I might have stuck to Top 20...
15. AbioCor artificial heart
However, Dr Robert Jarvik, inventor of the first artificial heart, points out that the Abiocor heart, because of its size, cannot be used on small men, children, and most women.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1120745/
The second patient, Tom Christerson, who was given less than a 20 percent chance of surviving 30 days at the time of his surgery, lived for 512 days after receiving the AbioCor, dying on February 7, 2003 due to the wearing out of an internal membrane of the AbioCor.[12] An additional 12 patients had the device implanted into 2004, resulting in an average life span of less than five months among all 14 patients. In some cases the device extended survival by several months, allowing the patients to spend valuable time with family and friends. In two cases, the device extended survival by 10 and 17 months respectively, and one patient was discharged from the hospital to go home. For a patient to be eligible for implantation with the AbioCor, the person must have had severe heart failure (with failure of both ventricles) and had to be likely to die within two weeks without transplantation.[1][2]
AbioCor was surgically introduced into 15 total patients, 14 of them during a clinical trial and one after FDA approval. However, due to insufficient evidence of its efficacy, AbioMed abandoned further development of the product.
https://en.wikipedia.org/wiki/AbioCor
(Oops, I might have stuck to Top 15)
Seems to me the artificial heart would be worth another attempt, tech has come a long way since early 2000... miniaturization etc... However I also think that a different approach to the pumping mechanisms needs to be considered, similar to the miniaturization of the dialysis machines took a complete different approach than previous large scale machines.
I don’t know what that approach may be, but I think the first successful artificial heart will NOT be a direct attempt to duplicate the heart in mechanics.. but to duplicate its function.