-converting enzyme inhibitor (ACE-I) was initiated based on myocardial strain imaging and its effects were determined in an animal model.

METHODS

Thirty-two male Dahl salt-sensitive rats, age 6 weeks, were divided into six experimental groups and compared with low-salt (n = 8) and high-salt control groups (n = 8). In the early treatment group, ACE-I was administered from the age of 6 weeks (n = 4); in the longitudinal strain (LS) group, at 10-12 weeks when LS impairment was >-21% (n = 4); in the circumferential strain (CS) group, at 16-18 weeks when CS impairment was >-18% (n = 4); and in the EF group, at 20 weeks when EF was <55% (n = 4). Subsequently, all rats were sacrificed at 23 weeks age, the LV and lung weight were measured, and pathologic analyses were performed.

RESULTS

At 23 weeks of age, the lung and LV weights increased in the high-salt control, EF, and CS groups, whereas the lung and LV weights in the LS and early groups were similar to those in the low-salt control group. The percentage of area of subendocardial fibrosis was >6% in the high-salt control, EF, and CS groups and <3% in the LS, early, and low-salt groups. Serial echocardiography demonstrated LS improvement in the LS group; however, the CS and EF groups showed no differences.

CONCLUSIONS

Heart failure-related lung congestion was prevented when ACE-I was administered soon after LS impairment, accompanied by suppression of cardiac hypertrophy and fibrosis, thereby suggesting that the point of no return of myocardial remodeling due to hypertension was present after LS but before CS impairment.

Myocardial strain may predict exercise tolerance in patients with reduced and mid-range ejection fraction

BACKGROUND

Conventional echocardiographic parameters, such as rest ejection fraction, perform poorly in the prediction of exercise tolerance in heart failure. The aim of the present study was to evaluate the contribution of hemodynamic instability in the observed lower functional capacity and investigate the role of left ventricular strain for the prediction of stress test duration in obese hypertensive patients with reduced ejection fraction.

METHODS

Sixty-one patients with reduced ejection fraction underwent treadmill exercise echocardiography. Systolic and diastolic echocardiographic parameters were recorded. Moreover, the presence of hemodynamic instability was assessed through N-terminal pro B-type natriuretic peptide (NT-proBNP) measurements at baseline and peak exercise.

RESULTS

Rest and peak NT-proBNP levels, and their difference, were significantly correlated with mean global strain at peak, which was the only parameter associated with changes in NT-proBNP levels. Rest and peak mean global strain were found to be predictive for the duration of treadmill stress test. In particular, mean global strain, but not left ventricular ejection fraction, was independently correlated with exercise ability.

CONCLUSIONS

Stress echocardiography may provide important information regarding exercise tolerance in obese hypertensive patients with reduced ejection fraction, mainly through the evaluation of left ventricular strain. The obtained evidence may also have prognostic value, particularly in the early stages of the syndrome.

Prognostic Utility of Right Ventricular Free Wall Strain in Low Risk Patients After Orthotopic Heart Transplantation

Global longitudinal strain (GLS) by speckle-tracking echocardiography is a sensitive measure of regional left and right ventricular (LV and RV) dysfunction, before onset of overt systolic dysfunction. We sought to evaluate the prognostic utility of measuring LV-GLS and RV free wall strain (FWS) in low risk patients at 1 year after orthotopic heart transplantation (OHT). We retrospectively studied 96 OHT recipients (age 52 ± 14 years, 64% men) free of antibody-mediated rejection or moderate to severe coronary allograft vasculopathy (CAV, grade 2 to 3) at 1 year after transplant. LV-GLS and RV-FWS were calculated using EchoPAC software. Cox models were developed after adjusting for the Index for Mortality Prediction After Cardiac Transplantation (IMPACT) score (post-transplant risk score), with the primary outcome of death, moderate to severe CAV, or treated rejection. At 1 year after transplant, LV ejection fraction and RV fractional area change (FAC) were 58 ± 7% and 42 ± 10%, respectively. LV-GLS was -17.0 ± 3.3% and RV-FWS -16.4 ± 4.5%. At an average follow-up of 4.5 years, 28 patients met the primary end point (10 death, 5 vasculopathy, 17 rejection). In sequential Cox models, markers of RV function were associated with the primary outcome (RV-FAC, p = 0.012; RV-FWS, p = 0.022), while LV ejection fraction and LV-GLS were not. We conclude that in low risk patients 1 year after OHT, markers of RV function (RV-FAC and RV-FWS) are independently associated with incident rejection, CAV, and death. Markers of RV dysfunction could potentially be incorporated into risk scores and future prospective studies to risk stratify patients after OHT.

