Employment of color Doppler echocardiographic video clips in a cardiac auscultation class with a cardiology patient simulator: discrepancy between students' satisfaction and learning

BACKGROUND

We have provided fourth-year medical students with a three-hour cardiac auscultation class using a cardiology patient simulator since 2010. The test results of 2010-2012 revealed that as compared with aortic stenosis murmur, students correctly identified murmurs of other valvular diseases less often. We investigated whether employment of color Doppler echocardiographic video clips would improve proficiency in identifying murmurs of aortic regurgitation and mitral regurgitation, and whether students' favorable responses to a questionnaire were associated with improved proficiency.

METHODS

A total of 250 fourth-year medical students were divided into groups of 7-9 students in 2014 and 2015. Each group attended a three-hour cardiac auscultation class comprising a mini-lecture, facilitated training, two different auscultation tests (the second test being closer to clinical setting than the first) and a questionnaire. We provided each student with color Doppler echocardiographic videos of aortic regurgitation and mitral regurgitation using a tablet computer, which they freely referred to before and after listening to corresponding murmurs. The test results were compared with those in 2010-2012. The students had already completed the course of cardiovascular medicine, comprising lectures including those of physical examination, echocardiography, and valvular heart diseases, before participating in this auscultation training class.

RESULTS

Most students indicated that the videos were useful or somewhat useful regarding aortic regurgitation (86.3%) and mitral regurgitation (85.7%). The accuracy rates were 78.4% (81.2% in 2010-2012) in aortic regurgitation and 76.0% (77.8%) in mitral regurgitation in the first test, and 83.3% (71.4%) in aortic regurgitation and 77.1% (77.6%) in mitral regurgitation in the second test, showing no significant differences as compared to 2010-2012. Overall accuracy rate of all heart sounds and murmurs in the first test and that of second/third/fourth sounds in the first and second tests were significantly lower in 2014-2015 than in 2010-2012.

CONCLUSIONS

Referring to color Doppler echocardiographic video clips in the way employed in the present study, which most students regarded as useful, did not improve their proficiency in identifying the two important regurgitant murmurs, revealing a discrepancy between students' satisfaction and learning. Video clips synchronized with their corresponding murmurs may contribute toward improving students' proficiency.

Extraction and assessment of diagnosis-relevant features for heart murmur classification

This paper presents a heart murmur detection and multi-class classification approach via machine learning. We extracted heart sound and murmur features that are of diagnostic importance and developed additional 16 features that are not perceivable by human ears but are valuable to improve murmur classification accuracy. We examined and compared the classification performance of supervised machine learning with k-nearest neighbor (KNN) and support vector machine (SVM) algorithms. We put together a test repertoire having more than 450 heart sound and murmur episodes to evaluate the performance of murmur classification using cross-validation of 80-20 and 90-10 splits. As clearly demonstrated in our evaluation, the specific set of features chosen in our study resulted in accurate classification consistently exceeding 90% for both classifiers.

Nonauscultatory clinical criteria are sensitive for cardiac pathology in low-risk paediatric heart murmurs

Background

Healthy children with likely innocent heart murmurs are frequently referred to cardiologists for reassurance. Existing guidelines that advise against these referrals are not consistently followed partly because they involve subjective auscultatory judgements with which many care providers are uncomfortable. Here, we investigate whether clinical criteria with no subjective auscultatory component are sensitive for cardiac pathology.

Methods

A retrospective chart review was performed of all new patients seen in our paediatric cardiology clinic for assessment of a murmur from January 1, 2016 through June 30, 2018. Patients were characterized as "low-risk" if they met all of the following criteria: asymptomatic; normal physical examination other than the murmur; no risk factors for congenital heart disease; and age over 12 months. The primary outcomes were the sensitivity for ruling out pathology and the negative predictive value of the proposed criteria.

Results

Of 915 total patients, 214 met the low-risk criteria. The sensitivity of our criteria for ruling out pathology was 97.2% (95% confidence interval 94.1% to 99.0%) and the negative predictive value was also 97.2% (95% confidence interval 94.0% to 98.7%). Six of the 214 low-risk patients had pathology (2.8%; 95% confidence interval 1.3% to 6.0%), none of which has required intervention since diagnosis. Each of these six children had a murmur that sounded pathological to the auscultating cardiologist.

Conclusions

Basic clinical criteria that do not require auscultation are highly sensitive for ruling out significant cardiac pathology in children over 12 months of age.

