User Manual
V1.4.0

Record ID:	MDRTH-IFU-H
Record Revision:	B
Record Issue Date:	16.07.2026

Instructions for Use are supplied electronically; the paper format is available on request at contact@happitech.com

Product

Name: Cardiovascular Monitoring Application Software

Model: Heart Rhythm SDK

Basic UDI-DI: 08720299815001

UDI-PI: V1.4.0-D20240917

Electronic Instructions for Use

These Instructions for Use are provided in electronic form within the Heart Rhythm SDK application, in accordance with Commission Implementing Regulation (EU) 2021/2226, as amended by Regulation (EU) 2025/1234 on electronic instructions for use of medical devices.

The most current version of the Instructions for Use is accessible within the app and this webpage: happitech.com/ifu-heart-rhythm-sdk

The Instructions for Use are served via a static link embedded in the application. Users always access the current version directly when opening the IFU within the app; no local copy is cached and no user action is required to receive updated content.

A paper copy of the Instructions for Use is available free of charge upon request. To request a paper copy, contact Happitech B.V. at info@happitech.com. Happitech will provide the paper copy within 7 calendar days of receiving the request.

The content of the electronic Instructions for Use is equivalent to any paper version provided. In the event of any discrepancy, the electronic version within the app shall be considered the current authoritative version.

Introduction

Product Description

Heart Rhythm SDK is a software-only mobile medical application that is intended to be used with iOS and Android smartphone cameras to measure heart rate, heart rate variability, and heart rhythm data. The device analyzes and displays this data in graphic form that can be used to provide information for identifying atrial fibrillation and sinus rhythm, and transmits the information for remote review.

Intended Purpose

Heart Rhythm SDK is a software-only mobile medical application intended for use with iOS and Android smartphone cameras to measure heart rate, heart rate variability, and heart rhythm (including atrial fibrillation and normal sinus rhythm). The software analyzes and displays the data in graphical form and may transmit the information for remote review.

Heart Rhythm SDK is classified as Software as a Medical Device (SaMD). It can function as a standalone mobile application or be integrated into Digital Health and Telehealth applications to support telemonitoring and remote patient management.

The Heart Rhythm SDK is a compiled software library that provides a SaMD solution without additional hardware dependency. It utilizes photoplethysmography technology to capture the pulse rhythm and analyze heart rate and rhythm parameters.

Heart Rhythm SDK is intended for monitoring and screening for atrial fibrillation. It is indicated for self-testing by patients who have been diagnosed with, or are at risk of developing, atrial fibrillation and who wish to monitor and record their heart rhythms on an intermittent basis.

General Safety Information

Heart Rhythm SDK is not an emergency service. In the event of acute or concerning symptoms, the user must seek immediate medical attention. The software is not intended to be used for diagnosis or treatment of a medical condition. Users are advised to consult a qualified healthcare professional regarding any questions or concerns related to their health status.

Product features (Functional description)

The Heart Rhythm SDK can measure heart rate, heart rate variability, and heart rhythm (either Normal Sinus Rhythm or Atrial Fibrillation).

The sensitivity and Specificity of Atrial Fibrillation is 98% based on the clinical trial conducted at OLVG Hospital. Heart Rate accuracy is 95% and Heart Rate variability is 86.7%

The SDK consists of the following components:

How Heart Rhythm SDK Works

Through the technology of photoplethysmography (PPG), which is an optical technique that measures light reflected in the blood, the Heart Rhythm SDK detects volumetric changes in blood in peripheral circulation at the surface of the skin. The Heart Rhythm SDK uses the smartphone camera to gather raw PPG data. The raw PPG data is used as input for the Heart Rhythm SDK to process the information. After the Heart Rhythm SDK processes the information, the measurement results (heart rate, heart rate variability, and heart rhythm) are shared with the user.

Recommendations

General

This Instruction for Use (IFU) deals with the specifications, operation, and maintenance of the Heart Rhythm SDK medical software. Happitech is by no means responsible for any malfunction or accident arising from a user ignoring the instructions for use and maintenance described in this IFU.

