Acetylcholine- and ergonovine-induced coronary microvascular spasm reflected by increased coronary vascular resistance and myocardial lactate production

Diagnosis of coronary microvascular spasm remains largely speculative becau se it has been mostly based on chest pain and electrocardiographic ST-segme nt shift with slow filling of contrast medium into the coronary artery. A p atient with resting chest pain and normal coronary angiograms underwent pro vocative tests with intracoronary acetylcholine (ACh) and ergonovine. Durin g the tests, coronary diameter and flow velocity in the left anterior desce nding (LAD) coronary artery were measured with quantitative coronary angiog raphy and intracoronary Doppler guide wire, respectively. Vascular resistan ce of the LAD and lactate production were determined separately. With injec tions of 100 mu g of ACh and 20 mu g of ergonovine, chest pain occurred wit h ST-segment elevation in the precordial leads in the absence of epicardial coronary spasm. Coronary vascular resistance increased by 2.2- and 1.6-fol d of the baseline value with ACh and ergonovine, respectively. Myocardial l actate production was noted during the ST-segment elevation. Coronary micro vascular spasm was verified by the increment in coronary vascular resistanc e and myocardial lactate production with concomitant ST-segment elevation i n the presence of normal coronary angiograms.