At least 225,000 people in the United States will die suddenly this year from coronary heart disease before they reach a hospital.¹,² In addition, an estimated 370,000 to 750,000 patients will have a cardiac arrest and undergo attempted resuscitation during hospitalization.³ The causes of cardiac arrest are numerous; by far the most common in adults is ischemic cardiovascular disease.⁴–⁶ The arrest is usually associated with the lethal arrhythmia of ventricular fibrillation triggered by an acutely ischemic or infarcted myocardium or by a primary electrical disturbance. The precipitants of a life-threatening arrhythmia such as ventricular fibrillation are poorly understood. . . .