Bedside assessment of myocardial viability using transmural strain profile in patients with ST elevation myocardial infarction: comparison with cardiac magnetic resonance imaging.
BACKGROUND
The accurate evaluation of myocardial viability after ST-elevation myocardial infarction (STEMI) is of clinical importance. Transmural myocardial strain distribution can be obtained as a form of transmural strain profile using a newly developed myocardial strain imaging system. The aim of this study was to determine whether strain profile could identify myocardial viability confirmed by contrast-enhanced magnetic resonance imaging in patients with acute STEMI.


METHODS
A total of 36 patients with STEMIs were enrolled. Transmural strain profiles in the infarct segments were obtained. The peak strain value and location of peak strain (percentage distance of the wall thickness from the endocardium toward the epicardium) were measured. The transmural extent of infarction (TEI) was determined by contrast-enhanced magnetic resonance imaging.


RESULTS
A significant inverse correlation (r = -0.74, P < .0001) was observed between TEI and peak strain value (TEI 1%-25% = 86 +/- 25%, TEI 26%-50% = 78 +/- 17%, TEI 51%-75% = 47 +/- 14%, and TEI 76%-100% = 24 +/- 10%). The location of peak strain was shifted from the endocardial side to the epicardial side according to the severity of TEI (TEI 1%-25% = 23 +/- 6%, TEI 26%-50% = 37 +/- 11%, TEI 51%-75% = 53 +/- 12%, and TEI 76%-100% = 69 +/- 7% of left ventricular thickness from the endocardium). The sensitivity and specificity to predict nonviable muscle by the combination of these two parameters were 100% and 96.6%, respectively.


CONCLUSIONS
Transmural strain profile assessed by tissue strain imaging is a useful and accurate method for evaluating myocardial viability at the bedside.
Tanimoto
Takashi
T
Department of Cardiovascular Medicine, Wakayama Medical University, Wakayama, Japan.
Imanishi
Toshio
T
Tanaka
Atsushi
A
Yamano
Takashi
T
Kitabata
Hironori
H
Takarada
Shigeho
S
Kubo
Takashi
T
Takemoto
Kazushi
K
Nakamura
Nobuo
N
Hirata
Kumiko
K
Mizukoshi
Masato
M
Akasaka
Takashi
T
D000368:Aged; D055119:Elastic Modulus; D054459:Elasticity Imaging Techniques / Q000379:methods*; D005260:Female; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology*; D017682:Myocardial Stunning / Q000175:diagnosis* / Q000503:physiopathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity