Heart murmurs recorded by a sensor based electronic stethoscope and e-mailed for remote assessment

Inequitable access: factors associated with incomplete referrals to paediatric cardiology

OBJECTIVE

To assess the variables associated with incomplete and unscheduled cardiology clinic visits among referred children with a focus on equity gaps.

STUDY DESIGN

We conducted a retrospective chart review for patients less than 18 years of age who were referred to cardiology clinics at a single quaternary referral centre from 2017 to 2019. We collected patient demographic data including race, an index of neighbourhood socio-economic deprivation linked to a patient's geocoded address, referral information, and cardiology clinic information. The primary outcome was an incomplete clinic visit. The secondary outcome was an unscheduled appointment. Independent associations were identified using multivariable logistic regression.

RESULTS

There were 10,610 new referrals; 6954 (66%) completed new cardiology clinic visits. Black race (OR 1.41; 95% CI 1.22-1.63), public insurance (OR 1.29; 95% CI 1.14-1.46), and a higher deprivation index (OR 1.32; 95% CI 1.08-1.61) were associated with higher odds of incomplete visit compared to the respective reference groups of White race, private insurance, and a lower deprivation index. The findings for unscheduled visit were similar. A shorter time elapsed from the initial referral to when the appointment was made was associated with lower odds of incomplete visit (OR 0.62; 95% CI 0.52-0.74).

CONCLUSION

Race, insurance type, neighbourhood deprivation, and time from referral date to appointment made were each associated with incomplete referrals to paediatric cardiology. Interventions directed to understand such associations and respond accordingly could help to equitably improve referral completion.

Cardiac screening in school children: Combining auscultation and electrocardiography with a crowdsourcing model

BACKGROUND/PURPOSE

School-based cardiac screening is useful for identifying children and adolescents with a high risk of sudden cardiac death. However, because of challenges associated with cost, distance, and human resources, cardiac screening is not widely implemented, especially in rural areas with limited medical resources. This study aims to establish a cloud-based system suitable for mass cardiac screening of schoolchildren in rural areas with limited medical resources.

METHODS

Students from three schools were included. They or their guardians completed a simple questionnaire, administered in paper or electronic form. Heart sounds were recorded using an electronic stethoscope. Twelve-lead electrocardiograms (ECGs) were recorded and digitalized. The signals were transmitted through Bluetooth to a tablet computer and then uploaded to a cloud server over Wi-Fi. Crowdsourced pediatric cardiologists reviewed those data from a web-based platform and provided remote consultation. In cases in which abnormal heart sounds or ECGs were noted, the students were referred to the hospital for further evaluation.

RESULTS

A total of 1004 students were enrolled in this study. Of the 138 students referred, 62 were diagnosed as having an abnormal heart condition and most had previously been undiagnosed. The interrater agreeability was high.

CONCLUSION

An innovative strategy combining a cloud-based cardiac screening system with remote consultation by crowdsourced experts was established. This system allows pediatric cardiologists to provide consultation and make reliable diagnoses. Combined with crowdsourcing, the system constitutes a viable approach for mass cardiac screening in children and adolescents living in rural areas with insufficient medical resources.

Feasibility of Digital Stethoscopes in Telecardiology Visits for Interstage Monitoring in Infants with Palliated Congenital Heart Disease

Infants with staged surgical palliation for congenital heart disease are at high-risk for interstage morbidity and mortality. Interstage telecardiology visits (TCV) have been effective in identifying clinical concerns and preventing unnecessary emergency department visits in this high-risk population. We aimed to assess the feasibility of implementing auscultation with digital stethoscopes (DSs) during TCV and the potential impact on interstage care in our Infant Single Ventricle Monitoring & Management Program. In addition to standard home-monitoring practice for TCV, caregivers received training on use of a DS (Eko CORE attachment assembled with Classic II Infant Littman stethoscope). Sound quality of the DS and comparability to in-person auscultation were evaluated based on two providers' subjective assessment. We also evaluated provider and caregiver acceptability of the DS. From 7/2021 to 6/2022, the DS was used during 52 TCVs in 16 patients (median TCVs/patient: 3; range: 1-8), including 7 with hypoplastic left heart syndrome. Quality of heart sounds and murmur auscultation were subjectively equivalent to in-person findings with excellent inter-rater agreement (98%). All providers and caregivers reported ease of use and confidence in evaluation with the DS. In 12% (6/52) of TCVs, the DS provided additional significant information compared to a routine TCV; this expedited life-saving care in two patients. There were no missed events or deaths. Use of a DS during TCV was feasible in this fragile cohort and effective in identifying clinical concerns with no missed events. Longer term use of this technology will further establish its role in telecardiology.

Cardiac Electromechanical Activity in Healthy Cats and Cats with Cardiomyopathies

Optimal heart function depends on perfect synchronization between electrical and mechanical activity. In this pilot study, we aimed to investigate the electromechanical activity of the heart in healthy cats and cats with cardiomyopathy with phonocardiography (PCG) synchronized to an electrocardiography (ECG) pilot device. We included 29 cats (12 healthy cats and 17 cats diagnosed with cardiomyopathy) and performed a clinical examination, PCG synchronized with ECG and echocardiography. We measured the following durations with the pilot PCG device synchronized with ECG: QRS (ventricular depolarization), QT interval (electrical systole), QS1 interval (electromechanical activation time (EMAT)), S1S2 (mechanical systole), QS2 interval (electrical and mechanical systole) and electromechanical window (end of T wave to the beginning of S2). The measured parameters did not differ between healthy cats and cats with cardiomyopathy; however, in cats with cardiomyopathy, EMAT/RR, QS2/RR and S1S2/RR were significantly longer than in healthy cats. This suggests that the hypertrophied myocardium takes longer to generate sufficient pressure to close the mitral valve and that electrical systole, i.e., depolarization and repolarization, and mechanical systoles are longer in cats with cardiomyopathy. The PCG synchronized with the ECG pilot device proved to be a valuable tool for evaluating the electromechanical activity of the feline heart.

