Key result
Mice that survived a large myocardial infarction had a significantly better native cardiac reserve (∆FS 37.4% vs 25.0%, p=0.02) and chronotropic reserve prior to the event compared to those that died.
Why the study?
Does native cardiac reserve predict survival after myocardial infarction in mice?
Observational (n=27)
Single-blind
No
Does native cardiac reserve predict survival after myocardial infarction in mice?
Absolute Event Rate: 37.4% vs 25%
p-value: p=0.02
Native cardiac and chronotropic reserve assessed by dobutamine stress echocardiography predicts survival in mice following acute myocardial infarction.
Should not change practice; hypothesis-generating for cardiac reserve in murine MI models.
UNLABELLED: Cardiac reserve can be used to predict survival and outcome in patients with heart failure. The aim of this study was to investigate if native cardiac reserve could predict survival after myocardial infarction (MI) in mice. METHOD: We investigated 27 healthy C57Bl6 mice (male symbol10-12 weeks old) with echocardiography using a high-frequency 15-MHz linear transducer. Investigations were performed both at rest and after pharmacological stress induced by dobutamine (1 mug/g body weight i.p.). The day after the echocardiography examination, a large MI was induced by ligation of the left anterior descending (LAD) coronary artery for evaluation of mortality rate. RESULTS: Two weeks after induction of MI, 7 mice were alive (26%). Evaluation of the difference between the surviving and deceased animals showed that the survivors had a better native ability to increase systolic performance (DeltaLVESd -1.86 vs -1.28mm p = 0.02) upon dobutamine challenge, resulting in a better cardiac reserve (DeltaFS 37 vs 25% p = 0.02 and DeltaCO 0.27 vs -0.10 ml/min p = 0.02) and a better chronotropic reserve (DeltaR-R interval -68 vs -19 ms p < 0.01). A positive relationship was found between ability to survive and both cardiac (p < 0.05) and chronotropic reserve (p < 0.05) when the mice were divided into three groups: survivors, surviving < 7 days, and surviving < 1 day. CONCLUSION: We conclude that before MI induction the surviving animals had a better cardiac function compared with the deceased. This indicates that native cardiac and chronotropic reserve may be an important determinant and predictor of survival in the setting of large MI and post-infarction heart failure.
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Täng et al. (2007) conducted an observational in Myocardial infarction (n=27). Native cardiac reserve vs. Lower native cardiac reserve (deceased mice) was evaluated on Native cardiac reserve (change in fractional shortening, ∆FS) (p=0.02). Mice that survived a large myocardial infarction had a significantly better native cardiac reserve (∆FS 37.4% vs 25.0%, p=0.02) and chronotropic reserve prior to the event compared to those that died.
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