Sunday, 11 December 2011
The athlete's heart
So what is "athlete's heart syndrome" (AHS) and what should you do about it? T
The most important distinction of AHS is that it is a diagnosis of exclusion, meaning you have to exclude more significant causes of heart problems, and that it is essentially benign, meaning that it is not associated with ill health or indeed sudden death which is pretty reassuring.
So what are the symptoms of athlete's heart syndrome?
Often there are no symptoms but features would include a slow heart rate (the bradycardia of fitness which most endurance athletes are aware of) such as exhibited by TdF cyclist Miguel Indurain who had a resting heart rate of 29 (which is definitely pathological in a non athlete). Other features might include occasional ectopic heart beats, leading to a slightly irregular pulse, but otherwise there is little else.
Where the problem comes is when you have either an ECG (electronic tracing of your heart rhythm, or an echocardiogram of you heart- an ultrasound scan of your heart which can look at how your heart functions).
What should you do if you have an irregular heart beat or other "unusual symptoms"?
1. See your doctor and get some tests
Firstly you should see you doctor and explain your symptoms: they should arrange some blood tests and a ECG. The blood tests are to exclude biochemical abnormalities such as a low a plasma potassium level, and other things that can cause problems such as an overactive thyroid which can cause arrythmias. They should also enquire about risks factors for arrythmias such as excess caffeine, alcohol, recreational drugs and fatigue all of which can induce abnormal heart rhythms. If you have had arrythmias then you should also have a 24 hr ECG and an echocardiogram.
2. The ECG, 24hr ECG and Echocardiogram
3. What is a fit heart, why does it cause problems interpreting tests and who should I see?
As we train (say more than an hour a day) our heart gets fitter, which means amongst other things the muscle of our heart gets bigger. This occurs especially in the bit that does the most work, the left ventricle or LV for short. When the heart muscle gets bigger it becomes more efficient at pumping blood and is one of the reasons why at rest our heart rate becomes slower, as with each heart beat we can pump more blood around our body. Enlargement of our LV can be pathological and his is one of the key causes of sudden death and is therefore a cause for concern when it is seen on an ECHO study of you heart. It is very unlikely that an athlete who has been training for more than a year at a high level will have a pathological cause of LV enlargement. Where concern arises there are some subtle differences in the pattern of the echo changes between the fit heart and the abnormal heart, and perhaps the ultimate test is to detrain for a period of 1-3 months in which case if it is an athletic heart the LV enlargement should reverse. Where this does not occur it may be pathological (the condition is called HOCM) and would need further tests.
Happily for me my heart studies were completely normal, for an athletes heart, so I can continue training.
Posted by runtilyoudrop