Atrial natriuretic peptide for monitoring cardiovascular system performance following pacemaker implantation

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

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

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.

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.

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.