Primary Pharmocological Therapy May Improve Left Ventricular Diastolic Function in Patients with Acute Myocardial Infarction

The aim of this study was to investigate the effects of thrombolytic therapy and delayed percutaneous coronary intervention (PCI) on the time constant of left ventricular (LV) isovolumic relaxation. Of 38 patients with acute myocardial infarction (AMI) recruited in the study, 26 patients (TL group) received intravenously thrombolytic therapy within 12 hours after the AMI event, and 12 patients (PCI group) received delayed PCI at fifth or sixth day after the AMI event. LV pressure was measured with Millar catheters during diagnostic catheterization both at first week after admission and at 3-month follow-up. We found that in the patients with the thrombolytic therapy, the time constant of the isovolumic relaxation significantly decreases from 50.1 +/- 11.0 ms measured at the first week to 44.2 +/- 8.8 ms measured at the 3-month follow-up (p < 0.05). In contrast, the time constant measured from the patients with PCI is significantly increased from 46.3 +/- 8.4 at the first week to 63.1 +/- 15.9 ms at the 3-month follow-up (p < 0.05). In addition, the time constant was considerably smaller in the TL group patients than in the PCI group patients three months after occurrence of AMI (p < 0.001). In conclusion, myocardial microvessels early reopened by the thrombolysis may dominantly contribute to the improvement in LV diastolic function, suggesting that the thrombolytic therapy may play a more progressive role in the AMI-related treatment as PCI equipment is not immediately available within 12 hours.