Right Ventricular Ejection Fraction Is Incremental to Left Ventricular Ejection Fraction for the Prediction of Future Arrhythmic Events in Patients With Systolic Dysfunction

Background—

Left ventricular ejection fraction remains the primary risk stratification tool used in the selection of patients for implantable cardioverter defibrillator therapy. However, this solitary marker fails to identify a substantial portion of patients experiencing sudden cardiac arrest. In this study, we examined the incremental value of considering right ventricular ejection fraction for the prediction of future arrhythmic events in patients with systolic dysfunction using the gold standard of cardiovascular magnetic resonance.

Methods and Results—

Three hundred fourteen consecutive patients with ischemic cardiomyopathy or nonischemic dilated cardiomyopathy undergoing cardiovascular magnetic resonance were followed for the primary outcome of sudden cardiac arrest or appropriate implantable cardioverter defibrillator therapy. Blinded quantification of left ventricular and right ventricular (RV) volumes was performed from standard cine imaging. Quantification of fibrosis from late gadolinium enhancement imaging was incrementally performed. RV dysfunction was defined as right ventricular ejection fraction ≤45%. Among all patients (164 ischemic cardiomyopathy, 150 nonischemic dilated cardiomyopathy), the mean left ventricular ejection fraction was 32±12% (range, 6–54%) with mean right ventricular ejection fraction of 48±15% (range, 7–78%). At a median of 773 days, 49 patients (15.6%) experienced the primary outcome (9 sudden cardiac arrest, 40 appropriate implantable cardioverter defibrillator therapies). RV dysfunction was independently predictive of the primary outcome (hazard ratio=2.98; P =0.002). Among those with a left ventricular ejection fraction >35% (N=121; mean left ventricular ejection fraction, 45±6%), RV dysfunction provided an adjusted hazard ratio of 4.2 ( P =0.02).

Conclusions—

RV dysfunction is a strong, independent predictor of arrhythmic events. Among patients with mild to moderate LV dysfunction, a cohort greatly contributing to global sudden cardiac arrest burden, this marker provides robust discrimination of high- versus low-risk subjects.

Difference in the Prognostic Impact of Left Ventricular Global Longitudinal Strain between Anterior and Nonanterior Myocardial Infarction

BACKGROUND

Speckle tracking-derived global longitudinal strain (GLS) of left ventricle is a potent prognostic marker for patients with ST-segment elevation myocardial infarction (STEMI). The purpose of this study was to investigate the difference of prognostic impact of GLS between anterior and nonanterior myocardial infarction.

METHODS

This study included 686 patients who underwent primary percutaneous coronary intervention for their first STEMI between November 2007 and April 2012. Differences in the prognostic impact of GLS between anterior MI group and nonanterior MI group were evaluated. The composite of all-cause mortality and hospitalization for heart failure in 2 years was investigated for outcome.

RESULTS

During the follow-up period, 77 (11.2%) adverse events occurred. The anterior and nonanterior MI groups included 339 and 347 patients, respectively. Among patients with anterior MI, GLS significantly predicted 2-year outcome in an adjusted model (adjusted hazard ratio [HR] 1.186; 95% confidence interval [CI] 1.071-1.314, P = 0.001), whereas the association between GLS and mortality was weaker in the nonanterior MI group (adjusted HR 0.977; 95% CI 0.884-1.081, P = 0.657). The interaction between the infarction territory and GLS was significant (P for interaction = 0.018), indicating that GLS was a more sensitive predictor of mortality in patients with anterior MI than that in those with nonanterior MI.

CONCLUSIONS

Speckle tracking-derived GLS of left ventricle more sensitively predicted clinical outcome in patients with anterior MI than in those with nonanterior MI.

Longitudinal strain of systemic right ventricle correlates with exercise capacity in adult with transposition of the great arteries after atrial switch

BACKGROUND

Systemic right ventricle (sRV) dysfunction in d-transposition of the great arteries following atrial switch (d-TGA) is associated with increased mortality. We aimed to characterize maladaptive sRV mechanisms in d-TGA patients, analyzing relation of echocardiographic parameters of sRV systolic function to objective measurements of exercise capacity.

