I'm not sure that's a foregone conclusion. Loads of interventions put extra pressure on other body systems (often, but not always, the liver and kidneys). Sometimes to the extent that even if you may "manage" the original complaint, it comes at a substantial cost to overall health. And heart muscle is pretty special anyway, so it's quite possible it's a separate treatment to skeletal muscle problems.

And pretty much any system failing can kill you so if long term life extension comes from targeted treatments per problem, you need to hit bones and cartilage, muscles, skin, nerves, brain, GI tract, kidneys, liver, immune system, endocrine system, lungs, etc etc, but also not overstress any one with the treatments of the others and also handle almost-inevitable cancers.