Comparison of early effects of right ventricular apical pacing on left ventricular functions in single and dual chamber pacemakers

Our study aimed to demonstrate the early negative impact of right ventricular apical pacing induced by single (VVI) and dual chamber (DDD) pacemakers on LV functions in patients with preserved EF. And to assess that single brain natriuretic peptide (BNP) after 2 months of implantation is correlated to ventricular dyssynchrony. 40 patients with implanted VVI and DDD pacemakers were examined before implantation and again after 2 and 6 months of implantation for BNP, left ventricular (LV) systolic and diastolic functions by echocardiography and pulsed tissue Doppler. After 6 months, patients with DDD pacemakers were crossed over to VVI mode of pacing for 2 weeks with lower rate programed to 60 beat per minute then sample for BNP was collected again. There was no statistically significant difference in LV systolic and diastolic functions except for myocardial performance index (MPI) with (P value of 0.03). Mean BNP level in VVI pacing was higher than DDD pacing after two months with P value = 0.001 while comparison after 6 months showed P value = 0.023. There was a statistically significant difference between both groups in results of aortic preejection delay (APED) (P value of <0.05). BNP was correlated to APED (r = 0.651 and P value = 0.001) and pacing percentage (r = 0.687 and P value = 0.00). Loss of atrioventricular synchrony in VVI mode leads to a significant difference in LV dyssynchrony between both groups. BNP level is correlated to LV dyssynchrony and pacing percentage.