Atrial natriuretic peptide for monitoring cardiovascular system performance following pacemaker implantation.

Background: The effects of different modes of pacing on cardiac performance have been investigated in a few small studies, and the results are not conclusive.

Aim: To assess the effects of different modes of pacing on atrial natriuretic peptide (ANP) plasma concentration and left ventricular ejection fraction (LVEF).

Methods: The study group consisted of 55 subjects without symptomatic CHF. Forty patients were in sinus rhythm and had a-v block. Twenty of them, aged 71-90 years, mean 77.5+/-5.9 years, received VVI pacemaker, and the remaining 20 patients aged 49-81 years, mean 68.9+/-11.9 years, received DDD or VDD pacemakers. The control group consisted of 15 healthy volunteers aged 58-80 years, mean 72.6+/-2.8 years. Blood samples for alpha ANP concentration were taken before pacemaker implantation and 7 as well as 30 days after pacemaker implantation. In controls, a single alpha ANP measurement was performed. Transthoracic echocardiography was performed in all patients and controls at the same time-points as ANP assessment in order to calculate LVEF.

Results: Before pacemaker implantation, ANP plasma concentration was the highest in VVI patients and was significantly greater in patients than in controls. Following VVI pacemaker implantation, ANP level significantly decreased, both 7 and 30 days after implantation when compared with baseline values. Also following implantation of dual-chamber pacing system, ANP concentration significantly decreased. The baseline LVEF values were significantly higher in patients than in controls. In patients with VVI pacemakers, LVEF significantly increased, both 7 and 30 days after implantation. In patients with dual-chamber pacemakers, LVEF tended to increase 7 days after implantation and slightly decreased 30 days after implantation, however, the differences were not significant.

Conclusions: ANP level decreases following pacemaker implantation in patients with advanced a-v block which suggests an improvement of cardiac performance. Assessment of ANP may be useful in selection of pacing mode.