Is it appropriate to refer a patient with dizziness to cardiology when cardiac risk factors or red‑flag cardiac symptoms are present?

Cardiology Referral for Dizziness: When and Why

Yes, cardiology referral is absolutely appropriate for dizziness when cardiac risk factors or concerning features are present, and an ECG should be obtained in all patients with dizziness as a Class I first-line test. 1, 2

Initial ECG is Mandatory

• Obtain a 12-lead ECG immediately in every patient presenting with dizziness, regardless of suspected etiology. 2
• The ACC/AHA explicitly designates dizziness as a Class I indication for electrocardiography, meaning it is the first-choice diagnostic test. 1, 2
• The ECG may reveal life-threatening conditions even when cardiac disease is not initially suspected, including silent myocardial infarction, long QT syndrome, or severe conduction abnormalities. 2
• An abnormal initial ECG predicts adverse outcomes and increased all-cause mortality at 1 year in patients with dizziness. 2

Immediate Cardiology Referral Criteria

Refer urgently to cardiology if any of the following are present:

Critical ECG Findings

• Second-degree Mobitz type II, high-grade, or third-degree atrioventricular block 1
• PR interval >240 ms, QRS duration >120 ms, or any degree of atrioventricular block 1
• QT prolongation suggesting risk for torsades de pointes 2
• Signs of structural heart disease (left ventricular hypertrophy, Q waves) 2
• Any conduction abnormality that may progress to complete heart block 2

High-Risk Clinical Features

• Syncope accompanying dizziness (strongly predicts cardiovascular etiology, P < .001) 3
• Dizziness described as "lightheadedness" with need to sit or lie down (P < .001) 3
• Pallor during symptoms (P < .001) 3
• Symptoms precipitated by prolonged standing (P < .05) 3
• Pre-existing cardiovascular disease (P < .05) 3
• Dizziness occurring during exercise 1, 2
• Known heart disease, documented arrhythmia, or pacemaker dependency 2

Understanding Cardiovascular Dizziness

A critical pitfall: cardiovascular dizziness frequently presents as vertigo (spinning sensation), not just presyncope. 4

• In patients with confirmed cardiovascular causes of dizziness, 63% (95% CI 57-69%) experienced vertigo, and it was the only symptom type in 37% (95% CI 31-43%). 4
• Cardiovascular diagnoses account for 28% of dizziness cases in older patients. 3
• Do not dismiss cardiac evaluation simply because the patient describes true vertigo rather than lightheadedness. 4

Additional Cardiac Evaluation Before or With Referral

• Obtain orthostatic vital signs to assess for orthostatic hypotension. 2
• Perform echocardiography if structural heart disease is suspected based on history, physical examination, or ECG findings. 2
• Consider exercise ECG testing for patients with exercise-related dizziness or suspected chronotropic incompetence. 2
• Carotid sinus massage may be appropriate for unexplained dizziness in patients >60 years old. 2

Special Populations Requiring Cardiology Evaluation

Patients with neuromuscular diseases (myotonic dystrophy, Kearns-Sayre syndrome) presenting with dizziness, palpitations, or syncope require:

• Annual cardiology evaluation with ECG and ambulatory monitoring 1
• Consideration for invasive electrophysiology study if conduction abnormalities are present 1
• Echocardiogram every 2-4 years even if asymptomatic 1

When Cardiology Referral May Not Be Needed

Do not refer to cardiology if:

• ECG is completely normal 2
• No cardiac risk factors or symptoms are present 3
• Clear peripheral vestibular diagnosis (e.g., benign paroxysmal positional vertigo confirmed by Dix-Hallpike maneuver) 5
• Description of vertigo with unilateral hearing loss suggests Meniere disease 5

However, maintain a low threshold for obtaining the initial ECG even in these cases, as the test is low-cost and may reveal asymptomatic but critical findings. 2

Prognostic Importance

• The prognostic value of identifying cardiac causes outweighs the modest diagnostic yield of ECG (approximately 5% specific diagnosis rate). 2
• At least 10% of dizziness/syncope is attributable to bradycardia or conduction disorders, with an additional 18% due to neurally mediated syncope. 2
• Cardiovascular disease causing dizziness carries significant mortality risk if untreated. 3