Treatment of Vasovagal Syncope
Patient education and reassurance about the benign prognosis is mandatory for all patients, followed by physical counterpressure maneuvers and increased salt/fluid intake, with midodrine as the only evidence-based first-line pharmacological option if non-pharmacological measures fail. 1, 2
When Treatment Is Actually Needed
- Treatment is NOT necessary for patients with a single syncope episode who are not in high-risk settings 3, 1, 2
- Treatment becomes essential when:
First-Line: Patient Education (Class I - Mandatory)
All patients must receive education explaining that vasovagal syncope is not life-threatening and has excellent prognosis. 3, 1, 2 This includes:
- Recognition of prodromal symptoms (lightheadedness, nausea, warmth, visual changes) to enable preventive actions 1, 2
- Trigger avoidance: hot crowded environments, prolonged standing, emotional upset, venipuncture when possible, volume depletion 3, 1, 2
- Discontinuation or modification of any hypotensive medications 3, 1
Second-Line: Physical Counterpressure Maneuvers (Class IIa)
These maneuvers should be taught to all patients with adequate prodromal warning (typically patients under 60 years). 3, 1, 2 They induce significant blood pressure increases that can abort or delay loss of consciousness:
- Leg crossing with muscle tensing 3, 1, 2
- Squatting 3, 1
- Isometric arm contraction or handgrip 3, 1, 2
- These are particularly effective in younger patients with sufficiently long prodromes 2
Third-Line: Volume Expansion Strategies (Class II)
Increased dietary salt and fluid intake (2-2.5 liters per day) is the safest initial approach unless contraindicated by hypertension, heart failure, or renal disease. 3, 1, 2 Additional options include:
- Salt tablets or sport drinks as volume expanders 1
- Head-up tilt sleeping (>10°) for posture-related syncope 3, 1
- Compression garments or abdominal binders to reduce venous pooling 3, 1
- Moderate exercise training, especially swimming 3, 1
- Tilt-training (progressively prolonged upright posture) in highly motivated patients 3, 1
Common pitfall: Avoid inducing supine/nocturnal hypertension with aggressive volume expansion 3, 1
Fourth-Line: Pharmacological Treatment
Midodrine (Class IIa - First-Line Drug)
Midodrine is the ONLY pharmacologic agent with consistent evidence of efficacy and should be the first-line drug for recurrent vasovagal syncope. 2, 4, 5
- Reduces syncope recurrence by 43% in meta-analysis of 5 randomized controlled trials 2
- Contraindicated in patients with hypertension, heart failure, or urinary retention 2
- Typical dosing: start low and titrate based on response 3, 1
Fludrocortisone (Class IIb - Second-Line Drug)
Consider fludrocortisone (0.1-0.2 mg daily) only in patients who don't respond to non-pharmacological measures and midodrine. 3, 1, 2
- Particularly useful in young patients with orthostatic form and low-normal blood pressure 2
- Monitor for supine hypertension 3, 1
Beta-Blockers (Class III - NOT Recommended)
Beta-blockers are NOT indicated for vasovagal syncope and should NOT be used as first-line therapy. 3, 1, 2
- Evidence fails to support efficacy 3, 1, 2
- May aggravate bradycardia in cardioinhibitory cases 3, 2
- Multiple studies show contradictory results 5
Fifth-Line: Cardiac Pacing (Class IIb - Highly Selective)
Dual-chamber pacing might be reasonable ONLY in highly selected patients meeting ALL of the following criteria: 3, 2
- Age >40 years 3, 2
- Documented cardioinhibitory response (prolonged asystole) 3, 2
- Frequency >5 attacks per year with severe physical injury 3
- All other therapies have failed 2
Important caveat: Pacing studies show mixed results - syncope recurred in 21% of paced patients vs 44% of non-paced patients, but all studies have significant weaknesses 3
Assessment Before Treatment
It is valuable to assess the relative contribution of cardioinhibition versus vasodepression before embarking on specific treatment, as therapeutic strategies differ. 3 This can be done via: