Torsades de pointes, a potential complication of diuretic-induced hypokalemia and hypomagnesemia in patients with congestive heart failure: Conference presentation of a generic patient

Background: Despite improvements in care, the prognosis for patients with congestive heart failure (CHF) remains poor. Fifty percent of patients with CHF suffer from arrhythmia and sudden cardiac death. This may be attributable in part to the use of medications that contribute to electrolyte imbalance. Objective: This article presents a case report of a woman with CHF due to left ventricular systolic dysfunction. Results: The case report involved a 52-year-old white woman with a history of paroxysmal atrial fibrillation, atypical chest pain, and dyslipidemia. Her medical treatment had included the use of furosemide (a loop diuretic), digoxin, and sotalol; she subsequently developed torsades de pointes (TdP). An electrocardiogram showed normal sinus rhythm; the QT_c interval was 530 msec. Levels of digoxin, K⁺, and Mg²⁺ were 1.8 ng/mL, 3.5 mEq/L, and 1.5 mEq/L, respectively. Results of a Holter monitor recording suggested that the hypomagnesemia and hypokalemia, interacting with the digoxin and sotalol, potentiated the development of a prolonged QT interval. To ensure the TdP did not recur, an IV bolus of Mg²⁺ was administered and oral triamterene therapy was added to the patient's current medications. These additions appeared to correct the electrolyte imbalance. Conclusion: This case exemplifies the importance of recognizing and managing electrolyte imbalance in the treatment of patients with CHF.