[Changes of ECG and arterial pressure at different periods of deep hypothermia during heart surgery in young children].

The changes in ECG and arterial pressure were analysed during "simple" deep hypothermia and radical surgery in 52 children with various congenital heart diseases. A comparatively high senitivity of the myocardium to mechanical trauma under body temperatures below 28 degrees C (especially below 25 degrees C) indicates the rationale of conducting all the intrathoracic manipulations, performed prior to the exclusion of the heart from the circulation, under superficial hypothermia. The necessity of fixation of epicardial electrodes is supported by the usefulness of electric stimulation immediately prior to surgery in case the signs of atrioventricular block persist when the body temperature reaches 29 degrees C at rewarming.