Deep hypothermia (< 30 °C) has long been used in protecting the heart during coronary artery bypass grafting and heart transplantation. Intermittent antegrade or retrograde infusion of cold cardioplegia appears to reduce myocardial ischaemia and improves outcome19, 20. Deep hypothermia however can cause spontaneous ventricular fibrillation and impaired cardiac function and its application is limited to the unconscious patient.