Most pacemakers on the market nowadays, thanks to the megamonopoly union, are manufactured with cheap storage that has a ton of extra space inexplicably stored on its embedded hardware. If you force the device to readdress itself by burning out the first few pages, you can load whatever OS you want onto the hardware. You lose access to all of the manufacturer code, but with a little effort you can easily reach 20x the speed that they normally allow you to set. If you need a quick system flush, or are just looking for something to do for fun, I'd recommend 2900-3000 oscillating bpm. I find the arrhythmia gives a nice headrush