[Simultaneous appearance of precordial pain and effort-induced left bundle branch block. A study of 6 patients with normal coronary angiography].

6 patients, 4 men and 2 women, aged 38 to 60 years, were hospitalised for chest pain on effort, labelled as angina. The resting electrocardiogram was normal, except in 2 cases with incomplete left bundle branch block. Exercise stress testing induced simultaneous chest pain and complete left bundle branch block (LBBB) (at a rate of 15 to 160 beats/min, mean 115). The pain lasted as long as the LBBB was present and eased as it disappeared. All patients had normal coronary angiography and negative provocative tests of coronary spasm with atrial stimulation (4 cases), isoprenaline test (2 cases), atropine injection (2 cases) and nitroglycerin (1 case). A 2D echocardiogram performed in all the patients, showed no signs of myocardial disease. Myocardial perfusion on effort was studied by Thallium 201 scintigraphy in all 6 patients. There were no perfusion defects. An exercise stress test was performed after beta-blocker treatment in 3 patients. LBBB appeared each time and the pain was always present. The induction of bradycardia with propranolol (5 cases) or verapamil (3 cases) did not reduce the frequency of chest pain. No serious complications were observed during follow-up (myocardial infarction, death). The syndrome of painful LBBB is not related exclusively to tachycardia. Myocardial ischaemia does not seem to be the underlying mechanism judged by the negative thallium studies.