Cardioversion of recent-onset atrial fibrillation using intravenous antiarrhythmics: A European perspective

Pharmacological cardioversion using intravenous antiarrhythmic agents is commonly indicated in symptomatic patients with recent-onset atrial fibrillation (AF). Except in hemodynamically unstable patients who require emergency direct current electrical cardioversion, for the majority of hemodynamically stable patients, pharmacological cardioversion represents a valid option and requires the clinician to be familiar with the properties and use of antiarrhythmic agents. The main characteristics of selected intravenous antiarrhythmic agents for conversion of recent-onset AF, the reported success rates, and possible adverse events are discussed. Among intravenous antiarrhythmics, flecainide, propafenone, amiodarone, sotalol, dofetilide, ibutilide, and vernakalant are commonly used. Antazoline, an old antihistaminic agent with antiarrhythmic properties was also reported to give encouraging results in Poland. Intravenous flecainide and propafenone are the only Class I agents still recommended by recent guidelines. Intravenous new Class III agents as dofetilide and ibutilide have high and rapid efficacy in converting AF to sinus rhythm but require strict surveillance with electrocardiogram (ECG) monitoring during and after intravenous administration because of the potential risk of QT prolongation and Torsades de Pointes, which can be prevented and properly managed. Vernakalant, a partial atrial selective was shown to have a high success rate and to be safe in real-life use.     

Cardioversion of atrial fibrillation in the elderly

The purpose of this investigation was to define cardioversion success rates, frequency of complications of cardioversion, and current treatment practices in elderly patients (aged > 65 years) with atrial fibrillation (AF). The results were compared with those in younger patients (aged < 65 years). The investigation was a prospective multicenter observational study with 61 participating cardiology clinics. Consecutive patients in whom cardioversion of AF was planned had to be prospectively registered. Of 1,152 patients registered, 570 (49.5%) were < 65 years old (group 1) and 582 (50.5%) were ≥65 years (group 2). The overall success rate of cardioversion on an intention-to-treat basis was 76.1% in group 1 and 72.7% in group 2 (p = 0.18). In multivariate analysis, left atrial size and New York Heart Association functional class before cardioversion were identified as predictors of success (p < 0.001, respectively; P = 0.025). These clinical factors were not equally distributed between the age groups: Left atrial size was larger in the elderly than in younger patients (44.0 ± 6.4 mm vs 42.8 ± 6.4 mm; P = 0.006) and a New York Heart Association functional class ≥II was more prevalent in group 2 than in group 1 (48.6% vs 29.6%; p < 0.001). The overall complication rates were not significantly different between the 2 groups (4.2% in group 1 vs 5.3% in group 2; P = 0.37). The frequency of patients who were adequately anticoagulated for cardioversion was 56.9% in age group 1 and 39.6% in age group 2 (p < 0.001). In chronic AF the same trend for age-dependent underuse of anticoagulation was observed. Age itself was not a predictor of cardioversion success and did not predispose to higher complication rates. Therefore, cardioversion should be considered in older patients with the same criteria and emphasis as in younger patients. Anticoagulation and antithrombotic medication is underused for cardioversion and in treating chronic AF, especially in elderly patients.     

