Early effects of right ventricular pacing on the left ventricle in single-chamber and dual-chamber pacemakers

Abstract

Objectives Our study aimed at demonstrating the early impacts of right ventricular apical pacing induced by single-chamber (VVI) and dual-chamber (DDD) pacemakers on left ventricular (LV) functions, and to assess whether brain natriuretic peptide (BNP) after 2 months of implantation is correlated for LV dyssynchrony. Background Long-term effects of right ventricular apical pacing have been studied, and not much information is available on the early effects of right ventricular pacing on the LV function and dyssynchrony. Patients and methods The study was conducted on 40 patients who came for the implantation of permanent pacemakers. Patients were divided into two groups of 20 patients each: group A included patients who were implanted with VVI pacemakers and group B included patients who were implanted DDD pacemakers. Both groups were examined before implantation and after 2 and 6 months of implantation for BNP and predetermined parameters for LV dyssynchrony and systolic and diastolic functions by echocardiography. After 6 months, patients with DDD pacemakers were crossed over to the VVI mode of pacing by programming for a period of 2 weeks, and then a blood sample was collected for BNP. Results The mean BNP level in VVI pacing (group A) was 196.5 ΁ 123 pg/dl, which was higher than that in DDD pacing (group B 79.35 ΁ 65.36 pg/dl), after 2 months, with P value equal to 0.001, while a comparison after 6 months showed P value equal to 0.023. There was a statistically significant difference between groups in their myocardial performance index with a P value of 0.03. Results of the aortic pre-ejection delay showed a significant difference with a P value of less than 0.05. BNP was correlated to aortic pre-ejection delay (r = 0.651 and P = 0.001) and the pacing percentage (r = 0.687 and P = 0.00). Conclusion Loss of atrioventricular synchrony in the VVI mode leads to a significant difference in LV dyssynchrony between both groups. Myocardial performance index was affected more than the other parameters for systolic and diastolic functions. The BNP level was correlated to LV dyssynchrony and the pacing percentage.