AF in the ER: Common Scenarios CASE 1. Fast facts. Diagnosis. Management

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1 AF in the ER: Common Scenarios Atrial fibrillation is a common problem with a wide spectrum of presentations. Below are five common emergency room scenarios and the management strategies for each. Evan Lockwood, MD, FRCPC and Bibiana Cujec, MD, FRCPC, FACC CASE 1 Mikhael, 35, presents to the emergency room (ER) with new-onset palpitations that began two hours ago. He has no chest pain or dyspnea. An electrocardiogram (ECG) shows atrial fibrillation (AF) with a ventricular rate of 160 beats per minute (bpm) without any signs of ischemia. The AF spontaneously converts while on a monitor. Mikhael has no medical history and he takes no medications. He has had similar palpitations that lasted up to three hours and were unrelated to alcohol, caffeine or illicit drugs. His physical exam is unremarkable. His blood pressure (BP) is 132/78 mmhg. Once he is back in sinus rhythm, his ECG is completely normal. Paroxysmal atrial fibrillation (AF) is selfterminating within seven days of onset; persistent AF is terminated pharmacologically or with electrical cardioversion; permanent AF can last > 1 year. Lone AF occurs in patients aged 65 years or younger without hypertension, diabetes or structural heart disease. Stroke prophylaxis in lone AF is acetysalicylic acid, 81 mg, daily, or no therapy at all because the risk of stroke is very low (< 1%). If AF is very sporadic, patients do not need to be on rate- or rhythm-controlling medications. Paroxysmal lone AF Consider acetysalicylic acid (ASA), 81 mg, daily, if little risk of bleeding Check thyroid-stimulating hormone (TSH) levels Order an echocardiogram to confirm the absence of structural heart disease Advise Mikhael to avoid excess alcohol and caffeine 38 Perspectives in Cardiology / October 2005

2 CASE 2 Hugh, 72, presents to the ER with palpitations and chest tightness for six hours. He also has mild dyspnea. His ECG shows AF with an uncontrolled ventricular rate of 130 bpm and ST depression of 3 mm in the lateral leads. Hugh s only medical history is hypertension, currently treated with a thiazide diuretic. He has previously had intermittent palpitations lasting one to three hours over the past six months. On examination, his heart rate is 130 bpm and his BP is 90/76 mmhg. He has a soft aortic ejection murmur. Initial investigations show a normal TSH level and markedly positive troponin I of 9 µg/l (normal: < 0.15 µg/l). Triggers of new-onset AF include: - Ischemia - Heart failure - Infection - Hyperthyroidism - Alcohol - Surgery The spectrum of unstable AF includes cardiogenic shock, myocardial infarction, ongoing ischemia and pulmonary edema. Patients with unstable AF should undergo immediate cardioversion, even if the AF has lasted more than 48 hours and they have not been anticoagulated. Unstable AF Non-ST-elevation myocardial infarction Admit Hugh to the hospital on a monitor ASA, 160 mg, orally Begin rate control with metoprolol, 5 mg, intravenously up to 15 mg Start IV heparin Electrical cardioversion Risk stratification of acute coronary syndrome with stress testing or coronary angiography About the authors... Dr. Lockwood is an Electrophysiology Fellow, Royal Jubilee Hospital, Victoria, British Columbia. Dr. Cujec is an Associate Professor of Medicine, Division of Cardiology, University of Alberta, Edmonton, Alberta. Perspectives in Cardiology / October

