Yes My Husband Is 68 Had A Arotic Valve Replacement

Yes My husband is 68 had a arotic valve replacement in 2011 and congestive heart failure! But works everyday he is also diabetic on insulin! His heart Dr has given him nitrostat but he has never taken one! So this evening comes home so out of breath struggling even took his blood pressure and only top number was high! So I think he thinks the nitro will help him brath, t don't know, tried to get him to let me take him to emergency, would not so he has a inhaler and I made him take to doses of it! Would the nitro have helped???