What is the initial workup for a patient presenting with palpitations?

Initial Workup for Palpitations

The initial workup for a patient presenting with palpitations should include a 12-lead ECG, basic laboratory tests (complete blood count, electrolytes, thyroid function), and 24-48 hour ambulatory ECG monitoring to identify the likely cause. 1

Detailed History and Physical Examination

When evaluating palpitations, focus on these specific elements:

• Characteristics of palpitations:

  • Timing and frequency of episodes
  • Duration of episodes
  • Position when palpitations occur (lying, standing)
  • Activity during episodes (rest, exercise)
  • Precipitating factors (caffeine, alcohol, stress)
  • Associated symptoms (syncope, near-syncope, dyspnea, chest pain)

• Physical examination findings to assess:

  • Signs of structural heart disease
  • Irregular cannon A waves or irregular S1 intensity
  • Thyroid abnormalities
  • Vital signs including orthostatic measurements

Diagnostic Testing Algorithm

Step 1: Initial Testing (For All Patients)

• 12-lead ECG (Class I, Level B-NR) - Essential even if the patient is not currently experiencing symptoms 1, 2
• Laboratory tests (Class I)
  • Complete blood count
  • Electrolytes (particularly potassium, magnesium)
  • Thyroid function tests
  • Consider additional tests based on clinical suspicion (e.g., cardiac enzymes if chest pain present)

Step 2: Risk Stratification

• High-risk features requiring urgent evaluation:
  • Syncope or near-syncope with palpitations
  • Family history of sudden cardiac death
  • Known structural heart disease
  • Palpitations associated with chest pain or severe dyspnea
  • ECG showing pre-excitation, prolonged QT, or other concerning abnormalities

Step 3: Ambulatory Monitoring (Based on Symptom Frequency)

• Frequent symptoms (daily or almost daily):

  • 24-48 hour Holter monitoring (Class I, Level B-NR) 1, 2

• Less frequent but recurrent symptoms (weekly):

  • 7-14 day external loop recorder or event recorder

• Infrequent symptoms (less than twice monthly):

  • 30-day event recorder or mobile cardiac telemetry
  • Consider implantable loop recorder for very infrequent but concerning symptoms

Step 4: Additional Testing (Based on Initial Results)

• Echocardiography (Class I) - Recommended to exclude structural heart disease, particularly in patients with sustained arrhythmias 1

• Exercise stress testing - For patients with exertional palpitations 1

• Extended monitoring (>24 hours) - For patients with palpitations and lightheadedness (Class I, Level B-NR) 1

Common Pitfalls to Avoid

1. Attributing all symptoms to anxiety without adequate cardiac evaluation - Even with normal initial testing, continue to monitor for cardiac causes if symptoms persist 1

2. Relying solely on short-term monitoring - Many arrhythmias are paroxysmal and may not be captured during brief monitoring periods 1, 3

3. Overlooking medication side effects - Many medications can cause palpitations, including bronchodilators, decongestants, and certain antidepressants 1

4. Dismissing patient symptoms despite normal testing - Correlation of reported symptoms with cardiac rhythm is essential; consider longer monitoring periods if initial tests are negative 1

When to Refer to Cardiology

Immediate cardiology referral is indicated for:

• Wide complex tachycardia of unknown origin
• Narrow complex tachycardias with drug resistance or intolerance
• Wolff-Parkinson-White syndrome
• Severe symptoms during palpitations
• Irregular palpitations suggesting atrial fibrillation in high-risk patients 1

By following this systematic approach, the underlying cause of palpitations can be identified in most patients, allowing for appropriate management and treatment.