New Pacemaker Uses the Heartbeat to Recharge its Battery

So a person gets a pacemaker because their heart doesn't always beat enough times per minute. And we are supposed to depend on a device that depends on said malfunctioning heart to keep the pacemaker working? Pacemaker surgery is very routine and you are in and out. They need to make a longer lasting battery. At the end of the day, other than a wound infection, the replacement battery process is a very simple surgery.