Delineating EKG data for users. The absence of Guest Mode limits the experience for shared users, making it harder to design for real-world use cases and show inclusive, growth-oriented thinking.
Kardia is a leading personal EKG device and app. This project focused on closing a specific gap: guest EKG recording.
Missed opportunity to acquire potential users.
Users unable to save recordings for others, creating friction in shared use.
Guest recordings polluted primary user data, reducing insight accuracy.
The user could only save a recording from the Instant Analysis screen — with no way to attribute it to a guest.
By forcing a “Save & Close” action at the end of a personal medical analysis, the app failed to account for shared users, forcing them to pollute the primary user's data or abandon the flow entirely.

Users were often unaware that guest recording was even an option.
EKGs recorded by guests without proper identification compromised the accuracy of the app’s insights for the primary user.
The existing flow did not capture guest user information, hindering future user acquisition.
One seamless guest recording experience, embedded in the existing flow — no separate mode, no disruption.

Understanding the Kardia user base. Guest users are typically spouses, family, and friends.
Iterating through mobile UI screens, integrating medical-grade accuracy with consumer-friendly aesthetics.
Reiterating on feedback through user flows and brainstorming sessions.
Asking users who is recording before it begins has faced resistance historically and doesn't serve the best experience.
Not ideal — hands are engaged with the Kardia device during recording.
Ideal. Confirm who recorded the EKG after the fact.

Checkbox at the bottom of the result page before saving.
Mid-page context box integrated with the clinical data.
Explicit assignment via a dropdown selector before the primary action.
Ideation 3 — Winning Flow
Existing Flow

We selected Ideation 3. It reduced friction for existing users while keeping options open for Guest users — an explicit, inline selection before the primary action.


Guest recording over time (avg. figures, since Q3 2024)
User mental models dictate how users navigate through a flow.
Understanding constraints and goals early on shapes the optimal design.
Better UI should not come at the cost of worse UX.
I believe identifying a guest even before the recording begins needs to be tested more. The intent for a user before recording is vastly different than a user who just wants to view the result post-recording.