First point I would make is that your doctor doesn't seem 100% convinced you've actually got ARVC and it's not clear from your post exactly what "boxes have been ticked" other than the implication from the fact that you're having an ablation on Friday, suggests you are already suffering from a very serious arrythmia. It's not easy to diagnose ARVC with absolute convinction and I presume you've already been through the usual gamut of MRI's, ECG's, Echocardiograms and the like. I really hope they are wrong.
Nevertheless, I'll tell you the gist of what the medics told my mate and what I know from my own experiences as a former nurse ...
...short of getting a heart transplant, once you've got ARVC you've got it for life. It is a progressive condition that will get worse over time. There is no known cure and no known cause. It tends to run in families. Symptoms are dealt with as and when they arise, usually when they become so intrusive that they affect quality of life. It's a condition you have to life-manage just as you would say for insulin dependent diabetes and one you should give very serious respect to, because it can undoubtable kill you. Sudden death in athletes, who previously appeared to be completely healthy is often attributed to this condition - not everyone gets symptoms, or any warning that such a serious condition has afflicted them.
I can't emphasize this enough, but if the medics really think you have the condition, your immediate family should be screened to see if they are affected by it too. As I said, they may not have had any symptoms to date but it does have a strong hereditary link.
Given that the condition gradually changes the tissue in your heart from healthy muscle to relatively useless fibrous tissue and even fat, sometimes causing pronounced arrythmias as a result, you can imagine the impact this will have on your heart's ability to function efficiently and what it will do over the longer term.
You simply cannot exercise vigorously with this condition without subjecting yourself to a high risk of a fatal attack. I'm afraid that doesn't leave you with too many options and I really feel for you, even more so given how much your life revolves around training.
The ablation will (if successful) address your arrythmia in the short term, but they could recur because the condition is progressive and you might need further ablations. The absence of arrythmia doesn't mean you are safe to exercise.
They can place something called an ICD in your heart which is a sort of automatic defibrillator that will kick in if things go pear-shaped but these are very expensive and are not commonly prescribed.
As I said in my last post, there's not much in this reply that will bring you any good cheer but remember that you might not actually have this condition. That has got to be your highest priority after your ablation - to get as much expert opinion that you can from the medical professionals to ascertain whether you have this condition or not.
I genuinely wish you all the best and hope that you've got nothing worse than an errant arrythmia that is sorted by your ablation. Keep us posted.
Regards, Groz.