[Myocardial potassium and H-ion loss during normothermic, ischemic heart arrest].

Arterial and venous [K+] and [H+] concentrations were determined during normothermic ischemic arrest in cat hearts intermittently perfused without resuscitation. The slight loss in [K+] was taken as evidence of a stable membrane potential. The decrease in [H+] activity appearing in the perfusate correlated well with the previously described increase in coronary resistance. This was interpreted as a sign of restricted coronary perfusion and not as evidence for reduced anaerobic metabolic activity. Thus the functional impairment of the coronary system was confirmed to be a limiting factor when resuscitating ischemically arrested hearts.