Wolff-Parkenson-White isn't dangerous unless you have structural problems with the heart such as a Hypertrophic Cardiomyopathy. It doesn't cause a heart attack which is where the coronary arteries, which are located on the outside of the heart, are blocked. You have the capability of having fast heart rates called arrhythmias. Those arrhythmias start when the electrical impulse starts off at the normal place in the heart (The SA Node) and instead of carrying through the right way down to the ventricle, it jumps over to another electrical tract that shouldn't be there in the first place. then the impulse continues going around that tract kind of like a child's toy train set. Just because you have this diagnosis, doesn't mean that this will ever even happen to you; it may or it may not. There are drugs that can be taken, there is also an ablation which can be done, but understand that the ablation will only be successful if the extra pathway is 'active' on the day of the ablation.
I was diagnosed with WPWS at the beginning of this year and have had an abalation procedure in March. It was, to be honest, very uncomfortable and not a very nice thing to go through as you are awake during the procedure and you are unable to control your heart rythym. However, I was as anxious as you are and after talking to my consultant I realised that WPWS is dangerous and you are prone to having server attacks and could have a heart attack. This could be just my condition though, and all related to my attacks etc so its best to have a chat with your doctor to put your mind at rest. Sorry to sound so negative, but thats my personal experience. I have since been diagnosed with eptopic heart rythyrm and still undergoing tests. I wish you the best of luck.