Clinical characteristics of ventricular preexcitation dilated cardiomyopathy induced by accessory pathway

Abstract

Objective To discuss the characteristics, diagnosis, mechanism and the prognosis of dilated cardiomyopathy(DCM) induced by accessory pathway(AP). Methods The clinical, electrophysiological and echocardiographic characteristics in four cases, who were diagnosed as AP-induced DCM in the Department of Pediatric Cardiology of Beijing Anzhen Hospital, Capital Medical University from Mar.2011 to Aug.2012, were analyzed before and after ablation. Results The electrocardiograms of the 4 patients all indicated type B ventricular preexcitation.The locations of the APs were the right-sided anteroseptum and the free wall.Dyschronous contractions between posterior wall of left ventricle and interventricular septum were demonstrated by M-Mode echo.The basal segments of the interventricular septum turned thin and moved similar to an aneurysm, with typical bulging during end-systole, which was observed in all cases by two-dimension echo.Dyschronous left ventricular contraction was shown by speckle tracing technique.All patients received successful radio frequency current ablations.Their physical activities and growth improved greatly in the 4 cases.The echocardiographic data demonstrated that their left ventricular contraction recovered to synchrony shortly after the ablation, left ventricular ejection fraction recovered to normal and left ventricular end diastolic diameter decreased to almost normal gradually during the follow-up. Conclusions Overt right-sided APs localized in anteroseptum or free wall may have adverse effects on ventricular wall motion and left ventricular function.They can even result in DCM.Dyssynchronous ventricular contraction induced by right-sided overt accessory pathway may be the vital mechanism.AP-induced DCM is an indication for ablation with good prognosis. Key words: Ventricular preexcitation; Speckle tracing; Dilated cardiomyopathy; Dyssynchrony