Combined static-dynamic effort decreased treadmill work load (7.1 vs 8.0 mets) and increased heart rate, systolic blood pressure, and rate-pressure product at the onset of ischemia (p<0.001).
Does combined static-dynamic effort alter the threshold for ischemic abnormalities compared to dynamic effort alone in men with chronic ischemic heart disease?
Combined static and dynamic effort increases the hemodynamic threshold at which ischemic abnormalities appear compared to dynamic effort alone.
p-value: p=<0.001
Thirty men, mean age 55 years, 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, one with and one without added static effort, were performed on each of two 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) multiples of resting oxygen consumption (mets), estimated; 141 +/- 3 vs 134 +/- 3 beats/min; 170 +/- 4 vs. 162 +/- 4 mm Hg and 239 +/- 8 vs 218 +/- 9 (p less than 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.
DeBusk et al. (1979) studied chronic ischemic heart disease (n=30). Combined static-dynamic effort vs. Dynamic effort alone was evaluated on Cardiovascular responses at the onset of ischemic ST-segment depression or angina pectoris (p=<0.001). Combined static-dynamic effort decreased treadmill work load (7.1 vs 8.0 mets) and increased heart rate, systolic blood pressure, and rate-pressure product at the onset of ischemia (p<0.001).