That’s a stress test.

Attach an EKG, have the patient ride a bike with significant exertion.

If there is a lack of blood flow, it will show up in the EKG as alteration of the electrical signals through the heart.

Well I've been subjected to these tests and I fell between the lines, I was clearly below normal health (had trouble walking) but they said there was no issues. So I wondered if there's not more subtleties. Like lag between effort and signals showing up, or vascular issues like micro clotting impeding flow.