Firstly, I'm not a medical professional.
The way I see it, there are two possible scenarios.
- Either your condition means that the tachycardia from SN could be worse for you than for the average person. That is, it could reach a higher rate than it does for normal people.
- Or perhaps your condition will not have an affect on the SN tachycardia. That is to say your heart rate is going to reach a ceiling point the same as it would with a normal person, and not go higher.
Either way, tachycardia itself is potentially distressing, but not painful. So propranolol would technically remain optional for you in the same way it is for a normal person.
However, your past coexistence of chest pain with episodes of tachycardia
may suggest you could also experience chest pain along with the SN tachycardia. This would presumably be painful as opposed to just distressing.
I don't know which scenario is the case, but I
personally would obtain and take the suggested amount of
propranolol just in case the first scenario is the correct one, and in the knowledge that taking it doesn't do any harm if the second scenario is actually correct.