An Extra Layer of Awareness for Your Heart

Cardiac
Alarm

High-frequency heart rate monitoring for your Apple Watch. If your pulse drops below 33 bpm or is no longer detected, a loud siren sounds from your wrist to alert those nearby.

Engineered for added awareness in Brugada syndrome and SCN5A-related conditions.

Download

33 bpm

Fixed Safety Threshold

Loud Siren

Designed to notify your surroundings

Test Mode

Customizable threshold for siren testing

See Why It Matters

Real-time pulse tracking. High-volume alerts when a drop is detected.

How It Works

Three silent steps. One loud alarm when it counts.

Step 01

Monitor

Cardiac Alarm is officially authorized for Apple Critical Alerts. It continuously monitors your heart rate in real time — even in the background or with the screen off.

Step 02

Detect

The moment your heart rate drops below the critical 33 bpm threshold or if your pulse cannot be detected — the app instantly identifies the emergency event.

Step 03

Alert

A loud siren sounds on your Apple Watch to wake nearby family members within seconds. Apple Critical Alerts ensure the alarm pierces through Silent, Sleep, and Low Battery modes instantly.

Why 33 BPM?

The threshold of 33 BPM is a deliberate, hard-coded monitoring threshold. In certain cardiac conditions, rapid or chaotic rhythms can lead to a sudden drop in detectable peripheral pulse. Cardiac Alarm monitors these trends at the wrist, identifying significant drops or signal loss. This fixed threshold is engineered to minimize false alerts while maintaining a high level of vigilance during your monitoring sessions.

Technical Specifications

Built exclusively for the Apple Watch to guarantee maximum reliability and precision.

Apple Watch Integration

Compatibility

Apple Watch Series 4, SE, or later · watchOS 9.0+

Sensor

Optical heart sensor (photoplethysmography)

Reading frequency

Continuous background heart rate via HealthKit

Apple Critical Alerts Approval

Bypasses Silent, Sleep, and Focus modes

Alert System

Alarm type

High-decibel audio siren via iPhone speaker at max volume

Trigger threshold

Fixed at 33 BPM to eliminate user error and ensure safety

False Alarm Prevention

Smart reading confirmation and multi-stage verification

Test Mode

Instant testing of critical alerts via custom triggers

Reliability & Privacy

Data storage

All data processed on-device — never sent to external servers

HealthKit

Fully integrated with Apple Health — read-only permissions

Battery optimised

Engineered for minimal drain

System Requirements

Apple Watch

Series 4, SE, or later · watchOS 9.0+

iPhone

iPhone 8 or later · iOS 16.0+

Permissions

Critical Alerts and other required permissions must be enabled for full app functionality

Connectivity

Works standalone on Apple Watch

Rest easy
with added awareness.

Cardiac Alarm alerts those nearby if a low pulse is detected while you sleep.