Effect of teaching and type of stethoscope on cardiac auscultatory performance

Diagnostic accuracy of heart auscultation for detecting valve disease: a systematic review

OBJECTIVE

The objective of this study was to determine the diagnostic accuracy in detecting valvular heart disease (VHD) by heart auscultation, performed by medical doctors.

DESIGN/METHODS

A systematic literature search for diagnostic studies comparing heart auscultation to echocardiography or angiography, to evaluate VHD in adults, was performed in MEDLINE (1947-November 2021) and EMBASE (1947-November 2021). Two reviewers screened all references by title and abstract, to select studies to be included. Disagreements were resolved by consensus meetings. Reference lists of included studies were also screened. The results are presented as a narrative synthesis, and risk of bias was assessed using Quality Assessment of Diagnostic Accuracy Studies-2.

MAIN OUTCOME MEASURES

Sensitivity, specificity and likelihood ratios (LRs).

RESULTS

We found 23 articles meeting the inclusion criteria. Auscultation was compared with full echocardiography in 15 of the articles; pulsed Doppler was used as reference standard in 2 articles, while aortography and ventriculography was used in 5 articles. One article used point-of-care ultrasound. The articles were published from year 1967 to 2021. Sensitivity of auscultation ranged from 30% to 100%, and specificity ranged from 28% to 100%. LRs ranged from 1.35 to 26. Most of the included studies used cardiologists or internal medicine residents or specialists as auscultators, whereas two used general practitioners and two studied several different auscultators.

CONCLUSION

Sensitivity, specificity and LRs of auscultation varied considerably across the different studies. There is a sparsity of data from general practice, where auscultation of the heart is usually one of the main methods for detecting VHD. Based on this review, the diagnostic utility of auscultation is unclear and medical doctors should not rely too much on auscultation alone. More research is needed on how auscultation, together with other clinical findings and history, can be used to distinguish patients with VHD.

PROSPERO REGISTRATION NUMBER

CRD42018091675.

Interrater and intrarater agreement on heart murmurs

OBJECTIVE

To investigate interrater and intrarater agreement between physicians and medical students on heart sound classification from audio recordings, and factors predicting agreement with a reference classification.

DESIGN

Intra- and interrater agreement study.

SUBJECTS

Seventeen GPs and eight cardiologists from Norway and the Netherlands, eight medical students from Norway.

MAIN OUTCOME MEASURES

Proportion of agreement and kappa coefficients for intrarater agreement and agreement with a reference classification.

RESULTS

The proportion of intrarater agreement on the presence of any murmur was 83% on average, with a median kappa of 0.64 (range k = 0.09-0.86) for all raters, and 0.65, 0.69, and 0.61 for GPs, cardiologist, and medical students, respectively.The proportion of agreement with the reference on any murmur was 81% on average, with a median kappa of 0.67 (range 0.29-0.90) for all raters, and 0.65, 0.69, and 0.51 for GPs, cardiologists, and medical students, respectively.Distinct murmur, more than five years of clinical practice, and cardiology specialty were most strongly associated with the agreement, with ORs of 2.41 (95% CI 1.63-3.58), 2.19 (1.58-3.04), and 2.53 (1.46-4.41), respectively.

CONCLUSION

We observed fair but variable agreement with a reference on heart murmurs, and physician experience and specialty, as well as murmur intensity, were the factors most strongly associated with agreement.Key points:Heart auscultation is the main physical examination of the heart, but we lack knowledge of inter- and intrarater agreement on heart sounds.• Physicians identified heart murmurs from heart sound recordings fairly reliably compared with a reference classification, and with fair intrarater agreement.• Both intrarater agreement and agreement with the reference showed considerable variation between doctors• Murmur intensity, more than five years in clinical practice, and cardiology specialty were most strongly linked to agreement with the reference.

Detecting and recording cardiac murmurs in clinically healthy puppies in first opinion veterinary practice at the first health check

Background

The frequency that cardiac murmurs are identified and recorded in first opinion veterinary practices at the first health check in puppies is unknown. The aims of the study were to assess the agreement between first opinion veterinary practitioners, a veterinary student and a veterinary cardiology specialist on detecting murmurs, and to establish whether abnormal auscultation findings had been recorded in the health certificates of clinically healthy puppies. The study included prospective and retrospective investigations, where the prospectively collected auscultation findings from a veterinary cardiology specialist and a trained veterinary student were compared to auscultation findings recorded by first opinion veterinary practitioners.

