From the Guidelines
The approach to a patient with recurrent syncope should begin with a thorough history, physical examination, and 12-lead ECG, as these three components can identify the cause in up to 50% of cases. The history should focus on circumstances surrounding the episodes, prodromal symptoms, position during events, and post-event symptoms. Physical examination should include orthostatic vital signs and a detailed cardiovascular and neurological assessment. Initial testing should include laboratory studies (complete blood count, electrolytes, glucose, renal function), and an ECG to evaluate for arrhythmias or structural heart disease. For patients with suspected cardiac syncope, additional testing may include echocardiography, ambulatory cardiac monitoring (Holter for 24-48 hours or event monitors for 2-4 weeks), and exercise stress testing. If neurally mediated syncope is suspected, tilt-table testing may be useful. For unexplained recurrent syncope, an implantable loop recorder can provide long-term monitoring for up to 3 years.
Treatment Options
Treatment depends on the underlying cause:
- cardiac syncope may require antiarrhythmic medications (such as beta-blockers like metoprolol 25-100mg twice daily), pacemaker, or ICD implantation 1
- orthostatic hypotension may be managed with increased salt and fluid intake, compression stockings, and medications like midodrine (2.5-10mg three times daily) or fludrocortisone (0.1-0.2mg daily) 1
- vasovagal syncope often responds to trigger avoidance, increased fluid intake, and occasionally medications like metoprolol (25-100mg twice daily)
Medication Management
Midodrine is reasonable in patients with recurrent vasovagal syncope (VVS) with no history of hypertension, heart failure, or urinary retention 1. The dosage of midodrine can range from 2.5-10mg three times daily. Fludrocortisone might be reasonable for patients with recurrent VVS and inadequate response to salt and fluid intake, unless contraindicated 1. Beta blockers might be reasonable in patients 42 years of age or older with recurrent VVS 1.
Lifestyle Modifications
Encouraging increased salt and fluid intake may be reasonable in selected patients with VVS, unless contraindicated 1. Patients should be advised to ingest 2 to 3 L of fluid per day and a total of 6 to 9 g (100 to 150 mmol) of salt per day. Reducing or withdrawing medications that cause hypotension when appropriate may also be beneficial 1.
This systematic approach is essential because recurrent syncope can significantly impact quality of life and may indicate serious underlying conditions that require specific treatment.
From the Research
Approach to Patient with Recurrent Syncope
To approach a patient with recurrent syncope, the following steps can be taken:
- Take a thorough history to identify the underlying cause of syncope, including any prodromal symptoms, triggers, and associated medical conditions 2, 3
- Classify the syncope into one of the three major types: neurally mediated, orthostatic hypotensive, or cardiac 4
- Perform a physical examination to assess for signs of heart disease, orthostatic hypotension, or other underlying conditions 3
- Use diagnostic tests such as electrocardiogram (ECG), tilt-table testing, and electrophysiologic study to evaluate the patient's condition 3, 4
Diagnostic Evaluation
The diagnostic evaluation of a patient with recurrent syncope may include:
- ECG to examine for signs of structural heart disease, conduction system disease, or primary electrical disease 5
- Tilt-table testing to diagnose orthostatic and neurally mediated syncope 2
- Electrophysiologic study to evaluate patients with heart disease 4
- Prolonged rhythm monitoring to detect any arrhythmias that may be causing the syncope 4
Treatment Options
Treatment options for recurrent syncope depend on the underlying cause and may include:
- Non-pharmacological options such as increasing fluid and sodium intake, avoiding rapid changes in body position, and using postural counter-maneuvers 2, 3
- Pharmacological options such as mineralocorticoids, vasoconstrictor agents, and beta-blockers 2, 6
- Pacemaker implantation in patients with cardiac causes of syncope 2
- Referral to a cardiologist for further evaluation and management 3