THE SUPERNORMAL PERIOD IN THE MAMMALIAN VENTRICLE

Abstract

The recovery cycle of the ventricle was explored in the hearts of 14 cats under barbiturate anaesthesia and in 9 decerebrate cats. In all of the former and 2 of the latter a supernormal period was found following the relative refractory period. This period lasted 0.04 to 0.10 sec, and always coincided with electrical activity in the ventricle. It fell either on the descending limb of the T wave or upon the U wave if this wave was present. The U wave is therefore to be considered as part of the ventricular complex.