Optimization of cardiac resynchronization therapy after implantation

Abstract

Many patients do not respond clinically to cardiac resynchronization therapy (CRT), despite clinical and survival benefits demonstrated in numerous clinical trials. This has led to focused evaluation from preimplant issues, as to who is an appropriate candidate for CRT, to postimplant issues, more specifically, optimizing device programming in CRT. CRT studies have used simultaneous biventricular pacing, but with advancing echocardiographic technology, the role of dyssynchrony, or mechanical delay in contraction of the ventricles, suggests that individually tailoring ventricular pacing improves hemodynamics. Atrial to ventricular timing affects left ventricular filling and cardiac output, whereas the right to left ventricular pacing delay also improves systolic and diastolic performance. The importance of device programming parameters and optimal pacing delays in biventricular pacing is reviewed in this article.

Device Therapy in Advanced Heart Failure: What to Put In and What to Turn Off

“…The other hurdle facing CRT in clinical practice is how to best optimize the device to provide the most benefit to individual patients. Optimization is based on how the device is set to resynchronize, and this is performed on three levels: (1) from the atria to the ventricles, or atrioventricular (AV) resynchronization; (2) interventricular (VV), between the right and left ventricles; and (3) intraventricular, among the different LV segments 38 . Several algorithms and methods exist for optimization at each level, but at this time there are no guidelines or methods that have standardized the approach to optimization.…”