atrial fibrillation atrial fibrillation assessment and management in the ed joseph r. cline md facep...

Atrial Fibrillation Atrial Fibrillation Assessment and Management in the ED Joseph R. Cline MD FACEP Associate Professor (CHS) Section of Emergency Medicine University of Wisconsin School of Medicine and Public Health

Atrial Fibrillation Objectives Review prevalence and associated and confounding conditions Review clinical assessment and categorization Review management strategy Discuss classification of antiarrhythmics and the use in AF Discuss thromboembolic risk in AF

In a cross-sectional study of almost 1.9 million men and women, the prevalence of atrial fibrillation increases with age, ranging from 0.1 for those less than 55 years of age to over 9 percent in those 85 years of age. At all ages, the prevalence is higher in men than women. Data from Go, AS, Hylek, EM, Phillips, K, et al, JAMA 2001; 285:2370. Atrial Fibrillation -- Prevalence --

Atrial Fibrillation -- Incidence and Prevalence -- Overall prevalence = 0.4% of U.S. population From 1996-2001, primary hospital discharge diagnosis of Atrial fibrillation increased by 34% Most common arrhythmia in the ED setting: 1 3% of ED visits overall Prevalence: age < 55 yrs < 0.1% > 55 yrs = 5% > 80 yrs > 9% Life-time risk = 25% for age > 40 yrs (M or F) Accounts for 15% of all strokes AF increases risk of stroke 5 X

Atrial Fibrillation -- Classification -- Paroxysmal AF duration less than 7 days and may be recurrent Persistent AF fails to self-terminate; duration greater than 7 days; can be terminated by cardioversion Permanent AF duration more than 1 year; cardioversion either failed or has not been attempted Lone AF paroxysmal, persistent, or permanent AF without structural heart disease

Atrial Fibrillation -- Prevalence in associated diseases -- Hypertension increased relative risk of only 1.42; however prevalence of hypertension accounts for the high association CAD AF is transient in 6-10% of MI patients; however it is almost never in isolation to other ECG findings of ACS (Zimetbaum et al. Incidence and predictors of myocardial infarction among patients with atrial fibrillation. J Am Coll Cardiol 2000; 36;1223) Incidence in chronic, stable CHD is 0.6% Valvular heart disease High prevalence with Rheumatic heart disease MS + MR 52% MS alone 29% MR alone - 16% AS alone 1% Degenerative MR incidence 5% per year

Atrial Fibrillation -- Prevalence in associated diseases, cont. -- Heart Failure 10-30% Pulmonary embolism 10-14 % (rarely the only sign or symptom) Hyperthyroidism low TSH in 5.4%; clinical hyperthyroidism present in 1% COPD Post cardiac surgery Pericarditis Obstructive sleep apnea ( for patients with AF and OSA, incidence of AF recurrence is 2X for those not treated with CPAP) Congenital heart disease Peripartum cardiomyopathy Holiday Heart

Atrial Fibrillation -- Pathogenesis -- Underlying heart disease of any cause that is complicated by: heart failure atrial enlargement elevated atrial pressure inflammation or infiltration of the atria Echocardiographic risk factors increased left ventricular wall thickness left atrial diameter > 4 cm reduced left ventricular fractional shortening Triggering event majority related to atrial premature beat minority related to atrial flutter or atrial tachycardia

Atrial Fibrillation -- History and Physical Exam -- Define symptoms Define pattern Paroxysmal Persistent Recurrent Permanent Onset or date of discovery Frequency and duration of episodes Precipitating causes and modes of termination

Atrial Fibrillation -- History -- Symptoms Palpitations, weakness, dizziness, reduced exercise capacity, dyspnea Angina, CHF symptoms, syncope (hypotension) relate to underlying heart disease Up to 90% of episodes are asymptomatic with approximately 20% of such episodes longer than 48 hrs 90% of AF patients have recurrent episodes

Atrial Fibrillation -- Exam -- ABCs Vital signs Rate / BP to assess perfusion and guide decision for urgent / emergent ECV Assess for signs of CHF Heart tones: variable intensity of S 1 is diagnostic of atrial fibrillation