From an innocent heart murmur to pulmonary arterial hypertension

Background

The detection of congenital heart disease in newborns, based on a heart murmur or cyanosis is not effective. Critical congenital heart diseases, such as truncus arteriosus (TA), cause most of neonatal deaths due to congenital malformations. The screening for pulse oximetry in newborns detects up to 70% of these heart diseases. TA presents high mortality in the first year of life.

Case report

A 4-year-old female patient with a heart murmur, palpitations, dyspnea, and perioral cyanosis was diagnosed with an innocent heart murmur at birth. TA was detected by echocardiography. Pulmonary vascular resistances were evaluated through right cardiac catheterization, and pulmonary arterial hypertension and pulmonary vasoreactivity were diagnosed as well. Surgical correction was performed. Currently, pulmonary arterial hypertension persists, for which Bosentan^® (Actelion, USA) has been implemented as a long-term treatment.

Conclusions

In newborns, the pulse oximetry screening after 24 hours of life is an effective method for suitable diagnosis of critical congenital heart disease before the signs of cardiovascular collapse. Therefore, it has become an essential diagnostic tool to reduce morbidity and mortality. Although the surgical correction of congenital heart disease with pulmonary arterial hypertension is feasible in some patients, its subsequent management is complex and has an adverse impact on the quality of life.

Left ventricle pseudoaneurysm: Diagnosis by a new murmur

Incomplete rupture of the ventricle free wall can occur after myocardial infarction. This occurs when an organized thrombus and the pericardium seal the ventricular perforation. This can progress to the formation of a left ventricle pseudoaneurysm (LVPA). A 70-year-old male with an antero-septal ST-elevation myocardial infarction (STEMI) underwent an emergent left heart catheterization which revealed severe three-vessel disease with occluded grafts, non-amenable to re-vascularization, and an apical thrombus. As he was high-risk for repeat coronary artery bypass graft, he was medically managed. Transthoracic echocardiogram (TTE) showed a normal left ventricle ejection fraction (LVEF), apical anterior and inferior wall akinesis, moderate sized apical thrombus, and pericardial thickening. On hospital day 7, examination revealed a new 3/6 to-and-fro murmur that was loudest at the apex. The patient was asymptomatic with normal vital signs. A repeat TTE revealed an apical wall rupture with flow into the pericardial cavity and absence of the apical thrombus. A LVPA was diagnosed and the patient was immediately referred for surgical repair. This case illustrates the potential for developing LVPA in STEMI patients and the importance of physical examination. If identified early a potential emergent situation in a previously asymptomatic patient can be averted, thereby preventing fatal consequences. <Learning objective: With the growing use of diagnostic testing the importance of physical examination is being lost. However, with an astute cardiac examination, potential complications such as a left ventricular pseudoaneurysm can be identified and promptly managed. In addition, a ventricular pseudoaneurysm must be considered in the differential as a rare complication in post ST-elevation myocardial infarction patients with a new murmur.>.

Variation in effectiveness of a cardiac auscultation training class with a cardiology patient simulator among heart sounds and murmurs

BACKGROUND

Effectiveness of simulation-based education in cardiac auscultation training is controversial, and may vary among a variety of heart sounds and murmurs. We investigated whether a single auscultation training class using a cardiology patient simulator for medical students provides competence required for clinical clerkship, and whether students' proficiency after the training differs among heart sounds and murmurs.

METHODS

A total of 324 fourth-year medical students (93-117/year for 3 years) were divided into groups of 6-8 students; each group participated in a three-hour training session using a cardiology patient simulator. After a mini-lecture and facilitated training, each student took two different tests. In the first test, they tried to identify three sounds of Category A (non-split, respiratory split, and abnormally wide split S2s) in random order, after being informed that they were from Category A. They then did the same with sounds of Category B (S3, S4, and S3+S4) and Category C (four heart murmurs). In the second test, they tried to identify only one from each of the three categories in random order without any category information.

RESULTS

The overall accuracy rate declined from 80.4% in the first test to 62.0% in the second test (p<0.0001). The accuracy rate of all the heart murmurs was similar in the first (81.3%) and second tests (77.5%). That of all the heart sounds (S2/S3/S4) decreased from 79.9% to 54.3% in the second test (p<0.0001). The individual accuracy rate decreased in the second test as compared with the first test in all three S2s, S3, and S3+S4 (p<0.0001).

CONCLUSIONS

Medical students may be less likely to correctly identify S2/S3/S4 as compared with heart murmurs in a situation close to clinical setting even immediately after training. We may have to consider such a characteristic of students when we provide them with cardiac auscultation training.

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.