How Low Sodium Affects Heart's Electrical Signals: New Research Findings

New research explains how low levels of sodium in the blood can disrupt the heartbeat timing in patients on rhythm-control medications like flecainide. This medicine is often prescribed for atrial fibrillation and other irregular heart rhythms. The study, conducted by Virginia Tech researchers, found that blocking sodium channels with drugs like flecainide can make the heart's electrical conduction sensitive to even small drops in blood sodium levels.

Sodium is crucial for nerve and muscle function. When sodium levels drop too low, a condition called hyponatremia, the heart's electrical signaling can become unstable, especially in patients on sodium channel blockers. The study sheds light on why the combination of sodium channel blockers and low sodium levels is risky.

Impaired sodium channels force the heart to rely more on backup pathways for electrical signals. These pathways include ephaptic coupling and potassium ion flow, which help maintain the heart's electrical balance. When sodium levels decrease, these mechanisms can't compensate as effectively, causing slower conduction.

The study suggests that interfering with ephaptic coupling or potassium ion flow can reduce the heart's sensitivity to low sodium when sodium channels are blocked. This insight could lead to better strategies for managing conduction risks in patients on sodium channel blockers.

Physicians should be aware of interactions between drug therapy and electrolyte imbalances, especially low sodium levels, in older adults or hospitalized patients. Monitoring sodium levels may be crucial for patients on heart rhythm medications like flecainide to prevent serious problems.

The study was led by Professor Poelzing and supported by the National Heart, Lung, and Blood Institute of the National Institutes of Health.

According to the source: News-Medical.