A contactless optical stethoscope for murmur detection compared to standard auscultation and using echocardiography as the clinical reference

ISRCTN	ISRCTN76316123
DOI	https://doi.org/10.1186/ISRCTN76316123
Integrated Research Application System (IRAS)	364868
Protocol serial number	CIP-LS-001
Sponsor	LightHearted AI Health Limited
Funder	LightHearted AI Health Limited

Submission date: 30/10/2025
Registration date: 26/11/2025
Last edited: 23/01/2026

Recruitment status: Not yet recruiting
Overall study status: Ongoing
Condition category: Circulatory System

Prospectively registered

Protocol

Statistical analysis plan

Results

Individual participant data

Record updated in last year

Plain English summary of protocol

Background and study aims
Doctors often listen to heart sounds using a stethoscope to check for problems like heart valve disease. These sounds, called heart murmurs, can sometimes be hard to interpret. A new device called LightScope uses laser technology to listen to the heart without touching the body. The aim of this study is to evaluate how well LightScope supports clinicians in detecting heart murmurs, compared with standard stethoscope auscultation, using transthoracic echocardiography as the clinical reference standard.

Who can participate?
Adults aged 18 years or older may take part in this study. This includes:
a) People with known or suspected valvular heart disease,
b) Individuals with atrial fibrillation, and
c) Participants with normal echocardiographic findings(control participants).

What does the study involve?
Participants will attend a single study visit. During this visit:
a) A trained clinician will listen to the participant’s heart using a standard acoustic stethoscope.
b) The LightScope device will then record heart sounds in a fully contactless manner from specific areas of the chest and neck.
c) The heart sound recordings will be interpreted by clinicians and compared with the participant’s existing echocardiogram results.

What are the possible benefits and risks of participating?
There are no direct health benefits for participants, but the study may help improve future heart diagnosis tools. The risks are very low. LightScope is safe, non-invasive, and does not use harmful radiation. The only small risk is if safety rules are not followed, the laser could accidentally shine into the eye.

Where is the study run from?
LightHearted AI Health Limited (UK)

When is the study starting and how long is it expected to run for?
March 2026 to July 2026

Who is funding the study?
LightHearted AI Health Limited (UK)

Who is the main contact?
Dilip Rajeswari, ops@lighthearted.ai, dilip11235@gmail.com

Contact information

Prof Sandosh Padmanabhan
Public, Scientific, Principal investigator

College of Medicine, Veterinary & Life Sciences
School of Cardiovascular and Metabolic Health
Queen Elizabeth University Hospital
1345 Govan Road
Glasgow
G51 4TF
United Kingdom

Phone	+44 7957 202687
Email	Sandosh.Padmanabhan@glasgow.ac.uk

Mr Dilip Rajeswari
Scientific

1 Barson Close
London
SE20 7HR
United Kingdom

Phone	+44 7522199912
Email	dilip@lighthearted.ai

Study information

Primary study design	Observational
Observational study design	Prospective, observational, comparative, single-centre clinical investigation
Study type	Participant information sheet
Scientific title	Clinical validation of LightScope: a contactless optical stethoscope for murmur detection compared to standard auscultation and using echocardiography as the clinical reference
Study objectives	The purpose of this clinical investigation is to evaluate the diagnostic performance of the LightScope device, a non-contact optical stethoscope, in detecting cardiac murmurs associated with valvular heart disease. The primary objective is to determine the sensitivity and specificity of murmur detection using LightScope phonocardiograms, as interpreted by clinicians, compared to standard auscultation, with transthoracic echocardiography serving as the reference standard. The secondary objectives of the study shall include: assessing inter-rater agreement among clinicians, evaluating the repeatability and signal quality of LightScope recordings, and assessing repeatability of signal acquisition across user settings. The Exploratory endpoints aim to further characterize device performance based on subgroup analyses by valve lesion type, patient demographics (ethnicity, BMI, skin tone), and clinician experience; evaluation of usability metrics (time-to-use, error rates, ease-of-use, qualitative feedback); and a comparative assessment with the Eko Core500 device in a subset of participants. The study aims to generate clinical evidence to support regulatory approval and CE marking of the device under the EU Medical Device Regulation (MDR).
Ethics approval(s)	Submitted 09/01/2026, South East Scotland Research Ethics Committee 2 (South East Scotland Research Ethics Service, Waverley Gate, 2-4 Waterloo Place, Edinburgh, EH1 3EG, United Kingdom; -; Ruth.Fraser4@nhslothian.scot.nhs.uk), ref: -
Health condition(s) or problem(s) studied	Detection of cardiac murmurs associated with normal and valvular heart disease in adult patients undergoing transthoracic echocardiography.
Intervention	This is an observational, comparative study. Each participant will undergo a single study visit during which a clinician will perform standard auscultation using a conventional stethoscope, followed by a non-contact phonocardiographic recording using the investigational LightScope device. The LightScope system captures heart sounds through laser-based speckle vibrometry from the neck and chest region without physical contact. All participants will have undergone transthoracic echocardiography within the preceding 180 days, which will serve as the reference standard for murmur classification. Clinician interpretations of both standard auscultation and LightScope recordings will be compared against echocardiographic findings to assess diagnostic performance.
Intervention type	Device
Phase	Not Applicable
Drug / device / biological / vaccine name(s)	LightScope (contactless optical phonocardiography device), Standard Acoustic Stethoscope, Transthoracic Echocardiography
Primary outcome measure(s)	Murmur detection performance (sensitivity and specificity) measured using clinicians' interpretation of LightScope phonocardiograms, compared with standard auscultation, using transthoracic echocardiography (TTE) as the clinical reference at a single study visit Previous primary outcome(s): Murmur detection performance (sensitivity and specificity) measured using clinicians' interpretation of LightScope phonocardiograms, compared with standard auscultation, using transthoracic echocardiography (TTE) as the clinical reference at a single study visit
Key secondary outcome measure(s)	Inter-rater agreement between clinicians interpreting LightScope phonocardiograms measured using Cohen’s or Fleiss’ kappa statistics at baseline Signal quality of LightScope recordings measured using a 5-point Likert scale rated by clinicians at baseline Clinician diagnostic confidence in murmur assessment using LightScope measured using a 5-point Likert scale at baseline Repeatability of signal acquisition across users and settings measured using the calculation of intra- and inter-user Intraclass Correlation Coefficients (ICC) from repeat recordings within the same session at baseline Ethnicity and body habitus subgroup performance diagnostic outcomes measured using LightScope phonocardiograms and compared with standard auscultation and transthoracic echocardiography (TTE) at baseline Atrial fibrillation subgroup performance diagnostic outcomes measured using LightScope phonocardiograms and compared with TTE once at baseline Device performance across valve types of murmur measured using detection results from LightScope phonocardiograms compared with echocardiographic valve findings at baseline Classification of murmurs by type (systolic, diastolic, ejection, holosystolic) measured using clinician interpretation of LightScope phonocardiograms and validated against echocardiography at baseline Clinician experience-related interpretation differences measured using diagnostic assessments compared across clinician experience levels at baseline Usability feedback from clinicians and participants measured using data collected via structured usability questionnaire and a brief interview at baseline Usability assessment in self-directed or booth-based workflow (subset of approximately 60 participants) — time-to-use, error rate, and user feedback measured using data recorded through observation and structured questionnaire at baseline Comparative signal quality and murmur detection LightScope performance compared with Eko Core500 digital stethoscope measured using blinded clinician rating at baseline -
Completion date	15/07/2026

