Transient left anterior hemiblock during angina pectoris: coronarographic aspects and clinical significance.

The data of 6 patients in whom a left anterior hemiblock appeared in the course of angina pectoris attacks were reviewed. All 6 patients were found to fulfill the criteria for unstable angina. 1 patient who presented the features of Prinzmetal variant angina was included in this group. Coronary arteriography showed significant coronary artery disease in all 6 patients involving 3 vessels in 2 patients, 2 vessels in 1 and 1 vessel in 3. A severe lesion (70--100%) of the left anterior descending artery in the vicinity of the first perforator was demonstrated in every case. The 2 patients with 3-vessel disease were not operable and died 4 and 5 days after the hemodynamic study. These deaths were caused by myocardial infarction with cardiogenic shock in one case and intractable ventricular arrhythmias in the other case. 4 patients were operable and underwent aortocoronary saphenous bypass surgery. There were 2 operative deaths. The 2 survivors are asymptomatic 7 and 16 mth after surgery. This study suggest that transient left anterior hemiblock during an attack of angina pectoris may be a feature of impending myocardial infarction and may be indicative of a severe obstruction of the left anterior descending coronary artery.