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Atrial Fibrillation, Diagnosis and Initial Treatment

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Atrial Fibrillation Diagnosis and Initial Treatment

Basic Information

Terminology

  • Atrial fibrillation is a supraventricular tachyarrhythmia characterized by chaotic, disorganized electrical activation and inefficient atrial contraction

Epidemiology

  • Atrial fibrillation is the most common sustained cardiac arrhythmia, with a worldwide prevalence of more than 37 million (0.5% of the global population)(1)

  • Incidence and prevalence have risen steadily over the past 20 years, and they are projected to continue to rise(1)

Etiology and Risk factors

Etiology

  • Atrial fibrillation episodes are initiated by premature atrial complexes

    • Typically originate in the pulmonary veins (called pulmonary vein triggers)

    • May also come from the other structures (called non–pulmonary vein triggers2), including: • Right atrium • Superior vena cava • Posterior wall of left atrium • Vein of Marshall • Left atrial appendage

Risk Factors

  • Risk factors for atrial fibrillation

    • Cardiac factors

    • Hypertension

    • Coronary artery disease

    • Heart failure

    • Hypertrophic cardiomyopathy

  • Extracardiac factors

    • Obesity

    • Metabolic syndrome

    • Sleep apnea

    • Diabetes mellitus

    • Excessive alcohol consumption

    • Hyperthyroidism

  • Genetic factors

    • Sometimes familial

      • Patterns of autosomal dominant inheritance have been described in some families3

      • Numerous genetic mutations have been linked to atrial fibrillation, including:

        • Ion channel mutations (sodium and potassium channels)

        • Non–ion channel mutations (eg, lamin, connexin, ryanodine receptor, cardiac transcription factors)3 European ancestry is a risk factor4

  • Advancing age

Diagnosis

Approach to Diagnosis

  • Presence is suggested by findings on physical examination and confirmed by ECG

Staging or Classification

  • Classified according to predominant duration of episodes

    • Paroxysmal (terminating spontaneously or by intervention in less than 7 days)

    • Persistent (more than 7 days, often requiring direct-current cardioversion)

    • Long-standing persistent (continuous atrial fibrillation for 1 year or longer)

    • Permanent (accepted as long-term by the patient and physician, with no plans to pursue rhythm control)