Yeah. You want to get vaccinated before your transplant, because the vaccines are less effective afterwards, due the the impact on the anti-rejection drugs on your immune system.

It's true that if you're heart is fucked you're at increased risk from the vaccination (and the disease for that matter), but the time to find out if you're going to die from covid is before the operation: There are fewer donor hearts than recipients that need them. (Except in China, where despite a very low proportion of the population being donors they seem to have sufficient organs for transplant).