Atrial Fibrillation -- ECG -- Verification of diagnosis irregularly irregular No discernable P waves Identify associated findings or complications MI LVH Bundle branch block Pre-excitation

Atrial Fibrillation -- ECG -- Aeschmann beats aberrently conducted beats following a shorter R-R interval than the previous R-R interval

Atrial Fibrillation -- Chest X-ray -- Identify heart size, vasculature Assess for additional complicating diseases COPD Pneumonia

Atrial Fibrillation -- Lab -- Standard electrolytes assess for hypokalemia TSH and free T 4 For all cases of new onset Atrial fibrillation Patients with low TSH and normal free T 4 have subclinical hyperthyroidism INR Most patients with AF will need anticoagulation Patients currently anticoagulated need confirmation of theraputic level

Atrial Fibrillation -- Management and Disposition -- Which category? Recent onset AF Recurrent paroxysmal AF Recurrent persistent AF Permanent (Chronic) AF and patient condition, determines Which primary option Rate control Urgent cardioversion Delayed cardioversion Rhythm control / maintenance if converted Systemic embolization prevention

Atrial Fibrillation -- Management and Disposition -- Elective cardioversion in the ED duration clearly identified less than 48 hrs No reversible cause low risk of intra-cardiac thrombus formation

Atrial Fibrillation -- ED Cardioversion in the stable patient -- Burton, John H. et al. Electrical cardioversion of ED patients with Atrial Fibrillation. Annals of Emergency Medicine 2004;44: 22-30 Retrospective, consecutive cohort 42 months, Oct 1998 March 2002 4 institutions 3,688 AF encounters Excluded: Cardioversion for unstable patients hypotension, dyspnea, ischemic chest pain, altered consciousness, CHF, acute MI No standardized protocol at any of the study sites 388 stable AF encounters (10.5%) Mean age = 61 +/- 13 yrs 332 successful (86%) 56 unsuccessful (14%) 91% discharged 55% discharged 9% admitted 45% admitted

Atrial Fibrillation -- Management and Disposition -- Urgent or Emergent cardioversion in the ED What are the indications? What are the contraindications?

Atrial Fibrillation -- Management and Disposition -- Urgent cardioversion Restoration of sinus rhythm takes precedence over mitigation of thromboembolic risk Indicated if any of the following is present: Active ischemia Significant hypotension where LV dysfunction (systolic or diastolic) or valvular disease is a factor Severe CHF Pre-excitation syndrome (eg WPW) Relative Contraindications to urgent cardioversion Duration of episode > 48hrs or uncertain duration Associated mitral valve disease, cardiomyopathy or CHF (known EF < 50%) Prior history of thromboembolic event

Atrial Fibrillation -- Management and Disposition -- Rate control indicated if starting Class 1a or 1c antiarrhythmic drug due to possible recurrence with Atrial flutter with 1:1 conduction Necessary for prevention of tachycaria-induced left venticular dysfunction Agents for rate control Beta blockers IV therapy: Metoprolol, Esmolol Oral therapy: Atenolol Calcium channel blockers Diltiazem Verapamil Digoxin Useful only in CHF patients or as second/third line agent

Atrial Fibrillation -- Antiarrhythmic agents --

Fast Channel (Na + ) Action Potential Purkinje fibers Slow Channel (Ca ++ ) Action Potential Sinus / A-V Nodes 0 1 23 4 2 0 Myocardial Cellular Electrophysiology Class 1 antiarrhythmics -Slowing of conductance -Phase 0 is determined by Na + channel -Slowing of conduction velocity and decreased excitability Class 4 antiarrhythmics -Slowing of AV nodal conductance -Phase 0 is determined by Ca ++ channel -Slowing of conduction velocity in sinus and AV nodes

