UP TO 124,000 PEOPLE A YEAR in the UK have a heart attack. Of these, 11% of males and 15% of females will die within six days, according to the British Heart Foundation. And as the population gets older, it seems reasonable to assume that heart disease will continue to be a major health risk.
In last year’s British Sub Aqua Club Incidents Report, 17 fatalities were recorded, of which two were definitely attributed to a heart attack and another possible.
BSAC also noted that the average age of a fatality was 50.5 years, compared to the average age of the diving population, which is 38. There is also a suspicion that a large number of “unexplained” diving deaths may have a cardiac element to them.
All very interesting, but what does this mean to the average diver Simply put, as a group we are getting older, less fit and more at risk of a diving incident related to our lack of fitness.

DIVING, CONTRARY TO POPULAR INTERPRETATION, can involve serious, sudden-onset exercise. The swim against a current, climbing back into the boat fully kitted up, the hauling-up of the anchor… you get the picture.
As such, it is important to keep our hearts fit and prepared for this exercise. Prevention, after all, is better than cure. DIVER has regularly run articles encouraging divers to become “dive fit”, and everyone should look at lifestyle choices such as smoking.
What if a diver does have a heart attack or get angina – is it an automatic bar to diving
The answer is not easy, but I will try to explain the medical standpoint on this.
Firstly, a heart attack in water or out at sea has a much greater chance of being fatal than one on dry land. Imagine an episode of central crushing chest pain as you are swimming against a current on your favourite wreck 30m down – it really isn’t the best place to have this experience.
It follows that if you develop a heart condition, it needs to be assessed fully and completely, and if anything you need to be “safer” than the average heart patient. This is not only to protect you but also your buddy.
There is also the psychological trauma that would occur to the rest of a dive group in the event of a fatal incident.
On the bright side, modern medicine is now extremely good at preventing significant heart damage if someone has a heart attack, and preventing an attack in the event of angina.
Clot-busting drugs, angiograms (dye placed into the coronary arteries to see the blockages) and angioplasties (opening up of the blockages, usually through the insertion of stents) have all contributed to the “rescuing of the heart”.
It is now quite rare to see someone having their chest opened up for bypass surgery.

SO HOW DO WE ASSESS the person who either has had a heart attack or has had a diagnosis of ischaemic heart disease (with or without angina) I would require the following:

  • The first screening test must be that the diver is back to full activities, with no hint of chest pain on significant exertion. If there are any residual symptoms, I would regard diving as too risky, and would not take the assessment further.
  • A good history, to find out what happened, what investigations were performed (and the findings) and what treatment was given.
  • Particularly important is any finding of blockages of the coronary arteries (the vessels that supply the heart with its blood supply). While some of the major blockages may have been stented (opened up and a device called a stent put in to keep it from closing up again) some others may have been left. These blockages may be regarded as not significant for land-based activities, but may be regarded as a problem for diving.
  • Confirmation, usually by an echocardiogram (ECG, an ultrasound scan), that the heart is contracting normally, that there are no heart-valve problems and no significant heart-muscle damage.
  • An exercise ECG is a controlled exercise on a treadmill in a hospital while the person is attached to an ECG machine to measure the heart’s electrical activity. Exercise intensity is increased until the person can’t complete any more (breathless, tired etc) or there is evidence of problems such as heart-rhythm, or changes on the ECG suggesting angina). A diver would be expected to achieve at least Level 3 (9min) of the Bruce protocol easily without undue distress or changes on the ECG. It’s a decent amount of exercise, but at a level that could easily be needed under water.
    The other area that needs to be taken into account is the often considerable amount of medication that a person can be using:
  • Aspirin and clopidogrel – often taken together for the first year to stop the stent from clotting and closing up – can cause stomach and bleeding problems, and may represent concerns of increased bleeding in nervous tissue should an episode of DCI occur.
  • Statins for cholesterol and clot-stabilisation are not usually a problem, but in a few individuals can cause severe muscle aching.
  • ACE inhibitors such as ramipril are also not usually a problem, but blood pressure and kidney function need to be watched.
  • Beta blockers are often used to slow down the heart and prevent over-exertion, and also to improve the contractions of the heart. These can prevent a person achieving a decent exercise response, and cause breathing problems. They need to be assessed on an individual basis, often with an exercise test and breathing tests before and after exercise.
  • Medication used for the prevention of angina is not permitted, as the heart must have enough function and minimal risk of a heart attack under water, and this may represent that the heart has a “vulnerable” weakness.

Any other medical condition will also have to be taken into account. There may be an “additive effect” of both the heart problem and other medical problems that makes the overall risk to the diver too high.
New or early divers would have a harder time being allowed back in the water than an experienced diver, because of the increased stress and exertion levels that occur early in training.

A DIVER CANNOT TURN UP a few weeks before a dive trip and expect a quick response. Medical information has to be collected from GPs and hospitals, and further tests such as an up-to-date exercise ECG, may be required.
The diver may have to pay for this data to be gathered. Further investigations required for “fitness to dive” assessments are often not available on the NHS, and may have to be sourced privately at a cost to the diver.
Finally, the diver can be given an opinion on whether he is regarded as fit to dive. Restrictions such as depth/time/deco limits may be given, but it is more likely that he will be required to dive with an experienced buddy and not be allowed to train/take novices in case he gets into problems. Annual medicals will also be the norm.
If diving is your passion, make sure that your heart stays up to the task, especially as you start getting older. Watch the diet, get the weight off, stop smoking and start that exercise.
Be heart-aware, and stay diving!