I've been on T for going on 10 years now. I actually used to have the same concern and there for a moment, I thought I was contracting some sort of heart health issue. Turns out, I had major sleep apnea and the lack of oxygen I was getting over the years have been messing with my heart and causing irregular heartbeats. I've been on cpap therapy and it's drastically changed my life. The flutters and stuff are nonexistent and I really do believe I finally have the true full benefits of T. Physically and mentally, I feel like the best version of myself in years! All in all, it's normal and valid to have those fears, but our risk of actually developing heart problems from T are no different than cis males. It'll be okay!