Abstract 12143: Ventricular Conduction Abnormality and Outcome of Patients With Mild to Moderate Systolic Dysfunction

Abstract

Introduction: In the context of mild-to-moderate systolic dysfunction (ejection fraction (EF) 36-50%), cardiac resynchronization therapy (CRT) is indicated only in patients with expected high burden of pacing but not in those with intrinsic ventricular conduction abnormalities. Hypothesis: Ventricular conduction delay is associated with a higher risk of mortality and HF hospitalization in patients with mild to moderate systolic dysfunction. Methods: We analyzed 5,966 patients with mild-to-moderate systolic dysfunction. Of those, 1,741 (29%) had a QRS duration of ≥120 milliseconds (ms). In the latter group, 68 (4%) patients were implanted with a CRT device. Patients were followed to the endpoints of death and the composite outcome of death or heart failure (HF) hospitalization. Results: Of the 1,741 patients with mild-to-moderate cardiomyopathy and wide QRS duration, 849 (51%) died and 1,004 (58%) had a HF hospitalization over a median follow-up of 3.35 years. Compared to patients with QRS<120 ms, patients with QRS>120 ms were at a higher risk of all-cause mortality (HR 1.11, CI 1.00-1.23, P=0.046) and of the composite of mortality or HF hospitalization (HR 1.10, CI 1.01-1.20, P=0.037) (Figure 1). Among patients with QRS>120 ms, those who underwent CRT implant, had a lower risk of all-cause mortality (HR 0.44, CI 0.45-0.89, P=0.02) and of mortality or HF hospitalization (HR 0.58, CI 0.39-0.87, P=0.008). Conclusions: Among patients with HF and intermediate EF, a wide QRS is associated with higher risk of mortality and heart failure hospitalization. CRT is associated with a reduction in these adverse outcomes. Randomized trials are needed to assess role of CRT in this patient population.