If I deleted the KardioPAC app on accident, will I need a new password or email?

No, you don't. You just need to re-download the KardioPAC app from the AppStore. After opening it, you can log in by inputting your email and password. If you need help with this you can also follow the steps in the "Getting the App Started" section of your Quick Start Guide that was sent to you in your Kura Care box