[Auriculo-Hisian conduction of patients with bundle branch block. Clinical significance]

The clinical and electrophysiological data in 52 consecutive patients with bundle branch block and followed-up for an average period of 20.8 +/- 10.4 months was reviewed. The patients were divided into two groups: Group A with normal AH intervals (36 patients) and Group B with prolonged AH intervals (16 patients). These two groups differed in age, the average being higher in Group B (p < 0.05), in history of syncope (more common in Group A: p < 0.01) and in the duration of PR interval (p < 0.05). On electrophysiological investigation the Wenckebach point was lower in Group B (118 +/- 29 ms) than in Group A (160 +/- 33) (p < 0.001). The effective right atrial refractory period was significantly longer in Group B (321 +/- 111 ms) than in Group A (246 +/- 59 ms) (p < 0.05). The effective refractory period of the atrioventricular node was also significantly longer in Group B (492 +/- 190 ms) than in Group A (333 +/- 125 ms (p < 0.05). On the other hand, there was no significant difference in the HV interval or in the number of patients managed by permanent pacing.