hi there , I wonder to ask about if I have case of DCM and it has AF just because the massive La and Ra enlargement, does Atenolol will be beneficial in that case over Diltiazem ? As you know DCM is a disease of systolic dysfunction and Atenolol will affect on the existing Systolic function . or I must use Atenolol just in case of stable or accepted LV systolic function. also I want to ask about the benefit of diltiazem in this case ? and thank you very much for this clear and straight forward webinar .