[Functional reserves of the heart under conditions of alimentary magnesium deficit].

Aim of the study was to assess functional reserves of myocardium in animals with deficit of magnesium during stress tests. Magnesium deficit was modeled by 10 week long magnesium deficient diet. After 54% lowering of magnesium level in erythrocytes we registered left ventricular pressure, myocardial contraction and relaxation rates, heart rate, systolic and diastolic arterial pressure, intensity of structures functioning. Than we subjected hearts of these animals to volume load, graded stimulation of cardiac adrenoreceptors, maximal isometric load by clamping ascending aorta. In animals with magnesium deficit we noted smaller increases of left ventricular pressure, myocardial contraction and relaxation rates under conditions of all functional tests, and of systolic arterial pressure during loading with volume and adrenaline. Lowering of myocardial reactivity under conditions of volume and adrenaline loading as well as isometric work load could constitute a basis of genesis of heart failure in magnesium deficit.