Eligibility

Participant type(s)	Healthy volunteer, Patient
Age group	Mixed
Lower age limit	18 Years
Upper age limit	100 Years
Sex	All
Target sample size at registration	150
Key inclusion criteria	1. Aged 18 years or older at the time of consent. 2. Undergoing or having undergone transthoracic echocardiography within the past 180 days, with documentation available. 3. Able and willing to provide written informed consent prior to participation. 4. Able to comply with study procedures and optional follow-up requirements, if applicable.
Key exclusion criteria	Current key exclusion criteria as of 23/01/2026: 1. Presence of an active skin infection, open wound, or dermatological condition over the neck or chest areas where the LightScope measurements would be performed. 2.Known diagnosis of congenital heart disease 3.Any cognitive, psychiatric, or physical condition that, in the opinion of the investigator, would impair the participant’s ability to comply with study procedures or provide reliable informed consent. 4. Pregnancy 5. Any previous surgical procedure or anatomical abnormality that prevents reliable recording of heart sounds from the standard measurement sites 6. Participants who are currently or have recently been involved in other research studies may be recruited, provided that their participation does not conflict with this investigation or pose any additional safety risk. As this is a non-invasive, observational study involving only contactless recording of heart sounds, clinical echocardiography and digital stethoscope auscultation, there are no overlapping safety or design considerations that would preclude co-enrolment. Each participant’s eligibility will be confirmed by the investigator prior to inclusion to ensure there are no protocol or safety conflicts with concurrent studies. _____ Previous key exclusion criteria: 1. Presence of an active skin infection, open wound, or dermatological condition over the neck or chest areas where the LightScope measurements would be performed. 2. Known diagnosis of congenital heart disease, unless a specific subgroup analysis for congenital lesions is planned. 3. Any cognitive, psychiatric, or physical condition that, in the opinion of the investigator, would impair the participant’s ability to comply with study procedures or provide reliable informed consent. 4. Any previous surgical procedure or anatomical abnormality that prevents reliable recording of heart sounds from the standard measurement sites.
Date of first enrolment	24/03/2026
Date of final enrolment	17/06/2026

Locations

Countries of recruitment

United Kingdom
England

Study participating centre

Healthcare Central London Ltd

South Westminster Center for Health, St George's House, 82 Vincent Square
London
SW1P 2PF
England

Results and Publications

Individual participant data (IPD) Intention to share	No
IPD sharing plan summary	Data sharing statement to be made available at a later date
IPD sharing plan

Study outputs

Output type	Details	Date created	Date added	Peer reviewed?	Patient-facing?
Participant information sheet	Participant information sheet	11/11/2025	11/11/2025	No	Yes

Editorial Notes

23/01/2026: The following changes were made to the study record:
1. Ethics details added.
2. The Completion date was changed from 15/04/2026 to 15/07/2026
3. The primary outcome(s) were changed.
4. The key exclusion criteria were changed.
5. The Date of first enrolment was changed from 15/01/2026 to 24/03/2026
6. The Date of final enrolment was changed from 15/04/2026 to 17/06/2026
7. The plain English summary was updated to reflect these changes.
24/11/2025: Study’s existence confirmed by the LightHearted AI Health Limited, UK.