Background: To investigate the contribution of right ventricular (RV) pacing sites to the cardiac function, this study compares plasma B-type natriuretic peptide (BNP) levels during RV septal and apical pacing in patients implanted with a pacemaker. Materials and Methods and Results: Seventy-four consecutive patients with indication for permanent pacing were included. To provide for the possibility of appropriate subgroup analyses, patients were stratified according to their pacing mode into two groups: Those with dual chamber DDD(R)/VDD pacemakers (41 patients, mean age 54.1±18.4 years), and those with single chamber VVI pacemakers (33 patients, mean age 60.6±18.4 years). A prospective single-blinded randomized design was used. Randomization (1:1 way) was between lead placement on the RV septum or RV apex and occurred during the implant in both groups. Compared to baseline, a significant decrease in BNP (429.8±103 pg/ml and 291.7±138 pg/ml, respectively) levels was observed during DDD(R) /VDD pacing after two months. In contrast, during VVI (R) pacing, a significant increase in BNP levels was observed (657.5±104 pg/ml and 889.5±139 pg/ml, respectively). To determine the impact of pacing sites on cardiac function, we assessed the changes in BNP levels in each group separately. Despite the significant difference in the pattern of changes between the two groups (P < 0.02), no significant changes were observed within groups regarding the acute effect of the pacing site (RV apex vs. RV septal) on BNP levels (P=NS). Conclusions: Our main result showed no significant differences between pacing sites and concluded that hemodynamic improvement could be substantially influenced by pacing mode, more than by pacing site.
Key words:B-type natriuretic peptide, right ventricular apical pacing, right ventricular septal pacing.