[Comparative assessment of inotropic reaction of isolated myocardium of patients with ischemic and rheumatic heart disease after short-term periods of rest at the background of amiodarone].

We studied inotropic reaction of isolated myocardium of patients with heart failure induced by ischemic and rheumatic cardiac involvement after periods of rest at the background of amiodarone. The studies were carried out on muscular trabeculi separated from right atrial auricle during surgery. It was shown that inotropic reaction of insufficient myocardium could be of 2 types. In type I inotropic reaction first contraction after period of rest either exceeded basal contractions or remained at their level. Type 2 was characterized by significant lowering of amplitude of contractions relative to regular ones. Exposure of the myocardium to amiodarone (1 micro/L) led to significant potentiation of trabeculi contraction after periods of rest of muscles with type I reaction and did not affect response of muscles with type II reaction. These results allow to conclude that the state of calcium transporting systems of sarcoplasmic reticulum (SR) is different in ischemic and rheumatic heart failure and that realization of therapeutic effect of amiodarone depends on functional state of SR.