Abstract
The use of ephedrin in complete heart block was first reported by Miller and later by Stecher. But the combined action of ephedrin and atropin on the human heart according to Chen and Schmidt 1 has never been investigated.
A case of complete heart block without Adams-Stokes' attacks was available to study its reaction to ephedrin alone. The patient was kept quiet in bed and undisturbed. Electrocardiograms were taken before and at frequent intervals after the administration by mouth of ephedrin. Blood pressure readings were made at frequent intervals and usually before the electrocardiograms, from which both auricular and ventricular rates were obtained. Results are shown in Table I. It will be seen that after the administration of 150 mg. of ephedrin in 20 minutes, there was no increase in ventricular or auricular rate, but an increase of 5 mm. Hg. in systolic and diastolic blood pressure.
Different explanations have been offered for the negligible pressor effect occasionally encountered as in this case. Chen and Schmidt attributed the depressant effect of large doses of ephedrin either to direct depression of heart muscle, or to a difference in the quantity of “receptors” present in the individual. Kreitmair explained the difference on the basis that small doses of ephedrin stimulate the sympathetic nerve endings, while large doses stimulate the parasympathetic. However in animal experiments according to Fujii and Kreitmair this depressant action of ephedrin on the heart is not antagonized by atropin, while on the other hand Mehes and Kokas believed that the depressant effect was partly removed by atropin. To test the validity of these hypotheses in the clinical case, atropin was given after the patient had been ephedrinized. The results are shown in Table II.
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