European Heart Journal Advance Access originally published online on April 7, 2009
European Heart Journal 2009 30(12):1467-1476; doi:10.1093/eurheartj/ehp112
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Impact of infarct transmurality on layer-specific impairment of myocardial function: a myocardial deformation imaging study
1 Medical Clinic I, University Hospital RWTH Aachen, Pauwelsstraße 30, 52057 Aachen, Germany
2 University RWTH Aachen, Medical Engineering, Helmholtz Institute, Aachen, Germany
3 Department of Medical Statistics, University Hospital RWTH Aachen, Aachen, Germany
4 Department of Radiology, University Hospital RWTH Aachen, Aachen, Germany
5 Department of Biomedical Engineering, University of Haifa, Haifa, Israel
Received 20 July 2008; revised 25 January 2009; accepted 4 March 2009; online publish-ahead-of-print 7 April 2009.
* Corresponding author. Tel: +49 241 808 8468; Fax: +49 241 808 2303, Email: rhoffmann{at}ukaachen.de
Aims: To evaluate deformation parameters of an endocardial, mid-myocardial, and epicardial myocardial layer in different transmurality of myocardial infarction and assess whether layer-specific deformation analysis allows definition of infarct transmurality.
Methods and results: Fifty-six patients (mean age 55 ± 9 years, 38 men) with chronic ischaemic left ventricular (LV) dysfunction underwent two-dimensional echocardiography and contrast-enhanced magnetic resonance imaging (ceMRI). The extent of myocardial infarction was determined as relative amount of hyperenhancement by ceMRI in a 16-segment LV model (0%, no infarction; 1–50%, non-transmural infarction; 51–100%, transmural infarction). On the basis of two-dimensional echocardiographic parasternal short-axis views peak systolic circumferential strain was determined for the total wall thickness and for each of three myocardial layers (endocardial, mid-myocardial, and epicardial) using an automatic frame-by-frame tracking system of acoustic echocardiographic markers (EchoPAC, GE Ultrasound). In non-transmural infarction impairment of circumferential strain was greater in the endocardial than the epicardial layer, relative reduction compared with control segments, 45% vs. 28% (P < 0.001), respectively. In transmural infarction additional impairment of circumferential strain was greater in the epicardial than the endocardial layer, relative reduction compared with non-transmural infarction 29% vs. 7% (P < 0.001), respectively. Endocardial layer circumferential strain allowed distinction of non-transmural vs. no infarction with higher accuracy than total wall thickness strain [area under the curve (AUC) 0.842 vs. 0.774, respectively, P = 0.001]. Epicardial layer circumferential strain allowed distinction of transmural from non-transmural infarction with higher accuracy than total wall thickness strain (AUC 0.819 vs. 0.762, respectively, P = 0.005).
Conclusion: Non-transmural infarction results in greater functional impairment of the endocardial than of the epicardial myocardial layer. In transmural infarction both layers are affected similarly compared with controls. A layer-specific analysis of myocardial deformation allows accurate discrimination between different transmurality categories of myocardial infarction.
Key Words: Echocardiography • Magnetic resonance imaging • Myocardial infarction • Revascularization • Viability