Abstract
Sixty-five percent in SSS and fifteen percent in AVB had retrograde V-A conduction. The retrograde conduction time was 259±31 msec (mean±SD). The amplitude of retrogradely conducted P waves was revealed to be lower than that of antegrade P waves, 2.7±1.7mV vs 4.1±2.4mV in bipolar leads, and 3.0±1.6mV vs 3.4±1.5mV in unipolar leads respectively.