Atrial fibrillation (main)

Background

Atrial fibrillation (AF) categories:

  • First detected episode
  • Recurrent (after 2 or more episodes)
  • Paroxysmal (if recurrent AF terminates spontaneously)
  • Persistent (if sustained beyond 7 days)

Causes

  • Cardiac (atrial enlargement)
  • Noncardiac (increased automaticity)
    • Thyrotoxicosis
    • Chronic lung disease
    • Pericarditis
    • Ethanol ("holiday heart")
    • PE
    • Drugs (cocaine, TCA)

Clinical Features

  1. Asymptomatic - 44%
  2. Palpitations - 32%
  3. Dyspnea - 10%
  4. Stroke - 2%
  5. Also can present with decompensated heart failure, acute pulmonary edema

Diagnosis

  • 3 patterns on ECG:
  1. Typical
    1. Irregularly, irregular R waves
    2. QRS rate 140-160/min
  2. Large fibrillatory waves
    1. May look like flutter waves
      1. Unlike a-flutter, the fibrillatory waves are irregular
  3. Slow, regular A-fib
    1. Due to complete AV block with escape rhythm
  • Ischemic changes?
  • Rate > 250? (think preexcitation)

Work-Up

  1. ECG
  2. Digoxin level (if appropriate)
  3. Chem-10
  4. TSH & free T4 (AF increased in subclinical hyperthyrodism)
  5. Eval for ACS only in:
    1. Pt with ECG changes suggestive of ischemia, hypotension, angina
    2. AF is rarely only manifestation of ACS, although RVR and hypotension can provoke demand ischemia
  6. Bedside echo if available can provide info in LV function and underlying structural abnormalities

Treatment

  • Rate control
  • Anti-thrombotic therapy
    • Chronic and paroxysmal a fib are associated with thrombus formation

CHA2DS2-VAsc Score

  1. CHF (1pt)
  2. HTN (1pt)
  3. Age ≥75 (2pts)
  4. DM (1pt)
  5. Prev stroke/TIA (2pts)
  6. Vascular disease (eg IHD, PVD) (1pt)
  7. 65 ≤ Age ≤74 (1pt)
  8. Female gender (1pt)
  • Score 0: consider no treatment or ASA
  • Score 1: consider warfarin or ASA
  • Score 2-6: consider warfarin (INR goal = 2-3)
  • All patients with significant valvular disease should be on anticoagulation

Anticoagulation in Atrial Fibrillation/Flutter

Anticoagulation Therapy

  • ACCP Recommendations
    • In patients with AF, including those with paroxysmal AF, with only one of the risk factors listed immediately above, we recommend long-term antithrombotic therapy (Grade 1A), either as anticoagulation with an oral VKA, such as warfarin (Grade 1A), or as aspirin, at a dose of 75-325 mg/d (Grade 1B)[1]
    • In patients with AF, including those with paroxysmal AF, who have two or more of the risk factors we recommend long-term anticoagulation with an oral VKA (Grade 1A).[1]
  • CCS Recommendations
    • Oral anticoagulants are recommended for all AF patients aged 65 or older or who have any one of the traditional CHADS2 risk factors of stroke, hypertension, heart failure, or diabetes (remember as CHADS-65). Otherwise, patients with a history of coronary artery disease or arterial vascular disease should be prescribed ASA. CCS recommends that the first choice for oral anticoagulation should be the novel direct-acting oral anticoagulants (i.e. NOACs, for non-valvular AF). The big paradigm change is that ED physicians should prescribe OACs to at-risk AF patients before they leave the ED.[2]

Disposition

  • Similar outcomes for Canadian vs. American strategies, despite lower admission rates in Canada[3]

Canadian

  • "Limit hospital admission to highly symptomatic patients in whom adequate rate control cannot be achived"[4]

American

Indications for hospitalization:

  • Pt with acute heart failure or hypotension after rhythm or rate control
  • AF 2/2 HTN, infection, COPD exacerbation, PE, ACS/MI
  • Age > 60 (high risk of thromboembolism, more likely to have comorbidities)
  • Initiation of heparin or other anticoagulant
  • If considering ablation of accessory pathway in pt with AF
  • Symptomatic recurrence in the ED
  • Hemodynamic instability

Indications for discharge (low-risk pts): Discharge with urgent cardiology f/u

  • <60 years old
  • No significant comorbid disease
  • No clinical suspicion for PE or MI
  • Conversion in ED or rate control

Complications

  1. Hemodynamic compromise
    1. A-fib lowers CO by 20-30%
    2. Impaired coronary blood flow
  2. Arrhythmogenesis
  3. Arterial thromboembolism

See Also

Source

  • UpToDate
  • Annals of EM; Jan 2011. 57(1)
  • EBmedicine.net
  1. ↑ 1.0 1.1 Singer DE et al. Antithrombotic therapy in atrial fibrillation: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition).Chest. 2008 Jun;133(6 Suppl):546S-592S
  2. ↑ Verma A, et al. 2014 Focused Update of the Canadian Cardiovascular Society Guidelines for the Management of Atrial Fibrillation Canadian Journal of Cardiology 30 (2014) 1114e1130
  3. ↑ Rising KL. Home is Where the Heart Is. Annals of Emergency Medicine. 2013;62(6):578-579
  4. ↑ Stiell, et al. Atrial Fibrilation Guidelines. Canadian Cardiovascular Society Atrial Fibrillation Guidelines 2010: management of recent-onset atrial fibrilation and flutter in the emergency department. Can J Cardiolol. 2011;27:38-46
Retrieved from "https://www.wikem.org/w/index.php?title=Atrial_fibrillation_(main)&oldid=32501"