Since it seems like such a sudden thing, I'm guessing it's psycological and related to the heart event. I've had similar stuff happen to me and it definitely affected my awareness of my heart rate during sex and can be a distraction at times.
Also, my libido rises and falls throughout the year. At times it's low, other times it's like I'm 19 again. It seems to cycle like this for me over 3 or 4 months.
I've had tachy episodes all my life and it never interfered with my love life. Then again, I'm a woman. Maybe there's a difference.
Perhaps this episode has set off a deep fear inside that you're not aware of. It's not uncommon for men and women to have some temporary sexual problems after a heart attack for example. After each of my ablations (a heart procedure that involves burning tiny bits of heart tissue) I was very nervous about getting back to business w/ my husband.
It sounds like your trip to the hospital was not easy so you may not even be aware of this fear. All I can suggest is to take it slowly. Try a little bit of fooling around with your wife now and then. As you become more confident that your heart will behave, I bet your interest will rise to the occasion (yes, pun intended.) Don't give up yet. You're too young.
irene