METHODS

Forty-seven adult patients with d-TGA and atrial switch (mean age 31.6±4.2years) underwent conventional echocardiography, bidimensional strain (2D-strain), cardiac magnetic resonance (CMR) imaging and cardiopulmonary exercise evaluation on the same day. Those with median peak oxygen uptake (VO2)>64.5% (n=23) constituted group A, those with VO2≤64.5% (n=24) constituted group B and 23 healthy age and gender matched subjects constituted the control group.

RESULTS

In group A, global longitudinal peak systolic 2D-strain (GLS) of sRV was significantly reduced compared to GLS of normal RV and LV in the healthy control group (p<0.01), however peak longitudinal 2D strain was similar at basal and mid-segment of sRV free wall than normal LV. In group B, GLS was significantly reduced compared to group A (-10.9±2.9% vs -13.1±2.3%, p<0.05), mostly due to significant decrease of interventricular septum longitudinal strain. Other echocardiographic systolic parameters were not significantly different between groups A and B. Only sRV GLS showed significant correlation with functional capacity as measured by VO2 (r=0.42, p<0.01), while CMR RVEF did not.

CONCLUSION

GLS of sRV predicts functional capacity and may be more sensitive than CMR RVEF in detecting early myocardial damage of sRV in patients with d-TGA and atrial switch.

Reversibility of left ventricular mechanical dysfunction in patients with hypertensive heart disease

OBJECTIVE

Prior studies indicate that hypertension is associated with mechanical systolic dysfunction, even in the presence of a normal ejection fraction, but whether this cardiac dysfunction may be ameliorated by antihypertensive treatment is unknown.

METHODS

To test the hypothesis that mechanical systolic dysfunction in hypertension may respond to blood pressure-lowering therapy, we studied 182 patients with uncontrolled hypertension who underwent a 24-week trial of intensive versus standard antihypertensive therapy (titrated to a goal SBP <130 versus <140 mmHg) and had both baseline and follow-up echocardiography. We examined changes in left ventricular systolic function, reflected by systolic global longitudinal strain (GLS), in the entire cohort and in the subset of patients with systolic dysfunction at baseline (defined as GLS >-15%).

RESULTS

Despite all patients having a preserved left ventricular ejection fraction (≥50%), almost a third (32%) had mechanical systolic dysfunction at baseline. In the total sample, GLS significantly improved in response to antihypertensive therapy (-16.8 ± 3.8 to -18.7 ± 3.4%; P < 0.0001), and this improvement was especially evident in patients with baseline dysfunction (13.1 ± 2.2 to -17.0 ± 2.9%; P < 0.0001). Improvement in GLS was associated with lower BMI (P = 0.015) and was greater in women than in men (P = 0.003). Although uncorrelated with blood pressure change, GLS improvement was related to having received high doses of antihypertensive therapy during the study (P = 0.040).

CONCLUSION

In patients with hypertensive heart disease and normal left ventricular ejection fraction, abnormalities in left ventricular mechanical systolic function can be ameliorated in the setting of targeted antihypertensive treatment.

Evaluation of Left Ventricular Diastolic Dysfunction with Early Systolic Dysfunction Using Two-Dimensional Speckle Tracking Echocardiography in Canine Heart Failure Model

BACKGROUND

This study evaluated the role of two-dimensional speckle tracking echocardiography (2DSTE) for predicting left ventricular (LV) diastolic dysfunction in pacing-induced canine heart failure.

METHODS

Pacing systems were implanted in 8 adult mongrel dogs, and continuous rapid right ventricular pacing (RVP, 240 beats/min) was maintained for 2 weeks. The obtained measurements from 2DSTE included global strain rate during early diastole (SRe) and during late diastole (SRa) in the longitudinal (L-SRe, L-SRa), circumferential (C-SRe, C-SRa), and radial directions (R-SRe, R-SRa). Changes in heart morphology were observed by light microscopy and transmission electron microscopy at 2 weeks.

RESULTS

The onset of LV diastolic dysfunction with early systolic dysfunction occurred 3 days after RVP initiation. Most of the strain rate imaging indices were altered at 1 or 3 days after RVP onset and continued to worsen until heart failure developed. Light and transmission electron microscopy showed myocardial vacuolar degeneration and mitochondrial swelling in the left ventricular at 2 weeks after RVP onset. Pearson's correlation analysis revealed that parameters of conventional echocardiography and 2DSTE showed moderate correlation with LV pressure parameters, including E/Esep' (r = 0.58, P < 0.01), L-SRe (r = -0.58, P < 0.01), E/L-SRe (r = 0.65, P < 0.01), and R-SRe (r = 0.53, P < 0.01). ROC curves analysis showed that these indices of conventional echocardiography and strain rate imaging could effectively predict LV diastolic dysfunction (area under the curve: E/Esep' 0.78; L-SRe 0.84; E/L-SRe 0.80; R-SRe 0.80).

