Welcome to Health care magic,
After going through your history it is not mentioned if you have chest pain
like angina pectoris
It is true in presence of LBBB Ischemic changes are difficult to diagnose but impossible.
Your doctor must be having something in his/her mind to get 2 D Echo and stress
and blood work up.
If there is sufficient evidence to suspect coronary pathology catheterization is done and if suspected even Cardiac C T with Calcium score may be done which will guide towards significant coronary disease is there or not.
If there is no angina and other test are negative cardiac cath may not be required.
If you have any doubt can always take second opinion