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Terms of Use The In the Clinic® slide sets are owned and copyrighted by the American College of Physicians (ACP). All text, graphics, trademarks, and other intellectual property incorporated into the slide sets remain the sole and exclusive property of ACP. The slide sets may be used only by the person who downloads or purchases them and only for the purpose of presenting them during not-forprofit educational activities. Users may incorporate the entire slide set or selected individual slides into their own teaching presentations but may not alter the content of the slides in any way or remove the ACP copyright notice. Users may make print copies for use as hand-outs for the audience the user is personally addressing but may not otherwise reproduce or distribute the slides by any means or media, including but not limited to sending them as e-mail attachments, posting them on Internet or Intranet sites, publishing them in meeting proceedings, or making them available for sale or distribution in any unauthorized form, without the express written permission of the ACP. Unauthorized use of the In the Clinic slide sets constitutes copyright infringement. © Copyright Annals of Internal Medicine, 2010 Ann Int Med. 153 (11): ITC6-1. * For Best Viewing: Open in Slide Show Mode Click on icon or From the View menu, select the Slide Show option * To help you as you prepare a talk, we have included the relevant text from ITC in the notes pages of each slide © Copyright Annals of Internal Medicine, 2010 Ann Int Med. 153 (11): ITC6-1. in the clinic Atrial Fibrillation © Copyright Annals of Internal Medicine, 2010 Ann Int Med. 153 (11): ITC6-1. Who is at risk for atrial fibrillation? Most common, clinically significant cardiac arrhythmia Occurs in <1% 60-65y; 8%-10% >80y Higher prevalence men than women, whites than blacks Risk for AF w/ presence & severity of underlying HF and valvular disease. Definition of Atrial Fibrillation (AF): When diffuse, chaotic electrical activity in atria suppresses/replaces normal sinus mechanism, leads to deterioration of mechanical function © Copyright Annals of Internal Medicine, 2010 Ann Int Med. 153 (11): ITC6-1. What symptoms and signs should cause clinicians to suspect AF? Symptoms Palpitations Shortness of breath Exercise intolerance Chest pain Malaise Result from Elevated ventricular rate (either at rest or exaggerated by exercise) Irregular ventricular rate Loss atrial contrib to cardiac output Signs on physical exam Faster-than-expected heart rate (varies greatly from pt to pt) “Irregularly irregular” time between heart sounds on auscultation Peripheral pulses that vary irregularly in rate & amplitude Symptoms greatest at AF onset (paroxysmal episode) Diminish over time, esp when arrhythmia persistent Many pts asymptomatic, esp elderly silent AF (some have severe symptoms with other AF episodes) © Copyright Annals of Internal Medicine, 2010 Ann Int Med. 153 (11): ITC6-1. Is a single electrocardiogram sufficient to diagnose or exclude atrial fibrillation? Single ECG sufficient to Dx if recorded during arrhythmia ECG of AF w/ rapid ventricular rate © Copyright Annals of Internal Medicine, 2010 Ann Int Med. 153 (11): ITC6-1. Is a single electrocardiogram sufficient to diagnose or exclude atrial fibrillation? Single ECG showing normal rhythm does not exclude Dx because AF often is paroxysmal With daily symptoms, 24- or 48-h continuous Holter monitoring usually is sufficient to make Dx With less-frequent symptoms, monitor longer with ECG loop recorder Must turn on recorder when symptoms begin, so it is not useful if arrhythmias are asymptomatic or if pt doesn’t recognize symptoms With very infrequent episodes may take yrs to confirm Dx (if symptoms nonspecific and long periods between episodes) © Copyright Annals of Internal Medicine, 2010 Ann Int Med. 153 (11): ITC6-1. Is a single electrocardiogram sufficient to diagnose or exclude atrial fibrillation? Newer event monitors, implanted pacemakers & defibcardioverters with atrial leads record symptomatic & asymptomatic AF Other new devices continuously record heart rhythms for ≥1 mo Wirelessly send data to central monitoring station for automated interpretation and Dx © Copyright Annals of Internal