An unusual cause of HV prolongation.

Hyperkalemia is among the most common electrolyte imbalances encountered in clinical practice, affecting up to 8% of hospitalized patients in the United States.1 The most common causes are renal disease (encountered in 75% of patients with severe hyperkalemia) and administration of medications that elevate serum potassium levels (found in 67% of patients), including drugs often employed in cardiovascular disease such as angiotensin-converting enzyme inhibitors, angiotensin-receptor blockers and aldosterone blocking agents.