Which electrolyte imbalance is most commonly associated with cardiac arrhythmias?

Potassium plays a crucial role in maintaining the cardiac membrane potential and electrical conduction system. Hypokalemia (<3.5 mEq/L) causes increased myocardial excitability, leading to arrhythmias such as ventricular tachycardia, premature ventricular contractions, and ECG changes like flattened T waves and U waves. Severe hypokalemia can result in life-threatening dysrhythmias, which is why potassium levels are closely monitored in hospitalized patients.