CORRELATION BETWEEN ARTERIOGRAPHIC AND ELECTROCARDIOGRAPHIC FEATURES DURING SPASM IN THE LEFT ANTERIOR DESCENDING CORONARY-ARTERY

Background The clinical role of collateral vessels, which are transien tly augmented during coronary artery spasm, remains controversial. Obj ective To examine the correlation between coronary arteriographic and electrocardiographic features during spasm in the left anterior descen ding artery (LAD). Methods We studied 45 patients in whom LAD spasms w ere induced by administration of acetylcholine or ergonovine maleate i nto the left coronary artery, or in whom spontaneous LAD spasms were d ocumented during diagnostic cardiac catheterization. Results During sp asm, only three patients had transient appearance or augmentation of c ollateral flow opacifying the LAD. In these three patients, electrocar diograms obtained from anterior precordial chest leads during LAD spas m showed ST-segment depression, ST-segment elevation followed by ST-se gment depression, and only T-wave change, respectively. Except for the se three patients, ST-segment elevations were observed in all other pa tients (31 of 34) with main-branch spasm of the LAD. However, ST-segme nt elevation was observed in only two of 11 patients in whom spasm of the diagonal branch alone was induced. Conclusions Our observations su ggest that the electrocardiographic changes during spasm are not alway s a sensitive indicator of LAD side branch spasm or LAD main-branch sp asm associated with collateral circulation. From consideration of the angiographic features of the collaterals in the three patients with LA D main-branch spasm, we speculate that the balance of tonus of both th e recipient and donor arteries, and the degree of organic stenosis of the recipient artery, may have important roles in the mechanism respon sible for the change in the appearance of collaterals in patients with coronary spasm.