title: Oral amiodarone increases the efficacy of direct-current cardioversion in restoration of sinus rhythm in patients with chronic atrial fibrillation.
abstract: OBJECTIVE
  Direct current cardioversion of persistent atrial fibrillation is one of the most widely used and effective treatments for the restoration of sinus rhythm, but may be hampered by a low success rate and a high percentage of early recurrence. Pre-treatment with amiodarone or a glucose-insulin-potassium solution could improve the efficacy of electrical cardioversion by reversing the partially depolarized diastolic potential of the subsidiary pacemakers in atrial fibrillation. In a controlled randomized study, we assessed the effectiveness of electrical cardioversion in patients with persistent atrial fibrillation after pre-treatment with amiodarone or potassium infusion and the efficacy of amiodarone in maintaining sinus rhythm after electrical cardioversion.
  
  
  RESULTS
  Ninety-two patients with persistent atrial fibrillation (>2 weeks duration) were prospectively randomized into three matched groups: A (n=31, oral amiodarone 400 mg. day(-1)1 month before and 200 mg. day(-1)2 months after cardioversion), B (n=31, 180 mg. day(-1)oral diltiazem 1 month before and 2 months after cardioversion and 80 mmol potassium, 50 UI insulin in 500 ml 30% glucose solution 24 h before cardioversion) and C (n=30, control patients, 180 mg. day(-1)oral diltiazem 1 month before and 2 months after cardioversion). Before cardioversion all patients were under 4 weeks effective oral anticoagulant therapy (warfarin). Before electrical cardioversion, the rate of spontaneous conversion to sinus rhythm was higher in group A (25%) than groups B (6%) or C (3%) (P<0.005). Electrical cardioversion was more successful in group A (88%) than groups B (56%) or C (65%) (P<0.05), while the electrical thresholds for effective cardioversion were lower in group B than the other groups (P<0.05). Twenty-four hours after cardioversion, the early recurrence of atrial fibrillation was similar in the three groups (P=ns), while at 2 months the recurrence rate was lower in group A (32%) than groups B (56%) or C (52%) (P<0.01).
  
  
  CONCLUSIONS
  Pre-treatment with low-dose oral amiodarone, compared with oral diltiazem or glucose-insulin-potassium treatments, induces a significantly high percentage of instances of spontaneous conversion, increases electrical cardioversion efficacy and reduces atrial fibrillation recurrence.
authors.affiliation: Cardiology Department, Piacenza General Hospital, Piacenza, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Capucci
authors.forename: G Q
authors.initials: GQ
authors.lastname: Villani
authors.forename: D
authors.initials: D
authors.lastname: Aschieri
authors.forename: A
authors.initials: A
authors.lastname: Rosi
authors.forename: M F
authors.initials: MF
authors.lastname: Piepoli
mesh_terms: D000328:Adult; D000368:Aged; D000638:Amiodarone / Q000627:therapeutic use*; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use*; D001281:Atrial Fibrillation / Q000150:complications / Q000188:drug therapy / Q000628:therapy*; D002908:Chronic Disease; D004554:Electric Countershock; D005260:Female; D006331:Heart Diseases / Q000150:complications; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D016896:Treatment Outcome
chemical_list: D000889:Anti-Arrhythmia Agents; D000638:Amiodarone