COMPARISON OF CARDIAC OUTPUT BY A DIRECT METHOD AND THE HAMILTON-REMINGTON PROCEDURE

Abstract

Three methods were devised by which the input of the right or left heart per min. could be measured directly, while aortic pressure pulses were recorded in large amplitude by calibrated Gregg manometers. The pressure pulses were analyzed according to the procedure of Hamilton and Remington and cardiac output was calculated. The analysis of 81 records from 11 dogs revealed that left ventricular output is generally 2 or more times as large as the measured input; further, that in isolated instances the directional trend of cardiac output was not even predictable from such analyses. While some reservation must be exercised in stating that discrepancies of similar magnitude exist in less extensively operated dogs, the results clearly show that the method is far from good enough to be of use in exptl. studies in cardiac output in dogs.