CONCLUSION

2DSTE was a sensitive and accurate technique that could be used for predicting LV diastolic dysfunction in canine heart failure model.

Prognostic importance of tissue velocity imaging during exercise echocardiography in patients with systolic heart failure

Resting echocardiography measurements are poor predictors of exercise capacity and symptoms in patients with heart failure (HF). Stress echocardiography may provide additional information and can be expressed using left ventricular ejection fraction (LVEF), or diastolic parameters (E/E'), but LVEF has some major limitations. Systolic annular velocity (S') provides a measure of longitudinal systolic function, which is relatively easy to obtain and shows a good relationship with exercise capacity. The objective of this study was to investigate the relationship among S', E/E' and LVEF obtained during stress echocardiography and both mortality and hospitalisation. A secondary objective was to compare S' measured using a simplified two-wall model. A total of 80 patients with stable HF underwent exercise stress echocardiography and simultaneous cardiopulmonary exercise testing. Volumetric and tissue velocity imaging (TVI) measurements were obtained, as was peak oxygen uptake (VO2 peak). Of the total number of patients, 11 died and 22 required cardiac hospitalisation. S' at peak exertion was a powerful predictor for death and hospitalisation. Cut-off points of 5.3 cm/s for death and 5.7 cm/s for hospitalisation provided optimum sensitivity and specificity. This study suggests that, in patients with systolic HF, S' at peak exertion calculated from the averaged spectral TVI systolic velocity of six myocardial segments, or using a simplified measure of two myocardial segments, is a powerful predictor of future events and stronger than LVEF, diastolic velocities at rest or exercise and VO2 peak. Results indicate that measuring S' during exercise echocardiography might play an important role in understanding the likelihood of adverse clinical outcomes in patients with HF.

Left ventricular global longitudinal strain is associated with exercise capacity in failing hearts with preserved and reduced ejection fraction

Aims

Heart failure patients with reduced and preserved left ventricular (LV) ejection fraction (EF) show reduced exercise capacity. We explored the relationship between exercise capacity and systolic and diastolic myocardial function in heart failure patients.

Methods and results

Exercise capacity, by peak oxygen uptake (VO₂), was assessed in 100 patients (56 ± 12 years, NYHA functional class: 2.5 ± 0.9, EF: 42 ± 19%). LV systolic function, as EF and global longitudinal strain (GLS), and right ventricular function were assessed by echocardiography. Left atrial volume index and the ratio of peak early diastolic filling velocity (E) to early diastolic mitral annular velocity (e′) were measures of diastolic function. Thirty-seven patients had heart failure with preserved EF (HFpEF), defined as EF ≥50% and echocardiographic diastolic dysfunction. LV GLS and peak pulmonary arterial systolic pressure were independently correlated to peak VO₂ in the total study population and in HFpEF separately. LV GLS was superior to EF in identifying patients with impaired peak VO₂ <20 mL/kg/min as shown by receiver operating characteristic analyses [areas under curves 0.93 (0.89–0.98) vs. 0.85 (0.77–0.93), P < 0.05]. In patients with HFpEF, GLS was reduced below normal (−17.5 ± 3.2%) and correlated to E/e′ (R = 0.45, P = 0.005) and left atrial volume index (R = 0.48, P = 0.003), while EF did not.

Conclusion

GLS correlated independently to peak VO₂ in patients with reduced and preserved EF and was superior in identifying patients with reduced exercise capacity. In HFpEF, systolic function by GLS was impaired. There was a significant relationship between diastolic function and GLS, confirming a coupling between diastolic and longitudinal systolic function in HFpEF.

Cardiac mechanics and ventricular twist by three-dimensional strain analysis in relation to B-type natriuretic peptide as a clinical prognosticator for heart failure patients

Background

Three dimensional (3D) echocardiography-derived measurements of myocardial deformation and twist have recently advanced as novel clinical tools. However, with the exception of left ventricular ejection fraction and mass quantifications in hypertension and heart failure populations, the prognostic value of such imaging techniques remains largely unexplored.

