부산대학교 도서관

Purpose: The no-reflow (NR) phenomenon in patients with ST-segment-elevation acute myocardial infarction (STEMI) is associated with a negative remodeling of the left ventricle and a worse clinical outcome. However, the effects of NR on mechanical ventricular synchrony in these patients is poorly known. In this study we investigated the impact of NR on synchrony of left ventricular (LV) contraction in patients with STEMI treated by primary percutaneous coronary intervention (PPCI).Methods: We enrolled 22 consecutive patients (average 54.6±14.3; 20 males) with a first STEMI undergoing PPCI within 12 hours of symptom onset. Angiographic NR was diagnosed when Thrombolysis in Myocardial Infarction (TIMI) coronary flow grade after PPCI was ≤2 and/or myocardial blush grade <2 in patients with TIMI flow grade of 3. Patients underwent real time 3D speckle-tracking (3DST) echocardiogram at baseline and at 1 month follow up. The standard 16-segment model of the LV anatomy was used for analysis of regional LV contraction. Presence and degree of mechanical desynchronization was evaluated with the systolic dyssynchrony index (SDI, standard deviation of the time to peak/16 LV-segment) for longitudinal (LS), circumferential (CS) and radial (RS) direction strain.Results: NR occurred in 7 of the 22 patients (31.8%). Patients with NR, compared to no-NR patients, were older (63□12.1 vs 50.7□13.2, p=0.05) and had a higher time to PPCI (<3h: 0 vs 50%; 3-6h: 57.1 vs 37.5%; >6h: 42.9 vs 12.5% respectively; p=0.05), while there were no differences between groups in gender, infarct site, culprit vessel and troponin peak serum level. LVEF was lower in NR patients both at pre-discharge (40±9% vs 50±14%, p=0,10) and at follow up (41±11% vs 59±8%, p=0.004). Moreover, patients with NR showed higher values of SDI on LS, CS and RS direction compared to those without NR both at baseline (21.7±2.9 vs 15.1±4.6, p=0.008; 18.2±6.5 vs 13.5±5.3, p=ns; 20.6±6.2 vs 15.1±3.6, p=0.04, respectively) and follow up (16.2±2.3 vs 10.5±3.1, p=0.01; 10.3±3.1 vs 7.4±3.1, p=ns; 14.9±2.1 vs 10.4±3.3, p=0.02, respectively).Conclusion: Patients with NR have a reduced LV function and increased LV mechanical dyssynchrony at pre-discharge. Furthermore, among our patients, those with NR did not show improvement of left ventricular function at 1 month follow up, whereas they showed improvement of dyssynchrony indexes. Left ventricular dyssynchrony, however, remained significantly increased in NR patients compared to patients with normal flow.