<Li> In 1973, a calf named Tony survived for 30 days on an early Kolff heart . </Li> <Li> In 1975, a bull named Burk survived 90 days on the artificial heart . </Li> <Li> In 1976, a calf named Abebe lived for 184 days on the Jarvik 5 artificial heart . </Li> <Li> In 1981, a calf named Alfred Lord Tennyson lived for 268 days on the Jarvik 5 . </Li>

When was the first successful artificial heart invented