Influence of Atrial Function and Mechanical Synchrony on LV Hemodynamic Status in Heart Failure Patients on Resynchronization Therapy

Abstract

AS is associated with preserved atrial contractility and atrial synchrony, resulting in optimal LV diastolic filling, stroke volume, and LV systolic mechanics. This pacing mode maximizes LV performance and the hemodynamic benefit of CRT in patients with heart failure.

Atrial remodelling in heart failure: recent developments and relevance for heart failure with preserved ejection fraction

“…In a recent report from a cohort of HF patients (51% HFpEF), atrial remodelling in HFrEF was characterized by increased LA volumes and lower contraction amplitude (pulsatility) as compared with HFpEF, whereas HFpEF was associated with higher LA pressures and increased LA wall stiffness 46. Vice versa, in patients with HFrEF receiving cardiac synchronization therapy (CRT), a reduction in LA strain induced by atrial pacing resulted in a significant reduction in global LV strain 49. Atrial contribution to ventricular filling can decline with the progression of HF, as increased atrial mechanical load leads to atrial dysfunction 50.…”

“…46 Vice versa, in patients with HFrEF receiving cardiac synchronization therapy (CRT), a reduction in LA strain induced by atrial pacing resulted in a significant reduction in global LV strain. 49 Atrial contribution to ventricular filling can decline with the progression of HF, as increased atrial mechanical load leads to atrial dysfunction. 50 HFpEF is characterized by impaired LV diastolic filling, and LA ejection volume contributes to LV filling.…”

“…110 Of note, maintaining intrinsic electrical atrial activation and contraction (as opposed to AV-sequential pacing) significantly improves cardiac output with CRT. 49 Specifically targeting AF as a result of atrial remodelling in HF has been proposed with the aim of reversing electrical remodelling induced by AF and preserve/restore contribution of the LA to ventricular filling in sinus rhythm. 53 Indeed, surgical and catheter-based AF ablation was associated with reverse atrial remodelling in non-failing [111][112][113] and also failing hearts (HFrEF 114 ).…”

Methodological Gaps in Left Atrial Function Assessment by 2D Speckle Tracking Echocardiography

“…In fact, the only independent determinants of LA functional recovery after CRT were positive response to CRT and the ischemic etiology of DCM 53 . Another study using tissue Doppler showed that in patients with heart failure and CRT, atrial strain was higher in the right atrium, interatrial septum, and left atrium in atrial-sensed compared to atrial-paced mode 54 . This study emphasized that, despite no difference in intraventricular dyssynchrony, patients with atrial-sensed mode had significantly lower atrial dyssynchrony that contributed to a better LV performance after CRT.…”

CRT Optimization

“…In this issue of iJACC, Liang et al (2) elegantly describe the acute hemodynamic effects of atrial sensing (AS) versus atrial pacing (AP) in CRT patients and find that AS is the optimal mode of programming in CRT. We would like to emphasize 3 main findings in this study.…”