Medicine, 2010 Ann Int Med. 153 (11): ITC6-1. What is the role of history and physical examination in patients with AF? Determine duration symptoms Identify potential underlying causes Cardiac causes Noncardiac causes Hypertension Pulmonary disease HF Hyperthyroidism Cardiac surgery Use of adrenergic drugs (e.g., for pulmonary disease) or other stim’ts Murmurs indicating stenotic or regurgitant valvular disease Other indications structural heart disease Alcohol use Family Hx might identify 1stdegree relatives with AF and may someday have therapeutic implications © Copyright Annals of Internal Medicine, 2010 Ann Int Med. 153 (11): ITC6-1. What other electrocardiographic arrhythmias can be confused with AF? Sinus rhythm with frequent premature atrial contractions Atrial flutter Atrial tachycardia Key ECG findings of AF Absence of P waves Presence of irregular ventricular rhythm without a recurring pattern When irregular rhythm present but Dx of AF uncertain Examine long recordings from multiple leads Look for partially obscured P waves in deformed T waves and ST segments © Copyright Annals of Internal Medicine, 2010 Ann Int Med. 153 (11): ITC6-1. What other electrocardiographic arrhythmias can be confused with AF? ECG of irregular rhythm that might be AF, but P waves & other features ID sinus rhythm with frequent premature atrial contractions © Copyright Annals of Internal Medicine, 2010 Ann Int Med. 153 (11): ITC6-1. What other electrocardiographic arrhythmias can be confused with AF? ECG of irregular rhythm that might be AF, but “sawtooth” P waves & varying ventricular response (2:1 to 4:1 AV conduction) identify atrial flutter © Copyright Annals of Internal Medicine, 2010 Ann Int Med. 153 (11): ITC6-1. How should clinicians classify AF? Paroxysmal: Episodes spontaneously terminate < 7d Persistent: Episodes last >7d and require intervention to restore sinus rhythm Permanent: Interventions to restore sinus rhythm have either failed or have not been attempted Same pt may be classified into different categories at different times. Classify to current or most common pattern Distinctions predict responses to Tx (antiarrhythmic drug Tx less likely to succeed as pattern goes from paroxysmal to persistent to permanent) Pts in all 3 categories require anticoagulation © Copyright Annals of Internal Medicine, 2010 Ann Int Med. 153 (11): ITC6-1. What lab studies should clinicians obtain in patients newly diagnosed with AF? Serum electrolytes and TSH (for possible causes) Renal & hepatic function blood tests (to guide selection of drug Tx) Stool Hemoccult test (before starting anticoagulation) Transthoracic ECHO (to measure left atrial size and assess for valvular heart disease, pericardial disease, and LV hypertrophy) Transesophageal ECHO (excludes atrial clot and is indicated when transthoracic images are inadequate or cardioversion is planned in a pt therapeutically anticoagulated <3 wks) Additional tests as necessary for possible PE, AMI, or HF © Copyright Annals of Internal Medicine, 2010 Ann Int Med. 153 (11): ITC6-1. What underlying conditions should clinicians look for in patients with AF? Structural heart disease causes 80% of AF Particularly hypertensive heart disease Also CAD, valvular heart disease, or cardiomyopathy Atrial fibrosis often occurs with structural heart disease May be central to arrhythmia's pathogenesis AF in absence of heart disease is “Lone” AF Some experts restrict Lone AF to pts <60y because it is hard to exclude structural heart disease in older pts © Copyright Annals of Internal Medicine, 2010 Ann Int Med. 153 (11): ITC6-1. What underlying conditions should clinicians look for in patients with AF? Illnesses associated with AF AMI Pulmonary embolism Thyrotoxicosis After major surgery (AF occurs in ≈40% after cardiac/thoracic surgery) During severe illness Obesity and sleep apnea May occur without predisposing conditions, typically in men 40-50y with symptoms at night, at rest, following vigorous exercise, or with alcohol use Other forms of AF without underlying conditions occur during waking hrs and are preceded by emotional stress or exercise © Copyright Annals of Internal Medicine, 2010 Ann Int Med. 153 (11): ITC6-1. Diagnosis… Atrial fibrillation is the most common clinically significant cardiac