Electrocardiographic correlates of mechanical dyssynchrony in recipients of cardiac resynchronization therapy devices

SummaryBackgroundThe relationship between electrical and mechanical indices of cardiac dyssynchronization in systolic heart failure (HF) remains poorly understood.ObjectivesWe examined retrospectively this relationship by using the daily practice tools in cardiology in recipients of cardiac resynchronization therapy (CRT) systems.MethodsWe studied 119 consecutive patients in sinus rhythm and QRS≥120ms (mean: 160±17ms) undergoing CRT device implantation. P wave duration, PR, ePR (end of P wave to QRS onset), QT, RR–QT, JT and QRS axis and morphology were putative predictors of atrioventricular (diastolic filling time [DFT]/RR), interventricular mechanical dyssynchrony (IVMD) and left intraventricular mechanical dyssynchrony (left ventricular pre-ejection interval [PEI] and other measures) assessed by transthoracic echocardiography (TTE). Correlations between TTE and electrocardiographic measurements were examined by linear regression.ResultsStatistically significant but relatively weak correlations were found between heart rate (r=−0.5), JT (r=0.3), QT (r=0.3), RR–QT intervals (r=0.5) and DFT/RR, though not with PR and QRS intervals. Weak correlations were found between: (a) QRS (r=0.3) and QT interval (r=0.3) and (b) IVMD>40ms; and between (a) ePR (r=−0.2), QRS (r=0.4), QT interval (r=0.3) and (b) LVPEI, though not with other indices of intraventricular dyssynchrony.ConclusionsThe correlations between electrical and the evaluated mechanical indices of cardiac dyssynchrony were generally weak in heart failure candidates for CRT. These data may help to explain the discordance between electrocardiographic and echocardiographic criteria of ventricular dyssynchrony in predicting the effect of CRT

Reply to the Editor—LA function is not the only key for best selection of candidates for cardiac resynchronization therapy, but LA strain provides valuable information!

International audienceTo the Editor: We thank Margulescu et al for their letter. It provides us with a unique opportunity to emphasize a few points that are extremely important to keep in mind about estimation of left atrial (LA) performance in cardiac resynchronization therapy (CRT) candidates. First, the main result of our study is that “LA peak systolic strain rate might be useful in predicting response to CRT.” This is not surprising if we consider that (1) previous studies have shown that LA volumes and function can be influenced by CRT; (2) superresponders to CRT have greater improvement in LA function1, 2, 3 and 4; and (3) increasing relevance has been given to LA function in overall heart physiology.1, 2, 3 and 4 Second, Margulescu et al state that “concerns have been raised that LA deformation indices cannot discriminate intrinsic LA function from the influence of LV function.” We agree that, as for many other echocardiographic parameters, LA strain is influenced by preload and afterload, and is impacted by left ventricular (LV) function, particularly by LV descent during systole.5 However, we need to emphasize that it is impossible to perfectly assess the function of an isolated cardiac cavity using current in vivo imaging techniques. Many studies have shown that LA strain is a rapid and highly reproducible method for estimating LA function. 6 Moreover, impaired LA strain is associated with a greater degree of LA fibrosis and with poor prognosis in the general population and in patients with mitral disease, which supports a potentially wider use of LA strain in clinical practice. 7, 8 and 9 Third, Margulescu et al observe that the “predictive value of LA SR for CRT response was modest and similar to other echocardiographic indices that have not been found useful, and is not recommended in current guidelines for selecting CRT candidates.” However, the goal of the present study was to explore a hypothesis and not to change current guidelines.10 With respect to our results, authors and readers should acknowledge that it is always difficult to demonstrate that an imaging technique can impact patient prognosis, even when large perspective studies have been specifically designed to prove it.11 and 12 Further studies are needed to support the role of LA strain in predicting CRT response, but exploration of LA function in this field is full of promise

