IRNF App

by Apple  · Based in United States → — Detecting irregular heart rhythms suggestive of Atrial Fibrillation (AFib) on Apple Watch.
Cardiology Internal Medicine
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Regulatory Status Disclosed

Overview

The Irregular Rhythm Notification Feature (IRNF), also known as IRNF App or IRNF 2.0, is a software-only mobile medical application developed by Apple Inc. It is designed to work in conjunction with Apple Watch and iPhone to analyze pulse rate data collected by the Apple Watch’s photoplethysmography (PPG) sensor. The primary purpose of IRNF is to identify episodes of irregular heart rhythms consistent with Atrial Fibrillation (AFib) and provide notifications to the user.

This feature operates as a background screening tool, meaning users do not initiate individual analyses. When an irregular heart rhythm suggestive of AFib is identified and confirmed, the Apple Watch app notifies the user and transfers this information to the iPhone Health App. The iPhone app also provides onboarding and educational materials that users must review prior to activation, and it displays a history of all prior AFib notifications.

The IRNF is intended for over-the-counter (OTC) use by individuals aged 22 years and over who have not been previously diagnosed with AFib. It is not intended to replace traditional methods of diagnosis or treatment, nor is it designed to provide a notification for every episode of irregular rhythm. Instead, it opportunistically surfaces notifications when sufficient data are available, typically when the user is still.

Note: This tool is a personal health monitoring feature and is NOT an AI tool for a physician directory, as was initially suggested in the prompt.

Reviewed by Pouyan Golshani, MD — Interventional Radiologist

Key Features

  • Irregular heart rhythm detection
  • Atrial Fibrillation (AFib) notification
  • Pulse rate data analysis using Apple Watch PPG sensor
  • Integration with Apple Health app for data storage and management
  • Onboarding and educational materials for users
  • History of AFib notifications
  • Over-the-counter (OTC) use
  • Utilizes machine learning for rhythm classification
  • Compatible with Apple Watch Series 3 and later, and iPhone 6s and later (with specific OS versions)

Use Cases

  • Early detection of potential AFib in asymptomatic individuals
  • Personal heart health monitoring for users aged 22 and over
  • Supplementing a clinician's decision for AFib screening
  • Tracking and reviewing a history of irregular rhythm notifications
  • User education on AFib and heart health

What Physicians Need to Know

ECG/EKG Analysis Capability
The IRNF app itself analyzes pulse rate data via photoplethysmography (PPG) for irregular rhythms. The broader Apple Watch ecosystem includes a separate ECG app that can generate a single-lead ECG waveform and classify it as sinus rhythm, atrial fibrillation (AFib), high/low heart rate, or inconclusive.
Arrhythmia Detection Accuracy
The Irregular Rhythm Notification Feature (IRNF) analyzes pulse rate data from the Apple Watch's PPG sensor to identify episodes of irregular heart rhythms suggestive of AFib. It has demonstrated an AF detection specificity of 99.3%. The feature operates as a background screening tool and opportunistically notifies users of potential AFib when sufficient data is available, typically when the user is stationary.
Cardiac Monitoring Integration
The IRNF is a software-only mobile medical application designed for use with the Apple Watch and iPhone. It analyzes pulse rate data collected by the Apple Watch's photoplethysmography (PPG) sensor. The feature integrates with the iPhone's Health App, allowing users to store, manage, and share their health and fitness data.
Real-Time Alert Capability
The primary function of the IRNF is to issue notifications to the user upon identifying episodes of irregular heart rhythms suggestive of AFib. Notifications are generated if an irregular heart rhythm consistent with AFib is detected and confirmed through multiple readings.
Physician Tip

The IRNF is a valuable screening tool for identifying potential atrial fibrillation (AFib) in asymptomatic individuals, but it is not a diagnostic device and should not replace traditional diagnostic or treatment methods. Physicians should advise patients that any irregular rhythm notifications warrant further medical evaluation to confirm a diagnosis. The app is not intended for use in individuals under 22 years of age or those already diagnosed with AFib. Data collected by the IRNF, accessible through the Health app, can supplement a clinician's decision for AFib screening and ongoing patient management.

