COMPARISON OF CARDIOVASCULAR-RESPONSES TO STATIC-DYNAMIC EFFORT AND DYNAMIC EFFORT ALONE IN PATIENTS WITH CHRONIC ISCHEMIC HEART-DISEASE

Men [30], mean age 55 yr, known to have treadmill-induced ischemic ST-segment depression, performed static and dynamic effort, i.e., forearm lifting and treadmill exercise, separately and combined. Static effort was sustained at 20%, 25% or 30% of maximal forearm lifting capacity. Two symptom-limited treadmill tests, 1 with and 1 without added static effort, were performed on each of 2 visits. Compared with dynamic effort alone, combined static-dynamic effort decreased treadmill work load and increased heart rate, systolic blood pressure and rate-pressure product at the onset of ischemic ST-segment depression or angina pectoris: 7.1 .+-. 0.4 vs 8.0 .+-. 0.5 (SEM [standard error of the mean]) multiples of resting O2 consumption, estimated; 141 .+-. 3 vs 134 .+-. 3 beats/min; 170 .+-. 4 vs. 162 .+-. 4 mm Hg and 239 .+-. 8 vs 218 .+-. 9 (P < 0.001). The prevalence of angina pectoris was significantly less with combined static-dynamic effort than with dynamic effort alone. Static effort causes a resetting of the threshold at which ischemic abnormalities appear during dynamic effort.