Heart sounds: Past, present, and future from a technological and clinical perspective - a systematic review

The high prevalence of cardiac diseases around the world has created a need for quick, easy and cost effective approaches to diagnose heart disease. The auscultation and interpretation of heart sounds using the stethoscope is relatively inexpensive, requires minimal to advanced training, and is widely available and easily carried by healthcare providers working in urban environments or medically underserved rural areas. Since René-Théophile-Hyacinthe Laennec's simple, monoaural design, the capabilities of modern-day, commercially available stethoscopes and stethoscope systems have radically advanced with the integration of electronic hardware and software tools, however these systems are largely confined to the metropolitan medical centers. The purpose of this paper is to review the history of stethoscopes, compare commercially available stethoscope products and analytical software, and discuss future directions. Our review includes a description of heart sounds and how modern software enables the measurement and analysis of time intervals, teaching auscultation, remote cardiac examination (telemedicine) and, more recently, spectrographic evaluation and electronic storage. The basic methodologies behind modern software algorithms and techniques for heart sound preprocessing, segmentation and classification are described to provide awareness.

Remote Teaching of Canine Cardiac Auscultation Using Digital Phonocardiograms

Veterinary students often struggle to correctly interpret heart sounds. This study sought to evaluate if additional online training using digital phonocardiograms (DPCGs) improves students' ability to identify normal and pathologic heart sounds in dogs. Thirty-six randomly assigned veterinary students listened to and interpreted 10 audio recordings of normal heart sounds (2), heart murmurs (4), and arrhythmias (4) at the start and the end of a 4-week period. Twenty-two students participated in training with DPCGs, including those created from these recordings during this period, via a self-study website (n = 12) or online webinar (n = 10). Their results were compared with those of a control group (n = 14) that did not undergo additional training. Although pre- and post-training test scores did not differ between groups, both training groups showed within-group improvement between the two tests (p = .024, p = .037); the control group did not (p = .49). Although neither training group showed differences in ability to differentiate normal heart sounds from arrhythmias, both showed increased ability to detect and specify heart murmurs and provide refined diagnoses of detected arrhythmias. These results suggest additional training, even without actual patients, improves students' ability to identify heart murmurs and provide specific diagnoses for arrhythmias. Further study with a larger sample size and an additional group without DPCG-based training would help evaluate the effectiveness of DPCGs regarding arrhythmias. Studying a larger sample size would also allow for a training group participating in both training methods, measuring cumulative effectiveness of both methods.

A digitális fonokardiográfia szerepe a kutyák szívhangjainak hallgatózásos vizsgálatának oktatásában

Absztrakt

Sok állatorvostanhallgatónak esik nehezére a szívhangok helyes értelmezése. Kutatásunk célja a digitális fonokardiogramokat felhasználó online, tanterven kívüli oktatás hatásának felmérése volt a hallgatók szívhangok felismerésével kapcsolatos diagnosztikai képességeire. Harminchat véletlenszerűen elosztott állatorvostanhallgató hallgatott meg és értelmezett 10 hangfelvételt élettani szívhangokról (2), szívzörejekről (4) és szívritmuszavarokról (4) egy négyhetes periódus elején és Végén. Huszonkét hallgató vett részt DPCG-ket felhasználó képzésben, egy önképző oldal (n = 12) és egy online webinar (n = 10) keretein belül. A két teszten elért eredményeiket egy kontrollcsoportéval vetettük össze (n = 14), akik nem vettek részt tanterven kívüli képzésben. Bár az elő- és utótesztek pontszámai nem különböztek szignifikánsan a csoportok között, mindkét oktatásban résztvevő csoport szignifikáns csoporton belüli javulást mutatott a két teszt között (p = 0,023, p = 0,037), míg a kontrollcsoport nem (p = 0,49). Bár egyik csoport sem ért el javulást az élettani szívhangok felismerésében és szívritmuszavaroktól való elkülönítésében, mindkét csoportban javulást láttunk a szívzörejek felismerésében és azonosításában, valamint az észlelt szívritmuszavarok azonosításában. Eredményeink alapján a hallgatók hallgatózásos vizsgálattal kapcsolatos diagnosztikai képességei javíthatóak tanterven kívüli oktatással, akár élő álatok igénybevétele nélkül is. További, nagyobb elemszámmal végzett, valamint DPCG-t nem használó oktatómódszereket alkalmazó kutatás szükséges a DPCG-k szerepének pontos meghatározásához. Egy emelt elemszámmal végzett kutatás lehetővé tenné továbbá egy kombinált oktatott csoport létrehozását, mérhetővé téve a két módszer kumulatív hatását.

This translation was provided by the authors. To view the original article visit: https://doi.org/10.3138/jvme-2021-0097

Evaluation of the electronic stethoscope (FONODOC) as a cardiac screening tool during the preoperative evaluation of children

Background and Aims:

An electronic stethoscope with an inbuilt phonocardiogram is a potentially useful tool for paediatric cardiac evaluation in a resource-limited setting. We aimed to compare the acoustic and electronic stethoscopes with respect to the detection of murmurs as compared to the transthoracic echocardiogram (TTE).

