title: Pharmacologic Conversion during Dofetilide Treatment for Persistent Atrial Fibrillation.
abstract: BACKGROUND
  Dofetilide is a pure IKrblocker and is one of the few drugs specifically studied and approved in the United States for the management of persistent atrial fibrillation (AF). Dofetilide has been noted to have a high rate of pharmacologic conversion during initial dosing in prior smaller studies. The intent of the study was to examine the safety of an inpatient loading strategy, and the incidence and patterns of pharmacologic conversion by dofetilide during the treatment of persistent AF in a large consecutive cohort.
  
  
  RESULTS
  This is a retrospective analysis of 308 consecutive patients with persistent AF electively admitted for inpatient dofetilide loading. The initiation dose of dofetilide was determined by the creatinine clearance. Overall, 88% (n = 271) successfully completed initiation of dofetilide and were discharged in sinus rhythm. The most common reason for failure to complete initiation of dofetilide loading was QTc prolongation in 24 patients (7.8%), and torsade de pointes occurred in three patients (1%). Pharmacologic conversion was observed in 56% (n = 151) after a median of two doses. The rate of pharmacologic conversion based on the final dose was 75%, 9%, and 0% for 500 mcg, 250 mcg, and 125 mcg, respectively (P < 0.05).
  
  
  CONCLUSIONS
  Dofetilide is a well-tolerated antiarrhythmic drug with a low incidence of proarrhythmia and an especially high rate of pharmacologic conversion in patients with persistent AF.
authors.affiliation: Heart Research Follow-up Program, University of Rochester School of Medicine & Dentistry, Rochester, New York.
authors.forename: Jonathan S
authors.initials: JS
authors.lastname: Steinberg
authors.affiliation: Heart Research Follow-up Program, University of Rochester School of Medicine & Dentistry, Rochester, New York.
authors.forename: Yash
authors.initials: Y
authors.lastname: Shah
authors.affiliation: Heart Research Follow-up Program, University of Rochester School of Medicine & Dentistry, Rochester, New York.
authors.forename: Barbara
authors.initials: B
authors.lastname: Szepietowska
mesh_terms: D000889:Anti-Arrhythmia Agents / Q000008:administration & dosage; D001281:Atrial Fibrillation / Q000175:diagnosis / Q000188:drug therapy* / Q000453:epidemiology*; D015984:Causality; D002908:Chronic Disease; D015331:Cohort Studies; D015897:Comorbidity; D064420:Drug-Related Side Effects and Adverse Reactions / Q000175:diagnosis / Q000453:epidemiology*; D004562:Electrocardiography / Q000187:drug effects*; D005260:Female; D006801:Humans; D008133:Long QT Syndrome / Q000175:diagnosis / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D009518:New York / Q000453:epidemiology; D010627:Phenethylamines / Q000008:administration & dosage*; D012189:Retrospective Studies; D012307:Risk Factors; D013449:Sulfonamides / Q000008:administration & dosage*; D016171:Torsades de Pointes / Q000175:diagnosis / Q000453:epidemiology*; D016896:Treatment Outcome
chemical_list: D000889:Anti-Arrhythmia Agents; D010627:Phenethylamines; D013449:Sulfonamides; C063533:dofetilide
keywords: antiarrhythmic drug; atrial fibrillation; cardioversion; dofetilide; pharmacologic conversion