Abstract 15006: Transmural Infarct Distribution in Reperfused Myocardium after STEMI
Background: The conventional distinction between transmural and non-transmural infarcts has been challenged by reports of irregular morphology of reperfused myocardium. This study investigates the transmural infarct distribution of reperfused myocardium.
Methods: We studies 62 patients 6 months after revascularization by PCI due to acute LAD-occlusion (STEMI). Myocardial infarction was visualized by late enhancement MRI, and quantified according to a 17-segment LV model. In each segment infarct extent was both measured as infarct area in percentage of total segment area (IA%) and as maximal endo- to epicardial infarct transmurality (ITM%; Figure). By both methods, infarct extent >50% was defined as transmural.
Results: Mean LV ejection fraction was 56±11%. LV infarct size was 19±12% of the total LV mass. By ITM%, 94% of the patients had ≥1 segment with transmural infarction, and the distribution between segments of non-transmural and transmural infarction was 23 vs. 77% (Table). By IA%, 80% of the patients had ≥1 segment with >50% infarction and the distribution between segments of non-transmural and transmural infarction 71 vs. 29%. Importantly, in segments classified as non-transmural by IA%, 66% were transmural by ITM%. Correlation between EF and infarct extent by the 2 methods were identical (r= 0.50, P<0.0001).
Conclusion: Due to the irregular distribution of infarct transmurality in reperfused infarcts, the conventional distinction between infarcts of transmural or non-transmural extent is ambiguous.
- © 2011 by American Heart Association, Inc.