Hypokalemia may lead to an irregular heartbeat, also known as arrhythmia. Some arrhythmias can be life threatening without treatment, but restoring potassium levels may help reverse symptoms alongside other treatments.

Hypokalemia occurs when potassium levels become extremely low. Potassium is an electrolyte that contributes to muscle contraction, including in the heart, and controls the movement of bodily fluids between cells. Various medications, nutritional imbalances, and health conditions can cause potassium levels to become too low.

Low potassium does not always cause symptoms. However, extremely low potassium levels can have a range of harmful effects across the body, such as an irregular heartbeat, muscle weakness and twitching, and excessive thirst and urination.

This article explores the link between hypokalemia and arrhythmia. It also discusses hypokalemia causes, diagnosis, and treatment. Finally, it suggests when a person may consider speaking with a doctor.

Electrocardiogram on paper 1Share on Pinterest
Lucidio Studio Inc/Getty Images

Hypokalemia can contribute to the development of arrhythmias.

According to a 2024 review, potassium is vital for regulatingTrusted Source electrical activity in the heart. It helps control muscle contractions that keep the heartbeat regular and blood pumping around the body. A 2017 reviewTrusted Source suggested that even moderate hypokalemia might trigger arrhythmias.

Common arrhythmiasTrusted Source in people with hypokalemia include:

  • Premature ventricular contractions: These are “extra” heartbeatsTrusted Source that cause a pause, leading to a more forceful beat following the pause. It may feel like the heart is “skipping a beat.”
  • Atrial fibrillation: This may present as a “quivering” heartbeatTrusted Source that can lead to blood pooling around the heart’s upper chambers. If this blood clots, a stroke may occur if the clot blocks blood traveling to the brain.
  • Torsade de pointes: This means that the heart’s lower chambers beat fasterTrusted Source than the upper chambers. It may progress to ventricular fibrillation over time.
  • Ventricular fibrillation: This is the most life threateningTrusted Source arrhythmia. It causes the lower heart chamber to vibrate instead of beating at a typical rhythm. It can cause sudden cardiac death within minutes unless a person receives treatment.

According to a 2018 review, studies estimate that 19% to 54%Trusted Source of people receiving treatment for heart failure have hypokalemia. Diuretics cause a large volume of potassium to leave the body in the urine. As some people take diuretics to treat heart failure, this can worsen outcomes in people who already have heart problems.

Cardiovascular health resources

Visit our dedicated hub for more research-backed information and in-depth resources on cardiovascular health.

According to older information from the National Organization for Rare Diseases (NORD), hypokalemia always occurs due to another health problem and is never a condition that exists on its own. Other causes of hypokalemia include:

The following groups of people with hypokalemia have a higher risk of developing an arrhythmia, including:

  • older adults
  • people who already have heart disease
  • individuals with hypokalemia who also take anti-arrhythmic medications
  • those who receive anesthetic before an operation, particularly in short-term hypokalemia

The use of certain diuretic medications is one of the main causesTrusted Source of low potassium in people with heart failure.

Diagnosing low potassium involves a simple blood test. This can also measure levelsTrusted Source of other electrolytes that affect potassium balance, such as magnesium. Healthcare professionals may also recommend urinalysis.

An electrocardiogram (ECG) can measure the heart rhythm, which helps identify arrhythmias and is a standard part of diagnosing any cardiac complications of hypokalemia. Changes in the T waves on the ECG may indicate abnormalitiesTrusted Source in potassium levels.

Although uncommon, a doctor may also request an imaging scan to identify the underlying cause of hypokalemia. This can include a kidney ultrasound to identify kidney disease, or an adrenal gland MRI or CT scan to highlight hormonal disorders that may be affecting potassium levels.

According to older information from NORD, treating hypokalemia first involves treating the underlying cause.

The National Heart, Lung, and Blood Institute suggests that a healthcare professional may try to correct an electrolyte imbalanceTrusted Source, such as low potassium, with supplements to help address an arrhythmia. A doctor can supplement potassium by administering potassium chloride either intravenously (IV) or orally (as a pill), depending on the severity of the deficiency.

They will also need to treat kidney disease or hormonal imbalances separately.

Supplementing potassium in the diet and restricting high-sodium foods may help to maintain potassium levels in people who take diuretics. High-potassium foods to eat includeTrusted Source:

  • fruits, such as bananas, dried apricots, and prunes
  • vegetables, including broccoli, spinach, and tomatoes
  • legumes, such as lentils, kidney beans, and soybeans
  • nuts
  • dairy products, including milk and yogurt
  • fish, meat, and poultry
  • salt substitutes, although the Office of Dietary Supplements advises that these may make potassium levels too high if a person does not use them with caution

Several medications may directly treat an arrhythmia, including:

If medications are not effective in treating an arrhythmia, various devices and procedures may help to restore regular heart rhythms, such as:

People should note that healthcare professionals usually reserve catheter ablation, ICDs, and pacemakers for recurrent arrhythmias that require ongoing treatment, rather than acute arrhythmia resulting from hypokalemia.

People who are losing a large volume of fluids, such as those experiencing diarrhea and vomiting, may benefit from medical attention to rule out hypokalemia. Those taking medication such as diuretics should discuss any side effects with a doctor, who may be able to recommend different medications.

A person should seek urgent medical attention upon experiencing severe hypokalemia symptoms. These include arrhythmias and attacks of severe muscle weakness, which may lead to respiratory failure and paralysis.

Hypokalemia can cause arrhythmia, as potassium is vital for controlling heart rhythm through electrical signals and regulating muscle contractions. Arrhythmias that may occur in people with low potassium include premature ventricular contractions, ventricular fibrillation, atrial fibrillation, and torsade de pointes.

Potential causes of hypokalemia include hormonal disorders, excessive sweating, and long-term misuse of laxatives.

Doctors may treat a potassium deficiency with supplements and diet, and recommend arrhythmia treatments such as medications to help restore a regular heart rhythm.