Atrial Fibrillation

Atrial fibrillation – an irregular, usually rapid supraventricular rhythm caused by simultaneous discharge and reentry at multiple atrial fociCAUSES

History

HPI

• Onset, duration (< or > 48 hours) and frequency
• Symptoms: palpitations, fatigue, dyspnea
• chest pain?
• fevers/ constitutional symptoms assoc’d with sepsis
• EtOH ingestion, drug use

PMHx

• CAD, MI, valve disease, CHF, other cardiac abnormalities
• thyroid disease
• COPD

Physical

• Vitals – irregularly irregular pulse +/- tachycardia
• CV – murmurs, S3 gallop, increased JVP, pedal edema
• Respiratory – crackles
• Neuro – assess for embolic complications

Investigations

• ECG – no organized P waves, chaotic baseline, irregularly irregular ventricular response, narrow QRS
• Initial labs – CBC/diff, elytes (hypokalemia can cause Afib), glucose, TSH, free T4, CXR
• Trop/ CK – if ACS suspected
• CT chest – possible PE
• ABG – CO poisoning, hypercarbia, shock, acidemia
• Echo – not usually used in acute assessment
• Holter monitor – used in some patients with paroxysmal Afib

Management
Dependent upon several factors: acuity of onset, associated symptoms, hemodynamic status, and the duration of the dysrhythmia (<48 h or >48 h).

Options:

• RATE CONTROL
  • B-blockers, diltiazem, verapamil
  • if CHF, use amiodarone or digoxin
  • initial management in hemodynamically stable patients
    Note: carotid massage may slow ventricular rate
• THROMBOEMBOLISM PROPHYLAXIS
  • Acute: heparin
  • Chronic: use CHADS2 score (see below) to determine appropriate Rx
    • 0 stroke risk factors – ASA 81 – 325 mg daily
    • 1 mod RF – ASA or warfarin
    • > 1 mod RF or any high risk factor – warfarin (goal INR 2.0 – 3.0)
• RESTORE SINUS RHYTHM
  • New onset
    • Self-limited episode – no antiarrhythmic drugs necessary if serious symptoms absent
    • if high stroke risk, anticoagulation beneficial
  • Persistent
    • rate control + anticoagulation OR
    • cardioversion
      •  
        • Chemical – amiodarone, sotalol, diltiazem, Class I anti-arrhythmic agent
        • Electrical – synchronized DC cardioversion
      • if duration <48 h, can cardiovert without anticoagulation
      • if duration>48h, MUST anticoag 3 wks prior/ 4 wks following cardioversion
      • use CHADS2 score to assess need for longterm anticoagulation
  • Recurrent/ Permanent
    • Brief episodes or minimal symptoms- rate control + anticoag
    • Prolonged or bothersome symptoms – antiarrhythmic drugs
    • Permanent Afib – rate control + anticoag (use CHADS2 score)