Archives of Gerontology and Geriatrics 27 (1998) 127 – 139 Pharmacological treatment of atrial fibrillation: a review on prevention of recurrences and control of ventricular response Giuseppe Boriani *, Mauro Biffi, Angelo Branzi, Bruno Magnani Institute of Cardiology, Uni6ersity of Bologna, Policlinico S. Orsola, Via Massarenti 9, 40138 Bologna, Italy Received 29 December 1997; received in revised form 17 April 1998; accepted 20 April 1998 Abstract Atrial fibrillation is the most common sustained arrhythmia, however its treatment remains controversial and problematic. Electrical or pharmacological cardioversion are able to restore sinus rhythm in many patients but maintenance of sinus rhythm requires long term treatment with antiarrrhythmic agents. Today there is major concern regarding the ventricular proarrhythmic effects of antiarrhythmic drugs because they may increase mortality. Even non-cardiac toxicity of these agents must be considered. An alternative strategy based on pharmacological control of ventricular response rate coupled with antithromboembolic prophylaxis can be followed. For rate control digoxin alone has some specific limitations, therefore, use of calcium antagonists (verapamil or diltiazem) or i-blockers must be considered. At the present time, the relative efficacy and risks of these two alternative strategies in specific patients subgroups remain to be established. Today, non-pharmacological treatments, as atrio-ventricular node ablation are also available. In elderly patients, moreover, advanced age, underlying heart disease, concomitant systemic illnesses and patient compliance to treatments condition our decision making and treatment needs to be individualized. Appropriate knowledge of the advantages, of the limitations and of the costs of every pharmacological or non-pharmacological treatment option is required for deciding in every patient in view of the best risk-benefit and cost-benefit ratio. © 1998 Elsevier Science Ireland Ltd. All rights reserved. Keywords: Antiarrhythmic drugs; Atrial fibrillation; Cardioversion; Prophylaxis * Corresponding author. Tel.: +39 51 349858; fax: + 39 51 344859. 0167-4943/98/$ - see front matter © 1998 Elsevier Science Ireland Ltd. All rights reserved. PII S0167-4943(98)00106-X 128 G. Boriani et al. / Arch. Gerontol. Geriatr. 27 (1998) 127–139 1. Introduction Atrial fibrillation is the most common sustained arrhythmia seen by the clinician and both its prevalence and its incidence increase with age (Kannel et al., 1982; Wolf et al., 1991). Atrial fibrillation can be recognized in 0.2–0.3% of subjects aged 25– 35, in 3 – 4% of those aged 55–60 and in 5–9% of those above the age of 60. Overall, 4% of a general population has paroxysmal or chronic atrial fibrillation (Kannel and Wolf, 1992). Atrial fibrillation is usually associated with some form of concurrent cardiovascular disease and systemic hypertension is quite common. Non-cardiac factors related to an increased likelihood of developing atrial fibrillation include hyperthyroidism and diabetes (Kannel et al., 1982). Infrequently, there is no identifiable cause for atrial fibrillation and the term idiopathic or ‘lone’ atrial fibrillation is employed. In the elderly, atrial fibrillation can be the manifestation of a sick sinus syndrome, in its so-called brady-tachy variant. Atrial fibrillation is a major cause of stroke, especially in the elderly (Wolf et al., 1991) and the risk of stroke is increased 6-fold in non-rheumatic atrial fibrillation, and 15- to 20-fold in rheumatic valvular disease (Wolf et al., 1991). The hemodynamic consequences of atrial fibrillation are related to: (i) loss of atrial contribution to cardiac output, which may result in a 20–40% reduction of stroke volume; and (ii) excessively rapid ventricular rate with irregular rhythm and with alteration of normal ability to regulate cardiac rhythm according to physiological activities. Patients symptoms may vary markedly, some patients being asymptomatic. However, palpitations, dizziness, dyspnea and chest discomfort are common in subjects with atrial fibrillation and may be related to reduced working capacity, aggravation or induction of heart failure or aggravation of ischemic heart disease. The relevance of atrial fibrillation is confirmed by considering that patients with atrial fibrillation and constant high ventricular rate (\ 120 bpm) may develop a tachycardia-induced cardiomyopathy with a pattern of severe congestive heart failure (Peters and Kienzle, 1988; Grogan et al., 1992; Crijns et al., 1997). The treatment of atrial fibrillation has different objectives, as reported in Table 1. Non-pharmacological approaches to atrial fibrillation treatment have been proposed (Harvey and Morady, 1995; Nattel, 1996; Jung and DiMarco, 1998), Table 1 Importance of treating atrial fibrillation To relieve symptoms of congestive heart failure, hypotension or angina that can be directly attributed to atrial fibrillation To improve overall cardiac function To improve exercise tolerance To prevent atrial fibrillation recurrences and related symptoms To reduce the risk of stroke and of thromboembolic events To prevent morbidity related to atrial fibrillation To prevent mortality related to atrial fibrillation G. Boriani et al. / Arch. Gerontol. Geriatr. 