Impact of QRS duration and morphology on the risk of sudden cardiac death in asymptomatic patients with aortic stenosis: the SEAS (Simvastatin and Ezetimibe in Aortic Stenosis) Study.

OBJECTIVES: The aim of the study was to examine the predictive value of QRS duration and morphology during watchful waiting in asymptomatic patients with aortic stenosis (AS).

BACKGROUND: QRS duration and morphology are associated with poor prognosis in many different populations, but the predictive value, particularly of the risk of sudden cardiac death (SCD), in asymptomatic patients with AS has not been well studied.

METHODS: Data were obtained in asymptomatic AS patients randomized to simvastatin/ezetimibe combination versus placebo in the SEAS (Simvastatin and Ezetimibe in Aortic Stenosis) study. The impact of QRS duration, evaluated as a categorical variable of <85 ms versus 85 to 99 ms and ≥100 ms (excluding bundle branch block [BBB]) and QRS morphology in those with BBB, on cardiovascular morbidity and mortality was assessed by adjusting for clinical and echocardiographic covariates.

RESULTS: QRS data were available in 1,542 patients who were followed for a mean of 4.3 ± 0.8 years (6,631 patient-years of follow-up). There were 68 cardiovascular deaths (4.6%), including 27 SCDs (1.8%). QRS duration was <85 ms in 900 patients (58.4%), 85 to 99 ms in 396 (25.7%), ≥100 ms in those without BBB in 144 (9.3%), and 102 (6.6%) in those with BBB. In multivariable analyses, those with QRS duration ≥100 ms had, compared with those with QRS duration <85 ms, a 5-fold higher risk of SCD (95% confidence interval: 1.8 to 13.7, p = 0.002) and a 2.5-fold higher risk of cardiovascular death (95% confidence interval: 1.2 to 5.1, p = 0.01).

CONCLUSIONS: QRS duration and morphology in asymptomatic patients with AS are independently associated with a poor prognosis, particularly the risk of SCD.