Anomalies of the T wave following treatment of complete chronic left branch block by massage of the carotid sinus or injection of adenosine triphosphate

: We studied the T wave during normal conduction in 25 patients aged 42 to 81 years (average 62 +/- 5) during sinus rhythm and complete left bundle branch block which regressed transiently after carotid sinus massage (22 cases) or injection of adenosine triphosphate (5 cases). Six patients had angina pectoris; coronary arteriography in 3 of the other 19 patients was normal. The reversion to normal intraventricular conduction was obtained with a lengthening of the ventricular cycle in all patients. The T wave axis with narrow QRS complexes was between + 70 degrees and -140 degrees (normal T axis in 11/25 patients); in the horizontal plane, the T wave was negative in V2 in 4 patients, in V2-V4 in 12 patients, in V2-V6 in 7 patients and in V4 in 1 patient. The amplitude of inversion in V2 varied from 0.1 to 1.5 mV; there was no significant difference between the patients with angina (0.50 +/- 0.31) and the remainder (0.43 +/- 0.16). In normal conduction, the T wave changes were more common in the horizontal plane (24/25 patients: 96%) than in the frontal plane (14/25 patients, 56%). The high incidence of abnormalities of ventricular repolarisation after regression of complete left bundle branch block does not appear to be related to coronary artery disease. Another explanation is proposed because of the analogy with the changes observed after terminating right ventricular pacing and after regression of a Wolff-Parkinson-White syndrome. An abnormality of initial ventricular depolarisation--common to left bundle branch block, the Wolff syndrome and right ventricular pacing--could be responsible for these T wave changes during normal conduction.(ABSTRACT TRUNCATED AT 250 WORDS)