27 (1998) 127–139 129 however their reliability and their risk-benefit and cost-benefit ratios are still under evaluation. Therefore, especially in elderly patients, the first approach to atrial fibrillation treatment is based on drug therapy. In this paper prevention of recurrences and pharmacological control of ventricular rate will be reviewed, with special attention to the requirements of elderly patients. 2. Classification and management of atrial fibrillation The temporal pattern of atrial fibrillation is of great importance in conditioning the appropriate management of a patient with this arrhythmia. Acute atrial fibrillation (onset within 48 – 72 h) is characterized by a high rate of spontaneous or drug-induced cardioversion and, usually, by lack of need for anticoagulation. Chronic atrial fibrillation can be distinguished into a paroxysmal form (spontaneous termination on at least one occasion), a persistent form (intervention required to restore sinus rhythm) and a permanent form (resistence to cardioversion attempts and recurrences prophylaxis) (Sopher and Camm, 1996). In clinical practice, the key problem is how long should attempts be made to restore and to maintain sinus rhythm as opposed to another treatment strategy based on simple control of ventricular rate coupled with antithromboembolic prophylaxis (Waktare and Camm, 1998). This problem applies mainly to patients with persistent atrial fibrillation and is particularly difficult in elderly patients in whom the risk-benefit and cost-benefit ratio of some treatment options may be more unpredictable and less favorable than in younger patients. 3. Maintenance of sinus rhythm versus control of ventricular response In patients with atrial fibrillation, restoration of sinus rhythm by electrical or pharmacological cardioversion may eliminate palpitations, fatigue and dyspnea, prevent left ventricular dysfunction and significantly reduce thromboembolic complications. Unfortunately, because of the high recurrence rate, only 30% of the patients without antiarrhythmic drug prophylaxis, maintain sinus rhythm for 6 months or more (Crijns et al., 1994). Therefore, attempts to maintain sinus rhythm by pharmacological prophylaxis of arrhythmia recurrences is required. Antiarrhythmic drugs may cause proarrhythmic effects or other adverse effects and for this reason this prophylactic strategy must be considered in opposition to another therapeutic strategy which is based only on ventricular rate control by appropriate drugs associated with antithromboembolic prophylaxis. Advantages and disadvantages of every therapeutic option are reported in Table 2. The impact of these two different approaches to atrial fibrillation management is currently under evaluation in a controlled trial, named AFFIRM (Atrial Fibrillation Follow-up Investigation of Rhythm Management) (AFFIRM Planning and Steering Committee for the NHLBI AFFIRM Investigators, 1997). 130 G. Boriani et al. / Arch. Gerontol. Geriatr. 27 (1998) 127–139 Table 2 Alternative therapeutic strategies for atrial fibrillation management Maintenance of sinus rhythm by antiarrhythmic drugs Control of ventricular rate+antithromboembolic prophylaxis Advantages Better hemodynamics Reduction in thromboembolic risk Advantages ‘Natural history’ Absence of significant proarrhythmic effects Disadvantages Risk of proarrhythmic effects Risk of other drug-related adverse effects Need for repeated cardioversions (if partial efficacy) Disadvantages Worsening hemodynamics Hemorragic risks due to anticoagulants Residual embolic risk 4. Drug prophylaxis of atrial fibrillation recurrences 4.1. Indications to antiarrhythmic drug prophylaxis Drug prophylaxis of atrial fibrillation recurrences can be used in patients with paroxysmal atrial fibrillation or following electrical cardioversion in patients presenting with permanent atrial fibrillation. Following electrical cardioversion the risk of atrial fibrillation recurrences is generally high in the first days and then declines. However some clinical factors are helpful in identifying patients at higher risk of arrhythmia recurrences (Table 3). The most important factors seem to be a long previous arrhythmia duration or a long total arrhythmia history, a low functional capacity, a large left atrial size, advanced age and mitral valve disease (Crijns et al., 1994). Table 3 Risk of atrial fibrillation recurrence after cardioversion Estimated risk Duration of atrial fibrillation \2 years \1 year Number of atrial fibrillation episodes \1 \3 Age Gender (female) Alcohol Mitral stenosis Dilated cardiomyopathy Left atrial diameter at echocardiogram \60 mm \45 mm Previous ineffective antiarrhythmic drugs trials ++++ +++ ++ +++ ++ + ++ +++ + ++++ +++ +++ G. Boriani et al. / Arch. Gerontol. Geriatr. 