-- Antiarrythmic Agent Classification Vaughn-Williams Classification (Journal of Clinical Pharmacology, 1984) Class 1- depression of Na + conductance during phase 0; slowed conduction velocity and decreased excitability 1a: moderate depression of Na + conductance in resting and depolarized tissue; depression of K + currents and prolongation of repolarization Quinidine, Procainamide, Disopyramide 1b: depression of Na + conductance in depolarized fibers only; Lidocaine, Tocainide, Phenytoin 1c: marked depression in Na + conduction; no effect on repolarization Encainide, Flecainide, Propafenone Class 2- -adrenergic receptor blockers Atenolol, Metoprolol Class 3- prolongation of action potential duration by varied effects Bretylium, Sotolol, Amiodarone, Ibutilide, Dofetilide Class 4- depression of Ca + -dependent slow channels Diltiazem, Verapamil

Atrial Fibrillation -- Management and Disposition -- Delayed cardioversion AF duration of 48 hours or duration unknown Associated mitral valve disease, cardiomyopathy or CHF Prior history of thromboembolic event Anticoagulate with a goal INR of 2.0 to 3.0 for at least three weeks before and four weeks after either electrical or pharmacologic cardioversion.

Atrial Fibrillation -- Management and Disposition for Delayed ECV -- Strategy 1 (Conventional) Oral anticoagulation with Warfarin Target INR 2.0 3.0 No antiarrythmics Rate control as needed hospitalization usually necessary if rate control needed Metoprolol Diltiazem Digoxin (useful only in presence of CHF) Scheduled ECV after minimum of 3 weeks of anticoagulation 4 weeks of anticoagulation after ECV Strategy 2 Indication recent onset but > 48 hrs useful for hospitalized patients (rate control, associated complications) and stable patients for which earlier timing is useful Patients with increased risk of hemorrhage with anticoagulation Screening Transesophageal echocardiography (TEE) No anticoagulation No antiarrhythmics Rate control as needed ECV if no thrombi seen

Atrial Fibrillation -- Indications for hospitalization -- For the treatment of an associated medical problem, which is often the reason for the arrhythmia For elderly patients who are more safely treated for AF in hospital For patients with underlying heart disease who have hemodynamic consequences from the AF or who are at risk for a complication resulting from therapy of the arrhythmia

Atrial Fibrillation -- Rate control alone vs rhythm control -- Rhythm control strategy Advantages: Better exertional capacity Improved cardiac function for CHF patients Mitigation of other arrhythmic related symptoms (eg palpitations) Disadvantages: frequent recurrences of AF 50% of patient recurr in 3-6 months repeated need for electrical cardioversion; adverse effects of prophylactic antiarrhythmic drugs including life-threatening events related to proarrhythmic effects No clear benefit of either approach for patients over 65 years of age; trend for increased mortality in rhythm control (AFFIRM trial, NEJM 2002, > 4,000 patients) Rate control with anticoagulation is acceptable in patients 65 yrs or greater Strategy is weighed for acutely symptomatic patient with new onset of Atrial fibrillation, particularly if < 65 yrs

Atrial Fibrillation -- Rate control alone vs rhythm control -- VanGelder, et al, A Comparison of Rate Control and Rhythm Control in Patients with Recurrent Persistent Atrial Fibrillation, NEJM 2002;347:1834-40 522 Patients with persistent AF after previous electrical cardioversion Mean age 68 +/- 8 Mean duration of AF diagnosis 315 d Mean duration of presenting episode 32 d No history of heart disease 21% Primary Endpoints: Death CHF TE event Bleeding Pacer severe drug adverse event Primary endpoint: Rhythm control = 23% Rate control = 17% Follow up period of at least 2 yrs Rhythm controlRate control Entry: ECV + Sotolol 1 st recurrence: ECV + Flecanide or Propafenone 2 nd recurrence: Amiodarone load + ECV + Amiodarone main. Target HR < 100 Digoxin, Diltiazem, blocker alone or In combination All patients anticoagulated: could be discontinued if In NSR 4 weeks after ECV

