Recognition of infarct localization by specific changes in intramural myocardial mechanics

Background After transmural myocardial infarction (MI), changes occur in in tramural myocardial function. This has been described in anterior MI only. The aim of this study was to determine the relation between variable infarc t locations and intramural deformation in patients with a first MI. Methods Forty patients (33 men and 7 women aged 57 +/- 11 years) with diffe rent infarct-related coronary arteries 125 left anterior descending, 7 circ umflex, and 8 right coronary) were studied 6 +/- 3 days after infarction wi th magnetic resonance tissue tagging and 2-dimensional finite element analy sis of myocardial deformation. Short-axis tagged images were acquired at ba se, mid, and apical level. Intramural deformation was measured in 6 circumf erential segments per level. Results were compared with 9 age-matched healt hy controls. Results Each infarct area demonstrated a-significant reduction of intramura l deformation. At mid-ventricular level, segments with maximum impaired int ramural function were the anteroseptal segment for left anterior descending -related MI (stretch: 16% vs 33% for controls, P < .001), the posterolatera l segment for related MI (stretch: 20% vs 34%, P < .01); and the inferior s egment for right coronary artery related MI (stretch: 18% vs 25%, P = .082) . In these infarct segments, the intramural regional systolic stretch was m ore circumferentially oriented compared with radilly oriented stretch in th e same segments in controls (P < .05). Conclusion The infarct area can be recognized by a specific spatial pattern of intramural deformation, In infarcted compared with noninfarcted myocard ium, deformation is significantly reduced and systolic stretch deviates fro m the radial direction. Left anterior descending related infarcts were foun d to have larger regional differences in intramural deformation than circum flex or right coronary artery related MI of enzymatically the same size.