THE ELECTROCARDIOGRAM ASSOCIATED WITH LOW LEVELS OF SERUM POTASSIUM

Abstract

Three cases with low serum K are reported, with electrocardiographic observations and a literature review. As other writers have reported, lowering of serum K produces a decrease in amplitude of T, and may proceed to inversion. Depression of the S-T interval may occur. Marked increase in the size of the U wave occurs in some instances. Lengthening of any part of the electrical cycle may appear. High voltage of the P wave appears occasionally. The author considers that the abnormalities may be combined in various ways, and that the curves have no characteristic form. In some instances the ecg. has an undulating form produced by a depressed S-T segment, a low or inverted T and a high and wide U wave. Contrary to previous reports the author found that a prolonged Q-T interval is not frequently due to a fall in serum K.