Regional myocardial function after myocardial infarction in mice: a follow-up study by strain rate imaging.
BACKGROUND
New therapeutic strategies aim to reduce the extent of myocardial infarction (MI) to decrease long-term left ventricular (LV) remodeling. These innovations are often developed on murine models of MI and have led to the need for a sensitive tool allowing follow-up. The aim of this study was to investigate by strain rate (SR) imaging early and long-term alteration in regional LV function occurring after MI in mice.


METHODS
Echocardiography was serially performed during a 4-month follow-up period in 3 groups of C57BL6 male mice: 7 normal, 5 sham operated, and 27 with left coronary artery ligation (the MI group). In addition to conventional measurements, SR was obtained from short-axis views in the anterior wall and posterior wall (PW). Triphenyltetrazolium chloride staining allowed the localization and measurement of the transmural extent of MI. A transmural MI was defined as an extension > 75% of the wall thickness.


RESULTS
In the MI group, LV ejection fractions significantly decreased, while LV dimensions and PW thicknesses increased from baseline to 4 months. On day 3, SR could differentiate transmural from nontransmural (1 +/- 1 vs 10 +/- 1 s(-1); P < .05) and noninfarcted myocardium (25 +/- 1 s(-1)). SR values did not significantly change between day 3 and month 4 and could still differentiate those segments at month 4. Wall thickening was not able to differentiate transmural from nontransmural infarcted segments at day 3 (16 +/- 3% vs 21 +/- 3%; P = NS) or at month 4.


CONCLUSIONS
In this murine model of MI, SR was able to predict the transmural extent of MI as early as 3 days after MI, then remained stable and still differentiated them at 4 months.
Thibault
Hélène
H
Inserm U886, Université Claude Bernard Lyon I, Lyon, France; Hôpital Louis Pradel, Hospices Civils de Lyon, Lyon, France.
Gomez
Ludovic
L
Donal
Erwan
E
Augeul
Lionel
L
Scherrer-Crosbie
Marielle
M
Ovize
Michel
M
Derumeaux
Geneviève
G
D000818:Animals; D054459:Elasticity Imaging Techniques / Q000379:methods*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009203:Myocardial Infarction / Q000150:complications* / Q000000981:diagnostic imaging*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D018487:Ventricular Dysfunction, Left / Q000150:complications* / Q000000981:diagnostic imaging*