Value of left atrial strain: a highly promising field of investigation

International audienceThe principal role of the left atrium (LA) is to modulate left ventricular filling and cardiovascular performance by functioning as (i) a reservoir for pulmonary venous return during ventricular systole, (ii) a conduit for pulmonary venous return during early ventricular diastole, and (iii) a booster pump that augments ventricular filling during late ventricular diastole. The interplay between these atrial functions and ventricular performance throughout the cardiac cycle is crucial in many pathophysiological conditions.1,2 However, in clinical practice, we do not really assess all of the components of LA function. In fact, quantification of LA function remains challenging. Calculating ejection fraction or atrial ejection force has occasionally been proposed as methods for quantifying LA function, but they are neither routinely used nor recommended in the literature.3 Standard recommendations in the literature propose using LA volume calculated from trans-thoracic 2D echocardiography orthogonal views.3,4 LA size correlates with both LA and left ventricular (LV) function and is a strong predictor of cardiovascular morbidity and death.5 The antero-posterior diameter, calculated with M-mode or 2D echocardiography, is no longer considered to adequately represent the true LA size. For these reasons, the ASE/EACVI joined paper3

0372: Impact of exercise mitral regurgitation on hypertrophic cardiomyopathy outcomes

International audienceBackground Rest echocardiography plays a role in the diagnosis and risk stratification of hypertrophic cardiomyopathy (HCM). Indeed, left atrial enlargement, severe left ventricle (LV) hypertrophy and rest LV outflow tract (LVOT) gradients ≥50mmHg are sudden cardiac death risk factors as highlighted in recent guidelines. Conversely, exercise echocardiography findings play only a limited role in prognosis evaluations. Therefore, we sought to determine whether exercise induced changes in myocardial and valvular functions could improve HCM risk stratification. Methods and results Consecutive HCM patients with a preserved LV ejection fraction underwent standardized exercise echocardiography (including the assessment of myocardial function, dynamic left intra-ventricular gradient and valvular regurgitations) at baseline and were clinically followed for a median of 29.3 months. The primary endpoint was a composite criterion that included death from any cause, cardiorespiratory arrest, and hospitalization for a cardiovascular event. A total of 126 patients were included. Eighteen patients reached the primary endpoint. According to univariate Cox regression analysis, exercise LVOT gradient ≥50mmHg (HR=3.31, p=0.01) and significant (≥2/4) exercise mitral regurgitation (HR=3.64, p<0.01) were associated with the primary endpoint. Patients with significant MR had significantly higher rest and exercise LVOT gradients (p=0.001 and p=0.001) and larger left atria (p<0.001). Conclusion Significant exercise mitral regurgitation appears to significantly impact the prognoses of HCM patients, and it is also associated with higher LVOT rest and exercise gradient

Prevalence and prognostic value of right ventricular dysfunction in severe aortic stenosis

International audienceAims Systolic pulmonary artery pressure (sPAP) is a well-known outcome predictor in patients with valvular heart disease. Limited data are available regarding the evaluation of right ventricular (RV) performance, particularly in patients with aortic stenosis (AS). The aim of this study was to evaluate the prevalence, determinants, and prognostic significance of RV dysfunction in severe AS independently from the strategy of treatment chosen. Methods and results Two hundred patients (mean age: 79.9 ± 8.8 years) with severe AS underwent two-dimensional and speckle tracking echocardiography for the evaluation of left ventricular (LV) and RV functions, aortic valve gradients, and sPAP. A tricuspid annular plane systolic excursion (TAPSE) ≤17 mm defined RV dysfunction. RV dysfunction was detected in 48 patients (24%). At multivariable regression analysis, LV global longitudinal strain (r = −0.29, P = 0.001), mean aortic gradient (r = 0.25, P = 0.002), and LV ejection fraction (r = 0.18, P = 0.02) were well correlated with TAPSE. After a median 16-month follow-up, cardiovascular death occurred in 17 patients. At multivariate Cox regression analysis, biventricular dysfunction (TAPSE ≤17 mm and LVEF ≤50%) emerged as the strongest predictor of prognosis (hazard ratio 4.08, 95% confidence interval 1.36–12.22; P = 0.012). Conclusions RV dysfunction is common in AS patients, and this finding can likely be accounted for by the RV–LV interdependence. Given that biventricular function impairment was a strong predictor of mortality in our population, we suggest that RV dysfunction should be systematically looked for in AS patient