Methods:

This was an observational study. Fifty children aged 0–12 years with congenital heart diseases (CHDs) and 50 without CHD scheduled for echocardiography were examined using both stethoscopes. The findings were corroborated with clinical findings and compared with the echocardiography report.

Results:

Among the 50 cases without CHD, no murmur was detected using either of the stethoscopes. This was in agreement with TTE findings. The calculated specificity of both stethoscopes was 100%. Amongst the 50 cases with CHD, the electronic stethoscope picked up murmurs in 32 cases and missed 18 cases. The acoustic stethoscope picked up murmurs in 29 cases and missed 21 cases. Thus, the sensitivity of electronic and acoustic stethoscopes as compared to TTE was calculated to be 64% and 58%, respectively. The positive predictive value of the electronic stethoscope as compared to TTE was 100% while the negative predictive value was 73%. The kappa statistic was 0.93 suggesting agreement in 93%. Mc-Nemar’s test value was 0.24 suggesting that the electronic stethoscope did not offer any advantage over the acoustic stethoscope for the detection of CHD in children.

Conclusion:

A comparison of the electronic stethoscope with an acoustic stethoscope suggests that the rate of detection of CHD with both stethoscopes is similar and echocardiography remains the gold standard.

Digital phonocardiography of cardiac arrhythmias in dogs - Preliminary experiences

Electronic stethoscopes and digital phonocardiograms (DPCGs) can be applied when diagnosing cardiac murmurs, but their use for cardiac arrhythmias is not described in veterinary medicine. Data of 10 dogs are presented in this preliminary study, demonstrating the applicability of these techniques. Although the number of artefacts and the amount of baseline noise produced by the two digitising systems used did not differ, the Welch Allyn Meditron system or similar ones capable of simultaneous recording of electrocardiograms (ECGs) and DPCGs provide a better option for clinical research and education, whilst the 3M Littmann 3200 system might be more suitable for everyday clinical settings. A combined system with simultaneous phonocardiogram and ECG, especially with wireless transmission, might be a solution in the future.

Telehealth for Pediatric Cardiology Practitioners in the Time of COVID-19

Due to the COVID-19 pandemic, there has been an increased interest in telehealth as a means of providing care for children by a pediatric cardiologist. In this article, we provide an overview of telehealth utilization as an extension of current pediatric cardiology practices and provide some insight into the rapid shift made to quickly implement these telehealth services into our everyday practices due to COVID-19 personal distancing requirements. Our panel will review helpful tips into the selection of appropriate patient populations and specific cardiac diagnoses for telehealth that put patient and family safety concerns first. Numerous practical considerations in conducting a telehealth visit must be taken into account to ensure optimal use of this technology. The use of adapted staffing and billing models and expanded means of remote monitoring will aid in the incorporation of telehealth into more widespread pediatric cardiology practice. Future directions to sustain this platform include the refinement of telehealth care strategies, defining best practices, including telehealth in the fellowship curriculum and continuing advocacy for technology.

Digital stethoscopes in paediatric medicine

AIM

To explore, synthesise and discuss currently available digital stethoscopes (DS) and the evidence for their use in paediatric medicine.

METHODS

Systematic review and narrative synthesis of digital stethoscope use in paediatrics following searches of OVID Medline, Embase, Scopus, PubMed and Google Scholar databases.

RESULTS

Six digital stethoscope makes were identified to have been used in paediatric focused studies so far. A total of 25 studies of DS use in paediatrics were included. We discuss the use of digital stethoscope technology in current paediatric medicine, comment on the technical properties of the available devices, the effectiveness and limitations of this technology, and potential uses in the fields of paediatrics and neonatology, from telemedicine to computer-aided diagnostics.

CONCLUSION

Further validation and testing of available DS devices is required. Comparison studies between different types of DS would be useful in identifying strengths and flaws of each DS as well as identifying clinical situations for which each may be most appropriately suited.

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.

Novel algorithm to screen for heart murmurs using computer-aided auscultation in neonates: a prospective single center pilot observational study

BACKGROUND

Automated detection of heart murmurs with computer-aided auscultation is not yet in clinical routine use. Aim of this study was to test sensitivity and specificity of a novel prototype algorithm in automated detection of heart murmurs from digitally recorded phonocardiograms in neonates admitted at the Neonatal Intensive Care Unit.

METHODS

In a prospective pilot observational study from November 2012 to December 2013 auscultations by pediatricians and computer aided auscultation were performed within 12 hours of neonatal echocardiography. Echocardiography was defined as pathological when resulting in any clinical consequences or causing murmur. Phonocardiograms and auscultation were defined as pathological if a murmur was detected. Phonocardiograms were analyzed offline with a novel algorithm prototype (CSD Labs, Graz, Austria) for detection of murmurs in neonates in a first run and with an optimized algorithm in a second run and were compared with echocardiography. Sensitivity and specificity of auscultation by pediatrician and computer aided auscultation were analyzed.

RESULTS

Thirty-six neonates (gestational age: 36±3 weeks) were included. Twenty-three (64%) neonates had pathological or murmur causing findings in echocardiography (positive echocardiography). Sensitivity and specificity of auscultation by pediatrician were 17% and 100%, respectively. In comparison to auscultation by pediatrician sensitivity of first run and second run were significantly higher with 70% and 83%, respectively. Specificity of first run and second run were 77% and 85%, respectively.

