ISCHEMIC BURDEN IN SILENT AND PAINFUL MYOCARDIAL-ISCHEMIA - A QUANTITATIVE EXERCISE SESTAMIBI TOMOGRAPHIC STUDY

Objectives. We sought to determine whether the amount of myocardial is chemic burden differs in patients with painful or silent myocardial hy poperfusion during exercise testing. Background. Whether a lack of sym ptoms during ischemia reflects an alteration in pain perception or les s myocardium in jeopardy remains a controversial issue. Methods. We st udied 300 consecutive patients with a well established history of isch emic heart disease and reversible hypoperfusion on exercise sestamibi tomography. Rest and stress sestamibi defects were quantitatively asse ssed and indexes of exercise left ventricular dilation derived. Result s. Painful and silent reversible ischemia was observed in 97 (32%) and 203 (68%) patients, respectively: Patients with painful ischemia had lower values for work load, exercise time and peak rate-pressure produ ct (p < 0.01) and more frequently showed significant ST segment depres sion during exercise than did patients with silent ischemia (69% vs. 4 0%, p < 0.001). On sestamibi tomography, patients with painful ischemi a had more reversible hypoperfusion than did patients with silent isch emia (mean +/- SD 16 +/- 10% vs. 11 +/- 7%, p < 0.001), despite a comp arable extent of stress hypoperfusion (22 +/- 12% vs. 22 +/- 13%); the y also had a higher endocardial dilation index (1.32 +/- 0.32 vs. 1.10 +/- 0.26, p < 0.001). By multivariate logistic analysis, the most pow erful correlate of painful ischemia was a history of effort angina; th e extent of reversible perfusion defect was the sole independent scint igraphic correlate of painful ischemia. Conclusions. To our knowledge, this is the largest study comparing the degree of hypoperfusion and t he presence of symptoms during exercise stress testing in a consecutiv e cohort of patients with ischemic heart disease and reversible hypope rfusion. The results suggest that the ischemic burden is greater in pa inful than in silent ischemia.