Amiodarone for pharmacological cardioversion of recent-onset atrial fibrillation

The efficacy and safety of amiodarone for pharmacological cardioversion of recent-onset atrial fibrillation was examined by reviewing the trials on the subject identified through a comprehensive literature search. Amiodarone has been used both intravenously (i.v.) and orally for the pharmacological cardioversion of recent-onset atrial fibrillation. Intravenous amiodarone has been used as a bolus only or as a bolus followed by a continuous i.v. infusion until conversion or up to 24 h. The dose of i.v. bolus given ranged from 3 to 7 mg/kg body weight and that of infusion from 900 to 3000 mg/day. The efficacy reported is 34-69% with the bolus only regimens, and 55-95% with the bolus followed by infusion regimens. Only the higher dose (>1500 mg/day) amiodarone is superior to placebo in converting recent-onset atrial fibrillation to sinus rhythm. The highest 24-h conversion rates have been reported with the i.v. regimen of 125 mg/h until conversion or a maximum of 3 g and the oral regimen of 25-30 mg/kg body weight administered as a single loading-dose (>90% and >85%, respectively). Most of the conversions occur after 6-8 h of the initiation of therapy. Predictors of successful conversion are shorter duration of atrial fibrillation, smaller left atrial size, and higher amiodarone dose. Amiodarone is not superior to the other antiarrhythmic drugs conventionally used for the pharmacological cardioversion of recent-onset atrial fibrillation but is relatively safe in patients with structural heart disease and in those with depressed left ventricle function. Therefore, amiodarone could be used particularly in patients with structural heart disease and in those with left ventricular systolic dysfunction as the use of class IC drugs, propafenone and flecainide, for cardioversion of atrial fibrillation is contraindicated in such patients.     

Intravenous amiodarone for cardioversion of recent-onset atrial fibrillation

BACKGROUND: Atrial fibrillation (AF) is one of the most common causes of hospital admission, with a prevalence of up to 5% of the population, increasing with advancing age. Emergency direct current cardioversion is the therapy of choice when arrhythmia leads to hemodynamic compromise, but in patients who are hemodynamically stable, antiarrhythmic drugs are usually given to restore sinus rhythm. HYPOTHESIS: The study was undertaken to assess the efficacy of intravenous amiodarone in cardioversion of recent-onset paroxysmal atrial fibrillation (AF). No standard antiarrhythmic therapy has been accepted for pharmacologic cardioversion of AF. Amiodarone seems to be a promising candidate, but only few randomized trials are available and the results are inconsistent. METHODS: In all, 160 patients with AF lasting < 24 h were randomly assigned (2:1 fashion) to the amiodarone group (n = 106) receiving 5 mg/kg as a 30 min intravenous (i.v.) infusion, followed by i.v. infusion of 10 mg/kg during 20 h diluted in 1000 ml of 10% glucose with 20 IU of rapid-action insulin, 80 mEq of potassium chloride, and 8 g of magnesium sulphate (GIKM), or to the control group (n = 54) receiving 1000 ml of GIKM alone. Treatment was continued up to 20 h independent of sinus rhythm restoration. RESULTS: Sinus rhythm was restored 20 h after initiation of therapy in 88 (83%) patients in the amiodarone group and in 24 (44%) patients in the control group (p < 0.0001). The difference between efficacy of the two treatment modalities became significant already after 8 h of therapy (53 vs. 14 patients with sinus rhythm, respectively, p < 0.05). The mean dose of amiodarone administered until sinus rhythm restoration was 740 +/- 296 mg. The presence and the type of underlying heart disease did not influence the conversion rate in either group. In two patients (1.8%) treated with amiodarone, the return of sinus rhythm was preceded by asystole. CONCLUSION: Amiodarone is effective in the termination of AF lasting < 24 h. It may be particularly useful in patients with organic heart disease in whom class I antiarrhythmic agents may be contraindicated. During treatment, the heart rhythm should be monitored continuously.     

Amiodarone and its infusion velocity in recent-onset atrial fibrillation]

Two intravenous amiodarone dosing schedules in 28 patients with atrial fibrillation arisen less than 10 days before, were evaluated. Their effectiveness in converting to sinus rhythm, the incidence of side effects and the relationship between efficacy and plasma concentrations of amiodarone and desethylamiodarone were compared. Schedule A, with amiodarone infusion at a rate of 1.5 mg/kg/h up to two hours after the restoration of sinus rhythm or to a maximum dose of 1200 mg, reverted 86.7% of all patients. Schedule B, with a single amiodarone infusion of 300 mg over 15 minutes, followed by a 300 mg dose maintenance over three hours, reverted 69.2% of all patients. Schedule A was more effective than schedule B (P less than 0.01). Schedule B reverted before A (P less than 0.05). The only transient adverse effects were: superficial phlebitis, symptomatic hypotension and silent QTc lengthening. Amiodarone and desethylamiodarone plasma concentrations were not related to efficacy of the drug in converting sinus rhythm. In conclusion, an intravenous infusion of amiodarone over few hours showed high efficacy (79.6%), wide therapeutic index, good compliance and irrelevant adverse effects in converting patients with recent-onset fibrillation.     

