The Journal of Thoracic and Cardiovascular Surgery, Vol 69, 203-211, Copyright © 1975 by The American Association for Thoracic Surgery and The Western Thoracic Surgical Association
An experimental model for studying myocardial ischemia. Correlation of hemodynamic performance and metabolism in the working swine heart
AJ Liedtke, HC Hughes and JR Neely
An intact, working swine heart preparation with controlled coronary
perfusion is described. In this model, hemodynamic and metabolic functions
were correlated in control and ischemic myocardium. A closed- loop,
extracorporeal coronary perfusion circuit in series with a perfusion pump
and oxygenator was designed to return reoxygenated coronary venous blood at
controlled flow rates to the left and right coronary arteries. In 9 swine
at normal flows (232 plus or minus 17 ml. per minute), the preparation
maintained stable hemodynamic performance and oxygen consumption for a 1
hour period, after which ischemia was induced by reducing coronary flow by
50 per cent. As a result, left ventricular end-diastolic pressure (LVEDP)
rose by 227 per cent, whereas heart rate (-17 per cent), aortic pressure
(-9 per cent), pressure time/minute (PTM) (-28 per cent), left ventricular
work (-47 per cent), and oxygen consumption (-39 per cent) all decreased.
The ischemic myocardium shifted from lactate extraction to production. With
this model, we can define, over a period of time, several mechanical and
metabolic collations as a function of total coronary blood flow in an
intact, large animal. We can also test interventions during the acute
phases of ischemia in an effort to reduce myocardial damage.
