Electrocardiography: Hypokalemia vs. Hyperkalemia

Camille Renee

Hypokalemia [K+] below 3.5 mEq/L

Hyperpolarization of resting membrane potential (more negative)

Action potential becomes more difficult to attain because threshold potential is now further from the RMP

Caused by beta agonists, inadequate potassium consumption, urinary excretion, diabetes, renal disorders, etc.

Prolonged PR Interval, ST segment depression, U waves and slurring of T waves into U waves present on EKG

Hyperkalemia [K+] above 5 mEq/L

Depolarization of resting membrane potential (less negative)

Action potential becomes more difficult to attain because sodium channels are inactivated

Caused by ACE inhibitors, beta blockers, excess potassium intake, extreme exercise, renal disorders, etc.

Lower P wave height, prolonged PR Interval, tall and tented T waves, widened QRS interval on EKG

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Images Cited

1. Kurzweil: Accelerating Intelligence. http://www.kurzweilai.net/computational-biomarkers-can-identify-at-risk-heart-attack-victims

2. Medscape. http://emedicine.medscape.com/article/907111-workup#a0756

3. Osteopathy New York. http://www.osteopathyny.com/tag/muscle-imbalance/