[Hemodynamics in ventricular and atrioventricular sequential stimulation in patients with bradycardia arrhythmias. Is...

In order to assess the effects of on-time atrial contraction on haemodynamics, the appropriate investigations were done in 16 patients with bradycardic arrhythmias before and two weeks after implantation of a pacemaker. Eight patients received a ventricular stimulating pacemaker (group A) and eight a sequentially stimulating atrioventricular pacemaker (group B). Haemodynamic data of both groups were identical before implantation of the pacemaker. After implantation the cardiac index in group A rose only slightly, whereas group B demonstrated a significant increase (P less than 0.001). Stroke volume decreased by 36% in group A, whereas the mean did not change in group B compared to baseline data. Both arteriolar pulmonary resistance and peripheral vascular resistance decreased more in group B, both parameters were significantly lower after pacemaker implantation than in group A. Thus patients with ventricular pacemaker stimulation benefit less haemodynamically than patients with atrioventricular sequential stimulation.