I'm still doing 300 hours a year instructional in my mid 70s and our examiner who is current on many types including a Cirrus has just turned 80.
As the article says, if you're current and can still see and hear, you're good to go.
As to the heart thing, the ECG is pretty much a waste of time, I'm told; vis the class 1 holding instructor in his 50s who died alongside the pilot he was checking out recently.
TOO