Amiodarone atrial fibrillation

Singh S, Singh B, Reda D, et al. [Abdellatif M]. Comparison of sotalol vs. amio-darone in maintaining stability of sinus rhythm in subjects with atrial Fibrillation (Sotalol-Amiodarone Atrial Fibrillation Effectiveness Trial [SAFE-T]). Am J Cardiol 2003 92 468-72. 

Class II Ventricular tachycardia WPW syndrome Postoperative atrial fibrillation (i.v. amiodarone)... 

Contraindications Concurrent use of drugs that prolong the QT interval concurrent use of amiodarone, megestrol, prochlorperazine, or verapamil congenital or acquired prolonged QT syndrome paroxysmal atrial fibrillation severe renal impairment... 

Ventricular tachycardia, atrial fibrillation, and flutter (can convert recent-onset fibrillation or flutter to sinus rhythm). Amiodarone is used in the management of patients with supraventricular and ventricular arrhythmias, and arrhythmias associated with the WPW syndrome... 

In the USA, amiodarone is approved for oral and intravenous use to treat serious ventricular arrhythmias. However, the drug is also highly effective for the treatment of supraventricular arrhythmias such as atrial fibrillation. As a result of its broad spectrum of antiarrhythmic action, it is very extensively used for a wide variety of arrhythmias. Amiodarone has unusual pharmacokinetics and important extracardiac adverse effects. Dronedarone, an analog that lacks iodine atoms, is under investigation. 

Low doses (100-200 mg/d) of amiodarone are effective in maintaining normal sinus rhythm in patients with atrial fibrillation. The drug is effective in the prevention of recurrent ventricular tachycardia. It is not associated with an increase in mortality in patients with coronary artery disease or heart failure. In many centers, the implanted cardioverter-defibrillator (ICD) has succeeded drug therapy as the primary treatment modality for ventricular tachycardia, but amiodarone may be used for ventricular tachycardia as adjuvant therapy to decrease the frequency of uncomfortable cardioverter-defibrillator discharges. The drug increases the pacing and defibrillation threshold and these devices require retesting after a maintenance dose has been achieved. 

The limited success of highly specific drugs that target single ion channels and the efficacy of multi-ion channel blockers such as amiodarone has shifted the emphasis in antiarrhythmic drug development to the multi-ion channel blockers class of drugs. Vernakalant is an investigational multi-channel blocker that was developed for the treatment of atrial fibrillation. 

Dronedarone Investigational amiodarone derivative multichannel actions, reduces mortality in patients with atrial fibrillation... 

Budesonide for collagenous colitis caused Cushing s syndrome in a patient with chronic renal insufficiency taking amiodarone for paroxysmal atrial fibrillation (477). 

A 62-year-old woman with paroxysmal atrial fibrillation who had taken amiodarone 300 mg/day had a serum sodium concentration of 120 mmol/1 with a normal serum potassium and a reduced serum osmolality (240 mmol/kg) the urinary sodium concentration was 141 mmol/1 and the urine osmolality 422 mmol/kg (25). There was no evident cause of inappropriate secretion of ADH and within 5 days of withdrawal of amiodarone the serum sodium concentration had risen to 133 mmol/ 1 and rose further to 143 mmol/1 14 days later. There was no rechallenge and no recurrence of hyponatremia during the next 6 months. Another case has been reported (28). 

Preliminary report effect of encainide and flecainide on mortality in a randomized trial of arrhythmia suppression after myocardial infarction. The Cardiac Arrhythmia Suppression Trial (CAST) Investigators. N EnglJ Med 1989 321 (6) 406—412. Donovan KD, et al. Intravenous flecainide versus amiodarone for recent-onset atrial fibrillation, Am J Cardiol 1995 75( 10) 693—697. 

Martinez-Marcos FJ, et al. Comparison of intravenous flecainide, propafenone, and amiodarone for conversion of acute atrial fibrillation to sinus rhythm. Am J Cardiol 2000 86(9) 950-953. 

