Closed loop stimulation improves ejection fraction in pediatric patients with pacemaker and ventricular dysfunction.

BACKGROUND The aim of this prospective study was to evaluate the effect of the closed loop stimulation (CLS) on the ejection fraction in pediatric patients, affected by complete atrioventricular block (CAVB) or CAVB and sinus node dysfunction (SND), with a previously implanted pacemaker (PM) and ventricular dysfunction. The role of electrical therapy in the treatment of pediatric patients with congenital atrioventricular (AV) blocks has been shown. Conventional right ventricular pacing seems to affect ventricular function. Up to now, the feasibility and the long-term results of biventricular pacing in pediatric patients were not entirely clear. METHODS In eight pediatric patients with a previously implanted single or dual chamber PM, ventricular dysfunction, and CAVB or SND and CAVB, a dual chamber PM INOS(2+)-CLS (Biotronik GmbH, Berlin, Germany) was implanted. The effect of the physiological modulation of CLS pacing mode on the ejection fraction was evaluated by Echo-Doppler examination. Measurements were performed before the substitution of the old PM and for up to 2 years of follow-up. RESULTS All patients showed correct electrical parameters at implantation and during follow-up. The mean value of the ejection fraction measured before the replacement of the old PM was 36 +/- 7%, while after 2 years it was 47 +/- 1% (P < 0.003). No patient showed any worsening of the ejection fraction, while only one showed no improvement. CONCLUSIONS DDD-CLS pacing seems to improve ventricular function in pediatric patients with CAVB and/SND in spite of the use of the apical right conventional stimulation.