Lisinopril Heart Beats, Heart Muscle Damage, Heart Beat, Toprol Xl, Defibrillator

I do not know if my side effects are from lisinopril or toprol Xl or just dying. I have defibrillator. had one for 7 years-no problems. Put in new one in March 2006. Did good first month except when laid on left side felt extra heart beat. TOld person who checks defibrillator. She reprogrammmed it and then I started feeling the fast beats when I laid any way. Had fast heart beats all the time in 2nd month ever since and shocked 8 times. Went in hospital. FOund out I have heart muscle damage and put on lisinopril and toprol. I still have the fast heart beats all the time. They are driving me crazy. COuld my leads be bad or what is wrong with this defib? Did the 8 shockings damage my heart muscele? For 7 years they told me my heart was fine except the rhythm-but had nothing wrong with rest of my heart. Help!