Redistribution of left ventricular strain by cardiac resynchronization therapy in heart failure patients

Abstract

AimsThe aim of this study was to investigate (i) the baseline patterns of segmental peak myocardial strain (PMS) in heart failure (HF) patients with ventricular conduction delay, (ii) changes in patterns of segmental PMS induced by cardiac resynchronization therapy (CRT), and (iii) whether they differ between CRT responders and non-responders. Methods and resultsSegmental and global longitudinal (L-) and radial (R-) PMS measurements derived from speckle tracking were prospectively obtained in 85 HF patients with intraventricular conduction delay before and 6 months after CRT device implantation and in 30 healthy subjects. Segmental strain analysis in HF patients showed pronounced heterogeneity both in longitudinal and in radial directions with the lowest amplitudes in the septum and the highest amplitudes in the lateral and posterior walls. After CRT, 60% of the patients were responders (≥15% reduction in endsystolic volume). Before CRT, responders showed higher global R-PMS than non-responders (19.5 + 13.4 vs.13.1 + 4.8%, respectively; P ¼ 0.04) despite similar global L-PMS. After CRT, responders showed an increase in L-PMS in most segments and a homogeneous increase in R-PMS, leading to a more uniform pattern of strain and an improved global L-PMS and R-PMS. In contrast, in non-responders, the gain in L-PMS and R-PMS in septal segments was completely offset by a decrease in posterolateral segments, failing to decrease segmental heterogeneity and to increase global L-PMS and R-PMS. ConclusionHeart failure patients with ventricular conduction delay show pronounced heterogeneous patterns of segmental PMS, which can be reversed by CRT.--

Novel Strain Rate Index of Contractility Loss Caused by Mechanical Dyssynchrony - A Predictor of Response to Cardiac Resynchronization Therapy -

“…11-13 CRT improves the heterogeneity of myocardial shortening by activation of the latest activated site, resulting in augmentation of global LV contractility. 26 Therefore, dyscoordination of contraction can more directly associate with the improvement of LV systolic function by CRT than the dispersion of the timing of regional contraction. In fact, the present study demonstrated that the time-delay indexes derived from TDI and 2DST could not predict the changes in LV systolic function (Tables 3,4).…”

Tissue Doppler Imaging Dyssynchrony Parameter Derived From the Myocardial Active Wall Motion Improves Prediction of Responders for Cardiac Resynchronization Therapy

“…27 Novel findings with STI of the pathophysiological relation between LV contraction abnormalities and conduction disturbances may contribute to better understanding of the response mechanism for CRT and prediction of CRT's effects. 28 …”

Non-Responders to Cardiac Resynchronization Therapy - The Magnitude of the Problem and the Issues -

“…38 Good resynchronization can also be assessed using echocardiographic analysis, especially 2-dimensional strain analysis. Good resynchronization coincides with a more uniform distribution of peak strain 39 and disappearance of septal re- Figure 2. The likelihood to respond to cardiac resynchronization therapy (CRT) (very high, no response, or worsening) appears to depend upon the presence or absence of some clinical, electrocardiographic, echocardiographic and magnetic resonance imaging parameters.…”

“…In contrast, in patients in whom distribution of regional peak strain did not become more uniform, or even became significantly more unequally distributed after CRT, resulted in an increase in LVESV and unchanged LVEF. 39 Several sophisticated cardiac imaging techniques have been proposed with the laudable intent to reduce the proportion of non-responders to CRT. Keeping in mind all previous arguments, one may ask: is there a better way to refine nonresponders by using cardiac imaging techniques?…”