Safety of dofetilide in stable patients and investigating traits of susceptibility to torsade de pointes.

Background: Atrial fibrillation is the most prevalent cardiac arrhythmia, presenting symptomatic patients with diminished quality of life and worsening of heart failure. Dofetilide, a class 3 antiarrhythmic agent, is a proven and safe rhythm control medication. Initial risk of QT prolongation leading to torsade de pointes (TdP) necessitates a standard protocol mandating hospitalization for three days for initiation. Objectives: To assess safety when adhering to initiation protocol and identify traits for susceptibility to TdP in elective dofetilide admissions. Methods: We conducted a retrospective study involving patients admitted to Mayo Clinic sites across four states for elective inpatient initiation of dofetilide between 2003 and 2022. Patients' charts underwent review, focusing on dofetilide-related TdP occurrences, baseline characteristics including QT intervals, laboratory values, comorbidities, and concomitant medications. Patients who experienced TdP were subjected to further evaluation to identify potential risk factors. Results: Of 2036 patients identified, mean age 66.4 ± 11.4 years, and 67.2 % male, 16 experienced dofetilide-related TdP (incidence rate 0.79%). Notably, 81% (13/16) of TdP cases occurred in patients who deviated from the FDA/manufacturer algorithm protocol. The concomitant use of active intravenous diuretic therapy, digoxin, and QT-prolonging drugs emerged as identifiable risk factors. Additionally, females exhibited a higher incidence of TdP (1.5%) than males (0.44%) {odd ratio [OR] 3.46; P = 0.017}. Conclusion: Overall incidence of TdP related to dofetilide initiation was low (0.79%). Adherence to protocol during elective hospital admissions appears extraordinarily safe. Patients who did not require concurrent use of intravenous diuretics, digoxin, or QT prolonging drugs exhibited lower risk of TdP.