CONCLUSIONS

Phonocardiogram analysis using the novel algorithm prototype had a higher sensitivity than auscultation by pediatrician in detecting positive echocardiography findings in neonates.

Auscultation While Standing: A Basic and Reliable Method to Rule Out a Pathologic Heart Murmur in Children

PURPOSE

The distinction between physiologic (innocent) and pathologic (organic) heart murmurs is not always easy in routine practice, leading too often to unnecessary cardiology referrals and expensive investigations. We aimed to test the hypothesis that the complete disappearance of murmur on standing can exclude cardiac disease in children.

METHODS

From January 2014 to January 2015, we prospectively included 194 consecutive children aged 2 to 18 years who were referred for heart murmur evaluation to pediatric cardiologists at 2 French medical centers. Heart murmur characteristics while supine and then while standing were recorded, and an echo-cardiogram was performed.

RESULTS

Overall, 30 (15%) of the 194 children had a pathologic heart murmur as determined by an abnormal echocardiogram. Among the 100 children (51%) who had a murmur that was present while they were supine but completely disappeared when they stood up, only 2 had a pathologic murmur, and just 1 of them needed further evaluation. Complete disappearance of the heart murmur on standing therefore excluded a pathologic murmur with a high positive predictive value of 98% and specificity of 93%, albeit with a lower sensitivity of 60%.

CONCLUSIONS

Disappearance of a heart murmur on standing is a reliable clinical tool for ruling out pathologic heart murmurs in children aged 2 years and older. This basic clinical assessment would avoid many unnecessary referrals to cardiologists.

Estimating pressure gradients by auscultation: How technology (echocardiography) can help improve clinical skills

AIM

To extend our previously-published experience in estimating pressure gradients (PG) via physical examination in a large patient cohort.

METHODS

From January 1, 1997 through December 31, 2009, an attending pediatric cardiologist compared clinical examination (EXAM) with Doppler-echo (ECHO), in 1193 patients with pulmonic stenosis (PS, including tetralogy of Fallot), aortic stenosis (AS), and ventricular septal defect (VSD). EXAM PG estimates were based primarily on a murmur’s pitch, grade, and length. ECHO peak instantaneous PG was derived from the modified Bernoulli equation. Patients were 0-38.4 years old (median 4.8).

RESULTS

For all patients, EXAM correlated highly with ECHO: ECHO = 0.99 (EXAM) + 3.2 mmHg; r = +0.89; P < 0.0001. Agreement was excellent (mean difference = -2.9 ± 16.1 mmHg). In 78% of all patients, agreement between EXAM and ECHO was within 15 mmHg and within 5 mmHg in 45%. Clinical estimates of PS PG were more accurate than of AS and VSD. A palpable precordial thrill and increasing loudness of the murmur predicted higher gradients (P < 0.0001). Weight did not influence accuracy. A learning curve was evident, such that the most recent quartile of patients showed ECHO = 1.01 (EXAM) + 1.9, r = +0.92, P < 0.0001; during this time, the attending pediatric cardiologist had been > 10 years in practice.

CONCLUSION

Clinical examination can accurately estimate PG in PS, AS, or VSD. Continual correlation of clinical findings with echocardiography can lead to highly accurate diagnostic skills.

Initial Field Test of a Cloud-Based Cardiac Auscultation System to Determine Murmur Etiology in Rural China

A system for collection, distribution, and long distant, asynchronous interpretation of cardiac auscultation has been developed and field-tested in rural China. We initiated a proof-of-concept test as a critical component of design of a system to allow rural physicians with little experience in evaluation of congenital heart disease (CHD) to obtain assistance in diagnosis and management of children with significant heart disease. The project tested the hypothesis that acceptable screening of heart murmurs could be accomplished using a digital stethoscope and internet cloud transmittal to deliver phonocardiograms to an experienced observer. Of the 7993 children who underwent school-based screening in the Menghai District of Yunnan Province, Peoples Republic of China, 149 had a murmur noted by a screener. They had digital heart sounds and phonocardiograms collected with the HeartLink tele auscultation system, and underwent echocardiography by a cardiology resident from the First Affiliated Hospital of Kunming Medical University. The digital phonocardiograms, stored on a cloud server, were later remotely reviewed by a board-certified American pediatric cardiologist. Fourteen of these subjects were found to have CHD confirmed by echocardiogram. Using the HeartLink system, the pediatric cardiologist identified 11 of the 14 subjects with pathological murmurs, and missed three subjects with atrial septal defects, which were incorrectly identified as venous hum or Still's murmur. In addition, ten subjects were recorded as having pathological murmurs, when no CHD was confirmed by echocardiography during the field study. The overall test accuracy was 91% with 78.5% sensitivity and 92.6% specificity. This proof-of-concept study demonstrated the feasibility of differentiating pathologic murmurs due to CHD from normal functional heart murmurs with the HeartLink system. This field study is an initial step to develop a cost-effective CHD screening strategy in low-resource settings with a shortage of trained medical professionals and pediatric heart programs.

[Heart murmurs in asymptomatic children: When should you refer?]

