I have a bum ticker and had one long before covid....since my vaccinations and boosters my heart rate has stabilized beyond anything I was experiencing before covid. All of my heart doctors are fully vaccinated...and none have died from heart failure, nor have any young athletes in any sports I follow. I check my heart rate daily and have for 8 years now...if covid vaccines caused heart failure, I'm the first guy who'd die from it...I've had the opposite experience...never felt better.Scientic method is demonstrable. the vast majority of basketball players have been vaccinated and not one NBA player has died on the court yet since covid. If you got covid early, it can incubate in your internal organs and cause health issues down the road from my understanding. As it is, the world I live around is healthy, happy and vaccinated. My children and grandchildren have no ill effects from being vaccinated to date. Check the fatalities from non vaccinated covid victims compared to vaccinated covid victims...it's not even a slightly close.