Left atrial function, a new predictor of response to cardiac resynchronization therapy?: Left atrium and resynchronization

International audienceBackground - Cardiac resynchronization therapy (CRT) improves left ventricular (LV) function and induces LV remodeling, and it is an established therapy for advanced heart failure with prolonged QRS duration. One third of patients will not benefit from this invasive therapy. Objective - The purpose of this study was to evaluate whether left atrial (LA) strain imaging (ε) parameters could help in predicting the response in terms of LV reverse remodeling after CRT. Methods - A total of 79 patients who underwent CRT were evaluated with echography before implantation. LA function and LV function were assessed with M-mode, 2-dimensional echocardiography, Doppler, tissue Doppler velocity, and ε. LV reverse remodeling was defined as a >15% reduction in LV end-systolic volume. Results - At 6 months, 54 patients (68%) were responders to CRT. In multivariable logistic regression, LA systolic peak of strain rate (SRA) (odds ratio [OR} 10.5, 95% confidence interval [CI] 1.76-62.1, P = .01), left bundle branch block (OR 6.8, 95% CI 1.06-43.9, P = .04), ischemic cardiomyopathy (OR 3.93, 95% CI 1.07-14.4, P = .04), and LV preejection index (OR 1.03, 95% CI 1.01-1.05, P = .01) were associated with CRT response. With an SRA cutoff of -0.75%, the negative predictive value for predicting CRT response was 0.62. Conclusion - This study demonstrated the possible relevance of assessing LA function before CRT. SRA appeared to be a good predictor of CRT response. Integrating this LA function analysis into the multivariable assessment of patient candidates for CRT should be considered

0344 : Pacemaker replacement in nonagenarians: procedural safety and long-term follow-up

International audienceBackground The rate of pacemaker (PM) implantations is continuously growing. A large number of elderly patients is expected to be implanted in the future. We aimed at analyzing the short and long-term outcome after PM replacement in nonagenarians. Methods Patients aged ≥90 yo referred for PM replacement from January 2004 to July 2014 were retrospectively included. The primary clinical endpoint was total mortality. Results 62 patients were included (93.3±2.9yo at the time of PM replacement). During the follow-up, 37 patients (59.7%) died. Survival rates were 84.2% (95%CI:71.8-91.5%), 66.9% (95%CI:51.8-78.2%) and 22.7% (95%CI:10.6-37.7%) after 1, 2 and 5 years, respectively. Atrial fibrillation (OR 2.44, 95%CI:1.07-5.58) and non-physiological pacing, (OR 2.52, 95%CI:1.12-5.65) were independent predictors of mortality. Conclusion PM replacement in nonagenarians is a safe and straightforward procedure. Patients living for a median time of 30 months after the replacement. Figure: Survival for nonagenarians after PM replacemen

0346 : Procedural safety and long-term follow-up after pacemaker implantation in nonagenarians

International audienceIntroduction The rate of pacemaker(PM) implantations is continuously growing. A large number of nonagenarian patients will be implanted in the future. We aimed at analyzing the outcome after PM implantation in the elderly. Methods Patients aged ≥90 yo referred for PM implantation from 2004 to 2014 were retrospectively included. The primary clinical endpoint was total mortality. Results 113 patients were included (92.6±2.1yo). Five patients (3.5%) had short-term device-related complications (3 pocket hematoma, 1 lead displacement, 1 hemothorax). During the follow-up, 48 patients (42.5%) died. Survival rates were 77.4% (95%CI:67.4-84.7%), 68.7% (95%CI:57.4-77.6%) and 36.4% (95%CI:23.3-49.7%) after 1, 2 and 5 years, respectively. Atrial fibrillation (OR 3.5,95%CI:1.6-7.2) and a cardiomyopathy (OR 2.3,95%CI:1.2-4.4) at the time of implantation were independent predictors of mortality. Conclusion PM implantation in nonagenarians is safe, with a low risk of procedural complications. Figure: Survival for nonagenarians after PM implantatio