THE ACID TOLERANCE OF THE DOG HEART

Publisher Website
Google Scholar
Abstract
The acid limit of blood acidity tolerated by the heart of the normal dog in situ was pH 6.25 as an avg. of 27 expts. The limit of tolerance was the same for hydrochloric and lactic acid. Neither cardiac slowing, nor auriculo-ventricular conduction delay were marked features of acid intoxication. The avg. P-R interval immediately before respiratory arrest was 0.14 sec. and 1:1 auriculo-ventricular conduction was maintained until after respiratory arrest had occurred. The most constant electrocardiographic finding was a progressive increase in the amplitude of the T wave and the R wave. The only certain sign of impending cardiac failure seen in the electrocardiogram was a depression of the S-T segment which occurred in over half the expts. and progressed rapidly in degree in the last few secs, before death, The most important effect of acid intoxication appeared to be an extreme impairment of myocardial contractility which appeared and progressed rapidly close to the terminal level. The lethal limit found here must have approached closely the lethal limit also of the cardiac pacemaker and the respiratory center.

This publication has 4 references indexed in Scilit: