Related Experiment Videos
Pretreatment with nicardipine preserves ventricular function after hypothermic ischemic arrest
P S Brown1, G L Parenteau, F W Holland
1Surgery Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland.
The Annals of Thoracic Surgery
|May 1, 1991
Summary
Pretreating rats with nicardipine before hypothermic cardiac arrest significantly improved postischemic myocardial function and recovery. This calcium antagonist enhanced cardiac performance and adenosine triphosphate levels, even under cold conditions.
Area of Science:
- Cardiovascular Research
- Pharmacology
- Cardiac Surgery
Background:
- Calcium antagonists protect postischemic myocardial function in normothermic cardioplegia.
- This protective effect is typically lost under hypothermic conditions.
Purpose of the Study:
- To investigate if a calcium antagonist, nicardipine, administered before hypothermic arrest improves postischemic myocardial performance.
- To determine the optimal pretreatment dose of nicardipine for myocardial protection.
Main Methods:
- Isolated working rat hearts were used.
- Rats were pretreated with varying doses of nicardipine (0-100 µg/kg) 20 minutes before heart excision.
- Hearts underwent hypothermic (24°C) or normothermic (37°C) arrest with cardioplegia.
Main Results:
- Nicardipine pretreatment significantly improved postischemic recovery of systolic pressure, cardiac output, stroke work, and adenosine triphosphate levels.
- A pretreatment dose of 25 µg/kg nicardipine showed the most significant improvement in cardiac function under both normothermic and hypothermic conditions.
- Higher doses of nicardipine (>25 µg/kg) resulted in decreased postischemic function.
Conclusions:
- Pretreatment with nicardipine effectively improves postischemic myocardial performance, particularly under hypothermic conditions.
- Nicardipine should be considered for administration before cardiac operations involving hypothermic arrest.
- The optimal pretreatment dose of nicardipine is approximately 25 µg/kg for myocardial protection.