My homograft aortic valve was replaced 15 months ago. My pacemaker was replaced 20 months ago. Ever since the heart surgery I have experienced pounding sensations around my heart accompanied by tendencies for shortness of breath. Over the past two months the pounding has increased so it is now present almost around the clock. Each doctor that I see at Duke says the piece of me he looks at is working well and he does not know why I am having the symptoms I do. The tests that have been done include echo cardiogram, pacemaker monitoring, EKW, Holter monitor, CT ScAn. Do you have any idea of what else to check? Because I am pacemaker dependent I seems logical to me that the symptoms must arise from some setting in it but the electrophysiologist strongly maintains it is working well and I have to look elsewhere.