The Therapeutic Use of Potassium in Certain Cardiac Arrhythmias. ∗

Abstract

The investigation of the action of potassium salts on the heart dates from the time of Ringer, 1 whose classical experiments on the frog heart are well known. Irrespective of osmotic tension, the necessity of sodium, potassium and calcium ions in a balanced solution was proved. Hering 2 stopped paroxysmal ventricular tachycardia and ventricular fibrillation in the dog, and many investigators including Rothberger and Winterberg, 3 Anrep, 4 and Wiggers 5 have similarly obtained immediate cessation of both auricular and ventricular ectopic rhythms by intravenous or intracardiac injections of solutions of potassium chloride. Wiggers 5 suggested the possibility of its therapeutic use in ventricular fibrillation of accidental electrocution. It thus seemed reasonable to attempt to disturb the calcium-potassium ratio in favor of potassium for certain other therapeutic reasons. Scherf 6 and others have demonstrated a reversal of the customary actions of potassium and calcium when used intravenously on ventricular ectopic rhythms caused by aconite. The calcium eliminated the aberrant beats, while the potassium precipitated showers or paroxysms of them. It is predicted that some cases may be encountered clinically in which the arrhythmias show such a paradoxical response to potassium.

Norn 7 showed an increment in blood potassium of 21% 40 minutes after the oral administration of 12 gm. of potassium chloride; and 61% increment in 2 hours. An appreciable increment was obtained in 30 minutes after 2 gm. of KCl in 2 of our cases.

Potassium salts were used clinically to check attacks of paroxysmal ectopic ventricular tachycardia, and to prevent the occurrence of auricular and ventricular ectopic beats. Four different soluble potassium salts were used: potassium chloride, potassium iodide, potassium citrate, and potassium acetate, all with apparently identical effect. It is presumed that the anion and acid-base influences are negligible.