Dilated cardiomyopathy in children with ventricular preexcitation: the location of the accessory pathway is predictive of this association.

Background: Ventricular preexcitation may be associated with dilated cardiomyopathy, even in the absence of recurrent and incessant tachycardia.

Methods: This report describes the clinical and electrophysiologic characteristics of 10 consecutive children (6 males), with median age of 8 years (range, 1-17 years), who presented with dilated cardiomyopathy and overt ventricular preexcitation on the 12-lead electrocardiogram. Incessant tachycardia as the cause of dilated cardiomyopathy could be excluded. Coronary angiography, right ventricular endomyocardial biopsy (4/10 patients), and metabolic and microbiologic screening were nondiagnostic.

Results: The electrocardiograms suggested right-sided pathways in all patients. A right-sided accessory pathway was demonstrated in 8 patients during invasive electrophysiologic study (superoparaseptal, n = 5; septal, n = 2; fasciculoventricular, n = 1). All pathways were successfully ablated (radiofrequency ablation in 7, cryoablation in 1). Two patients had spontaneous loss of ventricular preexcitation during follow-up. Left ventricular (LV) function completely recovered after a loss of preexcitation in all patients.

Conclusions: Right-sided accessory pathways with overt ventricular preexcitation and LV dyssynchrony may cause dilated cardiomyopathy. An association between such pathways and dilated cardiomyopathy is suggested by the rapid normalization of ventricular function and reverse LV remodeling after a loss of ventricular preexcitation.