Intra-Atrial Recording of Ventriculoatrial Conduction During Pacemakers’ Implantation

Ventriculoatrial conduction (VAC) is the causative factor of some cases of the so-called ‘pacemaker syndrome’ in patients with VVI pacemakers and can induce the ‘endless-loop arrhythmias’ (ELA), which is the principal drawback against the spreading of VDD or DDD pacemakers. During the last 30 months the presence of V AC was studied in 215 patients during the PM implantation; 104 (48%) were paced with a VVI unit, 100 (47%) with a dual-chamber system and 11 (5%) with a single leads’ VDD device. In the first 56 cases the ventricular pacing was initiated at 80 bpm or 10 bpm higher than the intrinsic rate, maintained during 2 minutes and ended at 130; in the rest of patients the pacing began at 50 bpm and ended at 150 bpm, because of the finding that some patients showed V AC only below 70 bpm. At the end of the study the response of V AC to the intravenous administration of amiodarone (150-300 mg) was tested. The atrial activity was recorded by way of the guide wire of the introducer or the ventricular lead left in the atrium in cases paced with VVI pacers.