Prognostic significance of systolic time intervals after recovery from myocardial infarction

This study tested the hypothesis that left ventricular global performance as assessed from systolic time intervals provides a prognostic indicator in patients with coronary artery disease. The ratio of preejection period to left ventricular ejection time ( PEP LVET) was determined in 136 patients an average of 14.3 months (standard deviation 2 months) after a clinically documented acute myocardial infarction. The patients were followed up a minimum of 24 and an average of 43 ± 15 months. Coronary arteriography was performed within 48 hours of determination of the solPEP LVET ratio. The cumulative 5 year survival rate was 70 percent for the entire series; it was 93 percent for patients with a normal PEP LVET ratio (0.42 or less) and 57 percent for patients with an abnormal ratio (greater than 0.42) (p < 0.001). There was diminishing cumulative survival with increasing extent of coronary arterial obstruction (p < 0.01). Among patients with a normal PEP LVET ratio and one, two or three vessel disease, the 5 year survival rate was 97, 92 and 87 percent, respectively. Among patients with an abnormal PEP LVET ratio, the respective rates were 82, 51 and 41 percent. Multivariate analysis of factors shown to vary significantly between groups with a normal or abnormal PEP LVET ratio or to have independent prognostic value (age greater than 60 years, angina pectoris, dyspnea, multiple sites of myocardial infarction on electrocardiography, third sound gallop, and cardiothoracic ratio greater than 0.5 on chest roentgenography) revealed that only a cardiothoracic ratio greater than 0.5 added significant predictive information to that of the PEP LVET ratio. The presence of dyspnea, a third or fourth sound gallop and a cardiothoracic ratio greater than 0.5, alone or in combination, did not permit accurate segregation of the patients with a normal or abnormal PEP LVET ratio. Determination of the PEP LVET ratio permits stratification of patients with a previous myocardial infarction into groups with markedly divergent survival patterns. The level of resting left ventricular performance in such patients constitutes a more potent prognostic indicator than does the extent of coronary arterial occlusive disease.