PFO, what are the risks of diving?

Good morning, in order to check if the PFO is present, I undertook an echocardiogram that gave an ambiguous result.

I followed with other checks by undertaking another colour Doppler echocardiography which resulted in: “basic slight right-to-left microbubbles shunt (<5 microbubbles) that increases in the late stages (moderate level, 5-10 microbubbles). After Valsalva, the shunt is moderate. There is no-aneurysm of the interatrial septum, nor Chiari network. In conclusion: the presence of PFO with basal slight moderate degree shunt and moderate after Valsalva.

Doctors weren’t able to tell me if this characteristic is compatible with diving. I contacted the DAN doctors that told me to follow the recommendations for a Low Bubble diving profile, according to the Swiss Underwater and Hyperbaric Medical Society (SUHMS).

I would like to know how to go on with the investigations to know the potential and real risks. I have been performing recreational diving for 4 years.



One comment on “PFO, what are the risks of diving?

  1. Paolo Della Torre on

    Dear Elena,
    After detecting the PFO presence, many divers are not sure whether to go on with safe diving, due to the lacking or generic indication in this field.

    This is due to the fact that in the in the great majority of cases, the same exams and the procedures through which they are made, are meant to detect the simple defect.

    Without considering its haemodynamic significance and without excluding other potential concomitant right-to-left shunts, the pure PFO diagnosis is not sufficient and it can’t provide indications regarding the risks and limitations which that specific defect may cause in diving.

    In your case, the diagnosis was made by a colour Doppler echocardiography (transthoracic? Transoesophageal?) that showed the passage of 5 bubbles (slight passage) at rest and after moderate Valsalva (how many sessions?).

    I remind you that also the transoesophageal exam has the best specificity to verify the presence of the PFO, but it is less specific to define how it is hemodynamically significant.

    I understand that DAN recommended you to prudently adopt the recommendations of the Swiss Underwater and Hyperbaric Medical Society (SUHMS), by maintaining a Low Bubble diving profile (fewer bubbles are formed, fewer bubbles can pass through).

    Nevertheless, I think that in case of a suspected presence of right-to-left shunt (PFO is one of the potential shunts), to meet the need of diver’s risk, the indications must derive from an evaluation of the results through a series of specific tests and exams.

    This is the reason why at the Ravenna Hyperbaric Centre we propose a diagnostic pathway which lasts a whole day that includes:

    • Transcranial Doppler with contrast medium in a salt solution, at rest and after Valsalva
    • Arterial blood gas and Transcutaneous oximetry before and after the effort and oxygen breathing
    • Diving visit, after which recommendations and eventual limitations to diving can be defined

    This is what you should have done or you can do to have more specific indications.

    Best regards,

    Paolo Della Torre
    Degree in Medicine and Surgery at the Second University of Milan and specialized in Medicine of Swimming and Diving Activities at the University “G. D’Annunzio” of Chieti.
    Subscribed to the Medical Council of Rome, Number 42375


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