A newly developed handheld medical device could potentially replace a stethoscope as a tool for detecting valvular heart disease, UK researchers report.
Unlike a stethoscope, the flexible multi-sensor device could be used by people without medical training to record heart sounds and could capture high-quality sounds when used over a patient’s clothing.
Reporting a proof-of-concept and validation study in the IEEE Journal of Biomedical and Health Informatics, researchers from the University of Cambridge said valvular heart disease was one of the most common causes of heart failure and had been described as the next ‘cardiac epidemic’.
Yet they noted more than half of patients with significant valvular heart disease remained undiagnosed, and more than half of patients in Europe received surgery too late, when surgery was less effective.
‘A key reason for this underdiagnosis is that accurate cardiac auscultation requires significant skill and can be a time-consuming and intimate process,’ they wrote.
Of note, they found auscultation was only performed on 35% of UK patients with symptoms indicative of valvular heart disease, and female patients were less likely to receive a complete cardiac exam.
In the UK, the NHS and NICE have identified early detection of heart valve disease as a key goal for improving patients’ quality of life and reducing healthcare costs.
How the device works
The newly developed device, which fits in the palm of the hand, has six high-sensitivity piezoelectric sensors embedded in a flexible substrate of silicone gel and is placed at key auscultaton locations by the patient.
The six sensors, compared with one on a digital stethoscope, increased the likelihood of capturing high-quality signals from the key auscultation sites and eliminated the need for skilled chest placement, they explained.
‘To address challenges from localised heart sound vibrations and noise interference, we developed time-frequency signal quality algorithms that automatically select the best sensor in the device and reject recordings with insufficient diagnostic quality,’ the study authors wrote.
In the study, researchers asked 40 healthy participants with a diverse range of ages and body mass index (BMI) measurements to use the device to record their heart sounds, with an expert researcher in the room to make sure the device was placed at the correct points.
For males, the device performance was deemed excellent at the three main auscultation sites: aortic, mitral and tricuspid. Every male participant achieved a passable recording at tricuspid and mitral sites regardless of BMI, the researchers reported.
There were similar results from the device for normal and underweight female participants, but performance was reduced for females with a higher BMI at tricuspid and mitral sites.
‘The impact of BMI was further compounded when recordings were attempted whilst patients wore a bra,’ they noted.
The researchers suggested future iterations of the device could use real-time signal quality feedback to guide the users on where to place the device to obtain an optimum signal and that female users could be asked to make a first attempt with a bra and then remove it if the signal quality was insufficient.
Further research would also be needed to assess if unsupervised patients could use the device, perhaps with directions from an instruction manual or smartphone app, they said.
Supporting early diagnosis of valvular heart disease
Senior study author Professor Anurag Agarwal, head of the Fluids Group and the Acoustics Lab at the University of Cambridge’s Department of Engineering, said the accuracy of stethoscope examination for diagnosing valvular heart disease was fairly poor, and required a clinician to conduct the examination.
‘To make sure we’re diagnosing heart valve disease early enough that simple interventions can improve quality of life, we wanted to develop an alternative to a stethoscope that is easy to use as a screening tool,’ he said.
‘If successful, this device could become an affordable and scalable solution for heart health screening, especially in areas with limited medical resources.’
The next step will be a prospective clinical study in a representative patient population, where the device will be integrated with a machine learning algorithm to support automated screening for valvular heart disease.
Cambridge Enterprise – the university’s commercialisation arm – has filed a patent on the device.