Results

Cardiac auscultation was performed on 331 client-owned, clinically healthy dogs at two time points: at age 34–69 days by a first opinion veterinary practitioner and at age 45–76 days, on average 9 days later, by a veterinary cardiology specialist and a trained veterinary student. Agreement among the three was compared for the presence of a murmur. The degree of inter-observer agreement was evaluated using Cohen’s kappa. Auscultation findings, as noted in the pets’ passports, from 331 puppies and 43 different first opinion veterinary practices, were retrospectively reviewed and prospectively compared with auscultation findings from a veterinary cardiology specialist. Agreement between the veterinary cardiology specialist and the first opinion veterinary practitioners was poor (ϰ = 0.01) and significantly different (P < 0.001). First opinion veterinary practitioners had recorded a cardiac murmur in only 1 of the 97 puppies in which the veterinary cardiology specialist detected a murmur. Two-hundred-and-fifty-two puppies were auscultated by both the veterinary cardiology specialist and the student. Their agreement was fair (ϰ = 0.40) and significantly different (P = 0.024). The agreement between the student and a first opinion veterinary practitioner on these 252 puppies was poor (ϰ = 0.03) and significantly different (P < 0.001).

Conclusions

This study shows that soft cardiac murmurs are rarely documented during the first veterinary health check in puppies by first opinion veterinary practitioners. Although soft murmurs may not be clinically relevant, finding and recording them is evidence of a carefully performed auscultation. Missing a non-pathological murmur is not of clinical importance; however, missing a pathological murmur could prove detrimental for the individual puppy.

Perceptual audio processing stethoscope

Stethoscopes are used to transmit body sounds related to various physiological processes to ears of a physician, providing basic or supportive information for eventual diagnosis. Unfavorably, the dominant frequency components of most of the auscultation signals are localized close to the lower frequency limits of the human auditory system, restricting the achievable selectivity and specificity. The present study introduces an approach that aims at overcoming the existing limitations. A signal processing scheme utilizing knock rejection, dynamic compressor, and pseudo-stereo synthesizer blocks is described, along with hardware implementation and results of the initial subjective evaluation.

A comparative study of electronic stethoscopes for cardiac auscultation

There are several electronic stethoscopes available on the market today, with a very high potential for healthcare namely telemedicine, assisted decision and education. However, there are no recent comparatives studies published about the recording quality of auscultation sounds. In this study we aim to: a) define a ranking, according to experts opinion of 6 of the most relevant electronic stethoscopes on the market today; b) verify if there are any relations between a stethoscope's performance and the type of pathology present; c) analyze if some pathologies are more easily identified than others when using electronic auscultation. Our methodology consisted in creating two study groups: the first group included 18 cardiologists and cardiology house officers, acting as the gold standard of this work. The second included 30 medical students. Using a database of heart sounds recorded in real hospital environments, we applied questionnaires to observers from each group. The first group listened to 60 cardiac auscultations recorded by the 6 stethoscopes, and each one was asked to identify the pathological sound present: aortic stenosis, mitral regurgitation or normal. The second group was asked to choose, between two auscultation recordings, using as criteria the best sound quality for the identification of pathological sounds. Results include a total of 1080 evaluations, in which 72% of cases were correctly diagnosed. A detailed breakdown of these results is presented in this paper. As conclusions, results showed that the impact of the differences between stethoscopes is very small, given that we did not find statistically significant differences between all pairs of stethoscopes. Normal sounds showed to be easier to identify than pathological sounds, but we did not find differences between stethoscopes in this identification.

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.

Physical examination education in graduate medical education--a systematic review of the literature

OBJECTIVES

There is widespread recognition that physical examination (PE) should be taught in Graduate Medical Education (GME), but little is known regarding how to best teach PE to residents. Deliberate practice fosters expertise in other fields, but its utility in teaching PE is unknown. We systematically reviewed the literature to determine the effectiveness of methods to teach PE in GME, with attention to usage of deliberate practice.

DATA SOURCES

We searched PubMed, ERIC, and EMBASE for English language studies regarding PE education in GME published between January 1951 and December 2012.

STUDY ELIGIBILITY CRITERIA

Seven eligibility criteria were applied to studies of PE education: (1) English language; (2) subjects in GME; (3) description of study population; (4) description of intervention; (5) assessment of efficacy; (6) inclusion of control group; and (7) report of data analysis.

STUDY APPRAISAL AND SYNTHESIS METHODS

We extracted data regarding study quality, type of PE, study population, curricular features, use of deliberate practice, outcomes and assessment methods. Tabulated summaries of studies were reviewed for narrative synthesis.

RESULTS

Fourteen studies met inclusion criteria. The mean Medical Education Research Study Quality Instrument (MERSQI) score was 9.0 out of 18. Most studies (n = 8) included internal medicine residents. Half of the studies used resident interaction with a human examinee as the primary means of teaching PE. Three studies "definitely" and four studies "possibly" used deliberate practice; all but one of these studies demonstrated improved educational outcomes.

