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. 

Syncope Checklist

– 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:

1. Conservative Measures:

a) Lifestyle Modifications: Certain lifestyle adjustments can help manage vasovagal syncope. These include avoiding triggers, such as standing for long periods, hot environments, or situations that induce emotional stress.

b) Adequate Hydration: Staying hydrated by drinking enough fluids is essential to maintain blood volume and reduce the risk of fainting. If your blood pressure is low or low normal (i.e. less than 120/80) , it may also be helpful for you to have additional salt in your diet. Typically we would advise that you have 2 teaspoonfuls of salt daily, ideally front-loaded which means taking a teaspoon at breakfast and a further teaspoon at lunchtime. 

c) Physical Manoeuvres: Isometric counterpressure techniques like leg crossing, tensing leg and abdominal muscles and improve your BP whilst standing. If your symptoms continue to worsen, then change your posture by sitting, crouching or squatting down, and if needed lay down with your feet elevated. 

d) Consider wearing compression garments, which should be compressive (ideally grade 2 graded compression – achieving 23-31mm Hg) from the ankles/toes to the waist, and also consider abdominal binders.

2. Drug Therapy:

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.

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