POSSIBLE MECHANISMS OF MYOCARDIAL-ISCHEMIA DURING VALSALVA TEST IN CORONARY PATIENTS

Changes in hemodynamics associated with Valsalva's test are responsible for a reduction in myocardial oxygen consumption and a decrease in diastolic coronary perfusion pressure in ischemic patients and subjects free of coronary heart disease. Due to stenosis and occlusion of coronary arteries lowering of perfusion coronary pressure in relevant patients becomes more profound and may induce ischemia in spite of diminished oxygen consumption. The main cause underlying onset of myocardial ischemia in patients with marked lesions of coronary arteries is initially low perfusion pressure and limited coronary reserve.