Ventricular pressure-volume relationships and oxygen consumption in fibrillation and arrest.

Pressure-volume relntionships and niyocnrdinl oxygen consumption (VOL) were obtiiined in nil isolated heart during ventricular fibrillation, potassium-induced arrest, and isovolumi'tric contractions. The heart was found to be less distensible in fibrillation than in diastole or arrest. The VOL increased from 4.6 to 14.6 ee./.lOO Gm. LV/min. as tlie fibrillatingventricle was distended. Duringarrest the VOL remained constant despite ventricular distention. When the fibrillating ventricle was distended beyond a critical point coronary flow was compromised and the V3., decreased. Beyond and only beyond this point could the VOL be increased by the greater coronary flow induced by a higher perfusion pressure.