It is still possible that Vincent was fully physically capable of performing his duties during the space mission. Even without the pre-recorded heartbeat from the real Jerome, he was still able to run on a treadmill for the required time, without a fatal heart attack occurring.
There was also a gyroscope visible in the same athletics training room, another stressful physical test he would have had to pass successfully to qualify for the mission, without triggering his heart to fail.
Andrew Niccol’s vision in this film still holds true that Vincent was not only meeting, but far exceeding his physical potential as determined by his genetics, which specified that the chance of his heart failing was only 99%, and the remaining 1% was far more influential in determining Vincent's physical potential, and his true human potential when his heart didn't fail, and he was able to surpass even the potential of a genetically 'valid' person while still being seen by society as invalid.