A 60 years old man c/o heaviness in both arms and discomforts in chest after walking for 0.5 km after taking food. He can walk in morning for 3 kms with out any discomforts. The patient is diabetic hypertensive under medications BP in normal range, Hba1c 7.4, lipid profile, lft, thyroid, renal profile normal, ECG normal.

What could be the cause and how to proceed further for investigation ? Kindly share.