CARDIAC OUTFLOW OF ENDOTHELIN, NEUROPEPTIDE-Y AND NORADRENALINE IN RELATION TO HYPEREMIA IN CORONARY SINUS FLOW FOLLOWING ELECTRICAL CONVERSION OF INDUCED VENTRICULAR-FIBRILLATION IN MAN

The implanted cardioverter defibrillator represents an alternative the rapy for patients with drug-refractory malignant ventricular arrhythmi as. Implantation and testing of the device requires that ventricular f ibrillation be evoked and converted, thus providing a situation in whi ch cardiovascular haemodynamics can be studied. In this study we have evaluated the effects of electrically induced ventricular fibrillation , followed by defibrillation, on coronary sinus blood flow and cardiac outflow of endothelin- and neuropeptide Y-like immunoreactivity (-LI) and of noradrenaline. Twelve patients were studied during implantatio n of a defibrillator. Ventricular fibrillation was induced and termina ted after 17 +/- 1 s 5 +/- 1 times in each patient. In six patients co ronary sinus blood flow was measured continuously. Plasma samples were obtained from four of these patients and another six patients, from t he coronary sinus, radial artery and central vein before and during fi brillation and at two time points (<30 s and 5 min). Basal coronary si nus blood flow decreased to 38% at 14 +/- 2 s of ventricular fibrillat ion. Immediately following defibrillation there was a short-lasting in crease in coronary sinus blood flow to 244% and a significant increase in the levels of neuropeptide Y-LI (146%( and noradrenaline (158%) in the coronary sinus while endothelin-LI remained unchanged (97%). Neit her fibrillation nor defibrillation evoked any changes in the peripher al arterial and venous levels of endothelin-, neuropeptide Y-LI or nor adrenaline. It is concluded that coronary sinus blood flow is markedly reduced during fibrillation and that restoration of normal impulse ac tivity is followed by short-lasting hyperaemia. There was no evidence for effects on the vascular endothelium as assessed by endothelin leve ls.