This IFU contains a description of all the functions available, please read this IFU carefully and familiarize yourself thoroughly with its contents before operating the unit. If any technical problem should arise, please contact Happitech technical support at contact@happitech.com.

Heart Rhythm SDK has no known side effects.

Residual Risks

All risk control measures have been implemented and verified. All identified risks have been reviewed and reduced to an acceptable level. Some risks remain as residual risks, and are described below.

• If you are experiencing complaints, please contact your healthcare professional regardless of the result.
• Please follow the digital health company’s instructions for downloading and updating the application and for sending your measurement.
• Please be aware of security vulnerabilities on the internet. Protect your smartphone or tablet against malware and ransomware.
• Please read the full contents of these Instructions for Use carefully before use.
• Despite the implemented cybersecurity measures, residual risks remain, including potential unauthorized access to data if the device is used on a compromised or unsecured system. Operate the application only on secure, unmodified devices with an up-to-date operating system.
• A result provided by Heart Rhythm SDK is not a diagnosis. Any result requires confirmation and interpretation by a qualified healthcare professional.

Warnings

• User needs to remain as still as possible during the measurement ideally seated;
• Where a person uses medication or an implanted device that regularizes the heartbeat, the pulse will also appear regular and the rhythm result may be unreliable. Such use falls outside the intended patient population. See Intended Patient Population, Limitations of Use.
• User should interrupt measurement if LED is too hot;
• User should remove phone case while using Heart Rhythm SDK to avoid heat accumulation;
• User finger should be properly positioned before measurement;
• User shouldn’t move finger during measurement;
• User shouldn’t speak during measurement;
• If the battery level is less than 10%, recharge the battery and start the application;
• The user might need an internet connection during the measurement
• User should have mild to warm temperature hands for optimal measurement
• If the result is of low quality, the user should take another measurement

Contraindications

Heart Rhythm SDK is contraindicated for:

• Persons unable to follow the measurement instructions, due to excess movement or to an inability to read or hear the instructions.
• Persons with cold fingertips or low perfusion in the fingertips, as these conditions prevent a valid measurement and will display an “Insufficient Quality” warning.

Intended Users

Heart Rhythm SDK is intended for adult patients (18 years and older) who are suspected of having, or at risk for, atrial fibrillation, or who wish to monitor their general heart rhythm for health purposes. Users are expected to have access to a smartphone (iOS or Android) and basic familiarity with mobile applications. Users may have low to high levels of education and varying levels of technological proficiency.

The device is intended for use by the general population, including health-conscious individuals, patients with known or suspected heart conditions, and those interested in intermittent self-monitoring of heart rhythm.

Exclusions and limitations applicable to intended users are defined under Intended Patient Population, Limitations of Use.

Intended Patient population

Heart Rhythm SDK is intended for use by adult patients (18 years and older) with known or suspected cardiac arrhythmias, including atrial fibrillation. It may also be used by health-conscious individuals for self-monitoring of heart rhythm parameters, provided they understand the limitations of use.

The relevant patient groups include, but are not limited to:

• Patients with a diagnosis of atrial fibrillation who require intermittent rhythm monitoring.
• Patients suspected of having paroxysmal or persistent atrial fibrillation, including those referred by a healthcare professional for rhythm monitoring.
• Patients experiencing transient symptoms potentially suggestive of arrhythmia (e.g., palpitations, dizziness, lightheadedness, syncope of unknown origin, dyspnea).
• Patients undergoing treatment where monitoring of rhythm and rate control is clinically indicated (e.g., pharmacological therapy for atrial fibrillation).
• Patients recovering from cardiac surgery, interventional procedures, or cardioversion, where post-procedure rhythm monitoring is required.
• Undiagnosed individuals with risk factors for atrial fibrillation who may require screening.

