LAUSR

BACKGROUND The pacemaker implantation in patients with single ventricle is known to be related with poor outcomes. OBJECTIVE To determine the reason underlying poor outcome of pacemaker implantation. METHODS We performed a retrospective chart review of patients with single ventricle who had undergone permanent pacemaker implantation. The patients were categorized into three groups according to the site of pacing and the proportion of ventricular pacing (VP): atrial pacing group with only atrial pacing (n=11); low VP group with low daily VP proportion (<50%, n=12); and high VP group with high daily VP proportion (≥50%, n=15). Pacing leads were placed at epicardium in all patients. RESULTS No patient died in the atrial pacing and low VP groups, whereas the survival rate in the high VP group was 58.9% and 39.3% after 10 and 20 years, respectively, after pacemaker implantation. Among the post-Fontan patients, plasma brain natriuretic peptide (BNP) levels significantly increased according to the proportion of VP at 11.7, 20.3, and 28.4 pg/ml for the atrial pacing, low VP, and high VP groups, respectively (p = 0.04). In the high VP group, the plasma BNP level was significantly lower in patients with apical pacing lead than in those with non-apical pacing lead (27.0 pg/ml vs. 82.8 pg/ml, respectively, p = 0.03). CONCLUSIONS A higher proportion of VP was associated with poor outcome and higher plasma BNP levels, probably due to ventricular dyssynchrony. In epicardial ventricular pacing, apical pacing is better to avoid the increase in ventricular stress and plasma BNP level.