3 CASE 3 Merle, 64, presents to the ER with a one-week history of palpitations and dyspnea with exertion. He has had similar palpitations over the last six months that only lasted five to 10 minutes. He had an anterior myocardial infarction eight years ago and has a left ventricular ejection fraction of 28%. Merle s medications include carvedilol, 25 mg, twice daily (bid); simvastatin, 40 mg, daily; ASA, 81 mg, daily; and enalapril, 10 mg, bid. Merle s BP is 110/84 mmhg. His jugular venous pressure is mildly elevated. A pansystolic murmur of mitral regurgitation is present at the apex. There is mild ankle edema. An ECG shows AF with a ventricular rate of 100 bpm and an old anterior myocardial infarction. His chest X-ray shows vascular redistribution and cardiomegaly. Merle has a normal TSH level and negative troponin I. His serum creatinine is 90 µmol/l and his potassium is 4.2 mmol/l. Persistent AF in a patient with heart failure Anticoagulate with warfarin titrated to a prothrombin time international normalized ratio of 2 to 3 for three to four weeks, then attempt electrical cardioversion Continue anticoagulation indefinitely, as AF is likely to recur Add diuretic for fluid retention (e.g., furosemide, 40 mg, daily) Add digoxin, mg, daily, to improve ventricular rate control Continue his beta-blocker, angiotensinconverting enzyme inhibitor and statin Consider referral to a cardiologist, as Merle may need antiarrhythmic therapy to maintain his sinus rhythm (i.e., amiodarone) Almost all patients should be given at least one trial of return-to-normal sinus rhythm with cardioversion. If AF is definitely < 48 hours in duration, then anticoagulation prior to cardioversion is not necessary, but should be given afterwards to high-risk patients. If AF is 48 hours in duration, patients need warfarin for three to four weeks prior to, and after, the cardioversion. Patients with AF at high risk for thromboembolic events include those with heart failure, hypertension, prior thromboembolic events, mitral stenosis and those aged > 75 years. These patients should receive long-term anticoagulation with warfarin in the absence of contraindications. The risk of thromboembolic events is similar in patients with paroxysmal, persistent and permanent AF. The importance of anticoagulation depends on the presence of the above high-risk features. Recurrent symptomatic paroxysmal AF should be referred to a specialist for the consideration of antiarrhythmic medications or ablation therapy. 40 Perspectives in Cardiology / October 2005

4 CASE 4 Fiona, 62, comes to the ER to have stitches placed in a laceration. On the monitor, she is found to be in AF with a rate of 116 bpm. An ECG also shows left ventricular hypertrophy. She denies dyspnea or chest tightness. Fiona has a two-year history of AF, as well as hypertension and diabetes mellitus. She is taking warfarin, metformin and ramipril. Permanent AF Begin rate control with a beta-blocker (e.g., metoprolol, 25 mg to 50 mg, bid; atenolol, 25 mg to 50 mg, daily; bisoprolol, 2.5 mg to 5 mg, daily) or a calcium channel blocker (diltiazem, 240 mg, daily, or verapamil, 240 mg, daily) Implement a Holter monitor in three to four weeks to determine rate control Continue lifelong warfarin The Atrial Fibrillation Followup Investigation of Rhythm trial 1 showed us that rate control is as good or better than rhythm control in patients who could tolerate either strategy (Figure 1). Even if a patient with AF is asymptomatic, there is a risk of tachycardia-induced cardiomyopathy if their ventricular rate is uncontrolled. A Holter monitor may be used to titrate rate control with targets of < 80 bpm at rest and < 110 bpm with exertion. 30 P = 0.08 Cumulative mortality (%) Rhythm control Rate control Years Number of deaths Number (per cent) Rhythm control 0 80 (4) 175 (9) 257 (13) 314(18) 352 (24) Rate control 0 78 (4) 148 (7) 210 (11) 275 (16) 306 (21) Figure 1. Rate control versus rhythm control. Perspectives in Cardiology / October

5 CASE 5 Ruby, 82, presents to the ER with a broken wrist she suffered after a fall. She describes dizziness prior to the fall, but did not lose consciousness. She has been having intermittent dizziness for the past two weeks, but denies dyspnea or chest pain. On the monitor, Ruby is found to be in AF at a rate of 85 bpm. During casting, she develops marked dizziness and nearly loses consciousness. Her monitor now shows sinus bradycardia at 54 bpm. A review of the rhythm strips demonstrates a five-second pause when she spontaneously cardioverted from AF. She has a three-year history of AF and has been on a beta-blocker until two weeks ago, when the dizziness began. She also takes warfarin, 5 mg, daily. Sick sinus syndrome (SSS) Admit Ruby to hospital on a monitor Consult Cardiology for the consideration of a permanent pacemaker Once a pacemaker has been inserted, restart the beta-blocker for rate control and warfarin for the prevention of thromboembolic events. PCard Sick sinus syndrome (SSS): Patients with AF having intermittent periods of tachycardia and bradycardia/pauses. Pauses often occur following a spontaneous conversion from AF to a normal sinus rhythm. Symptomatic SSS often requires the insertion of a pacemaker to allow the use of rate-slowing drugs to treat the tachycardia. Reference 1. Wyse DG, Waldo AL, DiMarco JP, et al: A comparison of rate control and rhythm control in patients with atrial fibrillation. N Engl J Med 2002; 347(23): Resources 1. Canadian Cardiovascular Society Consensus Conference: Atrial Fibrillation 2004 at Accessed on August 22, ACC/AHA/ESC guidelines for the management of patients with atrial fibrillation. J Am Coll Cardiol 2001; 38: Perspectives in Cardiology / October 2005