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It is estimated that up to 95% of the human population experienced an innocent heart murmur during their childhood. Although innocent heart murmurs that were originally found during childhood are not associated with any type of cardiovascular disease, the discovery of a heart murmur later in life can be indicative of a pathologic heart condition. In an effort to improve bedside auscultation of cardiac diagnoses for caregivers, a newly developed smartphone app has emerged.
Current Murmur Diagnostic Tools
In 1816, Rene Laennec invented the stethoscope, which is an acoustic medical device that is used to perform cardiac auscultation. Although this diagnostic tool has served as the foundation for many cardiac diagnoses, medical professionals have been fairly limited in their ability to accurately assess the timing, pitch, quality and pattern of murmurs upon discovery.
Some of the more sensitive tools used for cardiac auscultation include phenocardiograms (PCGs) and electronic stethoscopes. A phenocardiograph system utilizes a sound transducer (which is also known as a microphone), an amplifier, a filter and a series of systems capable of recording, analyzing and transcribing the acquired heart sounds. This system will then generate a graphic record of the acquired heard sounds, otherwise referred to as the PCG, which will provide information on the timing, intensity, frequency, quality, tone and location of the different components of the recorded heart sounds.
Although PCGs are critical for cardiac diagnoses, the PCG system is often immobile and bulky. In addition, the procedure required to obtain PCG data can also be extremely time consuming, which is unfavorable in critical cardiac situations. As a result, the use of PCGs has been widely replaced by echocardiograms (EKGs). Although EKGs are powerful diagnostic tools, they are also associated with certain disadvantages, such as an insensitivity for proper diagnosis of left ventricular hypertrophy.
A Novel Smartphone App
A 2017 Cardiology paper discussed the development of a novel smartphone app capable of providing medical professionals real-time visualization of the obtained heart sound waves. The smartphone app, which was designed to act as a voice recorder, utilized a stethoscope, external microphone and smartphone to obtain heart sounds and murmur measurements. The developers utilized several different programs including Android SDK 4.0.3, Java 1.7.0 and Eclipse 4.2 to create the app.
To evaluate the accuracy of this smartphone app’s measurement capabilities, the researchers compared sound waves taken from the app to those obtained from a diaphragm-type stethoscope and a bell-type stethoscope. Although the amplitude of the soundwaves obtained from the smartphone app varied from those obtained from traditional diagnostic tools, they were determined to be clinically similar when considering the overall sound waveform. Furthermore, the smartphone app proved to be capable of obtaining sound waves that show characteristic waveforms of a variety of cardiovascular conditions including patent ductus arteriosus, mitral valve prolapse, dilated cardiomyopathy, atrial fibrillation, innocent murmur, mitral valve clicking, mitral regurgitation and pulmonary stenosis, to name a few.
Through the use of this app, physicians are able to pinpoint the precise location in which the murmur’s sound waves are identified to provide a more accurate diagnosis for the patient. Furthermore, this smartphone app provides a greater level of sensitivity that even allows healthcare providers to immediately grade the intensity of the murmur from 1 to 6.
- Mamorita, N., Arisaka, N., Isonaka, R., Kawakami, T., & Takeuchi, A. (2017). Development of a Smartphone App for Visualizing Heart Sounds and Murmurs. Cardiology 137; 193-200. DOI: 10.1159/000466683.
- “The Phenocardiogram” – Ekuore
- Napononen, A., Lukkarinen, S., & Sepponen, R. Chapter 2: Phenocardiography. In: Multimodal Cardiovascular Imaging Principles and Clinical Applications.