27 (1998) 127–139 131 Table 4 Guidelines to drug prophylaxis of atrial fibrillation recurrences Indications Recurrent atrial fibrillation (at least two episodes) requiring hospitalisation Symptomatic recurrent atrial fibrillation Atrial fibrillation with arrhythmia-related hemodynamic impairment Recurrent atrial fibrillation with thromboembolic episodes Atrial fibrillation successfully treated by electrical cardioversion Atrial fibrillation in Wolff–Parkinson–White (even only one episode) (indeed transcatheter ablation can be the most appropriate choice) Contraindications Severe left ventricular dysfunction Congestive heart failure Sick sinus syndrome Non indications Asymptomatic recurrent self-terminating atrial fibrillation Infrequent recurrences of atrial fibrillation (less or equal to 2–3 episodes per year) can be managed by episodic drug treatment (Margolis et al., 1980; Capucci et al., 1994; Boriani et al., 1995, 1997) and do not require, in our view, continuous drug prophylaxis. Indeed, proper indications to pharmacological prophylaxis are required in order to minimize the risks of adverse effects and particular attention is mandatory in elderly patients due to concomitant heart diseases, decreased compliance to treatments and greater sensitivity to drug-related adverse effects. General indications and contraindications to drug prophylaxis are reported in Table 4. 4.2. Efficacy of antiarrhythmic drugs The prophylactic efficacy of antiarrhythmic drugs can be asssessed by evaluating the capacity to prevent atrial fibrillation recurrences after effective cardioversion. In Table 5, a summary of data from literature is reported. As shown, the percentage of patients who maintain sinus rhythm, without arrhythmia recurrence, under placebo treatment is around 30% after 3 months and around 20–25% after 12 months. Antiarrhythmic agents may increase the percentage of patients who maintain sinus rhythm, however, the overall efficacy is limited and, except for amiodarone, no more than 50% of the treated patients are free from arrhythmia recurrences after 6 – 12 months. For amiodarone efficacy rates of 75–78.5% at 6 months and of 50 – 73% at 12 months have been reported (Middlekauff et al., 1992), however, prospective large sale trials on the risk-benefit ratio of low dose amiodarone in atrial fibrillation are still lacking. Although amiodarone may be effective where other agents have failed, there is major concern about its use because it carries the risk of severe and sometimes irreversible adverse effects. Data from the literature indicate how a serial approach to drug therapy may be the most successful strategy: for example, 40% of patients with recurrences on a G. Boriani et al. / Arch. Gerontol. Geriatr. 27 (1998) 127–139 132 class 1A agent remained in sinus rhythm after 1 year with sotalol or propafenone (Reimold et al., 1993), whereas in another experience, the sequential use of flecainide, sotalol or quinidine and amiodarone allowed 63% of the treated patients to maintain sinus rhythm at 2 years, although with a mean of 1.8 cardioversions per patient (Crijns et al., 1991). 4.3. Proarrhythmic effects Today there is major concern over the risk of potentially lethal ventricular proarrhythmic effects caused by antiarrhythmic agents employed for a relatively benign arrhythmia, as atrial fibrillation (Falk, 1992; Waldo and Prystowsky, 1998). Indeed, one of the most important advances in this field has been the awareness of the risks related to drugs used for maintaining sinus rhythm. The proarrhythmic risks of quinidine were assessed by a meta-analysis of six randomized trials on quinidine after atrial fibrillation cardioversion (Coplen et al., 1990). Although more effective in preventing recurrences than placebo, quinidine was associated with a 3-fold increase in mortality risk (2.9% versus 0.8%). Caution has been suggested in interpreting these data in view of the limitations of metaanalysis, the possibility that concomitant treatment with digoxin or diuretics may have conditioned quinidine-related risks, the finding that the precise mode of death was not available in a significant proportion of deaths, and that sudden death occurred only in three out of 12 patients who died on quinidine. The most typical quinidine-related