Clinical significance of strain rate stress echocardiography in the early phase of acute myocardial infarction

Abstract

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[영문]

Background: Strain rate stress echocardiography (SRSE) offers left ventricular (LV) remodeling and even survival data in patients with suspected coronary artery disease. However, there are few reports about the role of SRSE on LV remodeling and survival in patients with acute myocardial infarction (AMI). And, the value of SRI parameters about diastolic and time interval was not fully evaluated in AMI. The aim of this study was to evaluate whether SRSE reflects initial LV diastolic function and predicts late LV remodeling and long-term prognosis by comprehensive SRI analysis in patients of the early phase after an AMI. Methods: Prospectively, 134 consecutive patients with AMI and akinetic wall motion in at least two segments were enrolled and underwent low-dose dobutamine stress echocardiography (LDDSE) 5~9 days after the event. The peak systolic tissue velocity, peak systolic strain, and seven strain rate parameters, including the peak systolic and diastolic strain rate and each timing parameters were measured at baseline and 10 mcg of the LDDSE. All 9 parameters were transformed to mean (segmental) and sum value of akinetic segments and mean (global) value of all segments. Within 6 hours of the LDDSE, left and right heart catheterization with recording of the LV end diastolic and pulmonary capillary wedge pressures were performed. Follow-up echocardiography with measurement of NT-proBNP was performed after 6 months. At the end of the study, we collected long-term follow-up (50.0 ± 2.0 months) data. Altogether, 45 patients and 520 segments were assessed.Results: The patients (66.7% males; mean age, 58.6±1.9 years; 66.7% anterior wall, and 71.1% ST-segment elevation) tolerated the LDDSE without significant complications. As expected, global peak strain rate of E (SRE) and time-to-peak (TTP) to peak strain rate of A (SRA) at 10 mcg correlated with the E/E’ ratio (r=-0.41 and p=0.02 and r=-0.35 and p=0.02, respectively). Interestingly, global TTP-SRA and segmental TTP-SRE at 10mcg independently predicted LV remodeling (an increase of >20% in left ventricular end diastolic volume) in 6 months of follow-up (β=-0.02 and p=0.04 and β=-0.04 and p=0.03, respectively). However, neither global nor segmental strain rate parameters predicted long-term survival.Conclusions: Diastolic time-interval strain rate parameters of LDDSE reflected LV diastolic function and late remodeling in the early phase of an AMI, but could not predict long-term survival in this study. Thus, SRSE may provide useful prognostic information for LV remodeling in patients in the early phase of an AMI.