Thank you for the details
Some area to cover here. I will discuss them one by one
There is evidence of likely past heart attack in inferior region (akinetic or dead area)
Diffuse disease is almost highly suggestive of diabetes the reason I asked this
His heart function is down but we do not expect only inferior akinesia to drop function to this extent so my strong suspicion is that he is still having ischemia or angina in other regions specially in LAD territory
Shortness of breath in diabetics is ANGINA EQUIVALENT and we treat it as angina until proven otherwise
From practical standpoint
He needs to be on treatment for diabetes. Tight control would stop progression. Diet alone may not be sufficient here
He needs to be on aggressive anti anginal therapy including aspirin, beta blockers, nitrates and ACE inhibitors
He needs to have his lipids/cholesterol controlled like LDL around 70 or less would be ideal. So Statin treatment is definitely warranted
To solve EF issue i would suggest to have discussion about non-invasive testing like nuclear perfusion imaging or dobutamine stress testing to see if there is any viable myocardium.....one which is temporarily non functional due to angina or reduced blood supply but can be made functional with restoration of blood supply with either stenting or bypass surgery
Historically Bypass is recommended in his scenario if testing shows viable myocardium but these days with better drug eluting stents and better therapy stenting is showing almost similar promising results so either of strategy would do
Please let me know if further details are needed
Best Regards