Prototype electronic stethoscope vs conventional stethoscope for auscultation of heart sounds

Comparison of remote and in-person respiratory function grading of brachycephalic dogs

OBJECTIVE

To compare the reliability of respiratory function grading (RFG) scores assigned in-person and remotely via video and electronic stethoscope recordings, evaluated by novice and expert graders.

STUDY DESIGN

Prospective study.

SAMPLE POPULATION

Fifty-seven brachycephalic dogs.

METHODS

Dogs were evaluated in person by expert graders and RFG scores were assigned. Audio and video recordings were made during the in-person evaluations. Four expert and four novice graders evaluated the recordings and assigned an RFG score to each dog. Agreement between in-person and remote RFG scores was assessed using Cohen's kappa statistic. Interobserver reliability was assessed using Fleiss' kappa statistic.

RESULTS

The median RFG score from the in-person assessment was 1 (range, 0-3). Distribution of RFG scores included 12 grade 0 scores, 19 grade 1 scores, 25 grade 2 scores, and 1 grade 3 score. The raw percentage agreements between remote and in-person scores were 68.4%, 59.6%, 64.9%, and 61.4% for the four experts, and 52.6%, 64.9%, 50.9%, and 42.1% for the four novices. Reliability between remote and in-person RFG scores was poor to moderate both for the experts (Cohen's kappa: .48, .37, .46, .41) and novices (Cohen's kappa: .28, .47, .28, .21). Interobserver reliability was moderate among the experts (Fleiss' kappa: .59) and poor among the novices (Fleiss' kappa: .39).

CONCLUSION

Remote RFG scores had poor to moderate interassessment and interobserver reliability. Novice evaluators performed worse than experts for remote or in-person RFG evaluations.

CLINICAL SIGNIFICANCE

Remote RFG, as measured in this study, is not reliable for assigning RFG scores. Modifications could be made to remote evaluation to improve reliability. Based upon the performance of novice evaluators, training of evaluators is justified.

Assessment of a Teaching Module for Cardiac Auscultation of Horses by Veterinary Students

Auscultation of heart sounds is an important veterinary skill requiring an understanding of anatomy, physiology, pathophysiology and pattern recognition. This cross-sectional study was developed to evaluate a targeted, audio-visual training resource for veterinary students to improve their understanding and auscultation of common heart conditions in horses. Fourth- and fifth-year 2021 and 2022 Bachelor of Veterinary Science students at the University of Queensland (UQ) were provided the learning resource and surveyed via online pre- and post-intervention surveys. Results were quantitatively analyzed using descriptive statistics and Mann-Whitney U tests. Open-ended survey questions were qualitatively analyzed by thematic analysis and Leximancer™ Version 4 program software analysis. Over the two-year period, 231 fourth-year and 222 fifth-year veterinary students had access to the resource; 89 completed the pre-intervention survey and 57 completed the post-intervention survey. Quantitative results showed the resource helped students prepare for practicals and their perception of competency and confidence when auscultating equine cardiac sounds improved (p < 0.05). Compared to fifth-year students, fourth-year students felt less competent at identifying murmurs and arrythmias prior to accessing the learning resource (p < 0.05). Fourth-year and fifth-year students' familiarity with detection of murmurs improved after completing the learning resource (p < 0.001). Qualitative analysis demonstrated a limited number of opportunities to practice equine cardiac auscultation throughout the veterinary degree, especially during the COVID-19 pandemic, and that integrated audio-visual resources are an effective means of teaching auscultation.

Evaluation of the heart sounds in children using a Doppler Phonolyser

BACKGROUND

Heart auscultation is an easy and inexpensive tool for early diagnosis of congenital heart defects. In this regard, a simple device which can be used easily by physicians for heart murmur detection will be very useful. The current study was conducted to evaluate the validity of a Doppler-based device named "Doppler Phonolyser" for the diagnosis of structural heart diseases in pediatric patients. In this cross-sectional study, 1272 patients under 16 years who were referred between April 2021 and February 2022, to a pediatric cardiology clinic in Mofid Children Hospital, Tehran, Iran, were enrolled. All the patients were examined by a single experienced pediatric cardiologist using a conventional stethoscope at the first step and a Doppler Phonolyser device at the second step. Afterward, the patient underwent trans-thoracic echocardiography, and the echocardiogram results were compared with the conventional stethoscope as well as the Doppler Phonolyser findings.

RESULTS

Sensitivity of the Doppler Phonolyser for detecting congenital heart defects was 90.5%. The specificity of the Doppler Phonolyser in detecting heart disease was 68.9% in compared with the specificity of the conventional stethoscope, which was 94.8%. Among the most common congenital heart defects in our study population, the sensitivity of the Doppler Phonolyser was 100% for detection of tetralogy of Fallot (TOF); In contrast, sensitivity of both the conventional stethoscope and the Doppler Phonolyser was relatively low for detecting atrial septal defect.

CONCLUSIONS

Doppler Phonolyser could be useful as a diagnostic tool for the detection of congenital heart defects. The main advantages of the Doppler Phonolyser over the conventional stethoscope are no need for operator experience, the ability to distinguish innocent murmurs from the pathologic ones and no effect of environmental sounds on the performance of the device.

Real-world evaluation of the Stemoscope electronic tele-auscultation system

BACKGROUND

With the spread of COVID-19, telemedicine has played an important role, but tele-auscultation is still unavailable in most countries. This study introduces and tests a tele-auscultation system (Stemoscope) and compares the concordance of the Stemoscope with the traditional stethoscope in the evaluation of heart murmurs.

