We analyzed transesophageal ECG recordings of 79 patients (42 men and women aged 17-85 mean 61 +/- 16 yrs) with present ventriculo-atrial conduction phenomenon during permanent VVI stimulation. All measurements we performed on basic and magnetic rate of the pulse generator. V-a conduction time was defined as mean (from 5 measurements) time from spike of the pulse generator to the first deflection of P wave recorded from esophagus and expressed in miliseconds. We compared v-a conduction time (v-act) on basic and magnetic rates of a stimulator and between groups with normal (group A, 49 pts) and prolonged a-v conduction time (group B, 30 pts). Group B was divided on group B-1 (19 pts without bundle branch blocks) and B-2 (11 pts with bundle branch blocks during observations). V-act during magnetic rate (cycle 596 +/- 70 ms) was significantly longer than during basic rate (cycle 834 +/- 66 ms) (191 +/- 48 ms vs 185 +/- 44 ms, p 0.05). V-act in patients with a-v block (group B) was significantly longer than in patients with normal a-v conduction (group B) (219 +/- 45 ms vs 190 +/- 47 ms, p 0.02). The longest v-act was observed in group B-2 (236 +/- 32 ms). CONCLUSIONS 1. Ventriculo-atrial conduction time could be measured in patients with permanent VVI stimulation using esophageal ECG recording. 2. Shortening of the stimulation cycle prolonges ventriculo-atrial conduction time. 3. Ventriculo-atrial conduction time is longest in group with atrio-ventricular conduction disturbances, especially in group with registered bundle branch block.