The IRNF is intrinsically integrated with the Apple Watch for pulse rate data acquisition via its photoplethysmography (PPG) sensor and with the iPhone's Health App for secure data storage, management, and sharing. This allows for a comprehensive view of a user's heart rhythm history. Users can export their health data from the Health app for sharing with healthcare providers. The Apple Watch also features a separate ECG app, which can provide single-lead ECG recordings to complement the PPG-based irregular rhythm notifications.

Details

Category Cardiology AI, Wearables & Remote Monitoring (RPM)
Pricing Free — Included as a feature with compatible Apple Watch and iPhone models.
DeploymentMobile (iOS, watchOS)
Compliance
BAA Available No AI-estimated
HIPAA CompliantUnknown AI-estimated
FDA Status 1 AI-estimated

The Irregular Rhythm Notification Feature 2.0 (IRNF 2.0) received FDA 510(k) clearance (K212516) on October 22, 2021, as a Class II medical device. It is classified as photoplethysmograph analysis software for over-the-counter use, intended to identify irregular heart rhythms suggestive of AFib.
Integrations
EHR Not specified
Specialties Cardiology, Internal Medicine

What the Web Says

The Apple Watch's Irregular Rhythm Notification Feature (IRNF) is a software-only mobile medical application designed to detect irregular heart rhythms suggestive of atrial fibrillation (AFib) using the watch's photoplethysmography (PPG) sensor. It operates as a background screening tool and integrates with the iPhone's Health App for data management and user education. While generally considered a valuable screening tool, it's not intended to replace traditional diagnostic methods and has limitations regarding its target demographic and the comprehensiveness of its detection.

Overall: Positive

Strengths

  • Opportunistically notifies users of potential AFib when sufficient data is available.
  • Integrates with the iPhone's Health App for storing, managing, and sharing health data.
  • Provides onboarding and educational materials for users.
  • Demonstrated high person-level sensitivity (88.6%) and specificity (99.3%) in clinical validation studies.
  • Accessible, non-invasive, safe, and easy for patients to use.

Limitations

  • Not intended to replace traditional diagnostic or treatment methods.
  • Not tested for use in individuals under 22 years old or those already diagnosed with AFib.
  • Does not catch every instance of irregular rhythm indicative of AFib.
  • Only gathers data opportunistically when the user is stationary.
  • Potential for false positives in low-risk populations, leading to unnecessary stress and tests.

Based on reviews from: Medical News Observer, accessdata.fda.gov

Last updated: 2026-07-17

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Clinical Value
Ease of Use
Integration
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Value for Money

Press & Coverage

accessdata.fda.gov
K212516.pdf - accessdata.fda.gov
The IRNF 2.0 Watch App and iPhone App, a software-only mobile medical application, received FDA clearance in October 2021 for over-the-counter use to identify irregular heart rhythms suggestive of Atrial Fibrillation (AFib) and notify users to seek medical care.
2021-10
MyStrategist
Apple Wins FDA Clearance for Machine Learning-Based AFib Notification - MyStrategist
Apple received 510(k) clearance in October 2021 for an update to its Irregular Rhythm Notification Function (IRNF) app, which now uses machine learning and a convolutional neural network to differentiate between AFib and non-AFib rhythms.
2021-11
JAMA Network Open
Availability of Evidence for Predictive Machine Learning Algorithms in Primary Care - PMC
A systematic review published in September 2024 included the Apple IRNF app as one of 43 predictive machine learning algorithms, noting its 2021 US approval for diagnostic decision support in cardiovascular health.
2024-09
FDA
K212516 - 510(k) Premarket Notification - FDA
This FDA 510(k) Premarket Notification details the regulatory information for the IRNF App, submitted by Apple Inc., under regulation number 870.2790 and classification product code QDB.
2026-01
AIS
Specs of the new Apple Watch SE 3 with AIS
The IRNF App, an irregular rhythm notification feature, is highlighted as a capability of the new Apple Watch SE 3, designed to analyze pulse rate data for signs of AFib, but it is not intended for users under 22 or those with a previous AFib diagnosis.
unknown
Physician Ai Tools
Hypertension Notification Feature (HTNF) vs IRNF App - Physician Ai Tools
The IRNF App is an FDA-cleared, AI-powered tool integrated into the Apple Watch ecosystem, specializing in detecting irregular heart rhythms indicative of Atrial Fibrillation, and benefits from extensive public clinical validation through the Apple Heart Study.
unknown
Orthogonal
SaMD Cleared by the FDA: The Ultimate Running List - Orthogonal
The IRNF App is listed among Software as a Medical Devices (SaMD) cleared by the FDA, with its clearance date noted as October 22, 2021, for cardiovascular use.
2024-10
The Open Public Health Journal
The Progress and Future of Artificial Intelligence in Nursing Care: A Review
A May 2024 review article discusses the Apple Irregular Rhythm Notification Feature (IRNF) app as a medical application that analyzes pulse rate data from the Apple Watch to notify users of Atrial Fibrillation, aiding in post-discharge patient care.
2024-05

