A simple cooling circuit for topical cardiac hypothermia.

Rapid uniform cooling of the heart is the most important requirement of any method using local hypothermia for protection of the myocardium during open intracardiac surgery. We report the construction and operation of a recirculation cooling circuit comprising a reservoir, pump, and heat-exchanger for this purpose. It is operated by the perfusionist and can deliver up to 1 litre of fluid per minute at 4 degrees C into the pericardium or interior of the heart. Advantages of the system include rapid cooling of the myocardium, simplicity of operation, and applicability to all routine cardiac surgical procedures.