Suppression of inducible painless myocardial ischemia by conventional medical therapy: Effect on short-term outcome and left ventricular systolic function

Abstract

To test the hypothesis that abolition of exercise-induced painless myocardial ischemia by antiischemic medication improves prognosis in patients with medically treated coronary artery disease, we studied such patients with painless ischemia during exercise radionuclide ventriculography performed after temporary discontinuation of medication. The test was repeated while patients received conventional medical therapy that rendered angina no worse than New York Heart Association class I. The relative risk of adverse cardiac events was reduced by >5-fold when painless ischemia was abolished by symptom-dictated therapy. Thus, the abolition of exercise-induced painless ischemia by conventional medical therapy carries a better short-term prognosis in medically treated coronary artery disease, suggesting that therapeutic efficacy may need to be assessed by titration against ischemia and not angina. In patients without overt cardiac events, there were no significant differences between baseline and 12-month measurements of ejection fraction at rest, peak exercise, and the change in ejection fraction from rest to exercise. Thus, in those who remain asymptomatic and event-free, painless ischemia that is easily inducible at baseline despite medication does not lead per se to deterioration of left ventricular systolic function at rest or during exercise over 12 months. Such an effect, if evident as early as at 12 months, would favor a strategy of early revascularization over medical treatment in asymptomatic patients who have inducible painless ischemia despite medication.