Videos

Product demos, reviews, and walkthroughs for IRNF App.

View all on YouTube

Frequently Asked Questions

The IRNF App can integrate with existing Electronic Health Record (EHR) systems to streamline tasks like clinical documentation, data entry, and organization of patient information. This integration allows the AI to access real-time patient data, provide clinical decision support, and automate repetitive administrative tasks, aiming to enhance efficiency and improve patient outcomes.
For an AI tool like the IRNF App to be HIPAA compliant, it must adhere to strict privacy, security, and breach notification rules, including features like end-to-end encryption, access controls, and comprehensive audit trails. Vendors typically sign Business Associate Agreements (BAAs) and employ zero-retention processing, meaning Protected Health Information (PHI) is processed in-memory and immediately discarded without being stored or used for model training.
AI tools, including the IRNF App, can have limitations such as potential for diagnostic errors, variability in interpretation, and the risk of perpetuating biases present in their training data. Over-reliance on AI without human oversight can lead to inaccurate or even harmful recommendations, emphasizing the need for clinicians to validate AI-generated content.
While AI can automate administrative tasks and provide decision support, there are concerns among physicians about potential deskilling, over-reliance on technology, and a reduction in human interaction with patients. The IRNF App is intended to augment, not replace, human intelligence, allowing physicians to focus more on complex cases and patient care by handling routine functions.
Alternatives to AI-powered solutions like the IRNF App include traditional knowledge-based Clinical Decision Support Systems (CDSS) such as UpToDate or DynaMed, which provide evidence-based recommendations and drug information. For administrative tasks, existing EHR functionalities or specialized software for scheduling and billing can serve as alternatives.
Healthcare AI solutions often use subscription-based models, charging recurring monthly or annual fees, which may scale with the number of users or features. Other pricing structures include usage-based models (per patient or per transaction) or hybrid models that combine a base fee with performance-based incentives, aligning costs with clinical or operational outcomes.
If the IRNF App is intended to diagnose, treat, or prevent disease, it would likely be regulated by the FDA as Software as a Medical Device (SaMD), requiring demonstration of safety and effectiveness. The FDA is developing a regulatory framework for AI/ML-based SaMDs that emphasizes data quality, bias analysis, human-AI workflows, and post-market performance monitoring to ensure responsible innovation.

Compare IRNF App

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IRNF App vs EchoNext
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While both tools are FDA-cleared cardiology AI solutions, they serve different primary functions. IRNF App focuses on continuous, passive monitoring for irregular rhythms suggestive of AFib using a…
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IRNF App vs Sleepiz One+
Cardiology AI Adjacent · 65/100
Tool A, the IRNF App, is an over-the-counter software for Apple Watch and iPhone focused on detecting irregular heart rhythms suggestive of AFib for users aged 22 and…
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IRNF App vs Tempus ECG-Low EF
Cardiology AI Adjacent · 60/100
Tool A is a consumer-facing application for detecting irregular heart rhythms suggestive of Atrial Fibrillation using a wearable device, providing notifications directly to the user. In contrast, Tool…
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IRNF App vs Tempus ECG-AF
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These tools are adjacent rather than direct competitors, as they address different aspects of Atrial Fibrillation (AFib) management. The IRNF App is a consumer-facing mobile feature for personal…

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Suggest an Edit → | Last Verified: 2026-04-17 | First Added: 2026-04-17

Investors who backed IRNF App

Funded through the company that built this tool.

Transformer VC
PE T3
Gru00fcnwald, Germany
unknown
Transformer VC is a German-affiliated venture firm with a LinkedIn presence under Transformer Capital but virtually no other public footprint to anchor…
AI/ML in Healthcare Digital Health
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