Vasovagal Syncope unpredictable FAQ

I occasionally have vasovagal/neuro-cardiogenic syncope and am trying to decide if I should dive. The fainting happens once every year or two. It has happened on roller coasters at points with a lot of downward force (likely from decreased cerebral perfusion) and sometimes when I have hurt myself (such as when I smashed my hand in a boat lift). It has happened once from an unknown trigger when I was just standing around talking. I know the recommendation is to get checked out by a doctor, but I am a doctor, and I have spoken with other doctor friends, some of whom dive, and no one really knows the answer.
Recurrent vasovagal/neuro-cardiogenic syncope is a significant risk factor when diving. One of the main problems is that it seems that your vasovagal syncope are brought on by basic Valsalvamanoeuvres. These are very common in diving, as they are used to equalise pressure in the middle ear during descent to depths as shallow at 5-10 feet. Also, people often perform a Valsalva or “bear down” unintentionally when lifting heavy objects; this may be necessary when handling gear or when getting into and out of a dive boat, for example.
Vasovagal syncope may also occur in times of pain or stress (such as in the situation of smashing your hand). While scuba diving is typically a relaxing recreational sport, the underwater environment can be unpredictable. Were you to have a syncopal episode and pass out underwater, you would beat high risk of death by drowning. A rapid, unconscious ascent also brings the risk of pulmonary over-expansion and decompression illness. Attempts at rescue by a buddy would put both you and your diving partner at risk.
Should you experience complications from diving (such as an arterial gas embolism resulting in loss of consciousness), it may be difficult to differentiate the dive-related illness from syncope.This dilemma might either lead to (1) unnecessary recompression treatment or,conversely,(2) result in delays in receiving appropriate recompression if decompression illness orgas embolismwere to occur,i.e., because of medical bias to attribute any cardio-neurological symptoms you may develop to your underlying condition.
Given these considerations, scuba diving does not seem advisable for you. Additional evaluation, and possible cardiological interventions, may clarify or even alter the situation. Typically, an echocardiogram, stress EKG test and 24-hour HolterEKG would be performed.
— Mala Trivedi, M.D.