Can shock therapy damage your heart?

My mother received shock therapy back in the late sixties,she had short term memory loss but seemed to come out of her depression for a short period of time,later we discovered she had a heart murmer that had not been detected before. We were always concerned that the shock therapy caused the heart conditions that gradually become more severe,she died at the age of 63 from a brain clot,we think it was all retlated to the treatmenta nd I would be very concerned for anyone who is thinking of getting this type of treatment...It is just speculation,but I would not have it EVER. Rosey fromTexas