Left Ventricular Dyssynchrony After Acute Myocardial Infarction is a Powerful Indicator of Left Ventricular Remodeling

ABSTRACT

BACKGROUND AND OBJECTIVES: Left ventricular (LV) remodeling (LVR) after an acute myocardial infarction (AMI) has important clinical implications. We have investigated the prognostic relevance of ventricular systolic dyssnchrony as an indicator of LVR after an AMI. SUBJECTS AND METHODS: We enrolled 92 patients (males, 72.8%; mean age, 61.0+/-13.0 years) with an AMI who underwent successful percutaneous coronary intervention. We analyzed the baseline characteristics, the laboratory and echocardiographic findings, and we performed follow-up echocardiography 6 months after the AMI. The patients were divided into two groups 1) the presence of LVR, which was defined as an increment of LV end systolic volume (LVESV) >20% compared with the baseline examination; and 2) the absence of LVR. RESULTS: Twenty-seven patients (29.3%) developed LVR after a 6 month follow-up. There was no statistically significant difference in the clinical and angiographic findings between the two groups. With respect to the laboratory findings, the LVR group had a higher peak creatine kinase MB (CK-MB) (149.9+/-155.0 vs. 74.6+/-69.7 U/L, p=0.001) and troponin-I (70.2+/-73.3 vs. 43.2+/-39.5 ng/mL, p=0.024) level than the group without LVR. With respect to echocardiographic findings, the baseline LV ejection fraction (EF) and LVESV were not significantly different (LVESV, 73.0+/-37.3 vs. 91.3+/-52.0 mL, p=0.013; and EF, 58.3+/-13.3 vs. 55.6+/-11.8%, p=0.329) between the groups with and without LVR, respectively. The degree of LV dyssynchrony, which was assessed by tissue Doppler imaging, was significantly higher in the LVR group than the group without LVR (75.2+/-43.4 vs. 38.3+/-32.5 ms), and the degree of LV dyssynchrony was an independent predictor for LVR based on multivariate analysis {hazard ratio (HR)=0.097, p<0.001}. In receiver operating characteristics (ROC) curve analysis, the area under the curve (AUC) was 0.754 and a cutoff value of 45.9 predicted the development of LVR with 74.1% sensitivity and 72.3% specificity. CONCLUSION: The presence of LV dyssynchroncy immediately after a myocardial infarction is an important predictive factor for development LVR.