proarrhythmic effect is torsade de pointe, whose occurrence is associated with marked QT interval prolongation and is favored by hypokalemia, but is not related to quinidine dose (Falk, 1992). Torsade de pointe occurrence is favored by bradycardia or by a relatively slow heart rate and for this reason during treatment with class 1A agents (quinidine, dysopiramide, procainamide) it occurs more often after termination of AF, when sinus rhythm is restored. Table 5 Efficacy of antiarrhythmic drugs in preventing atrial fibrillation recurrences after electrical cardioversion (summary from literature) Drug Sinus rhythm maintenance At 1 month (%) Quinidine Disopyramide Procainamide Propafenone Flecainide Amiodarone Sotalol Placebo At 3 months (%) At 6 months (%) At 12 months (%) 65 44– 75 72 39 44 44 27 – 58 44 – 50 23 – 51 54 25 54 58 49– 50 15– 56 40 75 – 78.5 46 – 50 19 – 35 34 – 42 50 – 73 37 – 46 0 – 45 G. Boriani et al. / Arch. Gerontol. Geriatr. 27 (1998) 127–139 133 The role of underlying heart disease and functional status in worsening the proarrhythmic risk of antiarrhythmic agents, mainly class 1A drugs, has been stressed by a post hoc analysis of the Stroke Prevention in Atrial Fibrillation (SPAF) trial (Stroke Prevention in Atrial Fibrillation Investigators, 1991) on warfarin and aspirin in non valvular atrial fibrillation (Flaker et al., 1992). In this paper use of antiarrhythmic agents was associated with a 2.5-fold increase in the risk of arrhythmic death and this increased to 5.8-fold in patients with congestive heart failure. In view of these findings, the use of quinidine has been restricted in recent years, and in patients who need to be treated with this drug, careful monitoring of QT interval changes in the first days of treatment is required. Initiation of treatment during in-hospital stay is recommended in patients at higher risk (Prystovsky, 1994; Waldo and Prystowsky, 1998). Sotalol, a i-blocker with class 3 antiarrhythmic activity, also may cause torsade de pointes, but the risk is dose-dependent, being around 1% for dosages between 160 and 240 mg daily and 4 – 5% for dosages higher than 480 mg daily (Falk, 1992). Class 1C antiarrhythmic drugs (flecainide, propafenone and encainide) have a marked effect on conduction velocity, and like class 1A agents, may organize and slow the rate of atrial fibrillation, converting it into atrial flutter. In some cases, the atrial rate is slow enough to allow 1:1 atrio-ventricular conduction, thus with rapid ventricular response, wide QRS complexes simulating ventricular tachycardia and risk of hemodynamic impairment (Falk, 1992). This proarrhythmic effect is favoured by adrenergic stimulation and has been reported in 3–5% of patients treated with flecainide or propafenone (Falk, 1992). The risk of ventricular proarrhythmia, like sustained ventricular tachycardia or ventricular fibrillation, during treatment with antiarrhythmics for supraventricular arrhythmias seems to be generally low, however patients with significant left ventricular dysfunction are at potentially higher risk. For amiodarone, a low risk of ventricular proarrhythmic effects has been reported, even in patients with structural heart disease (Middlekauff et al., 1992). Amiodarone has little or no negative inotropic effect and is usually tolerated in patients with congestive heart failure. The mortality rate associated with amiodarone treatment is around 0.4%, comparable to that of control patients. However, controlled trials are required to evaluate the effective risks related to non-cardiac adverse effects (Middlekauff et al., 1992). Other proarrhythmic effects, as aggravation of sinus node disease in the bradytachy syndrome or occurrence of high degree atrio-ventricular block in patients with previous conduction disease, may occur virtually with any antiarrhythmic drug and are of great importance in elderly subjects. In clinical practice, awareness of the problem of proarrhythmic effects is essential in order to prevent them, to identify them promptly and to solve them. Some categories of patients who are at higher risk of proarrhythmia and can be identified are: (i) patients with previous myocardial infarction; (ii) patients with overt or previous congestive heart failure; (iii) patients with significant left ventricular dysfunction; (iv) patients with previous conduction disease or sinus node dysfunc- 134 G. Boriani et al. / Arch. Gerontol. Geriatr. 27 (1998) 127–139 tion; (v) patients with electrolytes impairment; (vi) patients with concomitant renal or hepatic insufficiency; and (vii) patients with advanced age. For these patients effective need for antiarrhythmic treatment must be evaluated, and selection of most appropriate drug is required (Cobbe, 1997; Waldo and Prystowsky, 1998) together with close monitoring of the patient in the first 2–3 days of treatment. For some patients initiation of treatment during hospitalization has been recommended (Prystovsky, 1994; Waldo and Prystowsky, 1998). 