Abstract 9589: Conduction Abnormalities in Pediatric Patients with Restrictive Cardiomyopathy
Introduction: Pediatric restrictive cardiomyopathy (RCM) carries a poor prognosis secondary to a high risk of sudden cardiac death. Sudden death in pediatric patients has previously been attributed to ventricular tachyarrhythmias. There are many reasons why patients with RCM might develop conduction system disease and it is conceivable that in the acute setting, this might be a triggering event for sudden death.
Methods: A single center, retrospective chort of pediatric patients with RCM, diagnosed between April 1994 and April 2011 was analyzed for conduction system abnormalities and potential triggering events for sudden death. Patient demographic, cardiac and electrocardiographic characteristics were reviewed. Incidence of sudden cardiac events was determined (defined as death or an episode of acute hemodynamic compromise felt to be secondary to a cardiac arrhythmia). Non-parametric statistical methods were used to determine associations between clinical characteristics and sudden cardiac events.
Results: Fifteen patients (1 - 17 years) were reviewed; there were 5 sudden cardiac events including 4 deaths. Two of the deaths were precipitated by the abrupt onset of complete heart block. Another patient with syncope had intermittent heart block and survived as a result of the defibrillator pacing features. Sudden cardiac events were statistically associated with an older age (p<0.01). On initial presentation, the median PR interval (222 vs. 140 msec; p < 0.01) and the median QRS duration (111 vs. 73.5; p = 0.01) was significantly longer in those having an acute cardiac event. No other functional or echocardiographic variables were associated with a sudden cardiac event.
Conclusion: Pediatric patients with RCM are at risk for acute high grade heart block and bradycardic events may represent a significant portion of all arrhythmic events. Since PR interval prolongation and wider QRS complex were associated with acute cardiac events, these findings suggest increased monitoring for bradyarrhythmic episodes with consideration for prophylactic pacemaker implantation in certain patients. Particular care should be taken in patients with RCM and evidence of conduction system disease.
- © 2011 by American Heart Association, Inc.