Atrial Fibrillation and Flutter

Atrial Fibrillation & Flutter - Benjamin Palmer

Background

  • AF: 12-lead EKG with absence of p-waves and irregularly irregular QRS complexes
  • Flutter: typically sawtooth atrial activity with regular or regularly irregular QRS complexe
    • Look for “sawtooth” waves in inferior leads and V1; ventricular rate of ~150 or ~100
  • 3 classifications:
    • Paroxysmal (self-terminating within 7 days)
    • Persistent (not self-terminating, >7 days)
    • Permanent (normal rhythm cannot be restored)
  • Rapid ventricular response (RVR) is HR > 100 (ie AFib/Flutter w/ tachycardia)
    • RVR is the equivalent to sinus tachycardia in a patient with Afib
  • AF/RVR is far more often a consequence of hypotension than the cause of it
  • Avoid using antiarrhythmics (including amiodarone) in any pt you wouldn’t electrically cardiovert without TEE (e.g. not on chronic anticoagulation, unknown duration of AFib, possibility of prior asymptomatic episodes of AFib)

Evaluation

  • Causes: Mnemonic “H PIRATES”  
    • Hypertension
    • Pneumonia, Pericarditis
    • Post-op
    • Ischemia (rare)
    • Rheumatic Valve
    • Atrial Myxoma, Accessory Pathway
    • Thyrotoxicosis
    • Ethanol, Excess Volume
    • Sick sinus, sepsis

 

Management

Inpatient:

  • Always work to address the underlying cause (infection, volume overload etc)
  • Rate control is rarely an emergency unless the patient is hemodynamically unstable 
  • If acute rate control is NOT needed (i.e patient is hemodynamically stable), opt for PO meds
  • Treatment goals:
    • Rate control, Goal HR < 110
    • Anticoagulation
    • Rhythm Control (if indicated)
  • Rate control:
    • β-blockers (Metoprolol), calcium channel blockers (Diltiazem), Digoxin, Amiodarone
        • Before administering any nodal blocking agents be wary of WPW/pre-excitation
        • AV-node blocking in this setting can accelerate A-V conduction and VT/VF
        • Would use procainamide in those situations
  • HFrEF: low dose PO metoprolol provided pt is warm and well :perfused
      • Avoid CCB
      • Consider discussion with Cardiology for Digoxin or Amiodarone
  • If acute rate control needed, consider IV metoprolol 5mg x1 or IV diltiazem 15-20mg x1, must follow with maintenance therapy (See acute tachyarrhythmia section above)
  • Anticoagulation (AC):
    • If new onset a-fib and cardioversion is anticipated, begin AC as soon as possible, Lovenox > heparin drip initially, DOAC would also be acceptable
    • If new onset a-fib but no immediate plans for cardioversion, AC should be considered based off of CHA2DS2-VASc
        • AC in this setting is not an emergency
    • If arrhythmia persists >48 hours, AC should be initiated if indicated
    • If known a-fib continue his or her AC while inpatient
    • If procedures/surgery is anticipated, bridging AC w/ heparin or LMWH should be decided on a case-by-case basis, likely not indicated with low stroke risk
  • Rhythm Control:
    • New onset a-fib (first time diagnosis): most pts will be a candidate for trial of electrical cardioversion
        • If onset clearly within 48 hours, can proceed without TEE
        • If onset >48 hours, will need TEE to rule out LAA thrombus
        • If cardioversion is anticipated or performed, pts need AC for at least one month
    • If typical flutter, consider EP consult as ablation can be quickly and safely performed
    • If hemodynamically unstable, HFrEF, or highly symptomatic a-fib, should be considered for rhythm control strategies (options include class 1c agents (Flecainide) and class III agents (amiodarone, sotalol, dofetilide)​​​​​​​

Outpatient:

  • Rate control typically achieved with beta blocker therapy, metoprolol is most frequently used and can be converted to once daily dosing with metoprolol succinate
  • AC pending CHA2DS2-VASc scoring; DOACs are typically the agents of choice 
    • Warfarin indicated in valvular afib (AF 2/2 mitral stenosis)
  • Rhythm control is a complex decision, consider EP referral 
    • If highly symptomatic or HFrEF, consider ablation vs pharmacologic rhythm control
  • Serial monitoring for risks/benefits of AC and tachycardia induced cardiomyopathy