Cardioversion by internal electric shock of permanent atrial fibrillation

A new technique for cardioversion of chronic atrial fibrillation was used in 17 patients whose arrhythmia had resisted all attempts at electrical and pharmacologycal cardioversion. Atrial fibrillation was badly tolerated by all patients despite digitalis administered alone (8 patients) or combined with amiodarone (9 patients). Twelve patients had left atrial dilatation at echocardiography. The 200, 300 or 400 joule electrical shock was delivered between the proximal pole of a quadripolar catheter (cathode) and a back plate (anode). The catheter was positioned at the His bundle recording site then withdrawn into the right atrium. The internal shock restored sinus rhythm in 15 patients (88 p. 100). Transient atrioventricular block (3-315 sec) was observed in 8 patients. Eleven patients were discharged in sinus rhythm. In 4 patients, the atrial fibrillation recurred on day 8 and after 2, 4 and 9 months. A second shock was attempted in two patients and succeeded in one. After a mean follow-up period of 14.8 +/- 8 months (range 2 to 25 months), 8 of the 11 patients successfully cardioverted (72 p. 100) or of the attempted reductions (47 p. 100) were in sinus rhythm. The remaining 9 patients were treated with antiarrhythmic drugs (n = 5) or by his bundle catheter ablation (n = 4). High energy internal shock therefore seems to be an interesting treatment in patients with permanent atrial fibrillation after failure of external electric shock. It enabled 13 of the 17 patients in this series to avoid His bundle catheter ablation indicated by the quasi-impossibility to control the atrial rate and associated symptoms.(ABSTRACT TRUNCATED AT 250 WORDS)     

口服负荷量普罗帕酮转复新近发生的心房颤动

目的研究口服负荷量普罗帕酮转复新近发生的非瓣膜病心房颤动(房颤)的临床疗效和安全性.方法有症状就诊的房颤患者61例,最近房颤持续发作在48h之内,既往无心力衰竭表现,本次发作不伴急性心肌缺血和其他急性心外病症,临床排除心脏瓣膜病、预激综合征、病态窦房结综合征及甲状腺机能亢进.随机分为口服负荷量普罗帕酮组和静脉毛花甙C组.普罗帕酮组顿服负荷量普罗帕酮450mg(2例体重过轻者给以300mg).毛花甙C组采用0.4mg静脉小壶滴人,若4h仍未转复则追加0.2mg.所有患者均在心电监护下观察心电、血压及症状变化,记录从服药到转复为窦律的时间.比较两组4h和8h的转复率和转复时间.结果普罗帕酮组共31例,4h转复17例(54.8%),平均转复时间(1.6±0.2)h;4～8h转复6例(19.4%),未转复成功8例的房颤持续时间明显长于转复成功者(P<O.01),未发现明显副作用.静脉毛花甙c组共30例,4h内转复8例(26.7%),平均转复时间(2.7±0.9)h;4～8h转复5例(16.7%).两组比较4h内普罗帕酮组房颤转复率明显高于毛花甙c组(P<0.05),4h内的平均转复时间亦有明显差异(P<O.01).结论对于新近发生的(持续发作48h之内)、不伴心功能不全和急性心肌缺血及其他急性心外病症的非瓣膜病房颤患者,口服负荷量普罗帕酮是一个快速、方便、安全的转复方法.     

