Related Experiment Videos
Is there an alternative to potassium arrest?
N M Cohen1, R J Damiano, A S Wechsler
1Department of Surgery, Medical College of Virginia, Virginia Commonwealth University, Richmond 23298-0645, USA.
Background:
Mounting clinical and experimental evidence suggests that postoperative myocardial dysfunction is a frequent consequence of surgical global ischemia and reperfusion, despite our modern techniques of myocardial protection. The ubiquitous use of hyperkalemic depolarizing solutions in all forms of cardioplegia may be partly responsible for this phenomenon because of the known ongoing metabolic processes and damaging transmembrane ionic fluxes that occur at depolarized membrane potentials. Cardiac arrest at hyperpolarized potentials, the natural resting state of the heart, may avoid the shortcomings of depolarized arrest and provide an alternative means of myocardial protection.
Methods:
An adenosine triphosphate-sensitive potassium channel opener, aprikalim, was used to induce hyperpolarized arrest. Aprikalim was able to produce sustained and reproducible electromechanical arrest that was reversible by reperfusion.
Results:
In isolated heart models, when compared with depolarized hyperkalemic arrest, hyperpolarized arrest afforded better protection from global normothermic ischemia and resulted in better postischemic recovery of function upon reperfusion. Preliminary studies in a porcine cardiopulmonary bypass model also have revealed that hyperpolarized arrest can be achieved in a model more closely approximating the clinical setting, and can effectively protect the heart during normothermic surgical global ischemia.
Conclusions:
Hyperpolarized cardiac arrest may offer an effective alternative to traditional potassium arrest.
Insights
Hyperpolarized cardiac arrest, induced by aprikalim, offers superior myocardial protection compared to traditional hyperkalemic methods. This novel approach better preserves heart function during and after surgical ischemia and reperfusion.
Area of Science:
- Cardiology
- Cardiovascular Surgery
- Biomedical Engineering
Background:
- Postoperative myocardial dysfunction is a common complication of cardiac surgery, often linked to global ischemia and reperfusion injury.
- Current myocardial protection strategies using hyperkalemic cardioplegia may contribute to dysfunction due to sustained depolarization.
- Alternative methods for cardiac arrest are needed to improve myocardial protection.
Purpose of the Study:
- To investigate the potential of hyperpolarized cardiac arrest as a protective strategy during cardiac surgery.
- To evaluate the efficacy of aprikalim, a potassium channel opener, in inducing and maintaining hyperpolarized arrest.
- To compare the protective effects of hyperpolarized arrest with traditional hyperkalemic arrest.
Main Methods:
- Induction of cardiac arrest using aprikalim, an adenosine triphosphate-sensitive potassium channel opener, to achieve hyperpolarized arrest.
- Assessment of electromechanical arrest and its reversibility upon reperfusion.
- Comparison of myocardial protection and functional recovery between hyperpolarized and hyperkalemic arrest in isolated heart models and a porcine cardiopulmonary bypass model.
Main Results:
- Hyperpolarized arrest with aprikalim induced sustained and reproducible electromechanical arrest, which was reversible.
- In isolated hearts, hyperpolarized arrest provided better protection against global normothermic ischemia than hyperkalemic arrest.
- Hyperpolarized arrest demonstrated improved post-ischemic functional recovery upon reperfusion in both isolated hearts and a porcine model.
Conclusions:
- Hyperpolarized cardiac arrest represents a promising alternative to conventional hyperkalemic arrest for myocardial protection.
- This technique effectively protects the heart during normothermic surgical global ischemia, potentially reducing postoperative myocardial dysfunction.
- Further clinical investigation is warranted to validate hyperpolarized arrest as a superior myocardial protection strategy.