Heart murmurs are common in children and adolescents. Although most are innocent, an isolated heart murmur in asymptomatic children may be the sole finding indicating serious heart disease. Historical elements of familial heart disease, cardiovascular symptoms and a well-conducted medical examination can identify children with an increased risk of heart disease. The distinction between an innocent heart murmur and a pathologic heart murmur is not always easy for primary care physicians because most of them have little experience with auscultation searching for congenital heart malformation. Echocardiography provides a definitive diagnosis of heart disease but is not required in case of innocent murmur. Inappropriate pediatric cardiologist and echocardiographic referral leads to useless and expensive examinations, resulting in a work overload for pediatric cardiologists. The objective of this review is to provide the keys to differentiate innocent and pathologic murmurs, and to help physicians decide on the optimal diagnostic strategy.

Carotid artery ultrasonographic assessment in patients from the Fremantle Diabetes Study Phase II with carotid bruits detected by electronic auscultation

BACKGROUND

Electronic auscultation appears superior to acoustic auscultation for identifying hemodynamic abnormalities. The aim of this study was to determine whether carotid bruits detected by electronic stethoscope in patients with diabetes are associated with stenoses and increased carotid intima-medial thickness (CIMT).

SUBJECTS AND METHODS

Fifty Fremantle Diabetes Study patients (mean±SD age, 73.7±10.0 years; 38.0% males) with a bruit found by electronic auscultation and 50 age- and sex-matched patients with normal carotid sounds were studied. The degree of stenosis and CIMT were assessed from duplex ultrasonography.

RESULTS

Patients with a bruit were more likely to have stenosis of ≥50% and CIMT of >1.0 mm than those without (odds ratios [95% confidence intervals]=14.0 [1.8-106.5] and 5.3 [1.8-15.3], respectively; both P=0.001). For the six patients with stenosis of ≥70%, five had a bruit, and one (with a known total occlusion) did not (odds ratio=5.0 [0.6-42.8]; P=0.22). The sensitivity and specificity of carotid bruit for stenoses of ≥50% were 88% and 58%, respectively; respective values for stenoses of ≥70% were 83% and 52%. The equivalent negative predictive values were 96% and 98%, and positive predictive values were 30% and 10%, respectively.

CONCLUSIONS

Electronic recording of carotid sounds for later interpretation is convenient and reliable. Most patients with stenoses had an overlying bruit. Most bruits were false positives, but ultrasonography is justified to document extent of disease; CIMT measurement will identify increased vascular risk in most of these patients. The absence of a bruit was rarely a false-negative finding, suggesting that these patients can usually be reassured that they do not have hemodynamically important stenosis.

Skills of primary healthcare physicians in paediatric cardiac auscultation

AIM

To evaluate the performance of primary healthcare physicians in paediatric cardiac auscultation and the impact of a multimedia-based teaching intervention.

METHODS

A total of 106 primary healthcare physicians (77 paediatricians, 14 general practitioners and 15 medical graduates) attended four paediatric cardiac auscultation teaching courses based on virtual patients' presentation (digital phonocardiography). Their auscultatory performance was documented at the beginning of each course and at the end of two of the courses.

RESULTS

Participants initially detected 73% of abnormal murmurs and 17% of additional sounds, while 22% of innocent murmurs were interpreted as abnormal. Overall cardiac auscultation performance, assessed by a combined auscultation score, was low and independent of training level (graduates: 39.5/trainees: 42.8/board certified: 42.6, p = 0.89) or specialty (paediatricians: 42.7/general practitioners: 43.1, p = 0.89). Multimedia-based teaching was associated with a significant improvement in abnormal murmur (92.5%) and additional sound (40%) detection (p < 0.001), while 25% of innocent murmurs were still interpreted as abnormal (p = 0.127).

CONCLUSION

Clinical skills of primary healthcare physicians in paediatric cardiac auscultation, independent of training level or specialty, still leave potential for improvement. Multimedia-based teaching interventions represent an effective means of improving paediatric cardiac auscultatory skills.

An open real-time tele-stethoscopy system

Background

Acute respiratory infections are the leading cause of childhood mortality. The lack of physicians in rural areas of developing countries makes difficult their correct diagnosis and treatment. The staff of rural health facilities (health-care technicians) may not be qualified to distinguish respiratory diseases by auscultation. For this reason, the goal of this project is the development of a tele-stethoscopy system that allows a physician to receive real-time cardio-respiratory sounds from a remote auscultation, as well as video images showing where the technician is placing the stethoscope on the patient’s body.

Methods

A real-time wireless stethoscopy system was designed. The initial requirements were: 1) The system must send audio and video synchronously over IP networks, not requiring an Internet connection; 2) It must preserve the quality of cardiorespiratory sounds, allowing to adapt the binaural pieces and the chestpiece of standard stethoscopes, and; 3) Cardiorespiratory sounds should be recordable at both sides of the communication. In order to verify the diagnostic capacity of the system, a clinical validation with eight specialists has been designed. In a preliminary test, twelve patients have been auscultated by all the physicians using the tele-stethoscopy system, versus a local auscultation using traditional stethoscope. The system must allow listen the cardiac (systolic and diastolic murmurs, gallop sound, arrhythmias) and respiratory (rhonchi, rales and crepitations, wheeze, diminished and bronchial breath sounds, pleural friction rub) sounds.

Results

The design, development and initial validation of the real-time wireless tele-stethoscopy system are described in detail. The system was conceived from scratch as open-source, low-cost and designed in such a way that many universities and small local companies in developing countries may manufacture it. Only free open-source software has been used in order to minimize manufacturing costs and look for alliances to support its improvement and adaptation. The microcontroller firmware code, the computer software code and the PCB schematics are available for free download in a subversion repository hosted in SourceForge.

