R Waves Interrupting T Waves

In the course of some experiments on anesthe-tized dogs and cats concerned with the production experimentally of ventricular flutter and ventricular fibrillation, Fastier and Smirk (1948) noted that R waves sometimes appeared on the descent of the antecedent T waves, shortly before the onset of veit-tricular flutter. The flutter was induced by a sub-stance amarin * which had been found by one of us (F.H.S.) to alter the response of the animals to adrenaline so that a moderate dose of adrenaline, ordinarily well tolerated, would now give rise to ventricular flutter. These observations led me to seek more closely for such phenomena in human electrocardiograms. The present paper concerns 17 patients in whom R waves have been observed on the T waves of ante-cedent complexes. It seems that interruptions of T waves by R waves are not very uncommon, are likely to prove important prognostically, and seem to provide an indication for treatment. Little has been written on this subject either from the experimental or from the clinical standpoint, and such information as is available may be un-familiar to some of the authors who have published records without commenting upon the-phenomenon. The first reference I was able to discover to the occurrence of an R wave on a T wave was in a foot-note by Katz (1928) in the course of his compre-hensive review on the T wave. Katz mentioned here that an example of an R wave on a T wave has been observed by Dr. Ashman, three examples by Drs. reil and Seigel, and three by himself. He mentioned that the only published record was by Wenkebach and Winterberg (1927) and that Wiggers had seen it in dogs. I have been unable to find any record of subsequent reports on the finding of R waves on the T waves with the exception of Scherf * C.H5-CH-NH\\ C8H5-CH N ` f