Methods

We studied 200 subjects (mean age: 60.2±16 years, 54% female, female n = 107) with known hypertension (n = 51), diastolic heart failure (n = 61), or systolic heart failure (n = 30), recruited from heart failure outpatient clinics. Fifty-eight healthy volunteers were used as a control group. All participants underwent 3D-based myocardial deformation and twist analysis (Artida, Toshiba Medical Systems, Tokyo, Japan). We further investigated associations between these measures and brain natriuretic peptide levels and clinical outcomes.

Results

The global 3D strain measurements of the healthy, hypertension, diastolic heart failure, and systolic heart failure groups were 28.03%, 24.43%, 19.70%, and 11.95%, respectively (all p<0.001). Global twist measurements were estimated to be 9.49°, 9.77°, 8.32°, and 4.56°, respectively. We observed significant differences regarding 3D-derived longitudinal, radial, and global 3D strains between the different disease categories (p<0.05), even when age, gender, BMI and heart rate were matched. In addition, 3D-derived longitudinal, circumferential, and 3D strains were all highly correlated with brain natriuretic peptide levels (p<0.001). At a mean 567.7 days follow-up (25^th–75^th IQR: 197–909 days), poorer 3D-derived longitudinal, radial, and global 3D strain measurements remained independently associated with a higher risk of cardiovascular related death or hospitalization due to heart failure, after adjusting for age, gender, and left ventricular ejection fraction (all p<0.05).

Conclusions

3D-based strain analysis may be a feasible and useful diagnostic tool for discriminating the extent of myocardial dysfunction. Furthermore, it is able to provide a prognostic value beyond traditional echocardiographic parameters in terms of ejection fraction.

Autonomic dysfunction predicts poor physical improvement after cardiac rehabilitation in patients with heart failure

Background:

Cardiac autonomic dysfunction, clinically expressed by reduced heart rate variability (HRV), is present in patients with congestive heart failure (CHF) and is related to the degree of left ventricular dysfunction. In athletes, HRV is an indicator of ability to improve performance. No similar data are available for CHF.

Objectives:

The aim of this study was to assess whether HRV could predict the capability of CHF patients to improve physical fitness after a short period of exercise-based cardiac rehabilitation (CR).

Patients and Methods:

This was an observational, non-randomized study, conducted on 57 patients with advanced CHF, admitted to a residential cardiac rehabilitation unit 32 ± 22 days after an episode of acute heart failure. Inclusion criteria were sinus rhythm, stable clinical conditions, no diabetes and ejection fraction ≤ 35%. HRV (time-domain) and mean and minimum heart rate (HR) were evaluated using 24-h Holter at admission. Patients’ physical fitness was evaluated at admission by 6-minute walking test (6MWT) and reassessed after two weeks of intensive exercise-based CR. Exercise capacity was evaluated by a symptom-limited cardiopulmonary exercise test (CPET).

Results:

Patients with very depressed HRV (SDNN 55.8 ± 10.0 ms) had no improvement in their walking capacity after short CR, walked shorter absolute distances at final 6MWT (348 ± 118 vs. 470 ± 109 m; P = 0.027) and developed a peak-VO₂ at CPET significantly lower than patients with greater HRV parameters (11.4 ± 3.7 vs. an average > 16 ± 4 mL/kg/min). Minimum HR, but not mean HR, showed a negative correlation (ρ = -0.319) with CPET performance.

Conclusions:

In patients with advanced CHF, depressed HRV and higher minimum HR were predictors of poor working capacity after a short period of exercise-based CR. An individualized and intensive rehabilitative intervention should be considered for these patients.

Global longitudinal strain as a potential prognostic marker in patients with chronic heart failure and systolic dysfunction

INTRODUCTION AND OBJECTIVE

The prognostic value of myocardium deformation measurements in chronic heart failure (CHF) is still poorly addressed. The purpose of this study was to evaluate the correlation of left ventricular (LV) global longitudinal strain (GLS) with clinical and prognostic indicators in patients with CHF and systolic dysfunction.

METHODS

Ambulatory patients with CHF and LV ejection fraction (LVEF) <45% were studied by two-dimensional and Doppler transthoracic echocardiogram with assessment of GLS. An indication of prognostic status was obtained by the Seattle Heart Failure Model (SHFM) prognostic estimates for life expectancy.