Bernard EO, et al. Ibutilide versus amiodarone in atrial fibrillation a double-blinded, randomized study. Crit Care Med 2003 3 I (4) 1031-1034. 

Cotter G, et al. Conversion of recent onset paroxysmal atrial fibrillation to normal sinus rhythm the effect of no treatment and high-dose amiodarone. A randomized, placebo-controlled study. Eur Heart J 1999 20(24) 1833-1842. 

Peuhkurinen K, et al. Effectiveness of amiodarone as a single oral dose for recent-onset atrial fibrillation. Am J Cardiol 2000 85(4) 462-465. 

Tieleman RG, et al. Efficacy, safety, and determinants of conversion of atrial fibrillation and flutter with oral amiodarone. Am J Cardiol 1997 79(l) 53-57. 

Arruodarone is used in chronic ventricular arrhythmias in atrial fibrillation it both slows the ventricular response and may restore sinus rhythm it may be used to maintain sinus rhythm after cardioversion for atrial fibrillation or flutter. Amiodarone should no longer be used for the management of reentrant supraventricular tachycardias associated with the Wolff-Parkinson-White syndrome as radiofrequency ablation is preferable. 

Uses of electrical conversion in supraventricular and ventricular tachycardia, ventricular fibrillation and atrial fibrillation and flutter. Drugs can be useful to prevent a relapse, e.g. sotalol, amiodarone. 

This occurs in otherwise healthy individuals, who possess an anomalous (accessory) atrioventricular pathway they often experience attacks of paroxj mal AV re-entrant tachycardia or atrial fibrillation. Drugs that both suppress the initiating ectopic beats and delay conduction through the accessory pathway are used to prevent attacks e.g. flecainide, sotalol or amiodarone. Verapamil and digoxin may increase conduction through the anomalous pathway and should not be used. Electrical conversion may be needed to restore sinus rhythm when the ventricular rate is very rapid. Radiofrequency ablation of aberrant pathways will almost certainly provide a cure. 

Adenosine is the treatment of choice for diagnosis and reversal of supraventricular arrhythmias. Verapamil is an alternative for the management of narrow complex tachycardias. Amiodarone is the most effective drug at reversing atrial fibrillation, and in prevention of ventricular arrhythmias, but has several adverse effects. 

Roy D et al 2000 Amiodarone to prevent recurrence of atrial fibrillation. Canadian Trial of Atrial Fibrillation Investigators. New England Journal of Medicine 342 913-920... 

Amiodarone and carvedilol have been used in combination in 109 patients with severe heart failure and left ventricular ejection fractions of 0.25 (16). They were given amiodarone 1000 mg/week plus carvedilol titrated to a target dose of 50 mg/day. A dual-chamber pacemaker was inserted and programmed in back-up mode at a basal rate of 40. Significantly more patients were in sinus rhythm after 1 year, and in 47 patients who were studied for at least 1 year the resting heart rate fell from 90 to 59. Ventricular extra beats were suppressed from 1 to 0.1/day and the number of bouts of tachycardia over 167 per minute was reduced from 1.2 to 0.3 episodes per patient per 3 months. The left ventricular ejection fraction increased from 0.26 to 0.39 and New York Heart Association Classification improved from 3.2 to 1.8. The probability of sudden death was significantly reduced by amiodarone plus carvedilol compared with 154 patients treated with amiodarone alone and even more so compared with 283 patients who received no treatment at all. However, the study was not randomized, and this vitiates the results. The main adverse effect was s)mptomatic bradycardia, which occurred in seven patients two of those developed atrioventricular block and four had sinoatrial block and/or sinus bradycardia one patient developed slow atrial fibrillation. 

Cardiac glycosides such as digoxin are commonly used to treat uncomphcated atrial fibrillation. In those in whom digi-tahs is not completely effective or in whom s)mptoms (for example bouts of palpitation) persist despite adequate digitalization, a calcium antagonist, such as verapamil or diltia-zem, can be added, or amiodarone used as an alternative. 

