[Artificial intelligence technology in cardiac auscultation screening for congenital heart disease: present and future].

The electronic stethoscope combined with artificial intelligence (AI) technology has realized the digital acquisition of heart sounds and intelligent identification of congenital heart disease, which provides objective basis for heart sound auscultation and improves the accuracy of congenital heart disease diagnosis. At the present stage, the AI based cardiac auscultation technique mainly focuses on the research of AI algorithms, and the researchers have designed and summarized a variety of effective algorithms based on the characteristics of cardiac audio data, among which the mel-frequency cepstral coefficients (MFCC) is the most effective one, and widely used in the cardiac auscultation. However, the current cardiac sound analysis techniques are based on specific data sets, and have not been validated in clinic, so the performance of algorithms need to be further verified. The lack of heart sound data, especially the high-quality, standardized, publicly available heart sound database with disease labeling, further restricts the development of heart sound diagnostic analysis and its application in screening. Therefore, expert consensus is necessary in establishing an authoritative heart sound database and standardizing the heart sound auscultation screening process for congenital heart disease. This paper provides an overview of the research and application status of auscultation algorithm and hardware equipment based on AI in auscultation screening of congenital heart disease, and puts forward the problems to be solved in clinical application of AI auscultation screening technology.

Review: Most Recent Advancements in Digital Signal Processing of the Phonocardiogram.

The objective of the present paper is to provide a detailed review of the most recent developments in instrumentation and signal processing of digital phonocardiography and heart auscultation. After a short introduction, the paper presents a brief history of heart auscultation and phonocardiography, which is followed by a summary of the basic theories and controversies regarding the genesis of the heart sounds. The application of spectral analysis and the potential of new time-frequency representations and cardiac acoustic mapping to resolve the controversies and better understand the genesis and transmission of heart sounds and murmurs within the heart-thorax acoustic system are reviewed. The most recent developments in the application of linear predictive coding, spectral analysis, time-frequency representation techniques, and pattern recognition for the detection and follow-up of native and prosthetic valve degeneration and dysfunction are also presented in detail. New areas of research and clinical applications and areas of potential future developments are then highlighted. The Final section is a discussion about a multidegree of freedom theory on the origin of the heart sounds and murmurs, which is completed by the authors' conclusion.

A expertise clássica da ausculta cardíaca para o diagnóstico do prolapso da valva mitral / The expertise of the classic cardiac auscultation for the diagnosis of mitral valve prolapses

JUSTIFICATIVA E OBJETIVOS: O prolapso da valva mitral possui inúmeras etiologias, é a valvopatia mais frequentee é a causa isolada de insuficiência mitral mais comum. Possui uma clínica muito diversificada e ultimamente tem-se buscado critérios diagnósticos mais rígidos para padronizar a sua identificação.Este estudo teve como objetivo oferecer as bases da ausculta cardíaca, determinar sua importância e aprofundar nos critérios diagnósticos, na clínica e prognóstico do prolapso da valva mitral. CONTEÚDO: A invenção do estetoscópio por René Hyacinthe Laënec em 1816 mudou o cenário da medicina. Para uma boa prática médica é necessário se ter um bom conhecimento das bases da ausculta cardíaca, que se baseia na utilização correta do estetoscópio, sistematização do exame físico cardíaco e na correta caracterização dos sons auscultados. São frequentes as novas tecnologias que auxiliam no diagnóstico das valvopatias, porém os exames complementares possuem suas limitações. A ausculta cardíaca está perdendo espaço diante dos novos equipamentos,encarecendo a prática médica. CONCLUSÃO: Mesmo com as novas tecnologias, além da correta utilização dos exames complementares, é de extrema importância a realização da anamnese e exame físico para o diagnóstico do prolapso da valva mitral, se fazendo necessário o uso dos critérios diagnósticos vigentes.

