Myocardial Reperfusion Improves Ventricular Isovolumic Relaxation in Patients with Acute Myocardial Infarction

The study aimed to investigate the effects of thrombolytic therapy and 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 work, 26 patients (treated group) received intravenously thrombolytic therapy within 12 hours after the AM! event, and 12 patients (controlled group) received 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 treated patients than in the controlled 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 available.