Implication of QRS prolongation and its relation to mechanical dyssynchrony in idiopathic dilated cardiomyopathy in childhood.

摘要

We explored the role of QRS prolongation (>or=120 ms) and its relation to mechanical dyssynchrony and outcomes in childhood idiopathic dilated cardiomyopathy (IDC). A total of 89 patients 32.6 ms was used to define intra-LV dyssynchrony. The 1- and 5-year survivals were 70% and 53%, respectively. Requirement of intravenous inotropes at follow-up (hazard ratio 3.10) and initial LV ejection fraction (hazard ratio 0.95) were major prognostic factors. QRS prolongation, primarily left bundle branch block, was identified in 16 patients (18%) and tended to increase the risk of requiring inotropes. Moreover, none of those with QRS prolongation regained normal cardiac function at follow-up. Two patients with QRS prolongation showed marked improvement in cardiac function after cardiac resynchronization therapy. Mechanical dyssynchrony was noted in all patients with QRS prolongation and in 8% (interventricular) or 38% (intra-LV) of those without. In conclusion, QRS prolongation was common in childhood IDC and was possibly associated with persistent LV dysfunction and worse cardiac outcome. Mechanical (inter- and intraventricular) dyssynchrony was highly prevalent in those with QRS prolongation and was still often observed in those without.