Rogers: the heart stuff explained
It’s been a day since Michael Rogers announced he was retired from racing because of concerns about a heart condition.
To help our readers understand the diagnosis given to the former rider we asked cardiologist André La Gerche to explain what a bicuspid aortic valve is and how it may affect a professional athlete.
How does a bicuspic aortic valve affect an athlete?
– By Associate Professor André La Gerche and Dr Maria Brosnan
Department of Sports Cardiology
Baker IDI Heart and Diabetes Institute, Melbourne
What is a bicuspid aortic valve?
The aortic valve allows blood to pass freely out of the heart into the aorta and around the body. It normally has three leaflets (tricuspid) and offers no resistance to flow and doesn’t allow any blood to leak backwards. However, 1-2% of the population are born with an aortic valve with only two leaflets (bicuspid).
For many years, a bicuspid valve does not cause any problems and most people are completely unaware that they have a bicuspid aortic valve. It is often discovered accidentally on a medical test done for another reason.
However, bicuspid valves do not work as well as tricuspid valves. They cause turbulent blood flow which can lead to narrowing of the valve, leakiness of the valve or dilation of the aorta (the large blood vessel immediately after the aortic valve).
The resulting changes to the valve or aorta may become sufficiently severe as to require surgical replacement.
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What are ventricular ectopics?
Ectopic heart beats are extra heart beats. Normally the heart has its own pacemaker rhythm produced by specialised cells within the heart that produce a regular electrical discharge. However, every cell within the heart does have the capacity to discharge spontaneously and this results in extra heart beats.
Again, this is a common problem. Approximately 2% of the population have very frequent extra heart beats and there is good evidence to suggest that this occurs even more commonly in endurance athletes.
Some people feel the extra heart beats and find them quite disturbing whilst others do not feel them at all.
In general, these extra heart beats are not cause for concern. On the other hand, they can be a sign of a heart problem and heart specialists will frequently perform tests to ensure that there are no signs of prior heart damage. However, most commonly the heart is normal and in this situation the extra heart beats do not represent a health risk.
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Common questions from the athlete with a bicuspid aortic valve and palpitations?
- 1. Am I at risk of dying suddenly?
No. Bicuspid aortic valve disease is not associated with sudden events.
- 2. Am I likely to need heart surgery?
Possibly. The valve narrowing or leakiness that frequently accompany a bicuspid valve can progress to become severe thereby requiring heart surgery. However, many people with bicuspid aortic valves remain free of symptoms and do not require surgery.
- 3. Could sport increase the speed of the valve wearing out and increase the chance of needing surgery?
A difficult question. There are some theories that the high blood flows associated with exercise may increase the rate at which the valve becomes narrow and/or becomes leaky. However, these theories are not proven.
For patients with bicuspid aortic valve disease with normal or only mild valve dysfunction, there is no need to change exercise practices. However, if the valve dysfunction becomes severe or if the aorta becomes dilated then some degree of exercise restriction is recommended.
- 4. Could if affect performance?
Significant valve dysfunction can impact on exercise capacity.
Michael Rogers, for example, has been known to have some valve leakiness.
It is possible that this has been a slight handicap. For example, even with mild leakiness 10% of blood that is usually pushed around the body will ‘flow backwards’ into the heart. Thus the heart has to work 10% harder and this is an issue in the elite endurance athlete who needs to pump very large amounts of blood to the body’s muscles for sustained periods of time.
If it weren’t for some bad luck at birth, it is possible that Michael Rogers stellar career could have been even better.
– By André La Gerche and Dr Maria Brosnan
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