Topical cooling of the heart. A valuable adjunct to cold cardioplegia.

Topical (local) cooling of the heart is a valuable adjunct to cold cardioplegia, particularly to crystalloid cardioplegia and to cardioplegia in patients with long aortic cross-clamping times. The topical cooling not only enhances myocardial hypothermia but also prevents the heart from being rewarmed by coronary collaterals and by heat transmission from surrounding organs during the period of aortic cross-clamping. If ice slush is used for topical cooling, a cardiac insulating pad should be used to isolate the heart and to protect the left phrenic nerve from cold injury. To illustrate the use of the insulating pad and to demonstrate the efficiency of topical cooling during open-heart surgery, a series of temperature measurements were made.