The Journal of Thoracic and Cardiovascular Surgery, Vol 69, 17-29, Copyright © 1975 by The American Association for Thoracic Surgery and The Western Thoracic Surgical Association
Surgical aspects of regional myocardial blood flow and myocardial pressure
RJ Baird, F Dutka, M Okumori, A de la Rocha, MM Goldbach, TJ Hill and DC MacGREGOR
The surgical technique of cardiopulmonary bypass with either an empty
beating or an empty fibrillating ventricle produces marked changes in the
regional blood flow and oxygen demand of the left ventricle. This paper
describes the changes which occurred in the regional perfusion of both the
normal and the hypertrophied left ventricle during these conditions and
relates them to the known changes in oxygen demand. It also correlates the
changes in flow with the measurable changes in myocardial tissue
pressure-systolic when the heart is beating and continuous when
fibrillating. The various types of filbrillation had identical effects on
both regional tissue pressure and regional flow. The subendocardial blood
supply was adequate or more than adequate under each of these conditions so
long as the coronary perfusion pressure was maintained at an adequate
level. A low perfusion pressure during ventricular fibrillation of any type
led to a marked reduction in flow to the subendocardial portion of the left
ventricle: The presence of ventricular hypertrophy accentuated this danger.