Role of adenosine in the treatment of myocardial stunning.

Adenosine is an endogenous nucleoside produced from the breakdown of adenosine triphosphate (ATP) that possesses a number of complex cellular and metabolic effects that could ameliorate postischemic contractile dysfunction (myocardial stunning). Potential mechanisms include the repletion of high-energy phosphate stores, reduced myocardial oxygen consumption, a decrease in oxygen-derived free radicals, restoration of calcium homeostasis, and an increase in regional myocardial blood flow. Experimental studies have shown that adenosine can reduce myocardial stunning with or without a concomitant increase in the total myocardial ATP stores. Adenosine may be a useful pharmacologic strategy in the prevention and treatment of ventricular dysfunction following episodes of regional or global ischemia, although further studies are needed to clarify the precise cellular mechanisms involved.