Sports cardiology: questions from the heart

August 3, 2017 Posted by Dr. Duncan Hogg no Comment

Just before I went off on summer break a now stable paroxysmal atrial fibrillation (PAF) patient shared that he was taking Dr John Mandrola’s The Haywire Heart to read on his cycling holiday. He’ll definitely find resonance in Dr John’s recount of his AF episode whilst cycling, which is almost the same as my patient recalled. It’s a great read and discusses many sports cardiology questions beyond AF pertinent to the middle-aged athlete, and now in that group myself, there is a good bit to be concerned about!

I’m especially thoughtful about how I would feel in a similar situation to my patients if I too had this kind of challenge to my lifestyle.

My cycling PAF patient with a resting heart rate under 50bpm is on a small dose of Flecainide and, being assiduous in his hydration around rides, he hasn’t had a paroxysm for quite some time. But, will he follow the natural history of many mature sportsmen and develop more frequent episodes or even persistent AF in his later years? Can we modify his natural history by keeping paroxysms to a minimum in number and duration, minimising the electrical and anatomical remodelling we know underlies “AF begets AF” (a phrase that always sounds too biblical, nobody uses begets anywhere else do they?!). We’ll have to see. But like many, he won’t be modifying his sporting activity; he loves his high volume cycling and golf just won’t ever do the same thing!

Sporting individuals will naturally push their boundaries which on occasion leads to medical uncertainties. Supporting them in these can have different facets to usual clinical care.

A mid-twenty something man who had entered, diligently trained for and had a large amount of sponsorship to do the Marathon des Sables was referred to me when his mandatory ECG was quite rightly reported as abnormal. This was less than a month before the event and he had to have a cardiologist’s clearance to compete. The potential distress and disappointments of an enforced, late withdrawal were very clear.

All indications were in keeping with athletes heart but a single time point assessment can never give complete reassurance. He hadn’t been a habitual aerobic athlete prior to this and said he’d be happy to detrain after the event to prove the diagnosis, but the consequences of an occult cardiomyopathy could mean we’d never get that opportunity!

Thankfully his race went well. He returned having had a full two months off any aerobic exercise and the vast majority of his ECG change resolved, leaving him with partial RBBB.

But why don’t all athletes doing similar degrees of aerobic activity get the same phenotype, there surely is a genetic predisposition? Can the athlete’s heart adaptation be potentially both positive and negative? For those enjoying a high-level of exercise over decades longer-term consequences such myocardial fibrosis must be a worry if increasing the risk of ventricular arrhythmias; is there a threshold of time before the change becomes irreversible? Much to study and learn, but definitely from very willing research subjects, athletes usually like the attention!

For those patients with known heart disease it is often difficult finding the balance between being scared of exercising and doing enough to get the general health benefits. This discussion can be different but equally subtle in the middle-age groupers, as if diagnosed when their lifestyle patterns have become established and exercise is a large part of this, stopping something you enjoy is usually difficult to do.

We have significant concern about hypertrophic cardiomyopathy (HCM) patients doing strenuous exercise, as we have been convinced that this is a key time when they are at highest risk of sudden cardiac death. Guidance is quite clear that those with HCM should only participate in level 1A sports.

But, there is some evidence, to a degree, challenging that orthodoxy. Recent data has found that SCD in known HCM patients, especially in middle age, are much more likely to occur at rest and/or asleep than when active or doing sports. We do need more data to change position, but maybe we can have less concern about some of our patients?

Again shortly before an event, a HCM patient asked me to complete a medical form to take part in a distance cycling event on one of the western isles of Scotland. He was low risk by risk stratification, with no LVOT obstruction or recorded non-sustained VT, but he did have some fibrosis on his last MRI. He had been training with his friends without incident, and they knew he had HCM, although I wasn’t quite sure if any, some, or all knew CPR.

A number of years ago an anaesthetic trainee I knew saved the life of a fellow athlete who collapsed in front of him in a cycling event. I’m sure like me you know many anaesthetists who are active in multi-sports and distance events, but you can’t count on one always being that available! Of course, being medical is certainly not a prerequisite for bystander CPR, and there are many examples of similar life-saving by regular fellow athletes in sporting settings.

We discussed the situation and agreed that if the organisers could give us the reassurance of having an AED to him within 5 minutes of cardiac arrest, then even with this worst case scenario we could reasonably hope his overall safety was quite secure. But, it would remain essential his friends could do bystander CPR when needed.

There is robust ESC guidance on medical responses for sporting arenas, but having strong contingencies in a distance cycle event must be more challenging for a medical director.

Questions like these do now take up the time of dedicated sports cardiologists. For us generalists, having good access to individuals with additional expertise would be of help. We might also need them ourselves as some, maybe many of us, refuse to take up golf just yet!

This Blog is Posted by Dr. Duncan Hogg

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