RESULTS

We included 54 CHF patients (mean age 55±12 years; 80% male). GLS was significantly correlated with NYHA functional class (r=0.41, p=0.002), BNP levels (r=0.47, p=0.001), LVEF (r=-0.69, p<0.001) and LV end-diastolic pressure, assessed by E/e' ratio (r=0.35, p<0.014) and left atrial maximal volume index (r=0.57, p<0.001). A significant correlation was found between GLS and SHFM prognostic estimates for life expectancy (r=-0.41, p=0.002). The multivariate logistic regression analysis showed that GLS independently predicted an estimated life expectancy <10 years (OR 2.614 [95% CI 1.010-6.763]). The corresponding area under the ROC curve was 0.802 (0.653-0.951) and the best obtained threshold was -9.5 (80% sensitivity, 65% specificity, p=0.003).

CONCLUSIONS

GLS was strongly associated with a higher disease severity status and predicted a lower prognostic estimate for life expectancy.

Tissue motion annular displacement of the mitral valve using two-dimensional speckle tracking echocardiography predicts the left ventricular ejection fraction in normal children

BACKGROUND

The gold standard for determining the left ventricular ejection fraction is cardiac magnetic resonance imaging. Other parameters for determining the ejection fraction such as M-mode echocardiography are operator-dependant and often inaccurate. Assessment of the displacement of the mitral valve annulus using two-dimensional speckle tracking echocardiography may provide an accurate and simple method of determining the left ventricular ejection fraction in children.

METHOD

We retrospectively studied 70 healthy 9-year-old children with no history of cardiovascular disease who had been assessed using cardiac magnetic resonance imaging and two-dimensional transthoracic echocardiography. Mitral displacement was determined using the tissue motion annular displacement (TMAD) feature of Philips QLAB version 9. The midpoint displacement of the mitral valve was calculated, and the predicted left ventricular ejection fraction was compared with magnetic resonance imaging-derived and M-mode-derived ejection fractions.

RESULTS

The mean ejection fraction derived from magnetic resonance imaging (64.5 (4.6)) was similar to that derived from the TMAD midpoint (60.9 (2.7), p = 0.001) and the M-mode (61.9 (7), p = 0.012). The TMAD midpoint correlated strongly with the magnetic resonance imaging-derived ejection fraction (r = 0.69, p < 0.001), as did the predicted fraction (r = 0.67, p < 0.001). The M-mode ejection fraction showed a poor linear correlation with both magnetic resonance imaging-derived and TMAD-derived fractions (r = 0.33 and 0.04, respectively).

CONCLUSION

TMAD of the mitral valve is a simple, effective, and highly reproducible method of assessing the ejection fraction in normal children. It shows a strong linear correlation with magnetic resonance imaging-derived ejection fraction and is superior to M-mode-derived ejection fractions.

Right ventricular global longitudinal strain provides prognostic value incremental to left ventricular ejection fraction in patients with heart failure

BACKGROUND

Right ventricular (RV) global longitudinal strain (RV strain) is a sensitive measure of RV mechanics. Its relationship with standard clinical markers and long-term events in chronic systolic heart failure is not well established. The aim of this study was to examine the ability of RV strain to provide incremental prognostic value to left ventricular (LV) ejection fraction (LVEF) in patients with chronic systolic heart failure.

METHODS

In 171 patients with chronic systolic heart failure (LVEF ≤ 35%), a retrospective substudy of RV strain was performed using Velocity Vector Imaging to analyze previously recorded, comprehensive echocardiographic images. Death, cardiac transplantation, and heart failure hospitalization were tracked for 5 years.

RESULTS

In this study cohort (mean age, 57 ± 14 years; mean LVEF, 25 ± 6%), mean RV strain was -11.6 ± 5.4%. More impaired RV strain was associated with increasing New York Heart Association class (rank-sums P < .0001) and greater LV volume (LV end-systolic volume index: r = 0.35, P < .0001). Worse RV strain was associated with reduced LVEF (r = -0.45, P < .0001), worse LV diastolic dysfunction (E/e' septal: r = 0.19, P = .017; left atrial volume index: r = 0.18, P = .031), and standard indices of RV systolic and diastolic dysfunction (RV s': r = -0.43, P < .0001; RV e'/a': r = 0.16, P = .0040; right atrial volume index: r = 0.20, P = .015). RV strain predicted long-term adverse events (hazard ratio, 1.30; 95% confidence interval, 1.02-1.70; P = .037). Furthermore, RV strain ≥ -14.8% predicted adverse events after adjustment for age, LVEF, RV s', E/e' septal, and right atrial volume index.

