Atypical chest pain or epigatric pain with abnormal ECG needs to be corelated clinically if Troponin I is high . Even if Echo and Angigram is normal because cardiac damage may be due to temporary thrombus which is there and dislodged at the time of angiography
He can be on preventve therapy like Cholesterol lowering and Aspirin, minimum or Beta blocker
? because Heart rate is 45 BPM is it for short time or he always keep slow hert rate.
He must adapt to healthy life style eg. Ideal weighjt,diet,physical activity and stop smoking and alcohol if any.
Sometimes a very heavy exercise, Pulmonary Embolism
,Myocarditis,or Blunt chest trauma
can raise it even a septicemia can cause a clinical corelation is required.
Because these are some causes apart from IHD .Your cadiologist knows them so follow his advise.
Best of luck.