Cardiovascular response to combined static-dynamic exercise of patients with myocardial infarction

Background Graded dynamic exercise-stress testing of patients with acute my ocardial infarction prior to discharge from hospital has an important diagn ostic and prognostic implication. Although many daily tasks involve combina tions of static and dynamic exercise, little is known about cardiovascular responses during combined static-dynamic exercise. Objective To determine the difference between cardiovascular responses duri ng two types of combined static-dynamic exercise (a 10 kg weight in one han d, and a 10 kg weight bearing on the shoulder). Methods We studied 27 male patients who had recently suffered myocardial in farction using ear densitography. The patients were divided into two groups : group 1 was comprised of 14 patients with resting left ventricular end-di astolic volumes greater than or equal to 140 ml, and group 2 was comprised of 13 patients with left ventricular end-diastolic volumes <140 ml. Results For eight patients in group 1 we detected positive electrocardiogra phic changes during one-hand weight-carrying exercise, but for none of thes e patients was there an electrocardiographic change during weight-bearing e xercise. All the patients in group 2 completed both types of exercise witho ut significant ST-segment change. Although there were no significant differ ences between values of any of the indices measured for the two groups duri ng weight-bearing exercise, patients in group 1 had significantly shorter d iastolic times/min (21.8 +/- 2.1 versus 25.1 +/- 2.4 s/min, P < 0.01) durin g one-hand weight carrying. Conclusions In addition to decrease in subendocardial coronary blood flow a ssociated with increase in left ventricular end-diastolic volume, shortenin g of diastolic perfusion time during one-hand weight-carrying exercise for patients in group 1 can potentially contribute to subendocardial ischemia, which was favorably altered by bearing a weight on the shoulder. Coronary A rtery Dis 11:35-40 (C) 2000 Lippincott Williams & Wilkins.