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Should Ventricular Fibrillation Be Induced Prior to the Infusion of Cardioplegic Solution?

1983; Elsevier BV; Volume: 35; Issue: 4 Linguagem: Inglês

10.1016/s0003-4975(10)61586-x

1552-6259

Tomás A. Salerno, Miguel A. Chiong,

Mitochondrial Function and Pathology

The present study evaluates the metabolic effects on the left ventricular energy stores of a clinically used cardioplegic solution that was infused into the ascending aorta of pigs while the heart was either fibrillating (induced ventricular fibrillation) or in normal sinus rhythm prior to aortic clamping.Fibrillating hearts had lower stores of glycogen in the epicardium and endocardium compared with hearts in normal sinus rhythm.There was no difference in the stores of creatine phosphate between the hearts for both the epicardium and endocardium, but stores of adenosine triphosphate (ATP) in both layers were lower in fibrillating hearts.These results indicate that for ideal myocardial protection the cardioplegic solution should be infused while the heart is beating under cardiopulmonary bypass, and that ventricular fibrillation induced and maintained prior to cross-clamping may cause myocardial damage.Ventricular fibrillation is now rarely used as a means of myocardial protection because of its adverse effects [l-61.It is particularly harmful if employed for prolonged periods [7], if coronary perfusion is inadequate [8, 91, and if the fibrillating stimulus is maintained [lo].To our knowledge, the effects of short periods of induced ventricular fibrillation are not known.However, redistribution of blood flow to the myocardium with preferential flow to the subepicardial regions occurs with ventricular fibrillation [lo] and is accentuated in hypertrophied hearts [I, 6,[11][12][13][14][15].Theoretically this would occur at the moment fibrillation is induced and is later aggravated by ventricular distention.Some surgeons still induce fibrillation before clamping the ascending aorta and infusing the cardioplegic solution for fear of causing aortic tear during ventricular ejection, and