4.4. Non-cardiac ad6erse effects Non-cardiac adverse effects cause intolerance, thus limiting patient’s compliance. However, these effects are usually reversible after drug withdrawal. For amiodarone non-cardiac toxicity has limited the widespread use of this drug. Some side effects of amiodarone, including hypo or hyperthyroidism, are not dose-related. The most serious adverse effect of amiodarone is pulmonary toxicity, which occurs more frequently in older patients and when daily dose is higher than 300 mg daily (Antman, 1996). Unfortunately, for amiodarone the lowest effective dose which ca be considered at very low risk of toxicity remains to be defined. 4.5. Choice of antiarrhythmic drugs At the present time, selection of an antiarrhythmic drug for atrial fibrillation prophylaxis is largely an empiric process and different agents are used sequentially with a trial and error approach. Knowledge of pharmacokinetics and pharmacodynamics of every agent is required for choosing the most appropriate drug in a specific patient. An approach based on the characteristics of atrial fibrillation in terms of autonomic influences (vagal or adrenergic atrial fibrillation) is difficult to translate in clinical practice and has never be validated by a controlled trial. 5. Control of ventricular response 5.1. Importance of rate control Control of ventricular rate is very important for reducing symptoms related to atrial fibrillation and for preventing left ventricular dysfunction secondary to constantly high ventricular rates (Grogan et al., 1992; Crijns et al., 1997; Waktare and Camm, 1998). Avoidance of antiarrhythmic agents for prophylaxis of recurrences, limiting drug treatment to agents for rate control, coupled with antithromboembolic prophylaxis, seems to be a reasonable choice, at least in some patients (Table 6). In these patients permanent atrial fibrillation can be the best option, provided that appropriate ventricular rate control is achieved. Three categories of drugs are used to block the atrio-ventricular node in order to slow ventricular response in atrial fibrillation: (i) digoxin; (ii) calcium antagonists (verapamil and diltiazem); and (iii) i-blockers. G. Boriani et al. / Arch. Gerontol. Geriatr. 27 (1998) 127–139 135 Table 6 Indications to ventricular rate control plus antithromboembolic prophylaxis instead of attempts to prevent atrial fibrillation recurrences with antiarrhythmic drugs (‘permanent atrial fibrillation as a choice’) Atrial fibrillation lasting more than 2 years Marked left atrial enlargement Contraindications to antiarrhythmic drugs Frequent recurrences of atrial fibrillation despite prophylaxis with antiarrhythmic drugs 5.2. Limitations of digoxin for rate control Digoxin has a traditional role for controlling the ventricular rate and is widely used because this effect is coupled with a positive inotropic effect. Digoxin slows the ventricular response by enhancing vagal effects on the atrio-ventricular node and thereby prolonging nodal refractoriness (Sarter and Marchlinski, 1992). In conditions characterised by low vagal tone, as exercise, thyrotoxicosis or hyperadrenergic states, digoxin efficacy in controlling ventricular rate is limited (Nattel, 1996). Indeed, in the past few controlled studies were available and in clinical practice digoxin dosages and serum levels are often below required therapeutic levels. Digoxin may effectively slow ventricular rate at rest but there is no relationship between this effect and the ability to control ventricular rates during exercise (Cobbe, 1997). Overall, the slowing effect on ventricular rates during peak exercise is very weak and a reduction in heart rate of 3–8% compared to controls has been demonstrated (Sarter and Marchlinski, 1992). Control of ventricular rate at rest can be achieved with intravenous digoxin in a relatively long time and this is another limitation in comparison to calcium-antagonists and i-blockers which are effective within a few minutes. In a study evaluating effectiveness and costs of digoxin treatment for controlling heart rate in atrial fibrillation and flutter, long hospital stay and consequently high costs were demonstrated when digoxin alone was used and this finding stresses the need for a more aggressive approach to this problem (Roberts et al., 1993). In view of these limitations, the role of digoxin for rate control in atrial fibrillation has been redefined. Because of positive inotropic effects, it remains the agent of choice in patients with atrial fibrillation in the setting of significant left ventricular dysfunction. However, in the absence of left ventricular dysfunction digoxin should be considered as a second-line therapy and eventually can be used in association with calcium antagonists or i-blockers. 