Limitations of Use

• Persons under the age of 18 years.
• Persons with implanted cardiac devices (e.g., pacemakers, implantable cardioverter-defibrillators) or taking medications that regularize the heartbeat, as pacing or rate regularization may confound rhythm detection.
• Persons with conditions that cause tremors or that prevent holding the hand still for at least 90 seconds (e.g., Parkinson’s disease, dementia), which may prevent accurate measurement.
• Persons unable to follow the measurement instructions, whether due to excess movement or to a physical or cognitive limitation affecting the ability to read or hear instructions.
• Persons with reduced peripheral blood flow in the fingertips (e.g., perniosis, callus formation), cold fingers, or recent exposure to a cold environment, as these conditions may prevent sufficient photoplethysmography signal detection.
• Users in critical care or life-threatening scenarios.

The following limitations apply to the use of the device:

• The device is not intended for continuous monitoring or for emergency medical use.
• The device measures pulse rhythm rather than heart rhythm, and may not capture all rhythm changes.
• Where signal quality is insufficient, including as a result of cold fingertips or low perfusion, the software displays an “Insufficient Quality” warning and no result is provided.
• Any medical diagnosis, treatment decision, or clinical intervention based on the data requires confirmation and interpretation by a qualified healthcare professional.

Compatibility

Software requirements

The minimum system requirements for the Heart Rhythm SDK application are an Android operating system with minimal software version Android 8.0 or an iOS operating system with minimal software version iOS 13.

Hardware requirements

iOS

iPhone 8	iPhone 11 Pro Max	iPhone 14 Pro
iPhone 8 Plus	iPhone 12	iPhone 14 Pro Max
iPhone SE 2nd Gen	iPhone 12 Mini	iPhone 15
iPhone SE 3rd Gen	iPhone 12 Pro	iPhone 15 Plus
iPhone X Global	iPhone 12 Pro Max	iPhone 15 Pro
iPhone X GSM	iPhone 13	iPhone 15 Pro Max
iPhone XR	iPhone 13 Mini	iPhone 16
iPhone XS	iPhone 13 Pro	iPhone 16 Plus
iPhone XS Max Global	iPhone 13 Pro Max	iPhone 16 Pro
iPhone 11	iPhone 14	iPhone 16 Pro Max
iPhone 11 Pro	iPhone 14 Plus	iPhone 16e

Android

Fairphone 4	Samsung Galaxy A20e	Samsung Galaxy A56	Samsung Galaxy S23 FE
Google Pixel 6a	Samsung Galaxy A22 5G	Samsung Galaxy A6 (2018)	Samsung Galaxy S23 Ultra
Google Pixel 7	Samsung Galaxy A23 5G	Samsung Galaxy A7 (2018)	Samsung Galaxy S23+
Google Pixel 7a	Samsung Galaxy A25	Samsung Galaxy A70	Samsung Galaxy S24
Google Pixel 8a	Samsung Galaxy A26	Samsung Galaxy A71	Samsung Galaxy S24 FE
Huawei P30 lite	Samsung Galaxy A32	Samsung Galaxy A72	Samsung Galaxy S24 Ultra
Motorola Moto G84	Samsung Galaxy A32 5G	Samsung Galaxy A8 (2018)	Samsung Galaxy S24+
ONEPLUS NORD	Samsung Galaxy A33 5G	Samsung Galaxy J6	Samsung Galaxy S25
OnePlus Nord 2T	Samsung Galaxy A34	Samsung Galaxy S10	Samsung Galaxy S25 Ultra
OnePlus Nord 4	Samsung Galaxy A35	Samsung Galaxy S10+	Samsung Galaxy S25+
Oppo A53s	Samsung Galaxy A36	Samsung Galaxy S10e	Samsung Galaxy S8
Samsung Galaxy A10	Samsung Galaxy A40	Samsung Galaxy S20 5G	Samsung Galaxy S9
Samsung Galaxy A12	Samsung Galaxy A41	Samsung Galaxy S20 FE	Samsung Galaxy S9+
Samsung Galaxy A12 NACHO	Samsung Galaxy A42 5G	Samsung Galaxy S20 FE 5G	Samsung Galaxy Xcover 5
Samsung Galaxy A13	Samsung Galaxy A5 (2017)	Samsung Galaxy S20+ 5G	Samsung Galaxy Z Flip5
Samsung Galaxy A13 (SM-A137)	Samsung Galaxy A50	Samsung Galaxy S21 5G	Samsung Galaxy Z Flip6
Samsung Galaxy A13 5G	Samsung Galaxy A51	Samsung Galaxy S21 FE 5G
Samsung Galaxy A14	Samsung Galaxy A52	Samsung Galaxy S21 Ultra 5G
Samsung Galaxy A14 5G	Samsung Galaxy A52 5G	Samsung Galaxy S21+ 5G
Samsung Galaxy A15	Samsung Galaxy A52S 5G	Samsung Galaxy S22 5G
Samsung Galaxy A15 5G	Samsung Galaxy A53 5G	Samsung Galaxy S22 Ultra 5G
Samsung Galaxy A16	Samsung Galaxy A54	Samsung Galaxy S22+ 5G
Samsung Galaxy A16 5G	Samsung Galaxy A55	Samsung Galaxy S23

