My grandfather was told he needs to undergo Cardiac Catheterization because of an irregular heart beat and slow breathing. Is this procedure really necessary?

My grandfather is currenty at the age of 85. He has recently gone to the doctor for a check up. The doctor told my grandfather that he has an irregular heartbeat and that his breathing is slower than most common people. The doctor later suggests that my grandfather undergo Cardiac Catherization. I am currently overseas and was worried that these may lead to some complications because of my grandfather's old age. And thus was wondering if it is really necessary for him to undergo the procedure.