We are aware of an issue with the most recent build of Instant ECG. The app only shows Sinus and Atrial rhythms inadvertently leaving off other rhythms. We have submitted an update to Apple which will restore all of the functionality as soon as they approve the update. It was submitted Monday Aug 10th (it typically takes apple 3-7 business days to post the update), so early next week it should be updated.
We apologize for the inconvenience!