CONCLUSION

In patients with chronic systolic heart failure, worse RV strain provides prognostic value incremental to LV function.

Left Ventricular Strain and Transmural Distribution of Structural Remodeling in Hypertensive Heart Disease

Left ventricular (LV) systolic wall strain is a new candidate for prognostic indicator of hypertensive heart failure. It remains unclear how underlying transmural structural remodeling corresponds to LV wall systolic deformation as hypertensive hypertrophy progresses. We fed 68 Dahl salt–sensitive rats a high-salt (hypertensive group) or low-salt diet (control group) from 6 weeks old. At 10, 14, and 18 weeks, pressure–volume relation, transmural distribution of LV fibrosis, and myocyte hypertrophy were evaluated. LV global longitudinal and circumferential strain was measured with speckle tracking echocardiography. Emax was preserved throughout the study period, whereas τ and end-diastolic pressure–volume relation progressively deteriorated from 14 weeks (diastolic dysfunction stage). Lung weight increased significantly at 18 weeks (decompensated stage). Histological percentage area fibrosis and collagen type I/III, myocyte hypertrophy, and α-myosin heavy chain isoform increased in the subendocardial layer at 14 weeks and progressed into the midlayer at 18 weeks. Longitudinal strain progressively deteriorated in the hypertensive group versus control group at 14 weeks (hypertensive group: −17±3%, control: −27±4%; P <0.001), and circumferential strain decreased at 18 weeks (hypertensive group: −17±2%, control: −27±3%; P =0.002). After adjustment for systolic wall stress, subendocardial percentage area fibrosis was selected as the independent determinant of longitudinal strain. This study showed that LV wall strain alternations were accompanied by fibrosis and myocyte hypertrophy from subendocardium to epicardium, and longitudinal strain related significantly to subendocardial layer fibrosis. Longitudinal strain could be a surrogate of subendocardial fibrotic changes and may be useful for risk stratification of hypertensive heart failure.

Left ventricular global systolic longitudinal deformation and prognosis 1 year after femoral and apical transcatheter aortic valve implantation

BACKGROUND

Aortic valve replacement is the recommended therapy for patients with severe aortic stenosis who have symptoms or decreased left ventricular (LV) function. Transcatheter aortic valve implantation (TAVI) is a treatment alternative in surgically high-risk or inoperable patients with severe aortic stenosis. The objective of this study was to analyze LV function assessed by global LV longitudinal systolic strain (GLS) and relation to prognosis in patients with severe aortic stenosis treated with femoral or apical TAVI.

METHODS

Two-dimensional echocardiography was performed before and 1 year after TAVI. Ejection fraction (EF) was retrospectively measured using the biplane Simpson's method, and GLS was obtained as an average of 16 segments in the three standard apical views by speckle-tracking. GE Vivid 7 and Vivid 9 machines were used for echocardiography, and speckle-tracking analysis was performed using EchoPAC PC '08 version 7.0.1.

RESULTS

The total population consisted of 100 TAVI patients. Eighty-one patients survived to 1-year follow-up, with a mean age of 81 ± 7 years (range, 64-93 years) and a mean European System for Cardiac Operative Risk Evaluation score of 9.6 ± 2.7. Nineteen patients died before 1-year follow-up (12 women), with a mean age of 82 ± 7 years (range, 66-92 years) and a mean European System for Cardiac Operative Risk Evaluation score of 10.5 ± 2.8. No differences were found between the 19 patients who died before follow-up and the 81 patients who survived to 1-year follow-up. GLS was increased significantly 1 year after TAVI. In 34 patients with EFs > 50%, GLS increased from -15.3 ± 3.4 to -17.1 ± 3.6 (P = .04). In these patients, the mean EF increased numerically from 57.9 ± 5.3% to 60 ± 7.7% (P = .19). In 74 patients with EFs ≤ 50%, mean GLS and EF improved significantly from -10 ± 2.8 to -13.8 ± 3.8 (P < .0001) and 39 ± 9.4% to 52 ± 12.5% (P < .0001), respectively. The 1-year gain in EF was the same after femoral TAVI (9.7 ± 10.1%) and after apical TAVI (8 ± 10.8%) (P = .52). Furthermore, GLS did not differ significantly after femoral and apical TAVI (-3.8 ± 3.3 and -2.6 ± 3.7, respectively, P = .21). There was no difference in causes of death according to approach. In the total population (n = 100), 35 deaths occurred, 19 before 1-year follow-up and 16 afterward. The median follow-up time was 30 months. Twenty-five patients (71%) died from cardiac causes. Overall 1-year mortality was 19%, and overall 2-year mortality was 28%. In the patients who died, the median survival time in the apical group was 28.5 ± 15.4 months, compared with 31.6 ± 19 months in the femoral group (P = .47). There was no impact on prognosis according to high (≥47.5%) versus low (<47.5%) baseline EF or high (≥11.95%) versus low (<11.95%) baseline GLS. However, the magnitude of changes in GLS seemed to have a prognostic impact.

