Abstract
Many reports have been published concerning the effects of potassium on the electrocardiogram in various clinical states 1-13 and in experimental animals. 14-17 These have been concerned chiefly with its effect upon the T-wave. Relatively little attention has been devoted to its effect upon the QRS complex except in those cases in which toxic doses were given. Inspection of the published records, however, shows that in many instances a reduction in the size of the QRS deflections followed the administration of this drug. We refer particularly to instances in which potassium was given to patients with hypertensive heart disease. In the articles referred to the QRS changes were not mentioned in the texts or legends. In fact in some of these it was reported that no change in the form of these deflections took place. 4 , 13 In a previously reported study 18 sodium restriction in hypertensive vascular disease was followed by retrogressive electrocardiographic changes unaccompanied by a significant change in blood pressure. This raised the question as to whether a relative increase in tissue potassium secondary to sodium restriction was responsible for these electrocardiographic phenomena. Consequently the effect of potassium alone upon the electrocardiogram in cases of hypertension was investigated. Potassium in the form of the chloride, dibasic phosphate, or citrate was administered, on 25 occasions, to patients with abnormal electrocardiogams characteristic of hypertensive vascular disease, and, on ten occasions, to normal subjects. Electrocardiograms were obtained immediately before and at times ranging from 15 minutes to 3 hours after the ingestion of 5 to 20 g of one of the potassium salts mentioned. In several instances 10 to 24 g of potassium salts daily had been prescribed previously and the patient had continued on this dosage up to the time of the test.
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