Abstract
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.MethodWe investigated 27 healthy C57Bl6 mice (♂10–12 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 μg/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.ResultsTwo 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 (ΔLVESd -1.86 vs -1.28mm p = 0.02) upon dobutamine challenge, resulting in a better cardiac reserve (ΔFS 37 vs 25% p = 0.02 and ΔCO 0.27 vs -0.10 ml/min p = 0.02) and a better chronotropic reserve (ΔR-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.ConclusionWe 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.
Highlights
Dobutamine stress echocardiography (DSE) is a wellestablished method to investigate cardiac reserve in humans [1]
Evaluation of the difference between the surviving and deceased animals showed that the survivors had a better native ability to increase systolic performance (∆LVESd -1.86 vs -1.28mm p = 0.02) upon dobutamine challenge, resulting in a better cardiac reserve (∆FS 37 vs 25% p = 0.02 and ∆Cardiac output (CO) 0.27 vs -0.10 ml/min p = 0.02) and a better chronotropic reserve (∆R-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
Summary
Dobutamine stress echocardiography (DSE) is a wellestablished method to investigate cardiac reserve in humans [1]. Cardiac reserve can be used to predict survival and outcome in patients with cardiomyopathy [2,3,4]. Provides prognostic information to predict all-cause mortality and cardiac events in elderly patients [5]. A positive response during DSE is associated with a better clinical outcome and prognosis in patients with acute myocardial infarction (MI) treated with coronary angi-. A poor chronotropic reserve has been shown to predict mortality in cardiovascular disease [7,8]. Evaluation of cardiac reserve during stress provides more information about function and capacity than can be obtained merely by investigations during rest
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