Conclusions

It has been shown that real-time tele-stethoscopy, together with a videoconference system that allows a remote specialist to oversee the auscultation, may be a very helpful tool in rural areas of developing countries.

The promise of computer-assisted auscultation in screening for structural heart disease and clinical teaching

Abstract

Cardiac auscultation has been the central clinical tool for the diagnosis of valvular and other structural heart diseases for over a century. Physicians acquire competence in this technique through considerable training and experience. In Africa, however, we face a shortage of physicians and have the lowest health personnel-to-population ratio in the world. One of the proposed solutions for tackling this crisis is the adoption of health technologies and product innovations to support different cadres of health workers as part of task shifting.

Computer-assisted auscultation (CAA) uses a digital stethoscope combined with acoustic neural networking to provide a visual display of heart sounds and murmurs, and analyses the recordings to distinguish between innocent and pathological murmurs. In so doing, CAA may serve as an objective tool for the screening of structural heart disease and facilitate the teaching of cardiac auscultation. This article reviews potential clinical applications of CAA.

Paediatric telecardiology in Canada

Telemedicine is now an integral part of regular clinical and educational activity in Canadian paediatric cardiac centres. Transmission of echocardiograms is available to most paediatric cardiology centres from regional hospitals, allowing cardiac diagnosis at a distance. Teleconferencing networks are in frequent use for educational purposes, case conferencing and consultation with families. Teleauscultation is being investigated for remote screening of murmurs in children.

Sound recording and digital phonocardiography of cardiac murmurs in dogs by using a sensor-based electronic stethoscope

The goals of this study were to present a technique of digitalised sound recordings and phonocardiograms (dPCGs), and to analyse its diagnostic capabilities. Heart sounds of 20 dogs were auscultated in vivo (on-line) and recorded with dPCGs by two authors using a Welch Allyn Meditron Stethoscope System. Sound recordings were auscultated off-line and blindly by four different observers having various auscultatory experiences, then listened to while viewing dPCGs. The results were compared to echocardiographic diagnoses. There was a significant agreement (p < 0.001) between on-line and off-line auscultatory findings regarding the four observers, ranging from 45% to 75% (weighted kappa values: 0.72 to 0.87). The best agreement was achieved by Observer 1 having the highest experience. Significant differences (p < 0.05) were found between Observer 1 and Observer 4 (with the lowest experience) in judging the quality of the murmurs during the off-line and blind auscultation. However, there were only minimal differences (95% to 100% agreements) in dPCG analyses among the four observers regarding intensity and quality of the murmurs while simultaneously listening to and viewing the dPCGs. Significant correlations were found between the traditional '0 to 6 scale' and a new '0 to 3 scale' murmur intensity gradings by all observers (correlation coefficients 0.640 to 0.908; p < 0.01 to p < 0.001). Analysis of dPCGs might be a valuable, additional tool helping with the diagnosis of canine cardiac murmurs, especially for those with less cardiological experience.

Utility of store-and-forward pediatric telecardiology evaluation in distinguishing normal from pathologic pediatric heart sounds

Because pediatric cardiologists can accurately diagnose innocent murmurs by physical exam alone, the authors developed a system for remote cardiac auscultation. They hypothesized that their system could accurately classify auscultatory findings as normal/innocent or pathologic. Patients undergoing evaluation underwent examination, echocardiography, and heart sound recording. Pediatric cardiologists evaluated the heart sounds and classified the case as either normal/innocent or pathologic. They reviewed103 heart sound data sets; 85% of the cases were accurately classified as either normal/innocent or pathologic, with a sensitivity of 82% and specificity of 86%. However, when accounting for clinical diagnosis, reviewer uncertainty, and ECG abnormalities, the sensitivity and specificity improved to 91% and 88% (accuracy 89%), respectively. Degree of certainty with the telecardiology diagnosis correlated with correct interpretation (P < .005). Digital heart sound recordings evaluated via telemedicine can distinguish normal/innocent murmurs from pathologic ones. Such a system could improve the use of pediatric cardiology services.

Cardiovascular symptoms and signs in evaluating cardiac murmurs in children

BACKGROUND

The aim of the present study was to determine the usefulness of cardiovascular symptoms and signs in the recognition of significant congenital heart lesions that required surgical or catheter interventions in different pediatric age groups.

METHODS

A retrospective chart review was carried out of 110 patients with significant heart anomalies that required surgical or catheter interventions (group I) and 113 children, presenting with cardiac murmurs, with congenital heart conditions not requiring any interventions. (group II).

RESULTS

Clinical symptoms or signs were significantly more common in group I than in group II subjects (85% vs 32%, P < 0.0001). The odds of having significant lesions requiring interventions in the presence of either cardiovascular symptoms or signs were 37.5 (95% confidence interval [CI]: 6.5-218.1) for neonates, 14.5 (95%CI: 4.7-51.7) for infants, and 8.0 (95%CI: 3.3-19.2) for children and adolescents. In neonates, the negative predictive values of the absence of symptoms or signs in isolation were relatively low at 64% and 65%, respectively. In children beyond infancy, the positive predictive values of the presence of symptoms or signs in isolation were also low at 62% and 68%, respectively.

CONCLUSIONS

Clinical assessment of cardiovascular symptoms and signs remains useful in the evaluation of the significance of pathological cardiac murmurs in children in the present era of technology. Nonetheless, the predictive values vary with different pediatric age groups.

