Potassium loss, ventricular irritability, and the risk of sudden death in hypertensive patients.

In the past, potassium depletion in both non-digitalised patients and in patients without cardiac disease was thought to cause no adverse cardiac effects. However, several studies have now demonstrated a significant incidence of ventricular ectopic activity (VEA) with diuretic-induced hypokalaemia, even in hypertensive patients without overt heart disease. Additional evidence suggests that sudden death may occasionally result from this VEA. Potassium repletion with potassium-sparing diuretics or with potassium chloride supplementation has generally demonstrated a beneficial therapeutic effect in reducing VEA. However, after diuretic therapy occasional patients may have persistent VEA which may result from focal myocardial lesions associated with potassium depletion. In contrast, diuretic therapy in which normokalaemia is maintained has only been associated with a very low occurrence of VEA. Thus, with the preservation of normokalaemia, diuretic therapy for hypertension does not appear to be associated with the significant hazards of VEA.