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


METHODS
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.


RESULTS
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).


CONCLUSIONS
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.
Division of Pediatric Cardiology, Department of Pediatrics, Stanford University School of Medicine, Stanford, California.
Duy T
DT
Dao
Seth A
SA
Hollander
David N
DN
Rosenthal
Anne M
AM
Dubin
D000293:Adolescent; D001145:Arrhythmias, Cardiac / Q000453:epidemiology* / Q000503:physiopathology; D002311:Cardiomyopathy, Dilated / Q000150:complications* / Q000503:physiopathology*; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D004562:Electrocardiography; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D053208:Kaplan-Meier Estimate; D016015:Logistic Models; D008297:Male; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D018754:Ventricular Dysfunction / Q000453:epidemiology* / Q000503:physiopathology
QRS duration; dilated cardiomyopathy; heart failure; left ventricular posterior wall thickness; ventricular arrhythmia