Abnormal levels of which electrolyte can cause cardiac arrhythmias and even death?

Abnormal levels of which electrolyte can cause cardiac arrhythmias and even death?

• A. Potassium
• B. Calcium
• C. Sodium
• D. Magnesium

Answer: (A)

Potassium balances the heart’s electrical activity, so abnormal levels directly disrupt cardiac conduction and rhythm. When potassium is too high, the heart’s cells become less excitable and conduction slows, which can widen the QRS and progress to life-threatening rhythms. When potassium is too low, electrical instability increases, leading to dangerous arrhythmias such as ventricular fibrillation or torsades in some contexts. Because these voltage-gating changes specifically alter the heart’s rhythm and can lead to death quickly, potassium abnormalities are the most likely to cause cardiac arrhythmias and fatal outcomes among the electrolytes listed. Calcium mainly affects contraction and conduction but its disturbances don’t produce the same immediate, severe rhythm risks in the typical clinical context. Sodium changes influence fluid balance and general nervous system function more than direct, life-threatening cardiac rhythm collapse. Magnesium matters for rhythm too, especially torsades, but the direct and broad impact of potassium on cardiac electrical activity makes it the best answer.

Potassium balances the heart’s electrical activity, so abnormal levels directly disrupt cardiac conduction and rhythm. When potassium is too high, the heart’s cells become less excitable and conduction slows, which can widen the QRS and progress to life-threatening rhythms. When potassium is too low, electrical instability increases, leading to dangerous arrhythmias such as ventricular fibrillation or torsades in some contexts. Because these voltage-gating changes specifically alter the heart’s rhythm and can lead to death quickly, potassium abnormalities are the most likely to cause cardiac arrhythmias and fatal outcomes among the electrolytes listed.

Calcium mainly affects contraction and conduction but its disturbances don’t produce the same immediate, severe rhythm risks in the typical clinical context. Sodium changes influence fluid balance and general nervous system function more than direct, life-threatening cardiac rhythm collapse. Magnesium matters for rhythm too, especially torsades, but the direct and broad impact of potassium on cardiac electrical activity makes it the best answer.