Myocardial ischemic effects of isometric, dynamic and combined exercise in coronary artery disease.

The electrocardiographic effects isometric (handgrip) and combined isometric-dynamic (treadmill-plus-brief-case) exercise were evaluated and compared to a submaximal treadmill stress test in 140 patients with known or suspected coronary artery disease. Only 3 of 90 patients developed ischemic ST changes during handgrip, as opposed to 25 positive treadmill tests (p less than 0.01). Of 19 of 50 patients who were positive during the standard treadmill test, only 17 showed positive findings during the combined treadmill-briefcase test. Analysis of hemodynamic responses showed significant (p less than 0.01) differences between the handgrip and treadmill tests in terms of heart rate response (control 83 plus or minus beats/minute, handgrip 105 plus or minus 4, treadmill 151 plus or minus 6), diastolic blood pressure (control 80 plus or minus 2 mm Hg, isometric 93 plus or minus 3, treadmill 81 plus or minus 3) and heart rate-systolic pressure product (control 9940 plus or minus 564 units, handgrip 15022 plus or minus 779, treadmill 22270 plus or minus 1147). In comparing treadmill and combined treadmill-briefcase tests, significant differences were seen in systolic blood pressure (control 114 plus or minus 2 mm Hg, treadmill 143 plus or minus 3, briefcase 155 plus or minus 3), diastolic blood pressure (control 83 plus or minus 2 mm Hg, treadmill 82 plus or minus 2, briefcase 89 plus or minus 2) and rate-pressure product (control 10134 plus or minus 373, treadmill 19624 plus or minus 777, briefcase 21201 plus or minus 798). Isometric exercise alone is much less likely to produce myocardial ischemia than vigorous dynamic exercise. Higher arterial diastolic (coronary perfusion) pressure may retard the development of myocardial ischemia during isometric or combined isometricdynamic exercise in coronary patients.