Early flow propagation velocity for assessment of diastolic function in myocardial infarction treated with acute reperfusion.

INTRODUCTION

Acute myocardial infarction (MI) causes left ventricular (LV) diastolic dysfunction, which influences prognosis and clinical evolution. Early flow propagation velocity (FPV), evaluated by color M-mode Doppler, has been demonstrated to be a diastolic function parameter with excellent correlation with relaxation constant tau, and is relatively independent of pre- and afterload.

OBJECTIVE

The aim of this study was to evaluate left ventricular relaxation in MI patients treated with acute reperfusion therapy.

METHODS

Patients with ST-elevation MI treated with reperfusion therapy were evaluated by echocardiagraphy in the first 48 hours and after one week. The parameters studied were: early peak filling velocity (E), late peak filling velocity (A), E/A ratio, E-wave deceleration time (EDT), isovolumic relaxation time (IVRT) and FPV. The values obtained at the first and second evaluation were compared; we evaluated the relation between pain-to-reperfusion time (PRT; < or =3 hours vs. >3 hours) and the presence of single-vessel or multivessel disease with the parameters previously mentioned.

RESULTS

40 patients were studied and 19 included, 15 (80%) male, mean age 57+/-14 The most prevalent risk factors were: hypertension (11 patients - 58%), smoking (14 - 74%), diabetes (6 - 30%), and dyslipidemia (12 - 63%). MI location was anterior in six patients (31%) and inferior in 13 (69%). Five patients (26%) underwent fibrinolysis and 14 (74%) direct percutaneous coronary intervention. Mean pain-to-reperfusion time was 3.7+/-2.8 hours. Four patients (21%) had single-vessel disease and 14 (74%) had multivessel disease. Near significance was found for the difference in the E/A ratio between the two evaluations and a significant difference in the FPV. A significant correlation was also found between PRT and E/A ratio at the two evaluations (p=0.003, p=0.05), and between PRT and IVRT after one week (p=0.011). E/A ratio, IVRT and FPV were normal at the two evaluations in patients who had undergone earlier reperfusion therapy. No significance was found between the number of diseased vessels and the parameters of diastolic function assessed.

DISCUSSION AND CONCLUSIONS

In the early phase of M1 treated with acute reperfusion, a delayed relaxation pattern was observed, which evolved to a normal pattern by the second evaluation, as statistically confirmed by FPV. Earlier reperfusion therapy preserves diastolic function. FPV is a sensitive and independent parameter for assessment of diastolic function in MI patients treated with acute reperfusion therapy.