Atrial Fibrillation/Flutter

Atrial fibrillation (AF) and atrial flutter (AFl) are two common types of supraventricular tachycardia characterized by rapid and irregular heartbeats. Here’s a detailed overview of their diagnosis, differential diagnosis, and management:

Diagnosis

Atrial Fibrillation

  • Clinical Presentation: Palpitations, fatigue, dyspnea, chest pain, dizziness, or it may be asymptomatic.
  • Electrocardiogram (ECG): Characterized by irregular R-R intervals and absence of distinct P waves.
  • Holter Monitor: For intermittent AF, a 24-hour (or longer) ECG may capture episodes.
  • Echocardiography: To assess structural heart disease, ventricular function, and atrial size.
  • Laboratory Tests: TFT, FBC, UEC to rule out thyroid disease, anemia, and electrolyte imbalances.

Atrial Flutter

  • Clinical Presentation: Similar to AF, but often with more regular palpitations.
  • ECG: Shows characteristic “sawtooth” flutter waves, especially in leads II, III, and aVF.
  • Echocardiography: To assess the heart structure and function.
  • Electrophysiology Study (EPS): Sometimes used for definitive diagnosis and therapeutic ablation.
  • Laboratory Tests: TFTs, FBC, UEC to rule out thyroid disease, anemia, and electrolyte imbalances.

Differential Diagnosis

  • Adenosine: This can be used to block AV nodal conduction which can make defining the underlying problem easier, and in some cases convert the patient back to sinus rhythm
  • Sinus Tachycardia with Sinus Arrhythmia: Regular rhythm with normal P wave preceding each QRS complex.
  • Multifocal Atrial Tachycardia (MAT): Irregular rhythm but with multiple distinct P wave morphologies.
  • Other Supraventricular Tachycardias: Such as AV nodal reentrant tachycardia (AVNRT) or AV reentrant tachycardia (AVRT).
  • Ventricular Tachycardia: Differentiated by QRS complex width and morphology.

Management

Atrial Fibrillation

  • Rate Control
    • Acute
      • Metoprolol 2.5-5mg IV, repeat every 5 minutes up to 3 doses
      • Digoxin and Amiodarone as additional
    • Chronic
      • Atenolol 25-100mg oral OD
      • Metoprolol 25-100mg oral BD
      • Diltiazem MR 180-360 oral OD if BB contraindicated
  • Rhythm Control:
    • Electrical cardioversion in selected patients.
      • If AF < 48 hours can be done emergently
      • If AF > 48 hours we need 3/52 of anticoagulation
    • Pharmacological cardioversion
      • Flecanide or Amiodarone IV
    • Chronic
      • Sotalol 40-160mg oral BD
      • Flecanide or Amiodarone oral
  • Stroke Prevention:
    • Anticoagulation based on risk assessment using CHA2DS2-VASc score.
    • Options include
      • warfarin
      • direct oral anticoagulants (DOACs) like rivaroxaban, apixaban, or dabigatran.
        • Apixaban 5mg oral BD
  • Lifestyle Modification: Addressing underlying causes such as
    • hypertension
    • obesity, and
    • alcohol use.

Atrial Flutter

  • Rate Control: Similar to AF with beta-blockers or calcium channel blockers.
  • Rhythm Control:
    • Catheter ablation is more effective in AFl compared to AF.
    • DC Cardioversion can also be used, and is often used earlier
  • Stroke Prevention: Similar to AF, based on risk assessment.
  • Considerations for Ablation: Catheter ablation is often considered as a first-line treatment for AFl due to its high success rate.

General Considerations

  • Lifestyle and Risk Factor Management
    • Control of Comorbidities: Hypertension, diabetes, and heart failure.
    • Lifestyle Changes: Weight management, smoking cessation, and limiting alcohol intake.
  • Long-Term Monitoring
    • Stroke Risk: Regular reassessment of the need for anticoagulation.
    • Heart Failure: Monitor for signs of deterioration.
    • Recurrence of Arrhythmia: Especially in those with intermittent episodes.