Impact of infarct transmurality on layer-specific impairment of myocardial function: a myocardial deformation imaging study.
OBJECTIVE
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.


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).


CONCLUSIONS
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.
Medical Clinic I, University Hospital RWTH Aachen, Pauwelsstrasse 30, Aachen, Germany.
Michael
M
Becker
Christina
C
Ocklenburg
Ertunc
E
Altiok
Antje
A
Füting
Jan
J
Balzer
Gabriele
G
Krombach
Michael
M
Lysyansky
Harald
H
Kühl
Renate
R
Krings
Malte
M
Kelm
Rainer
R
Hoffmann
D003287:Contrast Media; D017023:Coronary Angiography; D004452:Echocardiography; D004699:Endocardium / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007089:Image Enhancement; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis / Q000503:physiopathology*; D010496:Pericardium / Q000503:physiopathology*; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis / Q000503:physiopathology*; D051598:Whole Body Imaging
D003287:Contrast Media