Good Morning Sir I Am A Uncontrolled Diabetic Patient. A

Good morning Sir I am a uncontrolled diabetic patient. A pacemaker is implement in my heart in 2013.In the month april 4th I had a mild heart attack I got angiography and got 50 % + block. I take ecosprin 150 mg and atorva 20 mg. After angiorgraphy doctor prescribe me to take Nitrocontin 26 mg tablet once ady. Is it essential. I am weaiting for your reply.
Regards