Right and left heart pressures in acute myocardial infarction.

AUTHORS' SYNOPSIS In dogs the effects of acute myocardial infarction (AMI) on right and left heart pressure relationships were studied. Right atrial pressure was a poor predictor of left heart pressures. Pulmonary artery end-diastolic, left atrial, and left ventricular end-diastolic pressures tended to equalize in normals (except with tachycardia) and after AMI. In a previously scarred left ventricle, however, after superimposed AM1 and marked elevations in left ventricular end-diastolic pressure, prominent atrial impact waves resulted in this being appreciably higher than the other two pressure measurements. Although pressure relationships between the right and left sides of the heart have long been of interest to cardiovascular physiologists, increasing utilization of right heart pressures in monitoring patients with acute myocardial infarction for indications of left-sided events underscores the need for a better appreciation of the uses and limitations of such measurements. While central venous pressure tends to rise with elevations of left atrial and ventricular end-diastolic pressures, use of the central venous pressure as an indicator of the level of left heart pressures in acute myocardial infarction has been Since, in the absence of mitral stenosis and pulmonary vascular obstruction, the pulmonary artery end-diastolic pressure has been shown to reflect the left ventricular end-diastolic pressure in stable patients studied at catheterization (Kalt-too, has been reported frequently to underestimate left-ventricular end-diastolic pressure, especially when the latter is significantly elevated in acute myocardial infarction Since the dog is frequently used in experimental studies of acute myocardial infarction, and can readily have pressures measured simultaneously in multiple chambers before and after acute infarction, the present study was under-taken in this model. Our purpose was to define right and left heart pressure relationships in the dog before and after myocardial infarction with and without shock, compare these findings with what is known in man, and attempt to determine various factors affecting and altering such relationships. Methods Mongrel dogs were anaesthetized with morphine sulphate (3 mg/kg) and sodium pentobarbital