Vasovagal syncope
10 June 23 | Dr Boon Lim and Patricia Taraborrelli
What is vasovagal syncope?
Vasovagal syncope is a common form of fainting that occurs due to a sudden drop in blood pressure and heart rate. It can be a distressing experience, but with proper understanding, diagnosis, and management, individuals can find ways to cope with this condition effectively. This article aims to provide a comprehensive overview of vasovagal syncope, covering its definition, diagnosis, management options, and the overall outlook for patients.
Vasovagal syncope, also known as neurocardiogenic syncope, is a temporary loss of consciousness caused by a reflex response within the autonomic nervous system. It typically occurs due to a sudden drop in blood pressure and heart rate. Vasovagal syncope is often triggered by emotional stress, pain, fear, prolonged standing, or other specific factors that activate the body’s vagus nerve and lead to a cascade of physiological responses resulting in fainting.
How is vasovagal syncope diagnosed?
Diagnosing vasovagal syncope typically involves an evaluation by a healthcare professional. The diagnosis process usually includes-
– Detailed Medical History: The doctor will inquire about your fainting episodes, triggers, associated symptoms, and medical history to rule out other potential causes. It is usually helpful to have a checklist of symptoms which you can present to your doctor. A helpful checklist can be found here.
– Physical Examination: A physical examination will be conducted to assess blood pressure, heart rate, and to look for murmurs. A lying a standing blood pressure measurement can be helpful, and you may be able to perform this yourself with a blood pressure upper arm cuff monitor. Click on this link to learn how to record a lying and standing blood pressure.
How to perform an active stand test
You can download either an excel spreadsheet, or a printable PDF document, to fill in these active stand data to show your doctor.
Active Stand Template (LINK TO THE EXCEL DOCUMENT)
Active Stand Template PDF (LINK TO PDF DOCUMENT)
– Diagnostic Tests: Additional tests may be recommended, such as an electrocardiogram (ECG) to evaluate heart activity, echocardiogram to assess heart structure and function, tilt table test to induce fainting in a controlled setting, or other specific tests depending on the history you present to your doctor.
Management of Vasovagal Syncope: 1. Conservative Measures:
The StopFainting team have prepared a downloadable PDF sheet on lifestyle management for vasovagal syncope. Key points are summarised below:
1. Conservative Measures
· Increase fluid intake aiming for 2.5-3L per day of non caffeinated drinks. These should ideally be front loaded in morning and lunchtime, for example to take 500mls by bedside and further 500mls by breakfast, a further 1L by lunchtime, and the rest by evening. Aim for urine to be a pale-yellow colour and to have more fluids in warm weather. A top tip when feeling unwell is to have a large glass of cold water quickly (bolus) which can help elevated blood pressure and lower heart rate.
· If blood pressure is typically low or low normal (<120/80), associated with dizziness, consider increasing salt intake (6-10g a day in divided doses, approximately 1-2 teaspoons) and having salty snacks.
· Consider trial of isotonic electrolyte tablets or drinks . These may be taken first thing in then morning, or 10-15 minutes before engaging in any activity known to trigger symptoms. Do check the labels and look for higher salt levels (typically 0.5 – 0.8g per serving) but not high sugar products (i.e. not Lucozade energy). Some examples include NUUN, ORS, SIS, LMNT, Vitassium or Precision 1500.
· If feeling dizzy, perform isometric counterpressure exercises, such as buttock, quadriceps, calf squeezing, and squeezing your abdominal muscles, ideally held throughout a change in posture from sitting to standing for approximately 10 -15 seconds.
· Waist high grade II compression stockings – to be worn during daytime. To also consider abdominal compression (for example abdominal binders or high-waisted compression shorts).
· If there are frequent episodes of loss of consciousness, to take early evasive action such as sitting, squatting, or lying down during periods of dizziness to avoid injury
· Maintain good sleep hygiene. Keep regular bedtime routines, and reduce stimulation, particularly with blue light (i.e. no phones, Ipads, TV) 2 hours before bedtime.
· If large meals provoke symptoms consider eating smaller portions and more frequently.
· Avoiding triggers, including dehydration, alcohol, caffeine, over-exertion, prolonged standing and warm environments. If syncope is induced by specific triggers, such as passing urine, then be mindful (consider sitting down to pass urine for me) and if triggered by medical procedures (blood taking), inform your health care professional and lie down for several minutes during and after having blood taken.
· If warm showers of baths are difficult to tolerate, to consider ending a shower/bath with cold water, or pulsing between hot and cold water (2min warm, 30sec cold) whilst showering, to promote skin vasoconstriction and avoiding pre-syncopal symptoms at the end of shower. When having baths, try to shower down with cool water before getting out of the bath, and get up very slowly to avoid dizziness and fainting when standing rapidly.
· Consider sleeping with head of bed tilted upright by 10-15 degrees (for example with a wooden block/brick underneath the foot of the bedhead) – this will gradually improve orthostatic intolerance and expand blood volume over a medium to long-term period.
Rarely, your doctor will need to consider drug treatment to help with vasovagal syncope. The 2 most common drugs used in vasovagal syncope include:
a) Midodrine, a drug to squeeze your blood vessels to increase the blood flow back into your heart and improve your blood pressure.
b) Fludrocortisone: In some cases, a mineralocorticoid medication called fludrocortisone may be recommended to increase blood volume and decrease the likelihood of fainting.
Outlook for Patients
The outlook for individuals with vasovagal syncope is generally positive. Most cases are benign and do not lead to serious complications. By adopting lifestyle modifications, identifying triggers, and adhering to prescribed treatment plans, many individuals can effectively manage their symptoms and prevent or reduce the frequency of fainting episodes. It is important to work closely with healthcare professionals to develop an individualized management strategy that suits your specific needs.
