Development of a Smartphone App for Visualizing Heart Sounds and Murmurs

Abstract

Background: Auscultation is one of the basic techniques for the diagnosis of heart disease. However, the interpretation of heart sounds and murmurs is a highly subjective and difficult skill. Objectives: To assist the auscultation skill at the bedside, a handy phonocardiogram was developed using a smartphone (Samsung Galaxy J, Android OS 4.4.2) and an external microphone attached to a stethoscope. Methods and Results: The Android app used Java classes, “AudioRecord,” “AudioTrack,” and “View,” that recorded sounds, replayed sounds, and plotted sound waves, respectively. Sound waves were visualized in real-time, simultaneously replayed on the smartphone, and saved to WAV files. To confirm the availability of the app, 26 kinds of heart sounds and murmurs sounded on a human patient simulator were recorded using three different methods: a bell-type stethoscope, a diaphragm-type stethoscope, and a direct external microphone without a stethoscope. The recorded waveforms were subjectively confirmed and were found to be similar to the reference waveforms. Conclusions: The real-time visualization of the sound waves on the smartphone may help novices to readily recognize and learn to distinguish the various heart sounds and murmurs in real-time.

Development of a Low-Cost Wireless Phonocardiograph With a Bluetooth Headset under Resource-Limited Conditions

“…Hence, recorded audio files can be played or further analyzed on the receivers’ mobile phone or PC. This facility is also available for wire-connected devices [2,3,4,5]. In WiPCGh, as the Bluetooth headset is still a functional headset, the user can immediately play the audio file on the headset.…”

“…This is an added advantage of WiPCGh. It is not possible on wire-based devices where the only microphone is used and the speaker of the earphone is sacrificed [2,3,4].…”

“…The author suggested that this earphone may be either connected to a mobile device or a personal computer to record the heart sounds [2]. Mamorita et al used a similar type of device while developing an application for phonocardiography [3]. This type of earphone-based device was also reported by Bhimani et al [4].…”

CardioER® - Using smartphone medical applications as an aid to clinical decision-making – are we ready for this?

“…Within cardiology, some smartphone applications have become popular in recent years and allowed the publication of data related to their use and viability 6,[10][11][12][13][14][15][16][17][18][19] .…”

Phonocardiography: new opportunities in the light of digital technologies

“…Как правило, подобные системы отли-чаются малым размером, высокой пропускной способно-стью, низкой стоимостью, возможностью уменьшения звуковых помех с помощью шумоподавителя. Подобные системы могут быть реализованы на основе персонального компьютера, ноутбука [5], смартфона с внешним микрофо-ном [6]. Компактность аппаратного решения и беспровод-ной характер регистрации позволяют использовать их как в домашних условиях (что удобно для пожилых больных и людей с ограниченными возможностями здоровья), так и при физических нагрузках и в чрезвычайных ситуациях.…”