METHODS

A total of 57 patients with murmurs were recruited, and echocardiographs were performed. Three cardiologists were asked to correctly categorize heart sounds (both systolic murmur and diastolic murmur) as normal vs. abnormal with both the Stemoscope and a traditional acoustic stethoscope under different conditions. Firstly, we compared the in-person auscultation agreement between Stemoscope and the conventional acoustic stethoscope. Secondly, we compared tele-auscultation (recorded heart sounds) agreement between Stemoscope and acoustic results. Thirdly, we compared both the Stemoscope tele-auscultation results and traditional acoustic stethoscope in-person auscultation results with echocardiography. Finally, ten other cardiologists were asked to complete a qualitative questionnaire to assess their experience using the Stemoscope.

RESULTS

For murmurs detection, the in-person auscultation agreement between Stemoscope and the acoustic stethoscope was 91% (p = 0.67). The agreement between Stemoscope tele-auscultation and the acoustic stethoscope in-person auscultation was 90% (p = 0.32). When using the echocardiographic findings as the reference, the agreement between Stemoscope (tele-auscultation) and the acoustic stethoscope (in-person auscultation) was 89% vs. 86% (p = 1.00). The system evaluated by ten cardiologists is considered easy to use, and most of them would consider using it in a telemedical setting.

CONCLUSION

In-person auscultation and tele-auscultation by the Stemoscope are in good agreement with manual acoustic auscultation. The Stemoscope is a helpful heart murmur screening tool at a distance and can be used in telemedicine.

Real-World Evaluation of the Eko Electronic Teleauscultation System

Heart murmur evaluation is the most common cause of referral to cardiology, and auscultation of heart sounds with a stethoscope remains a key component of the initial cardiovascular exam. Adoption of telecardiology has been limited by challenges in teleauscultation. We set out to compare in-person auscultatory findings with heart sounds recorded by the Core stethoscope (Eko, Berkeley, CA) in patients with normal heart sounds, innocent heart murmurs, and a variety of pathologic findings. Our study demonstrates that Eko recordings had a high percent of agreement with in-person auscultation findings and echocardiogram findings, with moderate inter-rater reliability. It was useful in identifying patients with pathologic murmurs who would benefit from further assessment. It was able to discern major types of pathological murmurs. Certain qualitative differences in the recorded sounds as compared to in-person auscultation were identified by the reading cardiologists. They were able to acclimate to these subtle differences. The system was felt to be easy to use, and most cardiologists in the study would consider using it in clinical settings. The Eko Core system may be a useful screening tool for murmur evaluation.

Comparison of analogue and electronic stethoscopes for pulmonary auscultation by internal medicine residents

BACKGROUND

Electronic stethoscopes are becoming more common in clinical practice. They may improve the accuracy and efficiency of pulmonary auscultation, but the data to support their benefit are limited.

OBJECTIVE

To determine how auscultation with an electronic stethoscope may affect clinical decision making.

METHODS

An online module consisting of six fictional ambulatory cases was developed. Each case included a brief history and lung sounds recorded with an analogue and electronic stethoscope. Internal medicine resident participants were randomly selected to hear either the analogue or electronic lung sounds. Numbers of correct answers, time spent on each case and numbers of times the recordings were played were compared between the groups who heard each mode of auscultation, with a p value of less than 0.05 indicating statistical significance.

RESULTS

61 internal medicine residents completed at least one case, and 41 residents completed all six cases. There were no significant differences in overall scores between participants who heard analogue and electronic lung sounds (3.14±0.10 out of 6 correct for analogue, 3.20±0.10 out of 6 for electronic, p=0.74). There were no significant differences in performance for any of the six cases (p=0.78), time spent on the cases (p=0.67) or numbers of times the recordings were played (p=0.85).

CONCLUSION

When lung sounds were amplified with an electronic stethoscope, we did not detect an effect on performance, time spent on the cases or numbers of times participants listened to the recordings.

Development of a Smartphone App for Visualizing Heart Sounds and Murmurs

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.

New Stethoscope With Extensible Diaphragm

BACKGROUND

This study compared the diagnostic efficacy of the common suspended diaphragm stethoscope (SDS) with a new extensible diaphragm stethoscope (EDS) for low-frequency heart sounds.

METHODS AND RESULTS

The EDS was developed by using an ethylene propylene diene monomer diaphragm. The results showed that the EDS enhanced both the volume and quality of low-frequency heart sounds, and improved the ability of examiners to auscultate such heart sounds.

CONCLUSIONS

Based on the results of the sound analysis, the EDS is more efficient than the SDS. (Circ J 2016; 80: 2047-2049).

The 200th anniversary of the stethoscope: Can this low-tech device survive in the high-tech 21st century?

In 1816, Laennec discovered that auscultation of the heart and lungs could effectively be performed by placing a hollow cylinder (initially made of a roll of paper) between the chest of the patient and the ear of the examiner. This was the first step in the development of the stethoscope, which was a breakthrough in the diagnosis and management of cardiac and pulmonary patients. Technical improvements of the stethoscope followed and in cardiac patients auscultation soon became a major diagnostic tool. In the second half of the 20th century, new powerful non-invasive diagnostic modalities were developed and the interest in auscultation declined. As a result, the auscultatory skills of students and physicians at all levels of training decreased to a disappointingly low level. We now must decide whether we should stimulate the use of and proficiency in auscultation or if we should accept the further decline and eventual abolishment of this component of the physical examination. Reviewing the literature and taking into consideration the setting in which the patients are presented, including the availability of advanced diagnostic facilities, we conclude that the time-honoured stethoscope, in spite of its limitations, still has potential as a patient-friendly, effective, and economical instrument in medical practice. However, new initiatives are required to train students, physicians and allied health professionals in cardiac auscultation to avoid misinterpretations that may harm the patients and generate extra costs. To be successful such programs will require wide support from the medical community.