Effects of Severe Hyperkalemia

Abstract

T he ECG, taken in the emergency department (ED), of a 38-year-old woman with renal failure complaining of weakness is shown below. The extreme widening (up to 350 ms) of the QRS complexes and their almost sine wave connection to their T waves is one sign of acute hyperkalemia that is particularly valuable in the ED. The patient's serum potassium level was 8.7 mEq/L. With treatment, the patient's ECG was normal 8 hours later, with normal P waves and sinus rhythm (P axis, +50 degrees), a QRS duration of 78 ms, and a QRS axis of +60 degrees. (Hyperkalemia induces QRS axis shifts, but if this is not a supraventricular rhythm that is a moot point.) The ED trace showed an irregularly irregular rhythm with no sign of atrial activity (the "bumps" in beats 2, 3, 5, and 7 are probably part of the QRS). One cannot rule out any atrial rhythm because hyperkalemia suppresses P waves even with sinus rhythm by electrical "paralysis" of the atria. (With a regular ventricular rhythm, the sinus can control the ventricles with suppressed P waves [sinoventricular rhythm], but here atrial fibrillation cannot be ruled out.) Although the QRS complexes fulfill criteria for ventricular tachycardia, idioventricular rhythm cannot be ruled out, but it is less likely because of the degree of irregularity. The extreme QRS widening is rare in ventricular rhythms in the absence of hyperkalemia or certain drug effects (eg, encainide). With hyperkalemia, the ECG effects depend on the rate of rise of serum potassium more than its absolute level.

Potassium Intake—(Un)Expected Non-Predictor of Higher Serum Potassium Levels in Hemodialysis DASH Diet Consumers

“…Due to impaired renal excretion, these patients are more prone to developing hyperkalemia and, therefore, suffer its consequences. Mild hyperkalemia (5.5–5.9 mmol/L) may be associated with symptoms such as nausea, fatigue, or muscle weakness, but severe hyperkalemia (≥6.5 mmol/L) can cause alterations in cardiac physiology, leading to chest pain, cardiac arrhythmias, shortness of breath, and fatal cardiac arrest [ 3 , 4 , 5 ].…”

The effect of hyperkalemia and long inter-dialytic interval on morbidity and mortality in patients receiving hemodialysis: a systematic review

“…While there is no universally agreed definition for HK, the most widely used thresholds for the categorization of mild, moderate and severe HK are 5.5-5.9, 6.0-6.4 and !6.5 mmol/L, respectively [2,3]. Mild HK may be associated with symptoms such as nausea, fatigue or muscle weakness [2]; however, more severe HK can cause alterations in cardiac physiology resulting in chest pain, cardiac dysrhythmia, shortness of breath, andin very severe casescardiac arrest and death [4,5].…”

The Relation of Serum Potassium Concentration with Cardiovascular Events and Mortality in Community-Living Individuals

“…Severe hyperkalemia is well recognized as causing fatal arrhythmias, including ventricular fibrillation, asystole, and cardiac arrest (1)(2)(3)(4). Although most individuals with hyperkalemic events concurrently have chronic or acute kidney disease, recent studies have suggested that patients admitted to the hospital with milder hyperkalemia and normal kidney function may also have a higher mortality risk (5).…”