Canadian Cardiovascular Society atrial fibrillation guidelines 2010: management of recent-onset atrial fibrillation and flutter in the emergency department

Atrial fibrillation (AF) is the most common arrhythmia managed by emergency physicians. There is increasing evidence that most patients with recent-onset AF or atrial flutter (AFL) can be safely managed in the emergency department (ED) without the need for hospital admission. The priorities for ED management of recent-onset AF/AFL include rapid assessment of potential hemodynamic instability and identification and treatment of the underlying or precipitating cause. A careful evaluation of the patient's history should be performed to determine the time of onset of the arrhythmia. All patients should be stratified using a predictive index for the risk of stroke (eg, CHADS(2)). For stable patients with recent-onset AF/AFL, a strategy of either rate control or rhythm control could be selected based on multiple factors including the duration of AF and the severity of symptoms. If a strategy of rhythm control has been selected, either electrical or pharmacologic cardioversion may be used. Before proceeding to cardioversion in the absence of systemic anticoagulation, physicians must be confident that the duration of AF/AFL is clearly <48 hours and that the patient is not at a particularly high risk of stroke. When the duration of AF/AFL is >48 hours or uncertain, rate control should be optimized first and the patients should receive therapeutic anticoagulation for 3 weeks before and 4 weeks after planned cardioversion. Adequate follow-up of patients with recent-onset AF/AFL is recommended to identify structural heart disease and evaluate the need for long-term antithrombotic or antiarrhythmic therapy.     

Reversion of recent-onset atrial fibrillation to sinus rhythm by intravenous flecainide

Spontaneous reversion to sinus rhythm is a frequent occurrence in recent-onset atrial fibrillation (AF). In a randomized, double-blind, controlled study, intravenous flecainide (2 mg/kg, maximum dose 150 mg) was compared with placebo in the treatment of recent-onset AF (present for greater than or equal to 30 minutes and less than or equal to 72 hours' duration and a ventricular response greater than or equal to 120 beats/min). Intravenous digoxin (500 micrograms) was administered concurrently to all patients in both groups who had not previously taken digoxin. The trial medication was administered over 30 minutes. Exclusion criteria included hemodynamic instability, severe heart failure, recent antiarrhythmic therapy, hypokalemia and pacemaker dependence. One hundred two consecutive patients with recent-onset AF were enrolled in the study. All patients underwent continuous electrocardiographic monitoring in the intensive care or coronary care unit. Twenty-nine (57%) patients given flecainide and digoxin, but only 7 (14%) given placebo and digoxin, reverted to sinus rhythm in less than or equal to 1 hour after starting the trial medication infusion and remained in stable sinus rhythm (chi-square 18.9, p = 0.000013; odds ratio 8.3, 95% confidence interval 2.9 to 24.8). At the end of the 6-hour monitoring period, 34 patients (67%) in the flecainide-digoxin group were in stable sinus rhythm, whereas only 18 patients (35%) in the placebo-digoxin group had reverted (chi-square 8.83, p = 0.003; odds ratio 3.67, 95% confidence interval 1.5 to 9.1).(ABSTRACT TRUNCATED AT 250 WORDS)     

房间隔缺损并发心房纤颤患者应用Amplatzer伞封堵房缺后心房纤颤的电复律治疗

目的 :初步评价房间隔缺损并发心房纤颤患者应用 Am platzer伞封堵房间隔缺损后心房纤颤的电复律疗效。方法 :2例患者 （5 1～ 5 3岁 ）。在透视及食管超声心动图监视下经导管置入 Amplatzer伞封堵房间隔缺损。术后即时行超声心动图 ,术后 2 4h,和 1,3,6月 ,分别行经胸超声心动图评价房间隔缺损治疗效果。术后 6月行电复律。结果 :2例患者疗效均佳 ,房间隔未见残余分流 ,电复律成功 ,患者转为窦性心律 ,复律后无并发症及 Amplatzer伞移位。结论 :应用 Am platzer伞封堵房间隔缺损并发心房纤颤患者 ,电复律易成功 ,是一种安全有效的复律方法。