Electrocardiographic Changes Associated with Induced Atrial Tachycardia

Abstract

SummaryAtrial tachycardia, with retained 1:1 A– V conduction, and a duration of 24 hours, has been induced in 17 young pigs by means of a pace‐maker. The intracardiac electrode is advanced percutaneously through a neck vein. During induced tachycardia, an increase in the mean amplitude of the T wave is observed in the right chest lead. Immediately after the cessation of tachycardia, an increase in amplitude occurs in the animals with the highest ventricular rate during the experiment, whereas a decrease in amplitude of the T wave occurs in those with a lower rate. The changes in amplitude of the T wave observed in these experiments are in agreement with those seen in human subjects during and after physical work.The reasons why changes of the type seen on the ECGs recorded after paroxysmal tachycardia in the clinical series did not appear during these experiments are discussed. It is suggested that further experiments with tachycardia of more than 24 hours' duration should be made, to determine whether the post‐tachycardiac EGG changes can be reproduced experimentally. The method used in the present study is appropriate for this purpose.