QRS prolongation is strongly associated with life-threatening ventricular arrhythmias in children with dilated cardiomyopathy

Abstract

The incidence of sudden death in children with dilated cardiomyopathy has been estimated at < 1% annually. This number, however, may underestimate the incidence of life-threatening arrhythmias. The objective of this study was to assess the incidence of and identify risk factors for life-threatening arrhythmias in children with dilated cardiomyopathy. We conducted a retrospective record review of 183 children with dilated cardiomyopathy treated at a single center between 2000 and 2011. Life-threatening arrhythmia was defined as any ventricular arrhythmia that resulted in syncope or hypotension and required medical intervention. Risk factors for life-threatening arrhythmias were identified with univariate analyses. A prediction model was constructed with multivariate logistic regression and receiver operating characteristic curves. Nineteen patients experienced life-threatening arrhythmias, representing an annualized rate of 4.9%. Outpatient life-threatening arrhythmias occurred at a rate of 2.2% per year. Predictors of outpatient life-threatening arrhythmias were longer QRS duration (p = 0.003) and increased left ventricular posterior wall (LVPWd) thickness (p = 0.03). Only QRS duration remained significant in multivariate logistic regression (odds ratio, 1.8 for every unit increase in z-score; 95% CI, 1.01-1.9; p = 0.04). For all life-threatening arrhythmias, prolonged QRS duration was the only significant risk factor in multivariate logistic regression (odds ratio, 1.5; 95% CI, 1.1-2.2; p = 0.02). In children with dilated cardiomyopathy, as QRS duration increases, so too does the risk of life-threatening arrhythmias. Life-threatening arrhythmias occurred at an annual rate of 5%, which was much higher than the previously reported rate of sudden cardiac death in this population.