What is the initial cardiac workup for a patient presenting with dizziness?

Cardiac Workup for Dizziness

The initial cardiac workup for a patient presenting with dizziness should include a 12-lead ECG, orthostatic blood pressure measurements, and assessment for cardiac arrhythmias through appropriate monitoring. 1, 2

Initial Evaluation

History and Physical Examination Components

• Timing and triggers of dizziness episodes
• Associated symptoms (especially syncope, near-syncope, palpitations)
• Orthostatic blood pressure measurements
• Complete cardiac examination focusing on:
  • Heart rate and rhythm
  • Murmurs suggesting valvular disease
  • Signs of heart failure
  • Carotid bruits

Essential Cardiac Testing

1. 12-lead ECG - Class I recommendation for all patients presenting with dizziness 1, 2

   • Should be performed within 10 minutes of arrival at healthcare facility
   • Look for:
     • Arrhythmias (especially bradyarrhythmias, tachyarrhythmias)
     • Conduction abnormalities (AV blocks, bundle branch blocks)
     • QT interval abnormalities
     • Evidence of ischemia or prior infarction

2. Rhythm monitoring based on frequency of symptoms 1:

   • For frequent symptoms: 24-hour Holter monitor
   • For infrequent symptoms: External loop recorder (14-30 days)
   • For very infrequent symptoms: Implantable cardiac monitor may be considered

Additional Cardiac Testing Based on Initial Findings

If initial evaluation suggests cardiac etiology:

1. Echocardiography - Indicated when:

   • Abnormal cardiac examination
   • ECG abnormalities
   • History suggesting structural heart disease
   • Symptoms occurring with exertion 1

2. Exercise stress testing - Consider when:

   • Dizziness is associated with exertion
   • Suspected ischemic heart disease 1

3. Tilt-table testing - Useful when:

   • Suspected vasovagal syncope
   • Suspected orthostatic hypotension not detected with standard orthostatic measurements 1

Specific Scenarios

For dizziness with suspected arrhythmia:

• If bradycardia or conduction abnormalities are detected, continuous ECG monitoring is indicated 1
• For patients with palpitations and dizziness, extended monitoring with external or implantable recorders should be considered 1

For dizziness with orthostatic changes:

• Document orthostatic blood pressure and heart rate changes
• Consider medication review for agents that may cause orthostasis
• Evaluate for volume depletion 1

Common Pitfalls to Avoid

1. Relying solely on a single normal ECG to rule out cardiac causes
2. Failing to obtain appropriate rhythm monitoring when arrhythmia is suspected
3. Not performing orthostatic vital signs in all patients with dizziness
4. Missing medication-induced causes of dizziness (antihypertensives, antiarrhythmics)
5. Overlooking the need for serial ECGs when symptoms are dynamic or recurrent

Decision Algorithm

1. Obtain 12-lead ECG for all patients with dizziness
2. Perform orthostatic blood pressure measurements
3. If normal ECG and no orthostatic changes:
   • If episodic symptoms: Proceed to rhythm monitoring based on frequency
   • If continuous symptoms: Consider echocardiography
4. If abnormal ECG or positive orthostatic changes:
   • Treat identified abnormalities
   • Consider more advanced cardiac testing (echocardiography, stress testing)
5. If exertional symptoms: Perform exercise stress testing
6. If vasovagal symptoms: Consider tilt-table testing

The cardiac workup should be tailored based on the clinical presentation, with the understanding that dizziness can be the presenting symptom of potentially serious cardiac conditions including arrhythmias and structural heart disease.