BACKGROUND AND OBJECTIVES: The mitral valve prolapsed have numerous etiologies and it is the most common valvular disease and the most common isolated cause of mitral insufficiency. Besides having a very diverse clinical, more stringent diagnostic criteria have been sought in order to reduce overdiagnosis that they had prior to these criteria. This aims to give the basics of cardiac auscultation, and deepen their importance in diagnostic criteria, the clinical course and prognosis of mitral valve prolapse. CONTENTS: The invention of the stethoscope by René Laënec Hyacinthe in 1816 changed completely the medicine scenario. For a good medical practice it is necessary to have a good knowledge of the bases of cardiac auscultation, which is focused on the correct use of the stethoscope, systematic physical examination and on the correct characterization of auscultation of heart sounds. Increasingly there are technologies that help the physicianin the diagnosis of valvular heart disease, and even studies showing that all these tests have their limitations, the cardiac auscultation has been put aside in exchange for these new technologies, making the medical practice more and more expensive. CONCLUSION: Even with new technologies, besides the correct use of supplementary tests, it is extremely important the anamnesis and physical examination for the diagnosis of mitral valve prolapse, if necessary making use of current diagnostic criteria.

Fetal monitoring during labor.

For three decades, cardiotocography has been the basic technique for fetal surveillance during labor, but its impact on fetal well-being remains controversial. The benefits and disadvantages of fetal monitoring with cardiotocography during labor are reviewed. Special reference is made to the possible effect on the rate of neonatal seizures in newborns and their long-term outcome.

Avaliação de um modelo de parâmetros distribuídos aplicado à estimação da geometria arterial na hipertensão / Evaluation of a distributed parameter model applied to arterial geometry estimation in hypertension

A hipertensão arterial provoca adaptações estruturais nas artérias, principalmente pelos processos de hipertrofia e remodelagem, as quais antecedem lesões de órgãos-alvo. A determinação de variáveis mecânicas e geométricas associadas ao sistema arterial possibilita ao clínico identificar precocemente as adaptações que decorrem da hipertensão arterial sistêmica no paciente, permitindo a intervenção terapêutica mais adequada. Este trabalho apresenta a avaliação de um modelo eletro-hidráulico e seu método associado para a determinaçãodos parâmetros geométricos do segmento arterial do antebraço. O método proposto requer somente a aquisição não-invasiva de ondas de pulso em dois sítios distintos. Séries de ondas de pulso da artéria radial foram simuladas a partir de ondas de pulso reais da artéria braquial, empregandoum modelo de parâmetros distribuídos simplificado das artérias do antebraço. O modelo é composto por três seções,representando os segmentos arteriais braquial, radial e a mão. As artérias braquial e radial foram representadas por componentes resistivos (atrito local), indutivos (massa do sangue) e capacitivos (complacência arterial), enquanto a mão foi representada por elementos resistivos (resistências de pequenos vasos da mão e periféricos) e capacitivos (complacência de pequenos vasos). Os resultados mostram um erro médio de estimação que pode ser considerado pequeno (3,7%) quando comparado aos valores de adaptação arterial in vivo (alterações de até 15%), indicando a utilização deste procedimento para estimar o processo de remodelagem das artérias de médio calibre observado na hipertensão arterial sistêmica.

Arterial hypertension leads to structural adaptation of arteries, mainly hypertrophy or remodeling, which precedes target-organ injuries. Determination of both mechanical and geometrical variables related to arterial system allows physicians to identify early arterial adaptation derived from systemic hypertension and to propose therapeutics. This work presents the evaluation of an electric-hydraulic model, and associated method, for determination of geometrical and mechanical parameters of forearm arteries. The proposed method requires only noninvasive acquisition of two pressure pulses at distinct sites. Series of pressure pulses from radial artery were simulated using acquired brachial artery pulses and a simplified distributed-model of the forearm arteries. The model presents three sections, representing brachial, radial, and hand vasculature. Brachial and radial arteries were represented with resistive (friction), inductive (blood mass), and capacitive (arterial compliance) elements. The hand was modeled with resistive (small vessels and capillaries) and capacitive elements (small vessels compliance). The results show that an average estimation error of 3.7% is small compared to “in vivo” findings (changes up to 15%), indicatingthat the procedure can be used to assess the remodeling of medium-sized arteries on primary systemic arterial hypertension.