arrhythmia, and its prevalence increases with advancing age. Typical symptoms include palpitations, shortness of breath, and exercise intolerance. However, some patients report only general malaise, and many patients are asymptomatic. Electrocardiogram recordings during episodes are the only way to confirm the diagnosis. If the diagnosis is suspected and the ECG is normal, longer monitoring with a loop recorder or a Holter monitor can be helpful. The initial assessment should include laboratory tests for electrolytes, thyroid-stimulating hormone, and renal and hepatic function to rule out underlying disorders or contraindications to therapies. An echocardiogram should be done to look for structural heart disease. © Copyright Annals of Internal Medicine, 2010 Ann Int Med. 153 (11): ITC6-1. What are the complications of atrial fibrillation, and how can therapy decrease the risk for these events? Symptoms (sometimes disabling) Usually caused by rapid ventricular rates or irregular ventricular response Loss of atrial contribution to ventricular filling (atrial kick) is well tolerated except by pts with ventricular hypertrophy Thromboembolism (stroke most common) In nonvalvular AF, the annual risk of arterial thromboembolism is 5% (higher in pts >75y) Atrial thrombi cause 75% strokes in AF Cardiomyopathy (prevent by treating tachycardia of AF) © Copyright Annals of Internal Medicine, 2010 Ann Int Med. 153 (11): ITC6-1. When should clinicians consider immediate cardioversion in patients with AF? When duration of arrhythmia is <48h (e.g., hospitalized pt on cardiac monitoring) May be appropriate in selected pts with Decompensated HF Severe angina or acute infarction Most pts with AF don’t require immediate cardioversion Hypotension High risk for acute stroke In patients with extremely rapid AV conduction mediated by the accessory pathway in Wolff-ParkinsonWhite syndrome © Copyright Annals of Internal Medicine, 2010 Ann Int Med. 153 (11): ITC6-1. Which patients with AF should clinicians consider hospitalizing? Uncertain or unstable underlying arrhythmia Acute MI, altered mental status, decompensated HF, or hypotension Intolerable symptoms despite hemodynamic stability Elective cardioversion (if monitored outpatient setting unavailable) Acute anticoagulation for very high stroke risk high Telemetry monitoring when initiating some drugs For procedures such as cardiac catheterization, electrophysiologic studies, pacemakers, implantable defibrillators, or catheter or surgical ablation © Copyright Annals of Internal Medicine, 2010 Ann Int Med. 153 (11): ITC6-1. Should clinicians attempt rate control or rhythm control? Traditionally clinicians preferred rhythm control to rate control Recently high-quality clinical trials have found that rhythm control doesn’t improve mortality, stroke, hospitalization, or QOL compared with rate control Rate control easier to accomplish, prevents exposure to the potential adverse effects of antiarrhythmic agents Rhythm control is useful in select pts with severe symptoms (before or after rate control failure) or younger pts without structural heart disease © Copyright Annals of Internal Medicine, 2010 Ann Int Med. 153 (11): ITC6-1. What strategies should clinicians consider for rate control in patients with rapid AF? Consider drugs to control ventricular rate in all pts with AF even those being treated for rhythm control Traditional target heart rate has been 60-80 beats/min at rest and 90-115 beats/min during mod exercise (criteria varies by age) Recent data found no advantage of a target of ≤80 beats/min compared to a target of ≤110 beats/min (Van Gelder et al, 2009) © Copyright Annals of Internal Medicine, 2010 Ann Int Med. 153 (11): ITC6-1. What strategies should clinicians consider for rate control in patients with rapid AF? ß-Blockers: 1st-line Tx to AV nodal conduction Metoprolol Propranolol Esmolol Pindolol Atenolol Nadolol Convenient IV admin in NPO pts, rapid onset action, Inexpensive, commonly avail dependable AV nodal blockade Short-acting, titratable on or off Side effects: Bradycardia, Side effects: w/ very rapid Bradycardia, half-life hypotension, heart block, hypotension, heartless block, Less bradycardia, bronchospasm, worsening CHF Side bronchospasm effects: Bradycardia, (less bronchospasm; less