Significance of extension of exercise-induced ischemia toward apex of left ventricle

Severity of exercise-induced ischemia with chest pain and recovery from ischemia after the disappearance of chest pain

The severity of exercise-induced painful ischemia and its recovery after the disappearance of pain are unknown. The aim of this study was to investigate the difference in severity of ischemia at both exercise and postexercise between painful ischemia and painless ischemia. After injections of technetium-99m tetrofosmin at peak ergometer exercise and thallium-201 at 3 minutes postexercise, dual-isotope single photon emission tomography was performed in 78 patients with angiographically proven ischemic heart disease. The extent of ischemic areas (the number of areas), the depth of ischemia in the ischemic area (the severity score of ischemia) and the extension of ischemia toward long axis of the left ventricle (the number of left ventricular levels with ischemic areas in apical, middle, and basal levels) at both exercise and postexercise were compared on the basis of the presence of pain and a history of diabetes mellitus (DM). The symptoms improved within 3 minutes postexercise in all painful ischemia patients. Of 59 patients with reversible ischemia, except for 4 painful ischemia patients with DM, the extent and depth of ischemia at postexercise were more severe in 14 painful ischemia patients without DM and 13 painless ischemia patients with DM than 28 painless ischemia patients without DM (extent; 2.9 +/- 1.7 areas, 3.5 +/- 2.8 areas versus 1.4 +/- 1.8 areas, P = 0.005, depth; 3.8 +/- 3.1 scores, 5.8 +/- 5.4 scores versus 1.9 +/- 3.0 scores, P = 0.0084, respectively) despite a comparable severity of ischemia at peak exercise (extent; 5.4 +/- 2.6 areas, 6.0 +/- 2.4 areas versus 4.3 +/- 3.3 areas, depth; 9.3 +/- 5.7 scores, 10.7 +/- 7.3 scores and 7.5 +/- 8.1 scores, all NS). The extension of ischemia toward long-axis of the left ventricle at both peak exercise and postexercise was more severe in the former 2 groups than the latter group (peak exercise; 2.4 +/- 0.6 levels, 2.5 +/- 0.7 levels versus 1.9 +/- 0.8 levels, P = 0.0263, postexercise: 1.8 +/- 0.7 levels, 1.5 +/- 0.9 levels versus 0.8 +/- 0.8 levels, P = 0.0014, respectively). The presence of chest pain is related to the extension of ischemia toward long-axis of the left ventricle, and the disappearance of pain was not related to the recovery of ischemia.