Myocardial Reperfusion and Long-Term Change of Left Ventricular Volume after Acute Anterior Wall Myocardial Infarction

Ahn, Jeong Cheon; Shim, Wan Joo; Rha, Seung Woon; Park, Sang Won; Hwang, Gyo Seung; Song, Woo Hyuk; Lim, Do Sun; Park, Chang Gyu; Kim, Young Hoon; Oh, Dong Joo; Ro, Young Moo

Abstract

BACKGROUND
In acute myocardial infarction, left ventricular remodeling, which was influenced by infarct size, location, and patency of infarct related artery(IRA), is a important prognostic factor for chronic heart failure and survival. Recently, several reports suggested that patent IRA does not always mean true myocardial reperfusion, and myocardial contrast echocardiography(MCE) may be a useful tool for assessing infarct size and viability of infarcted myocardium. So, we investigated the association between the degree of myocardial reperfusion assessed by MCE and long term change of left ventricular volume in acute anterior wall myocardial infarction patients who had patent IRA.
METHODS
The study population was consisted of 17 patients with first acute anterior wall myocardial infarction patients who had patent left anterior descending artery by thrombolytic therapy or rescue PTCA. MCE was done immediately after coronary angiography within two weeks of myocardial infarction onset and analyzed by semiquantitative method to get opacification index. For analysis of left ventricular ejection fraction, wall motion abnormality and left ventricular volume, echocardiogram was taken within 2 weeks of myocardial infarction oneset and 9 months later in each case. Wall motion abnormality was quantified as wall motion index. According to serial changes of left ventricular volume, patients were divided into two groups ; group 1(less than 10% increase of LV volume at follow-up compared to intial echocardiographic exam) and group 2(more than 10% increase of left ventricular volume). We compared the opacification index of infarcted myocardium, wall motion abnormality, and ejection fraction between the two groups.
RESULTS
Initial left ventricular volume and ejection fraction were not different between group 1 and group 2, but the opacification index was lower and initial wall motion index higher in group 2 than group 1. Opacification index, wall motion index, ejection fraction and left ventricular volume were closely correlated in the whole cases. By multivariate ananlysis, opacification index was the only significant factor predicting left ventricular volume increment.
CONCLUSION
Myocardial reperfusion, which is closely correlated with ejection fraction and wall motion abnormality, acts as a independent predictor of left ventricular dilatation after acute anterior wall myocardial infarction. This result suggests that assessment of microvascular integrity with myocardial contrast echocardiography may be a valuable indicator to predict long-term change of left ventricular volume, although this is suggestive result in a limited number of patients.