Digital phonocardiography as a screening tool for heart disease in childhood

AIM

To evaluate the performance of experienced cardiologists by use of digital phonocardiography for the correct identification of heart disease and innocent murmurs in children.

METHODS

Two independent paediatric cardiologists blindly evaluated 83 digital phonocardiograms obtained from consecutive paediatric cardiology outpatients. Each observer had to document the presence and characteristics of murmurs (intensity, quality, location), the presence of additional abnormal auscultatory findings (systolic click, second heart tone abnormalities) and whether he would recommend echocardiography (ECHO). The accuracy of their diagnoses was tested against the ECG diagnosis within two severity levels of heart disease.

RESULTS

Twenty-three out of 24 cases (95.8%) with moderate-to-severe heart defects and 12 to 13 out of 19 cases (63.2%-68.4%) with trivial-to-mild heart defects were correctly identified by phonocardiography. Additionally, 37 to 38 out of 40 cases (92.5%-95.0%) without ECHO evidence of heart disease were correctly interpreted as having innocent murmurs. The level of agreement between the two observers was substantial regarding their recommendations for ECHO (kappa, kappa=0.83) and in identifying abnormal murmurs (kappa=0.78).

CONCLUSION

Evaluation of digital phonocardiography by experienced cardiologists could allow for correct identification of moderate-to-severe forms of heart disease while preventing the majority of children with innocent murmurs from unnecessary referral.

Phono-spectrographic analysis of heart murmur in children

BACKGROUND

More than 90% of heart murmurs in children are innocent. Frequently the skills of the first examiner are not adequate to differentiate between innocent and pathological murmurs. Our goal was to evaluate the value of a simple and low-cost phonocardiographic recording and analysis system in determining the characteristic features of heart murmurs in children and in distinguishing innocent systolic murmurs from pathological.

METHODS

The system consisting of an electronic stethoscope and a multimedia laptop computer was used for the recording, monitoring and analysis of auscultation findings. The recorded sounds were examined graphically and numerically using combined phono-spectrograms. The data consisted of heart sound recordings from 807 pediatric patients, including 88 normal cases without any murmur, 447 innocent murmurs and 272 pathological murmurs. The phono-spectrographic features of heart murmurs were examined visually and numerically. From this database, 50 innocent vibratory murmurs, 25 innocent ejection murmurs and 50 easily confusable, mildly pathological systolic murmurs were selected to test whether quantitative phono-spectrographic analysis could be used as an accurate screening tool for systolic heart murmurs in children.

RESULTS

The phono-spectrograms of the most common innocent and pathological murmurs were presented as examples of the whole data set. Typically, innocent murmurs had lower frequencies (below 200 Hz) and a frequency spectrum with a more harmonic structure than pathological cases. Quantitative analysis revealed no significant differences in the duration of S1 and S2 or loudness of systolic murmurs between the pathological and physiological systolic murmurs. However, the pathological murmurs included both lower and higher frequencies than the physiological ones (p < 0.001 for both low and high frequency limits). If the systolic murmur contained intensive frequency components of over 200 Hz, or its length accounted for over 80 % of the whole systolic duration, it was considered pathological. Using these criteria, 90 % specificity and 91 % sensitivity in screening were achieved.

CONCLUSION

Phono-spectrographic analysis improves the accuracy of primary heart murmur evaluation and educates inexperienced listener. Using simple quantitative criterias a level of pediatric cardiologist is easily achieved in screening heart murmurs in children.

Diagnosis, access and outcomes: Update of a systematic review of telemedicine services

Telemedicine services are being increasingly used. Although insurers and other payers are covering some services in the USA, the rationale for these coverage decisions is not always evidence-based. We reviewed the literature for telemedicine services that substitute for face-to-face medical diagnosis and treatment. We focused on three types of telemedicine services: store-and-forward, home-based and office/hospital-based services. Studies were included if they were relevant to at least one of the three study areas, addressed at least one key question and contained reported results. We excluded articles that did not study a service requiring face-to-face encounters (i.e. teleradiology was excluded). Our search initially identified 4083 citations. After review, 597 were judged to be potentially relevant at the title/abstract level. Following a full-text review, 106 studies were included. Store-and-forward services have been studied in many specialties, the most common being dermatology, wound care and ophthalmology. The evidence for their efficacy is mixed. Several limited studies showed the benefits of home-based telemedicine interventions in chronic diseases. Studies of office/hospital-based telemedicine suggest that telemedicine is most effective for verbal interactions, e.g. videoconferencing for diagnosis and treatment in specialties like neurology and psychiatry. There are still significant gaps in the evidence base between where telemedicine is used and where its use is supported by high-quality evidence. Further well-designed research is necessary to understand how best to deploy telemedicine services in health care.

Assessing children's heart sounds at a distance with digital recordings

OBJECTIVE

The objective of this study was to assess whether computer-stored digital sound recordings can be used to distinguish innocent from pathologic systolic murmurs.

METHODS

Recordings of 55 children aged 1 month to 19 years were made remotely with the use of a digital stethoscope and were e-mailed to a computer in our center for later assessment. Eight-second recordings were made by a physician in 2 to 4 locations on the chest. Three cardiologists who were blinded to the diagnosis reviewed the recordings independently using stethophones to assess the splitting of the second heart sound and whether murmurs were innocent or pathologic. Diagnoses were confirmed with echocardiography.

