title: Effect on prognosis of abolition of exercise-induced painless myocardial ischemia by medical therapy.
abstract: During exercise radionuclide ventriculography, many patients with coronary artery disease exhibit painless myocardial ischemia defined as an abnormal left ventricular ejection fraction response without accompanying angina. To see if complete suppression of such exercise-induced painless ischemia by anti-ischemic medication implies a better prognosis in medically treated coronary artery disease, 34 patients underwent repeat testing at 4 weeks receiving regular conventional therapy that rendered angina no worse than class I. With such therapy, painless ischemia was abolished in 12 patients (group I) and persisted in 22 (65%, group II). Both groups were similar in age, number of diseased vessels, proportion with previous myocardial infarction, exercise ejection fraction, and degree of exercise-induced painless ischemia at baseline. At 9 months, adverse events had occurred in 11 patients (2 patients with myocardial infarction, 4 with unstable angina, 2 with angioplasty and 3 with bypass surgery). Only 1 of 12 patients (8%) in group I had experienced events compared with 10 of 22 (45%) in group II (chi-square, 5.4; p less than 0.025; 95% confidence interval, 12 to 61%). Thus, the relative risk of adverse events in patients whose painless ischemia was abolished was only 18% of that in patients in whom it was persistent. These results suggest that (1) the abolition of exercise-induced painless ischemia by conventional symptom-dictated medical therapy confers a better short-term prognosis in medically treated coronary artery disease, and (2) therapeutic efficacy may need to be assessed by titration against ischemia and not against angina.
authors.affiliation: Department of Cardiology, St. Bartholomew's Hospital, London, United Kingdom.
authors.forename: R
authors.initials: R
authors.lastname: Lim
authors.forename: L
authors.initials: L
authors.lastname: Dyke
authors.forename: D S
authors.initials: DS
authors.lastname: Dymond
mesh_terms: D000328:Adult; D000368:Aged; D016009:Chi-Square Distribution; D003327:Coronary Disease / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000209:etiology; D015444:Exercise / Q000502:physiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D011379:Prognosis; D011446:Prospective Studies; D015635:Radionuclide Ventriculography; D012306:Risk