The kidneys are the primary organ responsible for the regulation of electrolyte gradients within the cell and extracellular spaces. The hormonal activities of aldosterone, antidiuretic hormone, and parathyroid hormone also play a role in electrolyte balance. Disorders in these systems disrupt the balance of certain electrolytes and may result in medical emergencies.

Sodium imbalances are particularly problematic, especially in patients who need intensive care. Hypo- and hypernatremia are the most common causes of mortality. Calcium is the second most disrupted electrolyte, followed by potassium.

Abnormalities of serum potassium concentration have more significant effects on the ECG than calcium imbalances. The ECG changes seen with serum sodium imbalances are similar to those seen with serum magnesium changes. However, neither sodium nor magnesium concentrations result in particularly remarkable ECG changes. 

Only 30% of patients with electrolyte imbalances have detectable ECG changes. The diagnostic accuracy of ECG increases to 90% of cases when the electrolyte imbalance is severe. 

The ECG of a patient with severe hyperkalemia exhibits broad QRS complexes. Severe hypokalemia often causes polymorphic ventricular tachycardia.

The kidneys help maintain electrolyte concentrations.