Cardiac Events and ENG1
“Heart conditions are the commonest causes both of deaths at sea and of failure by middle aged seafarers to meet the current medical fitness standards. Also mortality studies show that sudden death that was subsequently attributed to cardiac causes was the predominant non-accidental cause of death (more than 80%) while at sea.” (MCA Approved Doctor’s Manual, November 2009)
The commonest warning sign of impending heart problems is angina.which is chest pain caused by heart muscle complaining of inadequate oxygen supply. This is usually due to furring of the arteries with cholesterol material and the early symptoms are chest pain with exertion. As the condition progresses, the symptoms come on more easily and more frequently. The tightness around the chest can also radiate to the arms, especially the left, and up into the neck and jaw. It usually settles with rest within fifteen minutes and responds to a spray (of glyceryl trinitrate) under the tongue without the patient becoming particularly unwell.
Heart attack pain is similar in many ways but the heart muscle is complaining of not having any oxygen due to a clot causing a permanent obstruction to an artery supplying a section heart muscle. The pain does not ease with rest, the affected muscle is dying and the heart pump may begin to fail causing a drop in blood pressure and signs of shock – at worst, the heart rhythm may become chaotic (fibrillation) and the person arrests. 30% of heart attack patients arrest and need urgent cardiopulmonary resuscitation and defibrillation.
There are well known risk factors such as smoking, obesity, diabetes, raised cholesterol and high blood pressure and, unfortunately for some, family history. Appropriate lifestyle related advice is part of the ENG1 assessment. to seek to prevent the onset of angina and possible heart attack and very adverse features, such as obesity with raised blood pressure, can lead to a shortened ENG1 certificate to facilitate an earlier medical review.
The development of symptoms such as angina can affect the exercise tolerance of an individual and a worsening of symptoms over a few weeks can herald an imminent heart attack, and possible cardiac arrest. These are “cardiac events” which definitely affect the ENG1 certification and they also raise the possibility of other circulatory problems such as a stroke or poor circulation in the legs – similarly these other circulatory problems can increase the probability of a cardiac event and must be taken into account when deciding on fitness for seafaring. Other cardiac events include ECG evidence of a previous heart attack, some heart conduction abnormalities, and surgery to the heart circulation to improve the calibre of narrowed arteries eg by grafting or by artificial stent.
There are a number of practical questions to answer following a cardiac event. Is exercise tolerance reduced and does this affect ability to undertake normal and emergency duties requiring physical effort? Is there an increased risk of sudden incapacity caused by, for example, a disturbed heart rhythm or another heart attack? This is a crucial question and even more so if vessel safety depends on performance of watch-keeping crew or if working in dangerous places or alone. Is there a risk of recurrence at sea of a condition which would be jeopardised by excessive distance and time from potentially life-saving treatment onshore. Is there a foreseeable risk of the condition progressing and does this imply a need for medical regular review which can also affect the duration of tours of duty? Do lifestyle related factors pose an unacceptably high level of risk and is the seafarer motivated to make significant improvements? Is there additional hospital information such as angiogram results mapping the heart´s circulation which, with specialist interpretation, can affect the risk assessment.
A cardiac event leads to an automatic temporarily unfit certificate for a three month period after which certification is based on risk assessment of recurrence.
A very low risk of recurrence requires only one prior cardiac event and no other form of circulatory problem, plus well-controlled associated relevant conditions such as diabetes or high blood pressure, and a determination to address adverse lifestyle risk factors, as well as a normal exercise ECG. This low risk candidate would be fit for an unrestricted ENG1 valid for six months initially then annually thereafter to confirm compliance with risk factor control.
A normal exercise ECG but a less favourable clinical condition poses a low risk assessment of recurrence but enough to produce a restricted time limited ENG1 with no solo working or watchkeeping in near coastal water and not fit for distant waters on vessels without a doctor. Initial review is at six months then annually to confirm compliance with risk factor control.
Persons at moderate risk of recurrence require case by case assessment with no solo working or solo watchkeeping and no lookout duties. A restricted time limited ENG1 can be issued on local coastal vessels unless working on a vessel with a ship’s doctor.
If all else fails, the person becomes permanently unfit unless they are capable to perform non-demanding customer service functions on short (less than one hour) ferry crossings with restrictions to specified duties on a specified route with annual review.
Fortunately the yachting industry has a skewed population in favour of the young and healthy but time catches up with us all and, even with good training on medical care at sea, nobody wants a cardiac emergency..
Dr Ken Prudhoe, MCA Approved Doctor, can be contacted at Club de Mar Medical Centre, Palma de Mallorca.