Energy demand of cardioplegically perfused human hearts
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Updated: Oct 5, 2026
Normothermic Ex Situ Heart Perfusion in Working Mode: Assessment of Cardiac Function and Metabolism
Published on: January 12, 2019
Insights
For optimal intra-ischemic myocardial protection in adult hearts, high-volume cardioplegic perfusion should last 6-7 minutes. This ensures sufficient myocardial protection during cardiac surgery.
Area of Science:
- Cardiology
- Cardiovascular Surgery
- Physiology
Background:
- Aortic valve disease and hypertrophic obstructive cardiomyopathy necessitate effective myocardial protection strategies during surgery.
- Cold histidine-buffered Bretschneider solution is commonly used for cardioplegic perfusion.
Purpose of the Study:
- To analyze the effects of a 7-minute cardioplegic perfusion on temperature, electrolytes, coronary artery resistance, and myocardial oxygen consumption in adult human hearts.
- To determine the optimal duration for high-volume cardioplegic perfusion to ensure adequate intra-ischemic myocardial protection.
Main Methods:
- Human adult hearts (n=21) with specific valve diseases were perfused with cold histidine-buffered Bretschneider solution.
- Key parameters including temperature, electrolyte levels (K+, Na+), coronary artery resistance (LCA, RCA), and myocardial O2 consumption were monitored throughout the 7-minute perfusion.
- Statistical analysis was performed to assess significant changes (p<0.025, p<0.001).
Main Results:
- Potassium (K+) equilibration was rapid, while sodium (Na+) equilibration took approximately 5 minutes.
- Right coronary artery (RCA) resistance remained stable, but left coronary artery (LCA) resistance significantly decreased, suggesting delayed calcium washout.
- Myocardial O2 consumption significantly decreased over the perfusion period, even after temperature stabilization, indicating effective metabolic suppression.
Conclusions:
- High-volume cardioplegic perfusion (1 ml/min x gm at 40-50 mmHg) requires at least 6-7 minutes for effective intra-ischemic myocardial protection in adult hearts.
- The observed decrease in LCA resistance highlights the importance of adequate perfusion duration for managing extracellular calcium.
- Findings support extended perfusion times for enhanced cardiac protection during surgical interventions.
Abstract:
Human adult hearts with aortic valve disease (n = 20) and hypertrophic obstructive cardiomyopathy (n = 1) were perfused intraoperatively with cold histidine buffered Bretschneider solution. During a seven minute cardioplegic perfusion the temperature level, the electrolyte level, the resistance of the left (LCA) and right coronary artery (RCA), and myocardial O2 consumption were analysed. Equilibration of K+ was terminated shortly after the start of the perfusion while Na+ equilibration lasted for about 5 minutes. Resistance of RCA did not change significantly, but that of the LCA was diminished significantly (p less than 0.025) within the perfusion period indicating a delayed washout of calcium from the extracellular space. Myocardial O2 consumption was reduced from 2.71 ml/min (1. minute) to 1.51 ml/min (4. minute) to 0.93 ml/min (7. minute) although the temperature had reached a low level after 3 minutes. The difference between 4. to 7. minutes is significant (p less than 0.001). By our results it is concluded that in adult hearts high-volume cardioplegic perfusion at a flow rate of 1 ml/min X gm at a perfusion pressure of 40 to 50 mmHg should be performed for at least 6 to 7 minutes to achieve a sufficient intra-ischemic myocardial protection.
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