RESULTS

Seventeen children had innocent murmurs and 38 had pathologic murmurs. For the 3 cardiologists, sensitivity was 0.87 to 1.0, specificity was 0.82 to 0.88, negative predictive value was 0.75 to 1.0, and positive predictive value was 0.93 to 0.95. Assessment of splitting of second heart sound was highly accurate.

CONCLUSIONS

Digital recordings of children's heart sounds allow reliable differentiation between innocent and pathologic murmurs. Use of this technology may allow remote diagnosis of childhood murmurs and avoid the expense and stress of travel to pediatric cardiology centers for some children. Cardiologists who use recordings should assess their diagnostic accuracy before clinical application.

Cardiac auscultation: a glorious past--and it does have a future!

Cardiac auscultation remains an important part of clinical medicine. The standard acoustic stethoscope, which has been useful for more than a century, cannot process, store, and play back sounds or provide visual display, and teaching is hindered because there is no means to distribute the same sounds simultaneously to more than one listener. Modern portable and inexpensive tools are now available to provide, through digital electronic means, better sound quality with visual display and the ability to replay sounds of interest at either full or half speed with no loss of frequency representation or sound quality. Visual display is possible in both standard waveform and spectral formats. The latter format is readily available and provides certain advantages over the time-honored waveform (phonocardiographic) method. Both methods, however, can and should be used simultaneously. Sound signals obtained electronically may then be subjected to objective visual and numerical analysis, transmitted to distant sites, and stored in medical records. Signal analysis shows early promise for clinical application, such as in the assessment of severity of aortic stenosis and in the separation of innocent from organic murmurs. In addition to their clinical value, these methods provide a critical vehicle for the teaching of cardiac auscultation, a method that can and should be preserved for future generations.

Comparison of two educational interventions on pediatric resident auscultation skills

OBJECTIVE

Multiple cross-sectional physician surveys have documented poor cardiac auscultation skills. We evaluated the impact of 2 different educational interventions on pediatric resident auscultation skills.

METHODS

The auscultation skills of all first-year (PGY1; n = 20) and second-year pediatric residents (PGY2; n = 20) were evaluated at the beginning and end of the academic year. Five patient recordings were presented: atrial septal defect, ventricular septal defect, pulmonary valve stenosis, bicuspid aortic valve with insufficiency, and innocent murmur. Residents were asked to classify the second heart sound, identify a systolic ejection click, describe the murmur, and provide a diagnosis. All PGY1 and most PGY2 (14 of 20) participated on the inpatient cardiology service for 1 month. PGY2 on the cardiology service also attended outpatient clinic. PGY1 did not attend outpatient clinic but were allotted 2 hours/week to use a self-directed cardiac auscultation computer teaching program.

RESULTS

Resident auscultation skills on initial evaluation were dependent on training level (PGY1: 42 +/- 15% correct; PGY2: 53 +/- 13% correct), primarily as a result of better classification of second heart sound (PGY1: 45%; PGY2: 63%) and diagnosis of an innocent murmur (PGY1: 35%; PGY2: 65%). There was no difference in the ability to identify correctly a systolic ejection click (20% vs 23%) or to arrive at the correct diagnosis (35% vs 40%). At the end of the academic year, the PGY1 scores improved by 21%, primarily as a result of improved diagnostic accuracy of the innocent murmur (35% to 65%). PGY2 scores remained unchanged (53% vs 51%), regardless of participation in a cardiology rotation (cardiology rotation: 50%; no cardiology rotation: 51%). Combined, diagnostic accuracy was best for ventricular septal defect (55%) and innocent murmur (60%) and worst for atrial septal defect (18%) and pulmonary valve stenosis (15%). However, 40% identified the innocent murmur as pathologic and 21% of pathologic murmurs were diagnosed as innocent.

CONCLUSIONS

Pediatric resident auscultation skills were poor and did not improve after an outpatient cardiology rotation. Auscultation skills did improve after the use of a self-directed cardiac auscultation teaching program. These data have relevance given the American College of Graduate Medical Education's emphasis on measuring educational outcomes and documenting clinical competencies during residency training.

Approach to a child with a heart murmur

The vast majority of children with heart murmurs have an 'innocent' murmur. Differentiation of such murmurs from those due to structural cardiac disease, so called 'pathological' murmurs, is largely clinical. Pediatricians are capable of differentiating one from the other, provided a detailed evaluation is done. This article outlines the salient features of innocent murmurs that help us recognize them clinically.

The paediatrician and cardiac auscultation

The cardiac auscultation (CA) skills of paediatric residents and office-based paediatricians have recently been shown to be suboptimal. CA is known to have a high degree of specificity and sensitivity, and is inexpensive. New teaching aids and availability of surrogate patient heart sounds and murmurs now allow most physicians to acquire CA skills. These teaching aids should be available in all medical schools and in all postgraduate paediatric training programs. While the relationship between musicality and CA skill has not been proven, the author assumes this relationship to be valid. Specific learning objectives in CA should be established. Recognizing that the current trend is away from clinical examinations, students frequently are unaware that a CA learning deficit exists. Therefore, students' CA skills should be evaluated before medical school graduation and at the Royal College of Physicians and Surgeons specialty examination. Students with amusia (inability to distinguish pitch of sound) should be identified and consideration should be given to directing them away from a clinical specialty in which CA is important. Further study is required in the physiology of learning of CA. Appropriate action by medical school and paediatric postgraduate program directors and the Royal College will effect a higher standard of patient care by increasing CA skills, resulting in a more financially efficient system - something everyone is trying to achieve in these times of increasing medical care costs.