CONCLUSIONS

LV EF and longitudinal systolic deformation were improved in TAVI independent of technical approach using the Edwards SAPIEN valve prosthesis during 1-year follow-up. The mortality rate was comparable between technical approaches and independent of baseline LV function. However, patients with the greatest improvement in LV systolic longitudinal deformation after TAVI had a lower mortality rate.

Longitudinal strain impairment as a marker of the progression of heart failure with preserved ejection fraction in a rat model

BACKGROUND

Recent advances in very high frame rate use of ultrasonography have enabled the application of two-dimensional speckle-tracking echocardiography (STE) to small animal cardiac functional assessments. In this study, two-dimensional STE was applied to a rat model of hypertensive heart failure with preserved ejection fraction to clarify consequences of left ventricular (LV) wall deformation in the progression of heart failure with preserved ejection fraction.

METHODS

STE was performed every 2 weeks in Dahl salt-sensitive rats fed a 0.3% (control group) or 8% (hypertension [HT] group) sodium chloride diet from 6 to 14 weeks of age. Longitudinal, radial, and circumferential global strain and strain rate were measured, and the time courses of these parameters were observed.

RESULTS

Deterioration of longitudinal strain occurred in the early phase of the progression of LV hypertrophy and continued to worsen until congestive heart failure developed (longitudinal strain in the HT group: 25 ± 3% at 10 weeks, 21 ± 4% at 12 weeks, and 18 ± 2% at 14 weeks; longitudinal strain in controls was preserved during the experimental period). At 12 weeks, radial strain (HT group, 35 ± 7%; controls, 41 ± 10%) had deteriorated at the late stage of manifest diastolic dysfunction. Throughout the experiments, circumferential strain was preserved (HT group, 35 ± 6%; control group, 35 ± 5%), and no significant increase in short-axis function was observed.

CONCLUSIONS

STE is applicable to the small animal heart and detected LV wall long-axis dysfunction preceding short-axis dysfunction or overt congestive heart failure in the progression of hypertensive LV hypertrophy in a rat model.

Early diastolic function during exertion influences exercise intolerance in patients with hypertrophic cardiomyopathy

BACKGROUND

Hypertrophic cardiomyopathy (HCM) patients with preserved left ventricular ejection fraction (LVEF) often develop dyspnea and exercise intolerance. Diastolic dysfunction may contribute to exercise intolerance in these patients. This study aimed to clarify our hypothesis as to whether diastolic function rather than systolic function would be associated with exercise intolerance in HCM using two-dimensional (2D) speckle tracking echocardiography during exercise.

METHODS

Thirty-three HCM patients (mean age 59.3 ± 15.7 years) underwent 2D speckle tracking echocardiography at rest and during submaximal semi-supine bicycle exercise. Global longitudinal strain (LS), LS rate during systole (LSRs), early diastole (LSRe), and late diastole (LSRa) were measured. The symptom-limited cardiopulmonary exercise testing was performed using a cycle ergometer for measuring the peak oxygen consumption (peak [Formula: see text]).

RESULTS

In the multivariate linear regression analysis, peak [Formula: see text] did not associate with strain or strain rate at rest. However, peak [Formula: see text] correlated with LS (β = -0.403, p = 0.007), LSRe (β = 6.041, p = 0.001), and LSRa (β = 5.117, p = 0.021) during exercise after adjustment for age, gender, and heart rate. The first quartile peak [Formula: see text] (14.2 mL/min/kg) was assessed to predict exercise intolerance. The C-statistic of delta LSRe was 0.74, which was relatively greater than that of delta LS (0.70) and delta LSRa (0.58), indicating that early diastolic function rather than systolic and late diastolic function affects exercise intolerance.

CONCLUSIONS

LSRe during exercise is closely associated with the peak [Formula: see text]. Early diastolic function during exercise is an important determinant of exercise capacity in patients with HCM.