The perioperative development of ventricular fibrillation (VF) represents an immediate threat to the patient's life and requires the simultaneous generation of a differential diagnosis, defibrillation, and therapy to prevent VF recurrence. Ventricular arrhythmias are associated with myocardial ischemia, heart failure, hypoxemia, various cardiomyopathies, electrolyte abnormalities, prolonged QT syndrome, inotrope administration, and mechanical manipulation of the heart. The AHA/ACC have developed extensive guidelines for the management of ventricular arrhythmias.7 Both VF and pulseless ventricular tachycardia (VT) require immediate resuscitative efforts as systemic blood flow ceases during these arrhythmias. Defibrillation should be undertaken immediately for VF and cardioversion for VT. In the operative setting the open sternum permits the delivery of defibrillation current through the use of internal paddles. Additionally, should the rhythm fail to be restored open chest cardiac massage can be initiated. Also, immediate institution of CPB can be undertaken to preserve tissue perfusion while efforts are made to restore cardiac function.