My Husband Has These Episodes Where It Appears His Heart

My husband has these episodes where it appears his heart has stopped and then starts several episodes in a roe he is exhausted after however feels fine. He has has echo cardio,stress test took nitro during an episode that continued for several minutes which gave him a head ache. Two notes in hospital and they found negative test for heart desease he is on diavan,labetalol,glimepiride,amlodipine besylate hydrochorothiazide he also has type 2 diabetes which aid is under 7. He,s a 62 year old. Can you help.