Mechanical combined heart supporting system for prevention of irreversible ventricular fibrillation after experimental cardiogenic shock.

To determine whether haemodynamic effective support of the failing heart can prevent spontaneous irreversible ventricular fibrillation (IVF) after experimental cardiogenic shock, 63 open chest dogs were assigned randomly into four groups--two control groups (combined heart failure--CHF) and two MCHSS-treated (combined heart failure and non-pulsatile bypass with intraaortic counterpulsation). The CHF was produced by occlusion of the anterior descending coronary artery (group I) or the left circumflex coronary artery (group II) and by an artificial shunt between the pulmonary artery and right atrium. IVF were observed in 10 out of 22 control dogs (group I) and im 17 out of 21 control dogs (group II). In the 20 dogs with the CHF (10 animals in each group) the MCHSS was performed in the course of two hours. During the heart support no IVF were observed in any of the dogs. The difference between the incidence of IVF in the control and treated animals is statistically significant (Chi square = 21.9767 greater than Chi square 0.005).