THE EFFECT OF ADENOSINE TRIPHOSPHATE ON THE ELECTROCARDIOGRAM OF MAN AND ANIMALS

Abstract

The increasing importance of adenosine triphos- phate (ATP) in the field of biochemistry demands a close study of its pharmacological properties.Earlier work on the lower nucleotides and nucleo- sides derived from ATP showed that these com- pounds have important effects on the cardiovascular system.Now that large amounts ot the higher derivatives, such as ATP, have become available, it has been shown that the action of these substances is not confined to the cardiovascular system but affects all the organs of the body (Green and Stoner, 1949).Although the effect of these compounds on the heart has been studied in some detail by Drury and his school (1936), their electrocardiographic observations were almost entirely confined to the lower members of the series.In the present paper we propose to describe the effects of ATP on the electrocardiogram of man and animals.The car- diographic method is the only satisfactory one available for the study of changes in cardiac rhythm in man.We have also applied this method to the study of the cardiac effects of ATP in animals in order to determine the effects of doses higher than those that would have been justifiable in man and also to analyse these actions by procedures im- practicable clinically.-The observations in animals will be reported first, then those in the human subjects, and finally the conclusions arrived at from the combined study. I. ANIMAL EXPERIMENTSEarly work on the effect of adenosine and its derivatives on the electrocardiogram has been well reviewed by Drury (1936).It has been shown that these substances affect the conducting system, causing sinus slowing and A-V block.In most animals the main effect is upon the S-A node but in the guinea pig the A-V node seems more sensitive to their action.It will be seen that the action of 0 5 mg.and 1 0 mg.MgATP per kg.body weight.With the smaller dose the effect on the heart com- menced almost immediately after the injection and lasted about 21 seconds, reaching a maximum in 6 to 9 seconds.The first effects were on the sinus rate and the P-R interval.The sinus rate was reduced by about 18 per cent and the P-R interval 55 on July 18,