Factors influencing retrograde conduction. Study of 30 patients during cardiac catheterization.

Retrograde conduction from ventricle to atrium is a well-recognized occurrence in the human heart. The phenomenon has been observed repeatedly during ventricular tachycardia (Kistin, 1961), with ventricular premature and interpolated beats (Kistin, 1959, 1963; Kistin and Landowne, 1951), in patients with ventricular pacemakers (Kastor and De Sanctis, 1967; Barold, Linhart, and Samet, 1968), and occasionally in the presence ofhigh-grade antegrade atrioventricular (AV) block (Cohn and Fraser, 1914; Winternitz and Langendorf, 1944; Scherf and Cohen, 1964; Castillo and Samet, 1967; Kastor et al., 1967; Fletcher and Morton, 1968). Study of such events has been useful in elucidating the functional characteristics of the cardiac conduction system, and in explaining the electrophysiology of arrhythmias with bidirectional conduction. The incidence of retrograde conduction, however, as reported, has shown considerable variation. This paper reports the result of a study designed to examine those factors which potentially might influence the frequency of ventriculo-atrial conduction in man. Particular attention was paid to the relation of the incidence and velocity of retrograde conduction to heart rate, the status of antegrade conduction, the nature of the underlying heart disease, and the presence of cardiac drugs.