Modified Starling heart-lung preparation for measuring coronary vascular resistance.

A simplified in situ heart-lung preparation has been developed for measuring coronary vascular resistance and left ventricular performance. It provides the ability to observe the direct, cardiac effects of an agent independent of the central nervous system and circulating hormones. It eliminates the need for cross-matched blood or the use of colloidal solutions and permits direct control of coronary driving pressure and heart rate, and partial control of myocardial compression. The preparation shows relative long-term stability with readily alterable acid-base and blood gas content. Total coronary flow and resistance may be measured and the systolic and diastolic components calculated. Measurement of the various parameters of ventricular performance, total cardiac oxygen consumption, and cardiac efficiency is readily accomplished with an appropriate data acquisition system.