Software requirements

iOS 13 and up
Android 8.0

Product Installation

For Telehealth Users:

If you’re using this medical device through a telehealth organization, please follow the organization’s instructions for installing, logging in, and accessing the Heart Rhythm SDK within their app. Refer to the installation guide provided by the telehealth organization.

For Non-Telehealth Users:

If you’re using this device independently of a telehealth platform, you can download the app from the Apple App Store or Google Play Store by searching for “Happitech Heart Rhythm App.” Ensure you have a stable internet connection for the download. Once installed, open the app to access the Heart Rhythm SDK.

Product Specifications

Heart Rhythm SDK Measurement

Performing a measurement

Click on the Digital Health App icon to open their app and follow their instructions to open the Heart Rhythm SDK. You will be asked if you are currently experiencing any cardiac symptoms and to indicate your symptoms. The screens then guide you to perform a sound check and to request access to the smartphone camera.

Before the measurement starts, a short tutorial of 4 screens provides clear instructions on how to create an optimal environment for measuring. After the tutorial, you will be instructed on what camera lens to place your finger. The SDK will automatically detect what type of smartphone and correct camera lens is used for the measurement. A custom animation is shown to guide you to the correct camera lens on the smartphone in addition to a visual viewer where you can see visual feedback on where your finger is being placed. Once the correct finger placement has been detected you will be requested to turn your phone upside down with your finger on the camera lens and to sit comfortably.

The voice guidance will inform the you that the measurement has started. Throughout the duration of the measurement, the voice guidance will provide you with the time remaining, along with any corrective actions that are needed during the measurement.

You will have to keep their finger on the smartphone camera lens for 90 seconds. Once the measurement is completed, you will be alerted by voice guidance that the measurement is complete.

Results You Might See

After you complete a measurement, you will see one of the following results on the results screen.

Errors you Might See

First No Finger Detected error

This error screen is shown when you have not placed your finger on the correct camera lens after the first forty-five (45) seconds. This error screen will instruct you how to properly place your finger.

Final No Finger Detected error

This error screen is shown when you remove your finger from the camera lens for more than five (5) seconds during a 90 second measurement or if you have not placed your finger after the first forty-five (45) seconds once the measurement has started.

Too Much Movement error

This error screen is shown when you have too much movement during the measurement and the data received is of insufficient quality. This could be caused by your hands shaking throughout the measurement or by you or your phone moving during the measurement.

Insufficient Quality error

This error screen is presented when the signal of the measurement is of insufficient quality. You are recommended to perform the measurement again following the instructions carefully, and to not take a measurement with cold hands. This error could appear for a couple of different reasons as bad lighting, cold fingers, and too much or too little pressure on the camera lens.

Measurement Interrupted error

This error screen is shown when during the measurement you have any type of system interruption: incoming calls, low battery alert, etc., or the application closing/minimizing, you clicking on the Back button while measurement is ongoing, or you pull the top system menu down the measurement will be interrupted.

