Atrioventricular dyssynchrony from empiric device settings is common in cardiac resynchronization therapy and adversely impacts left ventricular morphology and function

Impact of cardiac resynchronization therapy optimization inside a heart failure programme: a real-world experience

AIMS

This study sought to describe and evaluate the impact of a routine in-hospital cardiac resynchronization therapy (CRT) programme, including comprehensive heart failure (HF) evaluation and systematic echo-guided CRT optimization.

METHODS AND RESULTS

CRT implanted patients were referred for optimization programme at 3 to 12 months from implantation. The program included clinical and biological status, standardized screening for potential cause of CRT non-response and systematic echo-guided atrioventricular and interventricular delays (AVd and VVd) optimization. Initial CRT-response and improvement at 6 months post-optimization were assessed with a clinical composite score (CCS). Major HF events were tracked during 1 year after optimization. A total of 227 patients were referred for CRT optimization and enrolled (71 ± 11 years old, 77% male, LVEF 30.6 ± 7.9%), of whom 111 (48.9%) were classified as initial non-responders. Left ventricular lead dislodgement was noted in 4 patients (1.8%), and loss or ≤90% biventricular capture in 22 (9.7%), mostly due to arrhythmias. Of the 196 patients (86%) who could undergo echo-guided CRT optimization, 71 (36.2%) required VVd modification and 50/144 (34.7%) AVd modification. At 6 months post-optimization, 34.3% of the initial non-responders were improved according to the CCS, but neither AVd nor VVd echo-guided modification was significantly associated with CCS-improvement. After one-year follow-up, initial non-responders maintained a higher rate of major HF events than initial responders, with no significant difference between AVd/VVd modified or not.

CONCLUSIONS

Our study supports the necessity of a close, comprehensive and multidisciplinary follow-up of CRT patients, without arguing for routine use of echo-guided CRT optimization.

Cardiac Resynchronization Therapy Optimization: A Comprehensive Approach

Since the first report on biventricular pacing in 1994, cardiac resynchronization therapy (CRT) has become standard for patients with advanced heart failure (HF) and ventricular conduction delay. CRT improves myocardial function by resynchronizing myocardial contraction, which results in reverse left ventricular remodeling and improves symptoms and clinical outcomes. Despite the accelerated development of CRT device technology and its increased application in treating HF patients, almost one-third of these patients do not respond to the therapy or gain any clinical benefit from device implantation. Over the last decade, multiple cardiac imaging modalities have provided a deeper understanding of myocardial pathophysiology, thereby improving HF treatment management. However, the optimal strategy for improving the CRT response remains debatable. This article provides an updated overview of the electropathophysiology of myocardial dysfunction in ventricular conduction delay and the diagnostic approaches involving the use of multiple modalities.

Advances in atrioventricular and interventricular optimization of cardiac resynchronization therapy - what's the gold standard?

INTRODUCTION

Cardiac resynchronization therapy (CRT) is one of the most important advances in heart failure management in the last twenty years. Approximately one-third of patients appear not to respond to therapy. Although there are a number of possible mechanisms for non-response, an important factor is suboptimal atrioventricular (AV) and interventricular (VV) timing intervals. There remains controversy over whether routinely optimizing intervals is necessary and there is no agreed gold standard methodology. Optimization has classically been performed using echocardiography which has limits related to resource use, time-cost and variable reproducibility. Newer optimization methods using device-based sensors and algorithms show promise in reducing heart-failure hospitalization compared with echocardiography. Areas covered: This review outlines the rationale for optimization, the principles of AV and VV optimization, the standard echocardiographic approach and newer device-based algorithms and the evidence base for their use. Expert commentary: The incremental gains of optimization are likely to be real, but small, compared to the overall improvement gained from cardiac resynchronization itself. At this time routine optimization may not be mandatory but should be performed where there is no response to CRT. Device-based optimization algorithms appear to be practical and in some cases, deliver superior clinical outcomes compared to echocardiography.