Syncope is a medical term for a blackout or faint caused by a sudden drop in the supply of blood to the brain, leading to a short-term loss of consciousness. The Imperial College Healthcare syncope diagnostic unit is a high volume service investigating the causes of syncope events and providing care for sufferers of syncope. Additionally, we offer a unique nurse-led and patient-centred tilt table clinic service.

Conditions and treatments

We treat a range of conditions including:

  • blackouts
  • loss of consciousness
  • postural orthostatic tachycardia syndrome (POTS)
  • vasovagal syncope
  • reflex syncope
  • neurocardiogenic syncope
  • funny turns

We offer clinicians, patients and their families support by making clear diagnoses and recommending lifestyle changes to manage their condition.

Patients are normally referred to the service for a tilt test by their GP or another specialist. If symptoms persist patients may be referred directly to our syncope clinic for specialist advice and further investigation.

We also provide tilt tests for children, often with the support of a paediatric play specialist. We work with paediatric consultants to provide early diagnosis and appropriate management of paediatric patients with syncope and POTS.

Additional information

Contact information

For any enquiries about the syncope service or how to be referred, please email SYNCOPE.SMH@NHS.NET.

The Imperial College syncope diagnostic unit

This highly-regarded team is led by Dr Boon Lim, a dynamic cardiologist with an active research interest in developing novel strategies to treat arrhythmias and syncope. The focus of the unit is to provide compassionate, patient-centred care with a focus on communication to improve the understanding and wellbeing of patients with syncope. The unit, considered one of the best syncope units in London, is based at Hammersmith Hospital.

Research and clinical trials

Research is central to the ethos of our syncope service. We actively engage in research activity to understand mechanisms of syncope and to understand how to best treat it. Our medical staff work closely with the cardiovascular research department at Imperial College Healthcare NHS Trust, and our strategy is to reflect on our syncope service to enhance and improve it. Furthermore, we are also working nationally and internationally with syncope experts on research trials.

Further online resources

  • Stop Fainting - patient resources created by the Trust's syncope team as part of a study, supported by Imperial Health Charity
  • POTS UK (for patients with postural orthostatic tachycardia syndrome)
Hammersmith Hospital

Syncope nurse specialist Patricia is a thoroughly professional, committed, warm and friendly nurse who communicates very well with her patients and makes them comfortable. I felt I was in good and caring hands. I felt valued as an individual and very personally approached. Thank you again, Patricia, for your care.

Dr Mult Jan Carsten

My partner and I would like to thank you for your detailed assessment of my condition.  The consultation, test and immediate feedback on observations were expertly conducted with calm warmth, clarity and great understanding.  We are both so grateful for your time and expertise.


I visited the Imperial syncope diagnostic unit for a tilt table test. I wasn't nervous upon arriving as they sent me lots of information beforehand explaining what will happen. I feel very supported and cared for here at Hammersmith Hospital. They are an extremely dedicated and passionate team and I'm so glad to have found them.

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