When is an electrocardiogram (EKG) recommended for patients presenting with dizziness?

EKG for Dizziness

An electrocardiogram (EKG) is a Class I recommendation (first choice) for all patients presenting with dizziness, as it may identify life-threatening cardiac arrhythmias, conduction disorders, or structural heart disease that could predict sudden death or myocardial infarction. 1

When to Obtain an EKG

Universal Recommendation

• Obtain a 12-lead EKG in all patients presenting with dizziness, regardless of whether cardiac disease is suspected 1
• The ACC/AHA explicitly classifies dizziness as a Class I indication, meaning electrocardiography is the first choice for these patients 1
• Even when dizziness appears to have a non-cardiac cause, the EKG may reveal asymptomatic but life-threatening conditions such as silent myocardial infarction, long QT syndrome, or severe conduction abnormalities 1

Rationale for Universal EKG Use

• The EKG is the only practical, noninvasive method for detecting cardiac arrhythmias that may cause dizziness 1
• Electrocardiographic abnormalities may be the first indicators of life-threatening drug effects, severe metabolic disturbances, or electrolyte abnormalities 1
• An abnormal initial EKG predicts adverse outcomes and increased all-cause mortality at 1 year in patients presenting with dizziness or near-syncope 1
• The low cost of EKG justifies its use even when serious abnormalities are rare, as it can reveal potentially life-threatening but treatable disorders 1

High-Risk Features Requiring Urgent Evaluation

Patient Characteristics Demanding Immediate EKG

• Patients with known heart disease, previously documented arrhythmia, or pacemaker dependency presenting with dizziness require immediate EKG 1
• Dizziness associated with exertion when the cause is not established by other methods 1
• Patients with hypertrophic or dilated cardiomyopathies 1
• Suspected or documented long QT syndromes 1
• Prior surgery for congenital heart disease with significant residual hemodynamic abnormalities 1

Critical EKG Findings to Identify

• Conduction abnormalities (atrioventricular block, bundle branch blocks) that may progress to complete heart block 1, 2
• QT prolongation suggesting risk for torsades de pointes and sudden cardiac death 1
• Signs of structural heart disease (left ventricular hypertrophy, Q waves suggesting prior infarction) 1
• Bradycardia (typically <50 beats per minute when symptomatic) 2
• Evidence of acute ischemia or infarction 1

When EKG Alone Is Insufficient

Indications for Cardiac Rhythm Monitoring

• If the initial EKG is normal but cardiac cause is still suspected, cardiac rhythm monitoring is essential to establish correlation between symptoms and rhythm abnormalities 1, 2
• The specific type of monitor should be chosen based on symptom frequency: 1, 2
  • Holter monitor (24-48 hours): Only if dizziness occurs almost daily or if EKG shows conduction abnormalities requiring assessment for asymptomatic severe AV block 1
  • External event recorder: For symptoms occurring every few days to 1-2 weeks 1
  • Implantable cardiac event recorder: For infrequent episodes (<1 every 2 weeks) with suspected cardiac cause 1

Additional Cardiovascular Assessment

• Exercise electrocardiographic testing is reasonable in patients with exercise-related dizziness or suspected chronotropic incompetence 1
• Echocardiography should be performed if structural heart disease is suspected based on history, physical examination, or EKG findings 1
• Orthostatic vital signs should be obtained to assess for orthostatic hypotension 1
• Carotid sinus massage may be appropriate for unexplained dizziness in patients >60 years old 1

When EKG Is NOT Indicated (Class III)

• Dizziness when a definitive non-cardiac cause has been established (e.g., vestibular neuritis, benign paroxysmal positional vertigo confirmed by Dix-Hallpike maneuver) 1

Common Pitfalls to Avoid

• Do not rely on computer-interpreted EKGs alone—a physician qualified to interpret EKGs must review all tracings, as automated interpretation may miss critical abnormalities or generate false positives 1
• Do not assume a single normal EKG excludes cardiac causes—high-risk abnormalities such as QT prolongation and conduction abnormalities may be intermittent, and serial EKGs may be more sensitive 1
• Do not order brief Holter monitoring (24-48 hours) for infrequent symptoms—this has very low yield unless episodes occur almost daily 1
• Do not skip the EKG even in young, healthy patients—rare but life-threatening conditions like long QT syndrome, Brugada syndrome, or hypertrophic cardiomyopathy may present with dizziness as the only symptom 1

Diagnostic Yield Considerations

• The initial EKG provides a specific diagnosis in only approximately 5% of patients with dizziness or syncope 1
• However, approximately 10% of dizziness/syncope can be attributed to bradycardia or conduction disorders, and an additional 18% to neurally mediated syncope (often with bradycardia) 1
• The prognostic value of an abnormal EKG outweighs its modest diagnostic yield, as it identifies patients at increased risk for adverse outcomes who require urgent specialist evaluation 1