Clinical evaluation of left ventricular function in acute myocardial infarction--analysis of factors affecting left ventricular function

The clinical significance of the possible factors which may affect the cardiac function and prognosis of the patients with acute myocardial infarction were evaluated in 112 patients with this disease. Patients were subdivided into 4 groups according to the levels of pulmonary capillary wedge pressure (PCWP) and left ventricular stroke work index (SWI): Group I (52 patients) PCWP less than 18 mmHg, SWI less than or equal to 30 g.m/m2; Group II (18 patients) PCWP greater than or equal to 18 mmHg, SWI greater than or equal to 30 g.m/m2; Group III (15 patients) PCWP less than 18 mmHg, SWI less than 30 g.m/m2; Group IV (27 patients) PCWP greater than or equal to 18 mmHg, SWI less than 30 g.m/m2. Immediate mortality rate (4 weeks after the onset of myocardial infarction) was 17.0% in all patients and Group IV had the highest mortality rate (48.1%), in contrast to the lowest mortality rate (3.8%) in Group I. The episodes of previous myocardial infarction were noted more frequently in Group IV (74.1%) than in Groups I (7.7%) and II (11.1%) (p less than 0.001). Mean age in Group IV (68.0 +/- 5.2 (SE) years) was also significantly higher than those of the remaining 3 groups (p less than 0.001). In 55 patients without previous myocardial infarction, mean infarct size estimated from total released creatine phosphokinase (CPK) (sigma CPK) in Group IV was largest among the 4 groups, although it was similar to that in Group II: 919.0 +/- 70.0 (SE) IU/ml in Group I, 1470.0 +/- 126.0 in Group II, 958.0 +/- 107.0 in Group III and 1493.0 +/- 145.0 in Group IV. The number of involved coronary arteries differed significantly between Groups I and IV: in Group I involved coronary artery (75% narrowing) was absent or one at most, while in Group IV all 9 patients had at least one coronary lesion and 3 of 9 had triple vessel disease. In this study no significant difference was observed between the incidence of anterior and inferior myocardial infarctions in Groups I, III and IV. Thus, we conclude that age, previous myocardial infarction, infarct size and the number of involved coronary arteries may determine the cardiac function in acute phase of myocardial infarction and hence, immediate mortality of this disease.