ABSTRACT
Bigelow in Toronto introduced hypothermia to protect the heart for cardiac surgery in the 1950s. Deep hypothermia and circulatory arrest facilitated the repair of complex congenital cardiac defects. The initial attempt at induced cardiac arrest to facilitate intracardiac procedures was performed by Melrose in 1955. Unfortunately, the high potassium concentrations produced myocardial necrosis, which resulted in the early abandonment of induced cardioplegic arrest. Direct coronary perfusion and induced ventricular fibrillation were employed to protect the heart, but poor visualization and reports of myocardial injury encouraged cardiac surgeons to discover alternate approaches. For coronary surgery, sequential aortic cross-clamping was employed for the construction of distal coronary anastomoses, but the need for the intra-aortic balloon pump or fatal subendocardial necrosis were concerning.
