SOME EFFECTS OF TETRAETHYL AMMONIUM ON THE MAMMALIAN HEART

¹ Department of Pharmacology, Harvard Medical School, Boston 15, Massachusetts

1. Tetraethyl ammonium bromide, in concentrations from 1:100,000 (48 micromols per liter) upward, improves the work capacity of the heart in the heart-lung preparation of the dog. This improvement is slight in hearts with little evidence of failure, but is the more striking the more severe the heart failure. It occurs whether the failure is "spontaneous," or whether it is induced by sodium pentobarbital, 2-naphthyl-1'-methylimidazoline hydrochloride (Privine), or quinacrine.

2. Concentrations from 1:100,000 upward lead to slight to moderate acceleration of the rate of the denervated heart, followed by a slow progressive deceleration below the basal rate.

3. Concentrations of 1:10,000 upward produce changes in the T-wave and the S-T segment of the electrocardiogram, and larger doses produce ventricular extrasystoles or fibrillation.

4. The dose which produces cardiac irregularities is 200 mgm. when failure has been induced by sodium pentobarbital, but 1 gram in the other conditions studied.

5. In intact anesthetized dogs and cats, intravenous doses of 25 or more mgm. per kgm. produce the same changes in the T-wave and the S-T segment of the electrocardiogram, extrasystoles of the same nature, and the same slow deceleration of the heart as those observed in the heart-lung preparation.