Final error

This error screen is shown after you have three (3) unsuccessful attempts. After three (3) unsuccessful measurements you are requested to take a measurement at a later time and to read the instructions carefully.

Messages/Indicators

INDICATOR	MEANING
Please accept access to Camera and Video	Access is needed for using the video camera to measure your heart rhythm
Please sit still and do not move	The quality of the measurement is affected during movement. It is advised to stay as still as possible during the measurement.
Please do not press on the camera lens	The quality of the measurement is affected when pressing on the camera lens. Lay your finger gently on the camera lens.
Battery too low	The quality of the measurement is affected when the battery is running low. Charge your phone to over 10%

Error Codes

Heart Rhythm SDK has no alarms.

Code	Message	Meaning
ERROR-1	FINGER_ERROR	User has not placed finger correctly for 30 seconds
ERROR – 2	CAMERA_HAS_NO_PERMISSION	User has not given the app permission to access camera
ERROR – 3	BAD_FINGER_POSITION	User has not places finger fully on the camera lens for an extended period of time.
ERROR – 4	TOO_MUCH_MOVEMENT	User is moving too much.

Maintenance

Happitech will provide updates to the app upon big changes in the operating Apple and Android operating system at least 1 time a year. Moreover upon introduction of a new special camera, the devices are tested and added to the included devices.

Troubleshooting

Troubleshooting table

Observation	Potential Cause	Action
No Camera access	Pressed no access to the Camera	Settings -> Apps -> Camera Access
Measurement won’t start	Portrait Orientation Locked	Unlock Portrait orientation
Battery Low	Battery percentage below 10%	Please charge the phone

Contact Details

For more information or questions, please contact us at contact@happitech.com

In case of injury or serious incidents that have occurred in relation to the device must be reported to:

(1) the legal manufacturer via contact@happitech.com
(2) the local competent authority

Symbols

Symbol	Title/ Meaning	Function/ Description
	Operator’s manual; operating instructions	To identify the location where the operator’s manual is stored or to identify information that relates to the operating instructions. To indicate that the operating instructions should be considered when operating the device or control close to where the symbol is placed.
	CE approved product	Mark of conformity according to the European Medical Device Regulation (EU) 2017/745 , stating the manufacturer’s Notified Body.
	Manufacturer	To identify the manufacturer of a product. This symbol shall be used filled in all applications to differentiate it from ISO 7000-2497
	Medical Device	Indicates the item is a medical device
	Catalog number	Indicates the manufacturer’s catalog number so that the medical device can be identified
	Date of Manufacture	Indicates the date when the medical device was manufactured.
	Patient information website	Indicates a website where a patient can obtain additional information on the medical product.
	Unique device identifier	Indicates a carrier that contains unique device identifier information

Regulations and standards

Medical software Heart Rhythm SDK is classified according to MDR Annex VIII Class IIa, Rule 11. Heart Rhythm SDK is classified as Class B according to IEC 62304:2006/A1:2015 – Medical device software — Software life cycle processes. The device complies with the following product standards:

• IEC 62304:2006/A1:2015 – Medical device software – Software life cycle processes
• EN 62304:2006/AC:2008 – Medical device software — Software life cycle processes
• ISO 13485:2016 – Medical devices – Quality management systems – Requirements for regulatory purposes
• FDA QSR 21 CFR Part 820 – Medical Devices – Quality System Regulation
• IEC 82304-1:2016 – Health Software – Part 1: General requirements for product safety
• Medical Device Regulation – Regulation (EU) 2017/745 of the European Parliament and of the Council of 5 April 2017 (MDR)
• EN ISO 14971:2019 – Medical devices — Application of risk management to medical devices
• IEC 62366-1:2015 – Medical devices – Part 1: Application of usability engineering to medical devices
• ISO 15223-1:2021 – Medical devices – Symbols to be used with medical device labels, labeling and information to be supplied – Part 1: General requirements
• EN ISO 15223-1:2021 – Medical devices – Symbols to be used with medical device labels, labeling and information to be supplied – Part 1: General requirements