atrial fibrillation

epidemiology

  • most common sustained arrhythmia
  • affect more than 33 million persons worldwide
  • Lifetime risk for atrial fibrillation is 25% in patients older than 40 years.
  • Incidence is strongly associated with and increases with age.
  • 10% of persons older than 80 years.
  • fivefold increased risk for stroke
  • increased risk for heart failure and dementia
  • Among patients aged 55 years and older who have a cryptogenic ischemic neurologic event, such as a stroke or transient ischemic attack, occult intermittent atrial fibrillation is thought to be present in up to 25% of cases, and 30-day ambulatory ECG monitoring is indicated for detection. If 30-day ambulatory monitoring is inconclusive, implantation of a cardiac monitor (loop recorder) is reasonable to optimize detection of silent atrial fibrillation.

risks

  • DM
  • obesity
  • HTN
  • CAD
  • HF
  • sleep apnea
  • smoking
  • alcohol consumption

Duration

  • paroxysmal: stops within 7 days
  • persistent: last for 7 days or more
  • long standing persistent: > 1 year

Management

unstable

  • synchronized cardioversion: avoids R on T event and Vfib
  • unknown duration or > 48 hours duration: initiate AC and continue for 4 weeks at least

stable

  • testing
    • TSH
    • sleep apnea
    • echocardiogram for valvular or structural heart disease, left atrial size

Rate control

  • goal:
    • <60
    • <110 in pts without lower EF

Rhythm control

  • pill-in-the-pocket approach: pts with infrequent afib and no structural heart disease
    • on BB/CCB
    • flecainide/propafenone: take at onset of episode
    • fleicanide: need AV nodal blockade such as BB to avoid 1:1 Vfib from Afib
    • Class 1c: need ischemic work up prior to initiate in hospital. Could also initiate then ischemic work up afterwards
    • Class 3: watch out for QTc prolongation (sotalol)

Ablation

  • for symptomatic afib despite antiarrythmic
  • pulmonary vein isolation
  • AV nodal ablation: afib with tachycardia despite rate/rhythm control. Needs permanent pacemaker. Also will remain in afib afterwards and still need AC](##)

cardioversion

  • pharm cardioversion: pt without structural heart disease
    • can use Ibutilide: monitor on tele for 6 hours or until QTc return to baseline due to small risk of torsades

anticoagulation

When to start

  • afib duration < 48 hours or low risk for stroke/thrombus
    • preprocedural AC for men with chadsvasc more than 1 and women more than 2
  • unclear duration or > 48 hours
    • AC for 3 weeks before cardioversion
    • can use TEE prior to cardioversion
  • Continue at least 4 weeks following cardioversion due to increased risk for thrombus formation after sinus rhythm

Valvular vs Nonvalvular

  • non-valvular afib: base on CHA2DS2-VASc
    • men: AC if score ≥ 2
    • women: AC if score ≥ 3
    • other valves: aortic valve, MR, TR, mild mitral stenosis
    • can use non-vitamin K antagonist (NOAC)
  • valvular afib: needs AC
    • mechanical prosthesis (mechanical valve replacement)
    • moderate to severe MS
    • cannot use NOAC, only warfarin
  • Pt with HAS-BLED ≥ 3 needs regular evaluation

Agents

  • Warfarin
    • INR goal 2-3
  • NOAC
    • kidney/liver function, reevaluate at least annually
    • dabigatran: thrombin inhibitor, Pradaxa
      • less intracranial bleed
      • higher GI bleed
      • dyspepsia
    • rivaroxaban: 10a inhibitor, Xarelto
      • noninferior to warfarin with stroke or embolism
      • less intracranial/fatal bleed
      • higher GI bleed risk
    • apixaban: 10a inhibitor, Eliquis
      • superior for stroke prevention
      • less major bleed risk
      • less intracranial bleed risk
    • edoxaban:
      • noninferior for stroke prevention
      • less major bleed
    • reversal agents
      • andexanet alfa or 4-factor PCC: for life-threatening bleed 2/2 10a inhibitors
      • Idarucizumab: for dabigatran, emergency invasive procedures or life threatening bleeds
  • left atrial appendage occlusion: can consider in pt with CHADSVASC ≥ 3
    • lower risk for intracranial bleed
  • for pts with afib s/p PCI and CHADSVASC ≥ 2
    • double therapy: clopidogrel/ticagrelor + AC
    • better than triple therapy to reduce risk of bleed
  • for pts with afib and stable CAD
    • xarelto alone instead ASA + rivaroxaban