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Correspondence on 'Cardiovascular considerations for scuba divers' by Tso et al
  1. Peter Wilmshurst1,
  2. Mark Turner2,
  3. Philip Bryson3,
  4. Christopher Edge4,
  5. Margaret Clamp5,6,
  6. Mark Glover7
  1. 1 Cardiology Department, Royal Stoke University Hospital, Stoke on Trent, UK
  2. 2 Bristol Heart Institute, University Hospitals Bristol, Bristol, UK
  3. 3 Diving Services, International SOS, Aberdeen, UK
  4. 4 Anaethetic Department, Royal Berkshire NHS Foundation Trust, Reading, UK
  5. 5 Occupational Health, MC Occupational Health, Nottingham, UK
  6. 6 Medical Advisor, British Sub-Aqua Club and Sub-Aqua Association, Ellesmere Port, UK
  7. 7 Hyperbaric Medicine Unit, St Richard's Hospital, Chichester, UK
  1. Correspondence to Dr Peter Wilmshurst, Cardiology, Royal Stoke University Hospital, Stoke on Trent, UK; peter.wilmshurst{at}

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Correspondence on'Cardiovascular considerations for scuba divers' by Tso et al

We are writing on behalf of the UK Diving Medical Committee, which sets medical standards for amateur scuba diving in the UK. We are concerned that there are several errors in the article by Tso et al.1 Some examples of our concerns are detailed further.

When considering the effects of immersion, the authors state ‘Haemodynamic alterations while diving are driven by cold water exposure and external hydrostatic compression, which increases proportionally with water depth’. It is correct that absolute pressure increases linearly with depth and that as a person enters the water, the hydrostatic effects of increased ambient pressure cause an increase in venous return, but once fully immersed, the effect of water pressure on venous return is affected only by orientation of the diver in the water. Whether the diver is at a depth of 1 m of seawater (msw) equal to 1.1 bar absolute or 100 msw equal to 11 bar, a part of the body that is 1 m below the level of the heart has a pressure difference …

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  • Contributors All authors agreed on the letter.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Provenance and peer review Commissioned; internally peer reviewed.

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