Atrial Fibrillation -- Rate control alone vs rhythm control -- VanGelder, et al, A Comparison of Rate Control and Rhythm Control in Patients with Recurrent Persistent Atrial Fibrillation, NEJM 2002;347:1834-40 Factors related to lack of risk reduction with rhythm control strategy Tachycardia induced cardiomyopathy and heart failure also are likely reduced with rate control (incidence of CHF similar in the two arms of the study) Patients with risk factors for stroke are still at risk for stroke even when sinus rhythm is maintained (17% of the thromboembolic events occurred after cessation of anticoagulant therapy and in 5 of 6 cases the patient was in sinus rhythm at the time of the event) Senescent conduction disease is occasionally unmasked by rhythm control strategy

Atrial Fibrillation -- Maintenance of Sinus Rhythm after Chemical or Electrical Cardioversion -- Canadian Trial of Atrial Fibrillation Investigators Roy, et al Amiodarone to Prevent Recurrence of Atrial Fibrillation, NEJM, 2000;342:913-920 403 patients; 19 centers 201 Amiodarone202 Propafenone ; Sotolol 101 Propafenone101 Sotolol Mean 16 month follow-up 35% recurrence for Amiodarone 63% recurrence for Propafenone or Sotolol

Atrial Fibrillation -General Management Principles- -- Pharmacologic Cardioversion -- Semi urgent (hospitalization or Obs Unit) Class 1c used only if no pre-existant heart disease monitoring for rapid conducting At. Flutter Flecainide Propafenone Class 3 monitoring for QT prolongation; Torsade Dofetilide Ibutilide Out-patient / Ambulatory scenario Class 1c Pill-in-the-Pocket Flecainide Propafenone Used only when demonstrated effective under as in-patient Must have AV nodal blockade with blockade or Ca ++ channel blocker to prevent 1:1 AV conduction if Atrial flutter occurs Class 1c Extended dosing Amiodarone particularly with patients with pre-existing heart disease

Atrial Fibrillation -General Management Principles- -- Maintenance of Sinus Rhythm after Chemical or Electrical Cardioversion ACC / AHA / ESC anticoagulation recommendations

Atrial Fibrillation -General Management Principles- Assessment of Thromboembolic Risk

Atrial Fibrillation -- Risk for Thromboembolism -- Go, AS, Hylek, EM, Chang, Y, et al, JAMA 2003 Risk assessment CHADS2 CHF any history (1) Hypertension prior history (1) Age > 75 (1) Diabetes mellitus (1) Stroke, TIA or systemic embolic event (2)

Atrial Fibrillation -- Risk for Thromboembolism -- Risk assessment CHADS2 Go, AS, Hylek, EM, Chang, Y, et al, JAMA 2003 Score (risk) Event rate (% / yr) Warfarin Without Warfarin NNT 0 (low)0.250.49417 1 (interm)0.721.52125 2 (interm)1.272.50 81 3 (high)2.25.27 33 4 (high)2.356.02 27 5,6 (high)4.66.88

Atrial Fibrillation -- Prevention of Thromboembolism -- ACC / AHA / ESC anticoagulation recommendations Age < 60 + heart disease but no other risks: Aspirin Age 60 75 with no risks:Aspirin Age 65 75 with heart disease or DM: Warfarin Women > 75:Warfarin Men > 75: Warfarin or Aspirin Age > 65 with CHF:Warfarin EF < 35% + HypertensionWarfarin

Atrial Fibrillation -- Summary Patients with new onset atrial fibrillation of less than 48 hrs duration, who have normal ventricular function, no known mitral valvular disease and no history of thromboembolic event can be considered for cardioversion in the ED Up to 90% of atrial fibrillation episodes are asymptomatic with approximately 20% of such episodes longer than 48 hrs (Select your cardioversion cases carefully!) If the episode is greater than 48hrs, rate control, anticoagulate and refer for delayed cardioversion TSH and free T 4 are essential in the evaluation of initial onset AF is transient in 6-10% of MI patients; however it is almost never in isolation to other ECG findings of ACS CHAD2 scheme is extremely helpful in assessing thromboembolic risk and need for anticoagulation In patients greater than age 65, rhythm control strategy is very appropriate AF is transient in 6-10% of MI patients; however it is almost never in isolation to other ECG findings of ACS

atrial fibrillation atrial fibrillation assessment and management in the ed joseph r. cline md facep...

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