ECG: is basic examination tool, easy to do, takes minutes to do, available everywhere, cost is not costly, apparatus is not costly, not difficult to learn. Can show diagnosis in ore than 50% of cases when you correlates symptoms with changes and when doctor does not ignore half mm ST depression.

CT: is a fantastic tool to show coronary lesions without catheter and to show dissection. Useful after CABG to delineate the anastomosed vessels easier than trying to find them by catheter. Cost of apparatus is millions and need two months training for devoted imaging doctors. Cost of test is less than diagnostic catheter. Check kidney function before allowing injection of dye, ensure Heart Rate to be below 60 bpm and ensure the patient can hold his breath for 10 seconds.

Magnetic Resonance Imaging: Very valuable, no dye is injected (in some cases), Heart Rate is not an issue, apparatus is more expensive and cost of test is more than CT. Needs specialized imaging cardiologists or radiologists. Can show scar and wall motion, can define viability. Any cavitary thrombi, LV hypertrophy , valve incompetence and many other benefits.

Samir Morcos Rafla, FACC, FESC, FHRS. Emeritus professor of cardiology, Alexandria Univ.

For healthy person 40-65 years we use SCORE: it contains sex, age, BP, smoking and cholesterol level. For example, like this

https://www.escardio.org/static-file/Escardio/Subspecialty/EACPR/Documents/score-charts.pdf

At different populations there are different tables (at least two - for high and low risk population).

Accordong this SCORE we can calculate the risk of cardiovascular events next 10 years. But we can not diagnose the disease. This is risk only.

first clinical and history assessment to get the cardiovascular risks propability . second ,ECG is a simple tool ; available everywhere, noninvasive , easy to interpret by the juniors .Then go to higher level assessment by invasive (catheterization or EPS ) or noninvasive (CT angio or MRI ) accordingly .