The use of oral amiodarone in preventing recurrence of atrial fibrillation, for preventing recurrence after cardioversion or for pharmacological cardioversion of atrial fibrillation, has been reviewed (18). There is insufficient evidence to support its use as a first-line drug for... 

In 186 patients randomized equally to amiodarone 200 mg/day, sotalol 160-480 mg/day, or placebo, the incidence of atrial fibrillation after 6 months was higher in those taking placebo compared with amiodarone and sotalol and higher in those taking sotalol compared with amiodarone (19). Of the 65 patients who took amiodarone, 15 had significant adverse effects after an average of... 

In 208 patients with atrial fibrillation of various duration, including 50 with chronic atrial fibrillation, randomized to amiodarone or placebo, 80% converted to sinus rhythm after amiodarone compared with 40% of those given placebo (20). Amiodarone was given as an intravenous loading dose of 300 mg for 1 hour and 20 mg/kg for 24 hours, followed by 600 mg/day orally for 1 week and 400 mg/day for 3 weeks. Those who converted to sinus rhythm had had atrial fibrillation for a shorter duration and had smaller atria than those who did not convert. The shorter the duration of fibrillation and the smaller the atria the sooner conversion occurred. There was significant hypotension in 12 of the 118 patients who received amiodarone during the first hour of intravenous administration, but in all cases this responded to intravenous fluids alone. There was phlebitis at the site of infusion in... 

In 40 patients with atrial fibrillation, some with severe heart disease (including cardiogenic shock in eight and pulmonary edema in 12), amiodarone 450 mg was given through a peripheral vein within 1 minute, followed by 10 ml of saline 21 patients converted to sinus rhythm, 13 within 30 minutes and another 8 within 24 hours (21). There were two cases of hypotension, but in those that converted to sinus rhythm there was a slight increase in systolic blood pressure. There were no cases of thrombophlebitis. Efficacy is hard to judge from this study, because it was not placebo-controlled. 

In 72 patients with paroxysmal atrial fibrillation randomized to either amiodarone 30 mg/kg or placebo, those who received amiodarone converted to sinus rhythm more often than those given placebo (22). The respective conversion rates were about 50 and 20% at 8 hours, and 87 and 35% after 24 hours. The time to conversion in patients who converted did not differ. One patient developed slow atrial fibrillation (35/minute) with a blood pressure of 75/ 55 mmHg. Three other patients who received amiodarone had diarrhea and one had nausea. In the control group two patients had headache, one had diarrhea, one had nausea, and two had episodes of sinus arrest associated with syncope during conversion to sinus rhythm the last of these was thought to have sick sinus syndrome. 

In a single-blind study 150 patients with acute atrial fibrillation were randomized to intravenous flecainide, propafenone, or amiodarone (23). At 12 hours there was... 

Amiodarone, propafenone, and sotalol have also been compared in the prevention of atrial fibrillation in 214 patients with recurrent symptomatic atrial fibrillation. They were randomized to amiodarone 200 mg/day, propafenone 450 mg/day, or sotalol 320 mg/day. There was recurrence of atrial fibrillation in 25 of the 75 patients who took amiodarone compared with the 51 of 75 who took sotalol and 24 of the 64 who took propafenone. There... 

In a meta-analysis of five randomized, placebo-con-trolled trials of amiodarone 200-1200 mg/day for 2-7 days in the treatment of postoperative atrial fibrillation and flutter in 764 patients, the incidence of adverse events with amiodarone was no greater than with placebo (27). 

Of 85 patients with persistent atrial fibrillation after balloon mitral valvotomy given amiodarone (600 mg/day for 2 weeks and 200 mg/day thereafter), 33 converted to sinus rhythm (29). Of the other 52 patients, who underwent DC cardioversion at 6 weeks, 41 converted to sinus rhythm. Six patients had adverse effects attributable to amiodarone. Five had mild gastrointestinal symptoms, such as abdominal discomfort and nausea. One developed hypothyroidism after 3 months, which resolved when the dosage of amiodarone was reduced to 100 mg/day. 

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