LIMITATIONS

We used a non-validated deliberate practice assessment. Given the heterogeneity of assessment modalities, we did not perform a meta-analysis.

CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS

No single strategy for teaching PE in GME is clearly superior to another. Following the principles of deliberate practice and interaction with human examinees may be beneficial in teaching PE; controlled studies including these educational features should be performed to investigate these exploratory findings.

Improved auscultation skills in paramedic students using a modified stethoscope

BACKGROUND

The Ventriloscope® (Lecat's SimplySim, Tallmadge, OH) is a modified stethoscope used as a simulation training device for auscultation.

OBJECTIVE

To test the effectiveness of the Ventriloscope as a training device in teaching heart and lung auscultatory findings to paramedic students.

METHODS

A prospective, single-hospital study conducted in a paramedic-teaching program. The standard teaching group learned heart and lung sounds via audiocassette recordings and lecture, whereas the intervention group utilized the modified stethoscope in conjunction with patient volunteers. Study subjects took a pre-test, post-test, and a follow-up test to measure recognition of heart and lung sounds.

RESULTS

The intervention group included 22 paramedic students and the standard group included 18 paramedic students. Pre-test scores did not differ using two-sample t-tests (standard group: t [16]=-1.63, p=0.12) and (intervention group: t [20]=-1.17, p=0.26). Improvement in pre-test to post-test scores was noted within each group (standard: t [17]=2.43, p=0.03; intervention: t [21]=4.81, p<0.0001). Follow-up scores for the standard group were not different from pre-test scores of 16.06 (t [17]=0.94, p=0.36). However, follow-up scores for the intervention group significantly improved from their respective pre-test score of 16.05 (t [21]=2.63, p=0.02).

CONCLUSION

Simulation training using a modified stethoscope in conjunction with standardized patients allows for realistic learning of heart and lung sounds. This technique of simulation training achieved proficiency and better retention of heart and lung sounds in a safe teaching environment.

Heart murmur and N-terminal pro-brain natriuretic peptide as predictors of death in 2977 consecutive hospitalized patients

BACKGROUND

Little is known about the prognostic importance of murmur in unselected patients. It is difficult to distinguish between innocent and significant murmurs. N-terminal pro-brain natriuretic peptide (NT-pro-BNP) and BNP have recently been shown to be useful in small series of patients with valvular heart disease. We wanted to test whether murmur predicts mortality in unselected patients admitted to the hospital and whether NT-pro-BNP is capable of distinguishing between innocent and significant murmurs.

METHODS

Consecutive patients (n = 2977) older than 40 years admitted to a local hospital were studied. Auscultation, echocardiography were performed and levels of natriuretic peptides were measured.

RESULTS

A total of 21.8% of the 2977 patients had a murmur. After adjusting for sex and age there was a significant difference in the one-year mortality of patients with and without murmur (OR = 1.57, 95% CI = 1.27-1.94). NT-pro-BNP gave additional prognostic information for both patients with and without murmurs. Presence of a murmur was an independent predictor of 1-year mortality (OR = 1.36, 95% CI = 1.03-1.80) in a multivariate analysis. In patients with a murmur but normal NT-pro-BNP, discovery of valvular heart disease by echocardiography yielded no additional prognostic information.

CONCLUSIONS

Detection of a cardiac murmur during routine medical examination of hospitalized patients is associated with increased risk of death within a year. A blood test for NT-pro-BNP gives significant additional prognostic information of a murmur and could obviate the need for echocardiography in selected patients with a murmur and normal NT-pro-BNP for whom surgery is not feasible.

Grading and staging systems for inflammation and fibrosis in chronic liver diseases

Liver biopsy is an important part of the evaluation of patients with a variety of liver diseases. Besides establishing the diagnosis, the biopsy is often used to assess the severity of the disease in terms of both grade and stage. The stage in most chronic liver diseases relates to the degree of scarring with the end stage being cirrhosis with its clinical complications. The grade relates to the severity of the underlying disease process, with features that vary with the pathogenetic mechanisms. Chronic viral hepatitis has been the object of the most extensive efforts at grading and staging, stimulated by the advent of new forms of therapy. Systems have also been developed for fatty liver disease, allograft rejection and chronic cholestatic diseases, but these have not been as widely used. Simple grading and staging systems for chronic hepatitis, including the IASL, Batts-Ludwig, and Metavir systems, are most appropriate for management of individual patients, while more complex systems such as the Histology Activity Index (HAI) are appropriate for evaluation of large cohorts of patients when statistical analysis is required.