Serum electrolytes and the electrocardiogram

The Electrocardiographic Pattern of Hypopotassemia with and without Hypocalcemia

“…2' The detailed studies of the electrocardiographic pattern of hypocalcemia included in the present investigation were carried out in order to be able to evaluate the influence of hypocalcemia on the electrocardiographic pattern of hypopotassemia. Our method of measurement of the components of the Q-U interval, applied to the electrocardiograms of hypocalcemia compiled from the literature, confirmed the frequently described prolongation of the S-T segment with normal duration of the T wave3' 4, 9, 11,20,33,37 which results in a prolonged duration of the Q-oT, Q-aT and Q-T intervals, corrected for the heart rate and sex. Actual measurements of the S-T segment in the electrocardiogram of hypocalcemia have been reported previously,"' 37 but the method of measurement was not defined exactly.22 All cases studied by us with a serum calcium lower than 4.0 mEq.…”

“…* However, a prolongation of Q-T, which ranged from 105 per cent to 140 per cent and, therefore, could not have been caused bv inclusion of a U wave, was found in a considerable number of hypopotassemia cases which had a serum calcium above 4.0 mEq per liter. 33 It is possible that in some of these cases the total serum calcium was normal but the ionized calcium was low. Almost one-third of the group had acidosis and another one-third had renal insufficiency, and Q-T may be prolonged in these conditions independently of the serum calcium level.27, 22a, 20 (par.…”

Electrocardiographic Changes Following the Administration of Hypertonic Solutions to Dog

“…A low voltage of P and T waves is encountered when the con centration of serum potassium is low [2,6,7]. This could be the explanation for the results obtained after the injection of 20% NaCl, 40% urea and 50% glucose if we had not found the same changes after the injection of concentrated Ringer solution which contained 107 mEq K per liter.…”

Hypoglycemia detection by ECG recording?

“…The repolarisation properties at the mem-branes of electrical excitable cells are influenced by low potassium levels (1). There appeared to be a difference in the effect of hypoglycemia on R:T ratios related to the patients' degree of metabolic control.…”