Relationship between left ventricular mechanical dyssynchrony with cardiac resynchronization therapy response in chronic heart failure patients with left bundle branch block

Abstract

Aim. To investigate the relationship between left ventricular (LV) mechanical dyssynchrony with cardiac resynchronization therapy (CRT) response in chronic heart failure (CHF) pts with left bundle branch block.Methods. Forty-nine pts (male - 34 [69.4%], average age 58.3±11.4 years) with sinus rhythm, permanent left bundle branch block with QRS duration ≥150 ms and New York Heart Association (NYHA) II-III functional class of CHF were included in the study. In addition to full examination, myocardial perfusion scintigraphy (MPS) and gated blood pool single-photon emission computed tomography (gBPS) were performed before and 6 months after CRT devices with cardioverter-defibrillator function implantation. Pts were considered as responders to CRT if they fulfilled after 6-month follow-up the following combined criteria: NYHA FC improvement ≥1 class + LV end systolic volume decrease >15% or NYHA FC improvement ≥1 class + LV ejection fraction improvement >5%.Results. The 1st and 2nd groups included 35 (71.4%) and 14 (28.6%) pts with and without response to CRT respectively. Groups were comparable in terms of pre-CRT implantation clinical and instrumental parameters, except for MPS and gBPS parameters. The multivariate logistic regression had shown that only ∆interventricular dyssynchrony (adjusted odds ratio [OR] 1,0349; 95% confidence interval [CI] 1.0075-1,0631; р=0.01) and phase standard deviation of the anterior LV wall (OR 1.0669; 95% CI 1.0118-1.1251; p=0.01) were independently related with CRT response. An increase in the prognostic coefficient, calculated using the ∆interventricular dyssynchrony and phase standard deviation of the anterior LV wall, more than 0.67 was a predictor of CRT response (area under the curve 0.918; sensitivity 85.71; specificity 85.71; p <0.001).Conclusion. The mechanical dyssynchrony assessed by MPS and gBPS is associated with CRT response. According to our predictive model, an increase in prognostic coefficient more than 0.67 is a predictor of CRT response.