Assessment of Ventricular Function in Patients with Myocardial Infarction by Systolic Time Intervals

Abstract

We measured systolic time intervals (STI) on mechanocardiograms in 95 patients with myocardial infarction 1 month after its onset and compared them with findings of cardiac catheterization and nuclear cardiological examination. 1) Prolongation of the Q-I interval reflected a decrease in cardiac output, and an increase in the PEP/ET ratio reflected an increase in pulmonary capillary wedge pressure. The Q-I interval and PEP/ET can be used instead of Forrester's classification mapping obtained by invasive cardiac catheterization. 2) PEP/ET was significantly higher in the group with multivessel disease than in that with one-vessel disease. 3) The left ventricular ejection fraction at rest was not reflected by STI, but that after exercise in nucler cardiological examination was higher in the group with a higher PEP/ET. These findings show that a high PEP/ET indicates latent decrease in cardiac function even when left ventriclar funcion at rest is normal. In long-term follow up for cardiac function in patients with myocardial infarction, non-invasively obtained STI is a very useful subsitute for findings of cardiac catheterization or nuclear cardiological examination.