Ischemic Burden in Silent and Painful Myocardial Ischemia: Quantitative Exercise Sestamibi Tomographic Study

Objectives. We sought to determine whether the amount of myocardial ischemic burden differs in patients with painful or silent myocardial hypoperfusion during exercise testing. Background. Whether lack of symptoms during ischemi reflects an alteration in pain perception or less myocardium in jeopardy remains controversial issue. Methods. We studied 300 consecutive patients with well established history of ischemic heart disease and reversible hypoperfusion on exercise sestamibi tomography. Rest and stress sestamibi defects were quantitatively assessed and indexes of exercise left ventricular dilation derived. Results. Painful and silent reversible ischemi was observed in 97 (32%) and 203 (68%) patients, respectively. Patients with painful ischemi had lower values for work load, exercise time and peak rate-pressure product (p < 0.01) and more frequently showed significant ST segment depression during exercise than did patients with silent ischemi (69% vs. 40%, p < 0.001). On sestamibi tomography, patients with painful ischemi had more reversible hypoperfusion than did patients with silent ischemi (mean ± SD 16 ± 10% vs. 11 ± 7%, p < 0.001), despite comparable extent of stress hypoperfusion (22 ± 12% vs. 22 ± 13%); they also had higher endocardial dilation index (1.32 ± 0.32 vs. 1.10 ± 0.26, p < 0.001). By multivariate logistic analysis, the most powerful correlate of painful ischemi was history of effort angina; the extent of reversible perfusion defect was the sole independent scintigraphic correlate of painful ischemia. Conclusions. To our knowledge, this is the largest study comparing the degree of hypoperfusion and the presence of symptoms during exercise stress testing in consecutive cohort of patients with ischemic heart disease and reversible hypoperfusion. The results suggest that the ischemic burden is greater in painful than in silent ischemia.