Electrolyte disarray and cardiovascular disease

Thiazide diuretics have frequently been recommended as initial therapy in patients with mild to moderate hypertension. However, their undesirable metabolic consequences have been suspected of contributing to increases in cardiovascular morbidity and mortality. Even at low doses, there is a definite decrease in both potassium and magnesium levels. The degree of decrease in potassium and magnesium levels has been shown to be directly related to the hydrochlorothiazide dosage. Many investigators have now reported an increase in ventricular ectopy associated with diuretic-induced hypokalemia. Whereas there is no single study that conclusively proves that thiazide therapy results in malignant arrhythmias and an increased risk of sudden death, the circumstantial evidence is strong. Although sodium restriction is critical to potassium restoration, it rarely works alone. Potassium chloride supplementation can be effective in restoring potassium but not magnesium. Potassium-sparing diuretic combinations can both prevent and treat hypokalemia and hypomagnesemia, possibly reducing the risk of potentially lethal arrhythmias and sudden death.