Yitian Zhao ¹ and Quincy Stokes ² , ¹ USA, ² University of California, USA

Sudden cardiac arrest claims approximately 350,000 lives annually in the United States, with survival heavily dependent on immediate bystander CPR and rapid AED deployment. Heart Angel is a cross-platform mobile application built with Flutter that addresses this challenge through three integrated components: an accelerometer-based CPR feedback engine providing real-time compression quality assessment via audio and visual cues, a GeoJSON-powered AED locator displaying defibrillator locations on an interactive map, and a Firebase Cloud Functions-driven emergency notification system that dispatches GPS-targeted alerts to nearby CPR-certified community responders. Key challenges including accelerometer noise filtering, audio-visual synchronization, and secure notification delivery were resolved through configurable threshold calibration, timer-synchronized evaluation cycles, and server-side Cloud Function architecture. Experimental evaluation demonstrated 85.3% overall compression classification accuracy across 150 manikin-based trials. Compared to existing standalone CPR training or AED locator applications, Heart Angel provides a unified platform bridging training and real-world emergency response, empowering laypersons to act effectively during cardiac emergencies.

Cardiopulmonary Resuscitation (CPR), Mobile Health (mHealth), Accelerometer-Based Feedback, Automated External Defibrillator (AED) Locator, Emergency Push Notifications