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MEDICAL FAQs |
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Dive Medical questions & answers for common scuba diving conditions and illness provided in conjunction with the doctors at the London Diving Chamber and Midlands Diving Chamber. | |
All Categories » Cardiovascular System » Rhythm and Rate
QUESTION During the last 2-3 years I have suffered an increased frequency of irregular heart beat. The frequency was such that I consulted my doctor soon after Christmas about the condition. I have been referred to a consultant who has diagnosed atrial fibrillation from the results of a 24 hour ECG. Initially the irregular heart beats occurred when I was at rest, but latterly came on as well during vigorous exercise. I do not experience any other symptoms like shortage of breath during an attack.At present I swim 1 km in a local pool most mornings without detrimental effect. A recent unmedicated ECG on a running machine conducted by the consultant did not not bring on an attack even with the heart rate at 156. In the middle of July I am due to holiday in Cuba when I planned to scuba dive. (I have PADI Advanced Open Water Certification) My current medication is 25 mg of Metoprolol twice daily. With my current situation is it safe to dive or would I be a risk to myself and others? Your guidance would be appreciated. ANSWER This is an interesting question. Atrial fibrillation or AF is a condition where the heart beat becomes irregular, but in an irregular sort of way. Unsurprisingly doctors describe the rhythm as "irregularly irregular". Diagnosing it is easy but what is harder is finding out why this has happened. It can be due to valve problems in the heart or even thyroid disorders too. So it is important that your cardiologist has excluded the causes of this problem. QUESTION On March 9th this year I was admitted to hospital with a severe virus infection and I was kept in for four weeks. The virus was never identified but it caused me to become seriously ill and affected most of my organs.Blood potassium and sodium were extremely low and my kidneys started to fail. However, with good nursing, I have made a good recovery from the viral infection. While I was in hospital, I developed atrial fibrillation with a pulse rate of 156. This has now been brought back to normal and I am taking Amiodorone. I am told I have hypertrophic cardiomyopathy, HOCUM, which must have been present all my life and only caused problems when the virus struck. I am still on Warfarin but this will be stopped quite soon now. I have never had any previous illness and am a keen diver, diving twice a year for two weeks at a time. I have always been keen on tennis, swimming and walking. I am seventy. Do you think I could dive again next year? Would I be a bad buddy? Can one dive while taking Amiodorone? I now have no atrial fibrillation and my pulse rate is 70. Please could you give me your opinion. ANSWER You sound fit, fun and are obviously active. But sadly I have to be the bearer of sad news. I think diving is going to be beyond your medical capabilities. QUESTION I had an ECG in December 06 which has indicated possible enlargement of the left ventricle. My GP has also detected a heart murmur. I am due to have an ultrasound of the heart in Feb which will give more info about what is wrong. If I do have an enlarged left ventricle in addition to the heart murmur does this mean my diving career is over? I am 44 years old and an open water diver and at the moment I have stopped diving including swimming pool practice sessions. Grateful for your advice!ANSWER And much to tell you here. Left ventricular enlargement is not a bar to diving per sae. But rather like the fading male porn star, it’s all about the failure of the organ to pump properly. Bring out the fluffers I say. QUESTION I am a 26 year old female with anorexia nervosa. Been diving since I was 14. Just got an ECG test back that said my heart rate was slower than normal (in the 50's). Does this put me at increased risk for diving? I am going away for the next two weeks and was hoping to dive - is it safe?ANSWER Anorexia nervosa is not a new illness. “Fasting girls”, a Victorian term for non-eating pre-adolescents, have been around since the Middle Ages, and were often claimed to have miraculous or magical powers, usually by exploitative museums. Sadly, whenever these claims were tested, the girls in question starved. Today the condition is a formal psychiatric diagnosis, an eating disorder that causes low body weight, body image distortion and an obsessive fear of gaining weight. In general terms, the problems that this would cause for diving are several. Reduced strength and exercise tolerance are common, meaning kit-carrying and hard finning may produce early fatigue. Psychological issues might jeopardise safety, with panic and phobic behaviours a prominent feature. Any medication taken for the disorder might have repercussions also. QUESTION As well as diving, I also fly light aircraft - why do I chose expensive hobbies?! My pilot's licence requires that I have an annual medical with an ECG. At the last medical it was discovered that I had Right Bundle Branch Block (RBBB). The Civil Aviation Authority then required that I be subjected to additional tests, namely, a stress ECG, an echocardiogram and a 24 hour monitor ECG. The results were deemed satisfactory and I get to keep my flying licence. It was my understanding from this, that the RBBB is of little consequence and shouldn't affect my health or life expectancy. I didn't think to ask the consultant if there is any problem diving with a RBBB. Is it safe to continue diving?ANSWER The heart beats about 35 million times a year, or over 2.5 billion times during an average lifespan, so you’d expect it to have a fairly foolproof control system. In fact the electrical wiring of the heart is quite simple. There are two “nodes” and specialised bundles of conducting tissue (much like normal electrical cable) that pass “current” through the heart muscle to make it contract. Electrical impulses begin at the sino-atrial (SA) node, which under normal conditions generates them roughly 60 to 100 times a minute. Each stimulus then passes to the atrioventricular (AV) node, and after a brief pause it splits and flows down the right and left “bundles of His” (pronounced as in the snake noise). The end result is that the atria (top 2 chambers) of the heart contract first, emptying their blood into the ventricles (bottom 2 chambers), which squeeze the blood all around the body just afterwards. Clear as cocoa? Hopefully the diagram will explain things. QUESTION Recently, I experienced six days of ectopic heart beats. For the first few days they were extremely frequent, up to 10 a minute, gradually decreasing on the sixth day to an infrequent two or three an hour. I have never experienced anything like this before in my life. I have seen a cardiologist and all my blood tests have been normal. A 24 hr ECG monitor showed up a number of ectopics but at a rate low enough to be considered normal. An echocardiogram was also normal, and so no explanation could be given for the "flare up".Do these ectopics have any impact on my ability to dive? ANSWER The 2.5 billion beats a heart generates in an average lifespan are by and large regular as clockwork, thanks to the sino-atrial node, a little clump of cells that act as a natural pacemaker. Occasionally though, another bit of the heart tries to muscle in and fire off its own contraction; an ectopic is the result. Basically they’re extra beats out of sync with the regular heart rate. The vast majority are harmless and seen in many normal hearts, but if they occur too frequently or in long runs, they can indicate a diseased heart. Reassuringly in your case, the blood tests and echocardiogram were normal. Sometimes these ectopics can be due to excessive fatigue, caffeine, alcohol, nicotine or other drugs, so have a think if any of these factors are relevant. But if your cardiologist is happy that your heart is in good shape, then I think you’d be safe to dive again. |