Can exercise cause trouble for my heart?

Everyone thinks exercise is good for you. It certainly is! Being fit does reduce the chance of health problems including heart attacks strokes and diabetes.

But it becomes more complex if you have heart problems. People who have had heart attacks are offered cardiac rehab to put them through a graded exercise program to get them back into safe levels of exercise.

Some people have inherited problems such as hypertrophic cardiomyopathy which can increase the risk of heart rhythm problems with exercise.

Very rarely, these can result in cardiac arrest with dramatic examples such as Fabrice Muamba collapsing on the football pitch during a premier league match.

To combat this professional athletes undergo screening for cardiac disorders.

Last month Professor Sanjay Sharma published the results of his experience screening adolescent footballers. This study was funded by the English football association and its great to see them taking this issue seriously and perhaps more so than the US national (American) football league and their ongoing problems with chronic brain injuries.

I have worked with Prof Sharma previously on similar screening events of England cricketers and Manchester City football club, so I know how much work is involved as well as the worry it brings when something abnormal is found.

But this study has covered many more people to give us much better data. They looked at 11,148 players with an average age of 16 over a 20 year period. 95% of these were male. 42 players were found to have a cardiac disorder with a risk of sudden cardiac death. A further 225 had other cardiac problems that were picked up.

The players were all youth players at English professional football clubs. The 42 players who were found to have cardiac disorders associated with sudden cardiac death were advised not to compete.

After follow up (obviously of varying durations – 20 years for those screened at the beginning, down to 2 years for those at the end), 23 people had died, 8 of which from Cardiac causes.

Clearly the risk of cardiac problems is small but not zero in these players, with 0.38% if screened players having a Cardiac disorder associated with sudden cardiac death, and 2% having some form of cardiac problem.

We don’t know how effective screening is at preventing problems – this study doesn’t address that as there is no control group, but it does tell us that screening is not perfect at preventing sudden Cardiac death and some problems are not detected at the point of screening.

Nevertheless the absolute risk is small.

The big gap now in my mind is the risk in veteran athletes – the MAMIL’s or middle aged man in Lycra – or people like me!

There is a growing trend for fitness and certainly there are far more middle aged people cycling / doing triathlons / marathons and so on.

Every year there seems to be a death in the ride London event. There’s no data to show that screening in this population picks up treatable conditions but I would certainly want to think about it before I took on a big race or competition.

 

Atrial fibrillation – rate control, but how?

So we’ve decided that rate control is the best way forward for you – but how do we achieve it?

The mainstay is medication and there are different types that can be used.

First line are beta blockers such as bisoprolol.  These are usually very safe and well tolerated.  They can be taken safely for many years.  They can even be used in pregnancy!  The most frequent side effects that people complain to me about is feeling cold, and the second is that they can make some people feel tired.  Some people complain about vivid dreams.  There are of course other side effects noted in the sheet you get with the medicines, but these are the ones I hear about in the real world!

If these don’t suit a calcium channel antagonist such as diltiazem can be helpful.  Again, usually well tolerated and safe.

If these don’t do the trick or can’t be used because of low blood pressure then digoxin is a reasonable choice.  This is a drug that is made from the foxglove and has been known about for centuries.  It is quite effective, but oftentimes doesn’t control the heart rate on exercise so isn’t so suitable for active people.  I’ve linked a short film made a long time ago by one of my mentors Dr Holman for the Wellcome foundation.

Occasionally of course combination of these medications need to be used.  The alternative is a “pace and ablate” strategy where a pacemaker is implanted and the electrical connection between the atria and the ventricles is ablated thus making the ventricular rate controlled by the pacemaker.  This can be very effective in dealing with symptoms because it results in a regular pulse as well as a normal heart rate.