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.

Computer-aided auscultation of the heart: from anatomy and physiology to diagnostic decision support.

There is a clear and present need for computer-aided auscultation of the heart which arises from the highly informative nature of heart sounds, the inherent difficulty of auscultation and increasing pressure in healthcare for rapid, accurate, objective, documented and cost-effective patient evaluation and diagnostic decision making. There are advanced signal processing technologies that hold promise for developing computer-aided auscultation solutions that are intuitive, efficient, informative and accurate. Computer-aided auscultation offers an objective, quantitative and cost-effective tool for acquiring and analyzing heart sounds, providing archival records that support the patient evaluation and referral decision as well as serial comparisons for patient monitoring. There is the further promise of new quantitative acoustic measures and auscultatory findings that have more precise correlation with underlying physiological parameters. These solutions are being developed with the benefits of a rich literature of clinical studies in phonocardiography, the added insights derived from echocardiography, and advances in signal processing technology.

The teaching of chest auscultation during primary care training: has anything changed in the 1990s?

OBJECTIVE: To survey the teaching time and importance given to cardiopulmonary auscultation during internal medicine (IM) and family practice (FP) residencies, and to compare current practices to those of the early 1990s. DESIGN: A nationwide mail survey of IM and FP program directors (PDs). SETTING: All Accreditation Council for Graduate Medical Education-accredited IM and FP residencies. PARTICIPANTS: A total of 538 of 939 PDs (57.5%). MEASUREMENTS AND MAIN RESULTS: In contrast to the early 1990s, when there had been no significant difference in teaching practices between IM and FP programs, more IM than FP residencies taught cardiopulmonary auscultation in 1999 (cardiac auscultation: IM residencies, 48%; FP residencies, 29.2% [p < 0.001]; pulmonary auscultation: IM residencies, 23.7%; FP residencies, 12.2% [p < 0.001]). Across the decade there also had been a significant increase in the percentage of IM programs offering structured education in chest auscultation (cardiac auscultation increase, 27.1 to 48% [p < 0.001]; pulmonary auscultation increase, 14.1 to 23.7% [p < 0.02]), but no significant changes for FP residencies. IM PDs gave more clinical importance to auscultation and expressed a greater desire for expanded teaching than did their counterparts in FP programs. CONCLUSIONS: This study indicates a significant gain over the last decade in the percentage of IM residencies offering structured teaching of cardiopulmonary auscultation. This same gain did not occur for FP programs. Whether these differences in attitudes and teaching practices will translate into improved auscultatory proficiency of IM trainees will need to be determined.

Pediatric cardiology: auscultation from 280 miles away.

New long-distance audio/video and data communications links among health-care facilities promise to reduce rural patients' travel time and waiting time for subspecialty consultations. To offer a satisfactory alternative to face-to-face examination, the long-distance system must meet the subspecialty's minimum criteria. For pediatric cardiology in particular, the system has to permit satisfactory cardiac auscultation. A preliminary test of remote auscultation that uses an electronic stethoscope involved two pediatric cardiologists, one listening hands-on with an acoustic stethoscope, the other listening independently at long distance with the electronic instrument. Taking the acoustic findings as the reference standard, the electronic stethoscope did not miss the one case of heart disease, correctly recommended echocardiogram follow-up in the two cases requiring it, and agreed on 80% of the murmurs' qualitative specifics. The patients' parents also indicated that the system was highly acceptable. We are following up these results with a full-scale study of the effectiveness and parental acceptance of remote auscultation.