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Updated: Jun 23, 2026
Echocardiographic and Histological Examination of Cardiac Morphology in the Mouse
Published on: October 26, 2017
Effects of deep sedation or general anesthesia on cardiac function in mice undergoing cardiovascular magnetic
Christopher J Berry1, Daniel R Thedens, KellyAnn Light-McGroary
1Division of Cardiovascular Medicine, Roy J, and Lucille A, Carver College of Medicine, University of Iowa, Iowa, USA. christopher-j-berry@uiowa.edu
Background:
Genetically engineered mouse models of human cardiovascular disease provide an opportunity to understand critical pathophysiological mechanisms. Cardiovascular magnetic resonance (CMR) provides precise reproducible assessment of cardiac structure and function, but, in contrast to echocardiography, requires that the animal be immobilized during image acquisition. General anesthetic regimens yield satisfactory images, but have the potential to significantly perturb cardiac function. The purpose of this study was to assess the effects of general anesthesia and a new deep sedation regimen, respectively, on cardiac function in mice as determined by CMR, and to compare them to results obtained in mildly sedated conscious mice by echocardiography.
Results:
In 6 mildly sedated normal conscious mice assessed by echo, heart rate was 615 +/- 25 min-1 (mean +/- SE) and left ventricular ejection fraction (LVEF) was 0.94 +/- 0.01. In the CMR studies of normal mice, heart rate was slightly lower during deep sedation with morphine/midazolam (583 +/- 30 min-1), but the difference was not statistically significant. General anesthesia with 1% inhaled isoflurane significantly depressed heart rate (468 +/- 7 min-1, p < 0.05 vs. conscious sedation). In 6 additional mice with ischemic LV failure, trends in heart rate were similar, but not statistically significant. In normal mice, deep sedation depressed LVEF (0.79 +/- 0.04, p < 0.05 compared to light sedation), but to a significantly lesser extent than general anesthesia (0.60 +/- 0.04, p < 0.05 vs. deep sedation). In mice with ischemic LV failure, ejection fraction measurements were comparable when performed during light sedation, deep sedation, and general anesthesia, respectively. Contrast-to-noise ratios were similar during deep sedation and during general anesthesia, indicating comparable image quality. Left ventricular mass measurements made by CMR during deep sedation were nearly identical to those made during general anesthesia (r2 = 0.99, mean absolute difference < 4%), indicating equivalent quantitative accuracy obtained with the two methods. The imaging procedures were well-tolerated in all mice.
Conclusion:
In mice with normal cardiac function, CMR during deep sedation causes significantly less depression of heart rate and ejection fraction than imaging during general anesthesia with isoflurane. In mice with heart failure, the sedation/anesthesia regimen had no clear impact on cardiac function. Deep sedation and general anesthesia produced CMR with comparable image quality and quantitative accuracy.
Insights
Deep sedation in mice undergoing cardiovascular magnetic resonance (CMR) imaging causes less cardiac function depression than general anesthesia. This finding is crucial for accurate assessment in cardiovascular disease models.
Area of Science:
- Cardiovascular Research
- Animal Models
- Medical Imaging
Background:
- Genetically engineered mouse models are vital for studying human cardiovascular disease.
- Cardiovascular magnetic resonance (CMR) offers precise cardiac assessment but requires animal immobilization.
- General anesthesia can significantly alter cardiac function, potentially confounding study results.
Purpose of the Study:
- To evaluate the impact of deep sedation versus general anesthesia on cardiac function in mice using CMR.
- To compare these findings with echocardiography results from mildly sedated conscious mice.
- To determine the optimal imaging conditions for accurate cardiac assessment in mouse models.
Main Methods:
- Comparison of cardiac function (heart rate, ejection fraction) using CMR under light sedation, deep sedation (morphine/midazolam), and general anesthesia (isoflurane) in normal and heart failure mice.
- Echocardiography was used for baseline assessment in conscious, mildly sedated mice.
- Image quality and quantitative accuracy (left ventricular mass) were assessed.
Main Results:
- General anesthesia with isoflurane significantly reduced heart rate and ejection fraction in normal mice compared to deep sedation.
- Deep sedation also depressed ejection fraction in normal mice but to a lesser extent than general anesthesia.
- In mice with heart failure, sedation/anesthesia regimens did not significantly impact cardiac function measurements.
- CMR image quality and quantitative accuracy were comparable between deep sedation and general anesthesia.
Conclusions:
- Deep sedation is preferable to isoflurane general anesthesia for CMR in normal mice, minimizing cardiac function perturbation.
- Sedation/anesthesia choice has minimal impact on CMR assessment of cardiac function in mice with heart failure.
- Both deep sedation and general anesthesia yield comparable image quality and quantitative accuracy in mouse CMR.
