Relative Roles of Preload Increase and Coronary Constriction in Ergonovine-Induced Myocardial lschemia in Stable Angina Pectorig GABRIELE FRAGASSO, MD, GRAHAM J. DAVIES, MD, SERGIO CHIERCH!A, MD, FILIPPO CBEA, MD, VALTER BENCIVELLI, PhD, and AlTILl MASERI, MD To assess the relative ro!e of increased ventricular preload and critical coronary lesions in ergonovine- induced myocardial ischemia, 9 normal subjects (group A), 7 patients with stable angina (group B) and 5 with variant angina (group C) were studied. In all patients, the 12-lead electrocardiogram, blood pressure and left ventricular (LV) volume (techne- tium-9?m blood pool) were continuously recorded before and during administration of incremental doses Qf ergonovine given at S-minute intervals. In all subjects, an initial LV dilatation developed; in group B and C patients, this was followed by a de- crease in stroke volume and ejection fraction with subsequent onset of electrocardiographic changes and angina. The interval between these events was significantly shorter in group C and in 3 group B pa- tients, in these patients, signs of ischemla appeared with smaller ergonovine doses and at minimal pre- load increase, coronary constrictiqti being the likely mechanism of ischemia. In the remaining 4 group B patients, the onset of stroke volume,‘ejection frac- tion, electrocardiographic changes a?d- angina was signjficantly delayed, occurring after adt&ii+tratlon of larger ergonovine doses when LV volume was al- ready considerably increased. This finding suggests that the loading effect of ergonovine on LV vOium?j rather thaq on coronary Constriction’, could be the prevailing mechanism of ergonovine-induced ische- mia in these patients. (Am J Cardiol 1987;60:238-243) E rgonovine maleate provokes coronary spasm in more than 90% of patients with variant angina.1-3 Re- cent studies have reported that ergonovine also can cause myocardial ischemia in about 30% of patients with stable angina.4 A positive ergonovine test result in patients with critical coronary narrowings could be caused by either a small increase in coronary tone at the site of the stenosis5-7 or by an increase in preload, because ergot alkaloids also produce venoconstric- tions.B:Q This study investigates the possible role of in- creased left ventricular (LV) preload in ergonovine- induced myocardial ischemia in patients with stable angina and severe reduction of coronary flow reserve. The changes in LV volume after administration of er- ganovine were compared with those observed in pa- tients with variant angina and in control subjects. From the Cardiovascular Research Unit, Royal Postgraduate Medical School, London, England. Manuscript received NO- vember $3, 1986; revised manuscript received March 31, 1987, accepted April 2, 1987. Address for reprints: Gabriele Fragasso, MD, Divisione di Cardiologia, Ospedale S. Raffaele, Milano, Italy. Methods Patients: Twenty-one patients (19 men, 2 women, mean age 54 f 10 years] were selected for study: 9 patients [group A) with chest pain, negative exercise and ergonovine test results and normal coronary arte- ries served as control subjects; 7 patients (group B) had stable angina pectoris, a positive exercise test result at low workload (mean exercise duration 4.9 f 1 min- utes], positive ergonovine test result [angina and ST depression at least 0.1 mV) and severe coronary artery disease; and 5 patients (group C) had variant angina with coronary spasm documented at angiography and a positive ergonovine test result (ST elevation at least 0.2 mV). The characteristics of group B and C patients are listed in Table I. Each patient gave informed con- sent to the study. Protocol: Patients w&e studied in the fasting state while in the supine position and without antianginal therapy. The blood pool was labeled with 0.2 mg/kg of stannous pyrophosphate and 370 MBq of technetium- 99m pertechnetate. lo A single-crystal scintillation probe was positioned over the left ventricle in the 40” left anterior oblique projection, with 15~ craniocaudal 238