Cardiolite stress test ejection fraction 55%, 2d echocardiogram ejection fraction 58.5%, catheter angiogram 49.5%. which is accurate?

They are all pretty close numbers but the most accurate would be the catheter angiogram. But, for functional purposes, the difference in the numbers would not make much of a difference. See your cardiologist for interpretation since he/she knows your condition best. Good luck to you!

Yours is border line low I would say. But best to ask Dr who did studies.And will also depend on which formula they use.