Global longitudinal strain at baseline is a marker of ventricular arrhythmias in patients with cardiac resynchronization therapy

Abstract

Purpose: Pre-implant predictors of ventricular arrhythmia (VA) are not fully investigated in patients receiving cardiac resynchronization therapy (CRT). A sensitive marker of VA in these patients will be valuable for correct choice of CRT type, with or without a cardioverter defibrillator (CRT-D). We aimed to explore if assessment of left ventricular (LV) function by speckle tracking strain echocardiography could predict VA in heart failure patients eligible for CRT. Methods: We investigated heart failure patients with left bundle branch block treated with CRT. Echocardiography was performed before CRT-implantation and after 6 months (CRT turned on). Systolic myocardial function was assessed as LV ejection fraction (EF) by Simpson biplane method and global longitudinal strain (GLS) using speckle tracking technique. VA was defined as non-sustained ventricular tachycardia or appropriate anti-tachycardia pacing or shock during 2 years follow-up from CRT-implantation. Results: We included 73 heart failure patients (NYHA class 2.8±0.4, EF 28±9%), 44% with ischemic and 56% with non-ischemic dilated cardiomyopathy. VA was documented in 19 patients (26%). LV function by GLS was lower in patients with VA compared to those without VA during 2 years follow-up, both at baseline (-6.3±4 vs. -8.8±4%, p=0.03) and at 6 months (-5.9±6 vs. -9.7±5%, p=0.01). EF was not a marker of VA during 2 years follow-up, neither at baseline (26±10 vs. 29±9%, p=0.26) nor at 6 months (36±8 vs. 41±12%, p=0.18). Conclusions: In our study LV function by GLS was a marker of subsequent VA in heart failure patients receiving CRT, while EF was not. Our results suggest that EF measurement alone is not adequate for risk prediction of VA. Assessment of GLS might be considered as part of decision making for correct choice of CRT.