The evaluation is to make sure that you are healthy enough to donate a kidney, your remaining kidney can compensate and that any of your health conditions will not be made worse due to having a lone kidney. I would suggest you have a talk with your cardiologist. There may be medications that you need to take that need that additional kidney function you would be giving away. what happens if you need to have another cardiac catheterization, can you your one kidney handle the nephrotoxic dye. There are some studies that those with one kidney may be more at risk high blood pressure and protein in the urine. These are not issues someone with a heart condition would want to subject themselves to. it would be terrible to create a situation where a donor would go onto need a kidney .It happens but hopefully not due to something that could have been prevented in the evaluation process.
I hope your center does a thorough job in screening for your sake and for the overall kidney donor program. Accepting donors who are at risk jeopardizes everyone. There is more than one way to help a patient in end stage renal failure; donating a kidney is just one. The recipient and donor needs help with transportation to appointments, maybe monetary loss of wages while they are out with surgery, help with paying for medications if they have high co pays(recipient), babysitting, errands, cleaning.
Best of luck with your evaluation.
Sherri