frequently propensity for Lower incidence of crossing than heart ß-blockers), block, hypotension, Doesn’t cross blood-brain heartnonselective block than other ß-blockers blood–brain barrier, fewer CNS worsening bronchospasm of CHF (less frequent) barrier, fewer CNS side effects side Side effects effects: Bradycardia, Occasionally inconsistent Side effects: Bradycardia, hypotension, heart block effect Side effects: Bradycardia, in high-catecholamine states hypotension, heart block hypotension, heart block Available in oral form only © Copyright Annals of Internal Medicine, 2010 Ann Int Med. 153 (11): ITC6-1. What strategies should clinicians consider for rate control in patients with rapid AF? Nondihydropyridine calcium-channel antagonists (1st-line Tx to AV nodal conduction) Verapamil Consistent AV nodal blockade Diltiazem Side effects: Hypotension, heart block, direct myocardial depression Do not use in Wolff-Parkinson-White Cardiac glycoside syndrome digoxin Useful for rate control only with LV systolic function Side effects: Heart block and arrhythmias; dosage adjustment required in renal impairment Not useful for rate control during exercise or conversion of AF/aflutter to NSR © Copyright Annals of Internal Medicine, 2010 Ann Int Med. 153 (11): ITC6-1. What strategies should clinicians consider for rate control in patients with rapid AF? Dronedarone Recently approved, modestly effective, fewer side effects than amiodarone Amiodarone Blocks AV node, not recommended as 1st-line monotherapy for rate control because of associated toxicities Occasionally used to ventricular response if other agents fail © Copyright Annals of Internal Medicine, 2010 Ann Int Med. 153 (11): ITC6-1. What strategies should clinicians consider for rhythm control in patients with AF? Rhythm control is no longer the preferred strategy based on trials comparing rate vs. rhythm control Consider rhythm control in younger patients and patients with highly symptomatic AF because trials did not include these groups Experienced clinicians may prefer rhythm control with cardioversion for 1st episode symptomatic AF in younger patients because many such patients maintain sinus rhythm without drugs © Copyright Annals of Internal Medicine, 2010 Ann Int Med. 153 (11): ITC6-1. What strategies should clinicians consider for rhythm control in patients with AF? Direct electrical current to convert to NSR indicated if hemodynamically unstable Antiarrhythmic drugs: - conversion rate < direct electrical current in hemodynamically stable pts + deep sedation or general anesthesia not required © Copyright Annals of Internal Medicine, 2010 Ann Int Med. 153 (11): ITC6-1. What strategies should clinicians consider for rhythm control in patients with AF? Either direct electrical or antiarrhythmic drug cardioversion: AF >48h or undetermined duration: establish rate control & anticoagulation before elective cardioversion INR 2.0 – 3.0 for > 3 weeks prior and > 4 weeks after cardioversion Alternative- Transesophageal Echo: No clot: heparin for 48 hr prior to cardioversion & warfarin for 4 wks after Clot present: anticoagulation for 4 weeks; most confirm thrombus resolution with repeat TEE before cardioversion Serum K level should be >4.0 mmol/L, serum Mg level >1.0 mmol/L, and ionized Ca levels >0.5 mmol/L Conduct cardioversion in monitored hospital setting Because antiarrhythmic drugs generally have equal efficacy, except for amiodarone, choose a drug by side effects © Copyright Annals of Internal Medicine, 2010 Ann Int Med. 153 (11): ITC6-1. What strategies should clinicians consider for rhythm control in patients with AF? Class Ia antiarrhythmic drugs prolong conduction & slow repolarization by blocking inward Na+ flux Procainamide not recommended because of frequent side effects (hypotension, nausea, vomiting, lupus-like syndrome, QT prolongation, arrhythmia) Quinidine gluconate not recommded because of frequent side effects (proarrhythmia, nausea, vomiting, diarrhea, QT prolongation) © Copyright Annals of Internal Medicine, 2010 Ann Int Med. 153 (11): ITC6-1. What strategies should clinicians consider for rhythm control in patients with AF? Disopyramide: Use in pts with hypertension & normal LV function Adverse effects include QT prolongation, torsades de pointes, and