Open AccessElectrophysiological characteristics of junctional pacemakers in congenital A‐V block and following his bundle cryoablation
Author(s) -
Bexton R. S.,
Ward D. E.,
Camm A. J.
Publication year - 1982
Publication title -
clinical cardiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.263
H-Index - 72
eISSN - 1932-8737
pISSN - 0160-9289
DOI - 10.1002/clc.4960051102
Subject(s) - medicine , atropine , junctional rhythm , bundle of his , intracardiac injection , cryoablation , cardiology , ablation , anesthesia , electrocardiography , heart rate , electrophysiology , bundle branch block , electrical conduction system of the heart , blood pressure
The characteristics of the escape mechanism following surgically induced permanent A‐V block were investigated and compared with those seen in congenital complete heart block (CHB). Six patients had undergone elective cryothermal ablation of the His bundle for supraventricular arrhythmias unresponsive to pharmacological and pacemaker techniques (group A) and 12 patients had congenital CHB (group B). In the 12 patients in group B the site of block was localized by His bundle electrocardiography to be proximal to the point of recording of the His potential. In 3 patients in group A in whom intracardiac studies were performed it was impossible to record an His potential. There were no significant differences between the control escape rate, junctional recovery time (JRT), and corrected junctional recovery time (cJRT) of the two groups. In group A there were no significant changes in these parameters following the administration of atropine, whereas isoproterenol significantly increased the rate of the subsidiary pacemaker (p < 0.001) and shortened the JRT (p < 0.02) and cJRT (p < 0.02). In group B both atropine (A) and isoproterenol (I) significantly increased escape rate (A, p < 0.001; I, p < 0.001) and shortened JRT (A, p < 0.01; I, p < 0.001) and cJRT (A, p < 0.01; I, p < 0.001). It is concluded that the escape focus in patients with congenital CHB is situated in the A‐V node. The escape rhythm following His bundle section is unpredictable and elective permanent pacemaker implantation is indicated.