Can hypokalemia (low potassium levels) cause premature ventricular contractions (PVCs)?

From the Guidelines

Yes, hypokalemia can cause premature ventricular contractions (PVCs). When potassium levels in the blood fall below the normal range, the electrical stability of cardiac cells becomes compromised, making the heart more susceptible to irregular beats. According to the study by Sandau et al 1, hypokalemia is associated with a variety of arrhythmias, including PVCs, ventricular tachycardia (VT), torsades de pointes (TdP), ventricular fibrillation (VF), and cardiac arrest.

Key Points to Consider

• Potassium plays a crucial role in maintaining the resting membrane potential of cardiac cells, and its deficiency can lead to increased cardiac cell excitability and abnormal automaticity, resulting in PVCs.
• The classification of hypokalemia as mild (3.0–3.5 mEq/L), moderate (2.5–2.9 mEq/L), or severe (<2.5 mEq/L) is important in determining the risk of arrhythmias and the need for treatment.
• Treatment involves correcting the underlying potassium deficiency, typically through oral potassium supplements such as potassium chloride (KCl) at doses of 40-100 mEq/day divided into multiple doses for mild to moderate hypokalemia.
• For severe hypokalemia or symptomatic patients, intravenous potassium replacement may be necessary under close monitoring.
• Regular monitoring of potassium levels is essential during replacement therapy to prevent overcorrection, which can lead to hyperkalemia and its own set of cardiac complications.

Recommendations

• Identify and address the underlying cause of hypokalemia, which may include diuretic use, gastrointestinal losses, or certain medications.
• Use the most recent guidelines, such as the 2017 AHA/ACC/HRS guideline for management of patients with ventricular arrhythmias and the prevention of sudden cardiac death 1, to inform treatment decisions.
• Consider the potential risks and benefits of treatment, including the risk of arrhythmias and cardiac complications, and the importance of regular monitoring and follow-up.

From the Research

Hypokalemia and PVCs

• Hypokalemia, or low potassium levels, can contribute to the development of premature ventricular contractions (PVCs) and other cardiac arrhythmias, as seen in studies 2, 3, 4, 5, 6.
• A study published in the Indian pacing and electrophysiology journal found that hypokalemia can unmask underlying premature ventricular contraction induced polymorphic ventricular tachycardia 2.
• Another study published in the Lancet found that chronic mild hypokalemia can cause life-threatening ventricular arrhythmias, including torsade de pointes 3.
• A case report published in Cureus found that severe postoperative hypokalemia can lead to ventricular fibrillation (VF) and other critical arrhythmias 4.
• A retrospective registry study published in Clinical laboratory found that hypokalemia, but not hyperkalemia, is associated with recurrences of ventricular tachyarrhythmias in ICD recipients 5.
• A study published in Acta medica Scandinavica found that thiazide diuretics can cause hypokalemia and depletion of body potassium, leading to an increased propensity for PVCs 6.

Mechanisms and Associations

• The mechanisms by which hypokalemia contributes to PVCs and other arrhythmias are not fully understood, but may involve changes in cardiac electrophysiology and ion channel function 2, 3, 4, 5, 6.
• Hypokalemia has been associated with an increased risk of ventricular tachyarrhythmias, including PVCs, in various patient populations, including those with implantable cardioverter-defibrillators (ICDs) 5.
• The correction of hypokalemia has been shown to reduce the risk of arrhythmias and improve outcomes in patients with cardiac disease 3, 4.

Clinical Implications

• The findings of these studies suggest that hypokalemia should be considered a potential cause of PVCs and other cardiac arrhythmias in patients with low potassium levels 2, 3, 4, 5, 6.
• Clinicians should be aware of the potential for hypokalemia to contribute to arrhythmias and take steps to correct potassium levels and prevent arrhythmias in at-risk patients 3, 4, 5, 6.