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Atrial Fibrillation and Atrial Flutter (AFib, AFlut)

Basics

  • AFib: Rapid, irregular atrial electrical activity (400-600 bpm), irregularly irregular ventricular response.
  • AFlut: Rapid but organized atrial electrical activity (250-350 bpm), "saw-tooth" flutter waves on ECG; ventricular response often regular (e.g., 2:1 block).
  • Both can coexist; management differs.

Clinical Classifications

  • Paroxysmal: self-terminating, <7 days
  • Persistent: >7 days, requiring intervention
  • Permanent: sinus rhythm cannot be maintained
  • Nonvalvular AFib: no moderate-severe mitral stenosis or mechanical valve
  • Lone AFib: age <60, no cardiovascular disease

Epidemiology

  • Incidence/prevalence rise with age; lifetime risk ~25% in those ≥40 years.
  • AFib prevalence up to 8% in >80 years; AFlut less common.
  • Males more commonly affected, especially with lone AFib.

Etiology and Pathophysiology

  • Cardiac: HTN, ACS, CHF, valvular disease, cardiomyopathy, pericarditis, infiltrative disease
  • Pulmonary: PE, COPD, OSA, pneumonia
  • Others: ethanol, caffeine, nicotine, hyperthyroidism, DM, obesity, postoperative states, iatrogenic (amiodarone)
  • AFib involves atrial fibrosis and remodeling ("AFib begets AFib").
  • Genetic forms rare; autonomic tone may trigger arrhythmia.

Risk Factors

  • Age, hypertension, obesity predominant.

Commonly Associated Conditions

  • Hypertension, stroke, other cardiac diseases.

Diagnosis

History

  • Symptoms: palpitations, lightheadedness, fatigue, angina, dyspnea, syncope.

Physical Exam

  • AFib: irregularly irregular pulse, pulse deficit
  • AFlut: may have regular pulse

Differential Di