EM@3AM – Atrial Fibrillation

Author: Garrett Blumberg, MD (Resident, UTSW) and Erica Simon, DO, MHA (@E_M_Simon, EM Chief Resident, SAUSHEC, USAF) // Edited by: Alex Koyfman, MD (@EMHighAK, EM Attending Physician, UT Southwestern Medical Center / Parkland Memorial Hospital) and Brit Long, MD (@long_brit, EM Attending Physician, SAUSHEC, USAF)

Welcome to EM@3AM, an emdocs series designed to foster your working knowledge by providing an expedited review of clinical basics. We’ll keep it short, while you keep that EM brain sharp.

A 69-year-old male with a previous medical history of hypertension (lisinopril) and diabetes mellitus (metformin) presents to the emergency department for generalized weakness, palpitations, and shortness of breath of two days duration. The man denies chest pain, nausea, and diaphoresis. He denies tobacco use, a personal/familial history of heart disease, a personal/familial history of DVT/PE, recent hospitalization, immobilization, and sick contacts.

Initial VS: BP 141/89, HR 128, T 98.9F Oral, RR 14, SpO2 99% on room air.

Pertinent physical exam findings:
Neuro: No focal findings
CV: Irregularly irregular rhythm without murmurs, rubs, or gallops
Pulmonary: Lungs CTAB

EKG: Rate 126 bpm, irregularly irregular rhythm, absent p waves, LAD, no acute ST-T wave changes

What diagnosis do you suspect? What’s the next step in your evaluation and treatment?

Answer: Atrial Fibrillation (A. fib)1-5

  • Risk Factors: Increasing age, hypertension, diabetes, MI, heart failure, obesity, obstructive sleep apnea, smoking, alcohol use, hyperthyroidism, family history.
  • Presentation: Variable: patients may be asymptomatic, may present with palpitations or shortness of breath, or at the extreme, may suffer from CHF or stroke.
  • Evaluation:
    • Perform a thorough H&P to evaluate for underlying etiologies.
      •  Think “P-HEARTS”:
        • Pericarditis
        • Hypertension
        • Embolism
        • Atherosclerosis (MI)
        • Alcohol (Holiday Heart)
        • Rheumatic heart disease/Mitral valve disease
        • Thyrotoxicosis
        • Stimulants
        • Sepsis
  • EKG: an irregularly irregular rhythm absent discernible p waves.
  • Utilize the H&P to direct laboratory assessment as appropriate (i.e. TSH, UDS, etc.).
    • Troponin may be elevated in the setting of tachyarrhythmia => obtain a troponin level for patients with cardiac risk factors, those with a. fib who experience chest pain or hypotension, or for those with dynamic EKG changes.
      • A positive troponin is predictive of thromboembolic phenomena and cardiovascular death.1
  • Treatment:1-5
    • Unstable, symptomatic patient (e.g. EKG with signs of ischemia, hypotension, etc.):
      • A. fib duration < 48 hours: electrical cardioversion
      • A. fib duration ≥ 48 hours or unknown duration: electrical cardioversion + concomitant anticoagulation (see below).5
    •  Stable patient:
      • Rate Control: Goal heart rate < 110 bpm4
        • Diltiazem 20-25 mg IV (ACLS) or 0.25 mg/kg IV (max 20 mg) administered over 2 mins followed by 0.35 mg/kg IV (max 25 mg) administered over 5 mins if no resolution
          • Avoid in the setting of hypotension and decompensated heart failure.3
        • Metoprolol 5 mg IV (may repeat q 5 mins; max 15 mg)
          • Avoid in the setting of bronchospasm (history of pulmonary disease).
      • Rhythm Control:
        • Amiodarone 150 mg IV administered over 10 mins, then 0.5-1 mg/min
          • Contraindicated in the setting of cardiogenic shock, severe sinus node dysfunction, or 2nd or 3rd degree AV block.
      • All patients: Anticoagulation considerations:
        • Risk assessment: CHADS2-VASc
        • Unstable patient with a. fib of unknown duration, or duration > 48 hours: cardioversion + heparin (IV bolus followed by a continuous infusion (target 1.5-2 times the reference control aPTT).5
        • Stable patients with a. fib duration > 48 hours: anticoagulation required for a duration of 3 weeks prior to cardioversion.
  • Pearls:
    • Thyroid pathology is a common etiology of new onset atrial fibrillation.1
    • Warfarin is the drug of choice for stable patients > 75 years of age, those with a history of HTN, those with impaired LV systolic function (EF ≤ 35%), or patients with DM.5



  1. Hijazi Z, Oldgren J, Siegbahn A, et al. Biomarkers in atrial fibrillation: a clinical review. European heart journal. 2013;34:1475-80.
  2. Fromm C, Suau SJ, Cohen V, et al. Diltiazem vs. Metoprolol in the Management of Atrial Fibrillation or Flutter with Rapid Ventricular Rate in the Emergency Department. J Emerg Med. 2015;49:175-82.
  3. January CT, Wann LS, Alpert JS, et al. 2014 AHA/ACC/HRS guideline for the management of patients with atrial fibrillation: executive summary: a report of the American College of Cardiology/American Heart Association Task Force on practice guidelines and the Heart Rhythm Society. Circulation. 2014;130:2071-104.
  4. Van Gelder IC, Groenveld HF, Crijns HJGM, et al. Lenient versus Strict Rate Control in Patients with Atrial Fibrillation. N Engl J Med. 2010;362:1363-73.
  5. Anderson J, Halperin J, Albert N, Bozkurt B, Brindis R, et al. Management of patients with atrial fibrillation (compilation of 2006 ACCF/AHA/ESC and 2011 ACCF/AHA/HRS recommendations). JACC. 2013; 61(18):1936-1943.



For Additional Reading:

Management of Atrial Fibrillation: Do’s and Don’ts

Management of Atrial Fibrillation: Do’s and Don’ts



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