Quantification and Prognosis of Acute Myocardial Infarction: Comparison of Echocardiographic and Catheterization Indices

Abstract

Stroke work index (SWI), obtained by right heart catheterization as the product of stroke index (SI), and the difference of mean arterial blood pressure (BP) and mean pulmonary artery wedge pressure (PAW) SWI=SI(BPxPAW)1.36 has been demonstrated to accurately reflect the extent and prognosis of acute myocardial infarction. Echocardiography provides an atraumatic technique by which many parameters of cardiac function may be assessed. Therefore we attempted to utilize echocardiography to construct an index of ventricular performance of quantitative and prognostic value. Echocardiography and right heart catheterization were performed simultaneously in 38 patients within 36 hours (average 12 hours) of acute myocardial infarction. The patient population consisted of 31 males and 7 females with a mean age of 60. Echoes were performed in a standard fashion with a commercially available ultrasonoscope while right heart catheterization was performed using a Swan-Ganz catheter. 10 patients suffered pump failure and death following infarction and were classified as non-survivors (NS) while 28 patients survived (S) the infarction. Clinical data, including chest x-ray and physical examination could not distinguish NS from S. SWI, determined by catheterization was markedly reduced in NS 10.5 as compared with survivors 33.3 (p<.001).