Atrial Fibrillation: A Practical Guide for Junior Doctors

Introduction

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia encountered in emergency medicine. Understanding its presentation, diagnostic approach, and management is crucial for junior doctors. This blog post aims to provide a concise yet comprehensive guide on AF, focusing on history taking, examination findings, investigations, and management, drawing on key resources such as the Oxford Handbook of Emergency Medicine, WikEM, BMJ Best Practice, NICE guidelines, GPnotebook, and RCEM Learning.

History Taking

Effective history taking is the cornerstone of diagnosing atrial fibrillation. Here are the critical questions to ask:

Presenting Symptoms

1. Onset and Duration: "When did you first notice your symptoms?" AF can present as sudden (paroxysmal) or continuous (persistent).

2. Palpitations: "Do you feel your heart racing or fluttering?" Patients often describe a rapid, irregular heartbeat.

3. Chest Pain: "Do you have any chest pain?" Important to differentiate from ischemic heart disease.

4. Dyspnea: "Are you experiencing shortness of breath?" AF can lead to heart failure symptoms.

5. Syncope or Dizziness: "Have you felt faint or actually fainted?" Indicates potential hemodynamic instability.

Associated Symptoms

1. Fatigue and Weakness: "Have you been unusually tired or weak?" Common in AF.

2. Signs of Heart Failure: "Do you have swelling in your legs or abdomen?" Indicates worsening heart function.

3. Stroke Symptoms: "Have you had any sudden weakness or numbness?" Important to assess for cerebrovascular events.

Risk Factors and Medical History

1. Previous Episodes: "Have you had AF before?" Recurrence is common.

2. Cardiovascular Disease: "Do you have a history of hypertension, coronary artery disease, or heart failure?" Major risk factors.

3. Thyroid Disorders: "Have you had thyroid problems?" Hyperthyroidism can precipitate AF.

4. Lifestyle Factors: "Do you smoke, drink alcohol, or use caffeine excessively?" Modifiable risk factors.

5. Medications: "What medications are you currently taking?" Some drugs can influence heart rhythm.

Examination Findings

A focused physical examination is vital in patients with suspected AF. Key points include:

General Appearance

• Vital Signs: Check for tachycardia, irregular pulse, and blood pressure instability.

• Signs of Distress: Look for signs of discomfort or dyspnea.

Cardiovascular Examination

• Pulse: Palpate for an irregularly irregular pulse.

• Heart Sounds: Auscultate for an irregular rhythm and possible murmurs indicating valvular heart disease.

• Jugular Venous Pressure (JVP): Elevated JVP may suggest heart failure.

Respiratory Examination

• Breath Sounds: Assess for crackles or wheezes that might indicate pulmonary congestion.

Peripheral Examination

• Edema: Check for peripheral edema as a sign of heart failure.

• Capillary Refill Time: Prolonged refill time can indicate poor perfusion.

Investigations

Timely investigations help confirm the diagnosis and guide management.

Electrocardiogram (ECG)

• Key Findings: Look for absent P waves, irregularly irregular QRS complexes, and varying R-R intervals.

• Additional Features: Assess for signs of ischemia or other arrhythmias.

Blood Tests

• Full Blood Count (FBC): To rule out anemia or infection.

• Urea and Electrolytes (U&Es): To assess renal function and electrolyte imbalances.

• Thyroid Function Tests: To rule out hyperthyroidism.

• Cardiac Enzymes: If myocardial ischemia is suspected.

Imaging

• Chest X-ray: To assess for heart failure or other pulmonary conditions.

• Echocardiography: To evaluate cardiac structure and function, particularly if heart failure or valvular disease is suspected.

Management Plan

Management of AF involves rate or rhythm control, stroke prevention, and addressing underlying causes.

Acute Management

1. Hemodynamically Unstable Patients: Immediate electrical cardioversion is indicated.

2. Hemodynamically Stable Patients:

   • Rate Control: Use beta-blockers (e.g., metoprolol) or calcium channel blockers (e.g., diltiazem).

   • Rhythm Control: Consider pharmacological cardioversion with agents like flecainide or amiodarone, especially in younger patients or those with first-time AF.

Stroke Prevention

1. Anticoagulation: Assess stroke risk using the CHA2DS2-VASc score.

   • Low Risk: No anticoagulation or aspirin.

   • Moderate to High Risk: Anticoagulation with warfarin or a direct oral anticoagulant (DOAC) like apixaban or rivaroxaban.

Long-term Management

1. Rate vs. Rhythm Control: Decision depends on patient symptoms, comorbidities, and preferences.

2. Lifestyle Modification: Advise on smoking cessation, alcohol moderation, and weight management.

3. Follow-up: Regular monitoring and adjustment of treatment as necessary.

Conclusion

Atrial fibrillation is a complex condition requiring a thorough history, focused examination, and targeted investigations to guide appropriate management. By systematically approaching AF in this manner, junior doctors can ensure effective and comprehensive patient care. Keep this guide handy as a quick reference in your clinical practice.