5.3. Calcium antagonists Diltiazem and verapamil significantly slow atrio-ventricular nodal conduction and prolong atrio-ventricular node refractoriness. Their effects on ventricular rate during atrial fibrillation may be potentiated by the association with digoxin and ventricular rate at rest and during submaximal exercise can be reduced by 17–28% 136 G. Boriani et al. / Arch. Gerontol. Geriatr. 27 (1998) 127–139 in comparison with controls, whereas during maximal exercise the reduction is around 12 – 20% (Sarter and Marchlinski, 1992). Diltiazem and verapamil can be administered intravenously and a more rapid effect can be achieved in comparison with digoxin. Both these agents have potentially negative inotropic effects but these effects are counterbalanced by the beneficial effects related to mean ventricular rate slowing and left ventricular afterload reduction. Diltiazem has been employed safely even in patients with left ventricular dysfunction and congestive heart failure (Heywood et al., 1991), however, caution is required in these cases. During long term oral administration of diltiazem or verapamil an improvement in exercise tolerance has been demonstrated in comparison with digoxin (Sarter and Marchlinski, 1992). 5.4. i-blockers i-Blockers counteract the facilitating effects of catecholamines on atrio-ventricular node transmission of atrial imputs, thus they may be of limited efficacy when i-adrenergic tone is low, and of greatest efficacy in situations of enhanced sympathetic tone. The slowing of the ventricular rate is around 15–30% at rest or during submaximal exercise and around 27–31% during maximal exercise (Sarter and Marchlinski, 1992). i-Blockers have negative inotropic properties and a reduction in exercise capacity has been demonstrated (Sarter and Marchlinski, 1992; Sopher and Camm, 1996). i-Blockers can be used acutely or for long term treatment. For acute treatment esmolol, a short-acting agent, seems to have a better safety profile than long-acting agents as propranolol or metoprolol (Platia et al., 1989). 5.5. Combination therapy The addition of a calcium antagonist or a i-blocker to digoxin resulted in a significant reduction in resting heart rate and heart rate during exercise in several studies (Sarter and Marchlinski, 1992). 5.6. Rate control in elderly patients Calcium channel antagonists and i-blockers alone or in combination with digoxin may obtain a more appropriate control of ventricular rate during exercise than digoxin alone; however, their use in elderly patients implies more risks than in younger subjects. These risks are related to the possibility of inducing excessive sinus bradycardia or unmasking a sick sinus syndrome, to the possibility of inducing atrio-ventricular blocks or to potential negative inotropic effects. Moreover, the use of i-blockers in the elderly may have some limitations because they are contraindicated in patients with severe bronchospasm and may worsen symptoms of peripheral vascular insufficiency, two common conditions in advanced age. G. Boriani et al. / Arch. Gerontol. Geriatr. 27 (1998) 127–139 137 A satisfactory rate control is particularly difficult to achieve in patients with chronic obstructive pulmonary disease, in brady-tachy syndromes and in thyrotoxicosis. In some selected patients, in whom drugs are ineffective or contraindicated, non-pharmacologic treatments as atrio-ventricular node ablation followed by implantation of a ventricular pacemaker with rate-responsiveness (so-called VVIR pacemakers) or atrio-ventricular node modulation can be appropriate even in elderly subjects (Harvey and Morady, 1995; Crijns et al., 1997; Jung and DiMarco, 1998). 6. Conclusions Atrial fibrillation is the most common sustained arrhythmia, however, its treatment remains controversial and problematic. Electrical or pharmacological cardioversion are able to restore sinus rhythm in many patients with atrial fibrillation but maintenance of sinus rhythm requires long term treatment with antiarrrhythmic agents. Today there is major concern regarding the ventricular proarrhythmic effects of antiarrhythmic drugs because they may increase mortality. An alternative strategy based on pharmacological control of ventricular response rate coupled with antithromboembolic prophylaxis can be followed. At the present time, the relative efficacy and risks of these strategies in specific patient subgroups remain to be established and also non-pharmacological options as atrio-ventricular node ablation are currently available. 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