Left Ventricular Septolateral Mechanical Delay Is Associated with Reduced Long-Term Survival in Systolic Heart Failure with Narrow QRS Duration: Nine-Year Outcome in 109 Patients

Abstract

Background The long-term prognostic importance of left ventricular (LV) dyssynchrony in patients with systolic heart failure is not known. We investigated this question in 109 consecutive patients with systolic heart failure with an LV ejection fraction (EF) ≤35% and QRS duration <130 ms. Methods The cohort is a prospective series of 109 patients with EF ≤35% and QRS duration <130 ms who did not receive a defibrillator. Onset to onset septolateral and anteroposterior mechanical delays were computed from tissue Doppler velocity signals of the four quadrants of the mitral annulus and related to mortality. Results Patient characteristics included age 53 ± 12 years, 73% male, 23% with coronary artery disease, LVEF 24 ± 7%, LV end-diastolic dimension 64 ± 9 mm, LV end-systolic dimension 55 ± 9 mm, QRS duration 107 ± 30 ms, and 92 with QRS duration <120 ms. Over a follow-up of 9 years, there were 51 deaths. Univariate predictors of mortality included LV septolateral delay (HR 1.01 per ms, P < 0.0001), anteroposterior delay (P = 0.003), and age (P = 0.005), but not EF, LV size, or QRS duration. Using Cox regression analysis, LV septolateral delay was an independent predictor of higher mortality (P = 0.0005) after adjusting for age, gender, EF, LV size, QRS duration, coronary artery disease, diabetes mellitus, and use of beta blockers or angiotensin-converting enzyme inhibitors. Conclusion In patients with heart failure, LVEF ≤35% and QRSd < 130 ms, LV mechanical dyssynchrony is a strong and independent predictor of long-term mortality.