How about when I'm flying an airplane; I'm also putting my life in the hands of people that wrote the code that controls it and I have to trust that the plane won't shut itself down mid-flight because of faulty code. Should a similar argument be made here?
A pacemaker is something you bought and owned, when flying in a plane you are buying a service, this is similar to earlier discussions about being able to change your car's software under DMCA etc...
A pacemaker is also personal, in that it's something that only you have and for your specific pacemaker the only affected party is you. A specific flight has hundreds of affected people which makes the burden of responsibility (for lack of a better word) shared between many people.