heart block Rarely used in current era © Copyright Annals of Internal Medicine, 2010 Ann Int Med. 153 (11): ITC6-1. What strategies should clinicians consider for rhythm control in patients with AF? Class Ic antiarrhythmic drugs block Na+ channels Flecainide is effective in paroxysmal AF with structurally normal hearts Adverse effects include atrial flutter and atrial tachycardia with rapid ventricular response; also VT, and VF in diseased hearts Do not use in pts with structurally abnormal hearts Propafenone is effective in paroxysmal and sustained AF Adverse effects include atrial flutter or atrial tachycardia with rapid ventricular response Do not use in pts with structurally abnormal hearts © Copyright Annals of Internal Medicine, 2010 Ann Int Med. 153 (11): ITC6-1. What strategies should clinicians consider for rhythm control in patients with AF? Antiarrhythmic drugs (class III) Ibutilide prolongs action potential duration (and atrial and ventricular refractoriness) Effective in acute & rapid conversion of AF to NSR Adverse effects include torsades de pointes and QT prolongation © Copyright Annals of Internal Medicine, 2010 Ann Int Med. 153 (11): ITC6-1. What strategies should clinicians consider for rhythm control in patients with AF? Amiodarone blocks Na+ channels Safest agent for use in pts with structural heart disease, good efficacy maintaining NSR chronically; can be used in Wolff– Parkinson-White syndrome Adverse effects include bradycardia, QT prolongation, hyperthyroidism, lung toxicity, blue discoloration of skin Sotalol is a nonselective ß - and 1ß -blocking agent that prolongs action potential duration Similar in efficacy to quinidine but with fewer adverse effects and better rate control. Initiate on telemetry Adverse effects include fatigue, depression, bradycardia, torsades de pointes, and CHF ß-blocking properties, but some inotropic activity; lethal arrhythmias possible; adjust dose in pts with renal insufficiency © Copyright Annals of Internal Medicine, 2010 Ann Int Med. 153 (11): ITC6-1. What strategies should clinicians consider for rhythm control in patients with AF? Dofetilide prolongs refractoriness without slowing conduction More effective than quinidine in conversion to and maintenance of NSR; initiate on telemetry Adverse effetcs include QT prolongation and, torsades de pointes Dose strictly according to renal function, body size, & age; contraindicated in pts with creatinine clearance <20 mL/min Dronedarone is similar to amiodarone—blocks sodium, potassium, and calcium channels—but without iodine Adverse effects include GI intolerance Contraindicated for decompensated CHD; less efficacious but better tolerated than amiodarone © Copyright Annals of Internal Medicine, 2010 Ann Int Med. 153 (11): ITC6-1. When should clinicians use antiarrhythmic drugs to prevent the recurrence of AF? Have only modest effects prolonging time to recurrence The Canadian Trial of Atrial Fibrillation randomly assigned 403 patients to amiodarone, sotalol, or propafenone and found that after mean followup of 16 mos, recurrence of AF was 35% for amiodarone Tx compared w/ 63% for sotalol or propafenone Tx (NEJM, 2000) Some nonantiarrhythmic drugs (ACE-inhibitors, statins) reduce the incidence of AF in pts with HF presumably because of antifibrotic effects © Copyright Annals of Internal Medicine, 2010 Ann Int Med. 153 (11): ITC6-1. When is anticoagulation indicated for patients with atrial fibrillation? When thromboembolism risk exceeds the risk for anticoagulation-associated bleeding For example, a >65y pt with AF and no other risk factors has ≈1% risk for thromboembolism, which approximates the risk for major bleeding on warfarin when the INR is between 2.0-3.0 Same indications for anticoagulation in pts with paroxysmal, persistent, & permanent AF Use CHADS2 score (Cardiac Failure, Hypertension, Age, Diabetes, and Stroke [Doubled]) to identify which pts with AF warrant anticoag Tx © Copyright Annals of Internal Medicine, 2010 Ann Int Med. 153 (11): ITC6-1. When is anticoagulation indicated for patients with atrial fibrillation? CHADS2 Risk Criteria Score Past stroke or TIA 2 Age >75 y 1 Hypertension 1 Diabetes mellitus 1 Heart failure 1 Reproduced from ACC/AHA/ESC 2006 Guidelines for the Management of Patients