Hemodynamic findings in 123 patients with acute myocardial infarction on admission.

Hemodynamic and clinical evaluations of 123 patients with acute myocardial infarction were performed during the first hour of admission to the hospital. In the 123 patients, the right atrial pressure was less than 10 mm Hg in 49 patients, the right atrial oxygen saturation was less than 70% in 97 patients, the arteriovenous oxygen difference was greater than 5.0 vol% in 78 patients. The arterial Po2 was less than 90 mm Hg in 101 of 107 patients who could be evaluated while breathing room air. The cardiac index was depressed below 3.0 L/min/m2 in 65 of 98 patients. The hemodynamic findings generally correlated with the clinical status of the patient; however, within each clinical class of patients there was a wide spectrum of values for each measurement evaluated. There was also considerable overlap of the values found within each clinical classification. It is concluded that hemodynamic evaluation of patients with acute myocardial infarction presents a profile of the patient which is frequently different from the profile that clinical evaluation presents. An objective hemodynamic classification of patients with acute myocardial infarction may provide a more useful index for the evaluation of the patient's prognosis and for the assessment of preventative therapy.