My wife suffers with the same condition.
Hers also only started in her mid 30s.
We originally thought it was caused from a bite of a Tick whilst on holiday in Spain.
I am no cardiologist, so have no idea.
All i do know is that it scares the shit out of me when she has episodes. She goes a funny grey color, and starts sweating up.
Speculating is not helpful for Sergio, and is distressing for him and his family right now
The wife condition is partly managed by medication, which suppresses some of the symptoms. She lives as normal life as she can. One day she will likely need to have a pacemaker. fitted It is a horrible condition to have, your Heart suddenly, and inexplicably beating all over the show, feeling like it is trying to beat out of your Chest.
Hopefully Sergio having it now detected, will make a recovery of sorts, and manage the condition.
Good luck Sergio,and get well.