with Atrial Fibrillation 2006 (PMID: 16908781) with permission from the AHA. © Copyright Annals of Internal Medicine, 2010 Ann Int Med. 153 (11): ITC6-1. When is anticoagulation indicated for patients with atrial fibrillation? Consider long-term anticoagulation in pts with High risk for recurrent AF Asymptomatic AF Intracardiac thrombus Known risk factors for thromboembolism (age ≥75y, recent HF, LV dysfunction, diabetes mellitus, hypertension, previous thromboembolism) Many clinicians use cutoff of 65 rather than 75 yrs to initiate warfarin Tx when pt also has CAD Genetic tests can identify pts who require different warfarin dosing, but the tests are not recommended because they have not been shown to improve pt outcomes © Copyright Annals of Internal Medicine, 2010 Ann Int Med. 153 (11): ITC6-1. What anticoagulation regimens should clinicians use in patients with AF? Warfarin is the preferred drug. Adjust the dose to an INR of 2.03.0 (2.5-3.5 for patients with prosthetic valves) Aspirin is an alternative to warfarin when there are contraindications to warfarin; no previous stroke or transient ischemic attack; no hypertension, diabetes, or HF, and the patient is < 75 Aspirin + clopidogrel together prevent more strokes than aspirin alone but are not as effective as warfarin and have a bleeding risk that is equivalent to warfarin Dabigatran recently has been approved by the FDA to prevent stroke and systemic embolism in pts with AF & creatinine clearance ≥30 mL/min © Copyright Annals of Internal Medicine, 2010 Ann Int Med. 153 (11): ITC6-1. When should clinicians consider nondrug therapies for patients with AF? AV nodal catheter ablation inactivates parts of the atrium where AF begins Occlusion Use when ofdrug the left Tx atrial doesn’t appendage achieve rate to prevent controlstrokes (usually because of drug intolerance in the elderly or in pts Prevents recurrent symptomatic AF inlimits highly selected with advanced HF or COPD, which β-blocker patients, ideally young, otherwise healthy person without use) structural Selected heart high-risk pts not candidates for oral disease & with paroxysmal AF Highly effective but requires pacemaker insertion, can anticoagulation therapy lead Maytobeprogressive reasonableLV when antiarrhythmic drug Tx fails in dysfunction highly Additional studies needed verify the safety & symptomatic pts withtoparoxysmal AF Pacing therapy without AV nodal ablation has little effectiveness of these devices effect on burden of AF (but may help with paroxysmal AF and symptomatic bradycardia, a side effect drug Tx) © Copyright Annals of Internal Medicine, 2010 Ann Int Med. 153 (11): ITC6-1. How should clinicians monitor patients with atrial fibrillation? Regular follow-up to Determine effectiveness of Tx Monitor warfarin anticoagulation Check if symptoms adequately controlled (ask about palpitations, easy fatigability, dyspnea on exertion) If on amiodarone, check liver and thyroid function every 6 months and order chest x-ray annually (otherwise routine tests for drug side effects unnecessary) © Copyright Annals of Internal Medicine, 2010 Ann Int Med. 153 (11): ITC6-1. Treatment… Atrial fibrillation treatment goals include reducing the frequency and severity of symptoms, preventing stroke, and preventing tachycardia-related cardiomyopathy. Selection of patients for anticoagulation with aspirin or warfarin should be based on the CHADS2 score. Focus treatment first on rate control by using beta-blockers or calcium-channel antagonists aiming for a resting rate between 60 and 110 beats per minute. Rhythm control may be reasonable in patients who do not respond to rate control. Atrial ablation and atrioventricular nodal ablation therapy may be appropriate for selected patients with highly symptomatic AF despite drug therapy. © Copyright Annals of Internal Medicine, 2010 Ann Int Med. 153 (11): ITC6-1. What do professional organizations recommend with regard to the management of patients with AF? American College of Physicians & American Academy of Family Physicians guideline on AF mgmt (2003) American Heart Association & American College of Cardiology guideline on AF mgmt (2006) European Society of Cardiology guideline on AF mgmt (2010) © Copyright Annals of Internal Medicine, 2010 Ann Int Med. 153 (11): ITC6-1.