Investigation of the theory and mechanism of the origin of the second heart sound.
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To investigate further the origin of the second heart sound we studied human subjects, dogs, and a model in vitro of the cardiovascular system. Intra-arterial sound, pressure, and, where possible, flow and high speed cine (2,000 frames/sec) were utilized. The closure sound of the semilunar valves was of higher amplitude in be ventricles than in their respective arterial cavities. The direction of inscription of the main components of intra-arterial sound were opposite in direction to the components of intraventricular sound. Notches, representative of pressure increments, were noted on the ventricular pressure tracings and were coincident with the components of sound. The amplitude of the closure sound varied with diastolic pressure, but remained unchanged with augmentation of forward and retrograde aortic flow. Cines showed second sound to begin after complete valvular closure, and average leaflet closure rate was constant regardless of pressure. Hence, the semilunar valves, when closed, act as an elastic membrane and, when set into motion, generate compression and expansion of the blood, producing transient pressure changes indicative of sound. The magnitude of the initial stretch is related to the differential pressure between the arterial and ventricular chambers. Sound transients which follow the major components of the second sound appear to be caused by the continuing stretch and recoil of the leaflets. Clinically unexplained findings such as the reduced or absent second sound in calcific aortic stenosis and its paradoxical presence in congenital aortic stenosis may be explained by those observations. (+info)
A new sign of occlusion of the origin of the internal carotid artery.
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When the origin of the internal carotid artery is occluded, the transmission of cardiac sounds along the carotid stops at the site of the occlusion. This is a new neurovascular sign which is being reported. (+info)
Apical systolic click and murmur associated with neurofibromatosis.
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In this report we describe a child who had an apical systolic click and murmur, as well as widespread cutaneous neurofibromatosis. We were not able to show an anatomical basis for the click and murmur. (+info)
Current management of mitral valve prolapse.
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Mitral valve prolapse is a pathologic anatomic and physiologic abnormality of the mitral valve apparatus affecting mitral leaflet motion. "Mitral valve prolapse syndrome" is a term often used to describe a constellation of mitral valve prolapse and associated symptoms or other physical abnormalities such as autonomic dysfunction, palpitations and pectus excavatum. The importance of recognizing that mitral valve prolapse may occur as an isolated disorder or with other coincident findings has led to the use of both terms. Mitral valve prolapse syndrome, which occurs in 3 to 6 percent of Americans, is caused by a systolic billowing of one or both mitral leaflets into the left atrium, with or without mitral regurgitation. It is often discovered during routine cardiac auscultation or when echocardiography is performed for another reason. Most patients with mitral valve prolapse are asymptomatic. Those who have symptoms commonly report chest discomfort, anxiety, fatigue and dyspnea, but whether these are actually due to mitral valve prolapse is not certain. The principal physical finding is a midsystolic click, which frequently is followed by a late systolic murmur. Although echocardiography is the most useful mode for identifying mitral valve prolapse, it is not recommended as a screening tool for mitral valve prolapse in patients who have no systolic click or murmur on careful auscultation. Mitral valve prolapse has a benign prognosis and a complication rate of 2 percent per year. The progression of mitral regurgitation may cause dilation of the left-sided heart chambers. Infective endocarditis is a potential complication. Patients with mitral valve prolapse syndrome who have murmurs and/or thickened redundant leaflets seen on echocardiography should receive antibiotic prophylaxis against endocarditis. (+info)
Epidemiology of rheumatic heart disease in black shcoolchildren of Soweto, Johannesburg.
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A survey to determine the prevalence of rheumatic heart disease (R.H.D.) in Black children was conducted in the creeches and primary schools of the South Western Townships of Johannesburg (Soweto). A total of 12 050 Black children were examined by 10 cardiologists in May to October 1972. The overal prevalence rate of R.H.D. was 6.9 per 1000, with a peak rate of 19.2 per 1000 in children of the seventh school grade. The maximal age incidence was 15-18 years and there was a female preponderance of 1 6:1. A rise in prevalence occurred with increasing family size. Most children (92%) were asymptomatic, and in 82.5% R.H.D. was diagnosed for the first time during the school survey. The commonest valve lesion was mitral regurgitation, which was present in 93% and occurred as an isolated lesion in 47.5%. Lancefield's group A beta-haemolytic streptococcus was isolated from the throats of 52 per 1000 Soweto children. The auscultatory features of a non-ejection systolic click and late systolic murmur were prevalent (13.9 per 1000) and had several epidemiological factors in common with R.H.D. A comprehensive preventative campaign is urgently needed in South Africa, directed at both primary and secondary prophylaxis of R.H.D. The socioeconomic status of the community must be improved if optimal prevention is to be achieved. (+info)
Using a multimedia tool to improve cardiac auscultation knowledge and skills.
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OBJECTIVE: Today's medical school graduates have significant deficits in physical examination skills. Medical educators have been searching for methods to effectively teach and maintain these skills in students. The objective of this study was to determine if an auscultation curriculum centered on a portable multimedia CD-ROM was effective in producing and maintaining significant gains in cardiac auscultatory skills. DESIGN: Controlled cohort study. PARTICIPANTS: All 168 third-year medical students at 1 medical school in an academic medical center. INTERVENTIONS: Students were tested before and after exposure to 1 or more elements of the auscultation curriculum: teaching on ward/clinic rotations, CD-ROM comprehensive cases with follow-up seminars, and a CD-ROM 20-case miniseries. The primary outcome measures were student performance on a 10-item test of auscultation skill (listening and identifying heart sound characteristics) and a 30-item test of auscultation knowledge (factual questions about auscultation). A subset of students was tested for attenuation effects 9 or 12 months after the intervention. RESULTS: Compared with the control group (1 month clinical rotation alone), students who were also exposed to the CD-ROM 20-case miniseries had significant improvements in auscultation skills scores (P < .05), but not knowledge. Additional months of clerkship, comprehensive CD-ROM cases, and follow-up seminars increased auscultation knowledge beyond the miniseries alone (P < .05), but did not further improve auscultation skills. Students' auscultation knowledge diminished one year after the intervention, but auscultation skills did not. CONCLUSION: In addition to the standard curriculum of ward and conference teaching, portable multimedia tools may help improve quality of physical examination skills. (+info)
Because of rising interest in new methods to detect arterial diseases, we compared data from 3 different compliance-related techniques to measure arterial stiffness: systolic pulse contour analysis, diastolic pulse contour analysis (modified Windkessel model), and muscular (brachial) artery compliance by cuff plethysmography. Variables measured in the sitting position were compared with each other, with clinic blood pressures (BPs), and with the cardiac time-tension integral (CTTI) in 63 established hypertensive and 28 age-matched normotensive subjects. Hypertensives demonstrated marginal reductions in C(1) (thought to represent reduced large vessel compliance) and increased central systolic BP augmentation. In contrast, muscular artery compliance tended to be greater in the hypertensives despite normal brachial arterial diameters. C(2), suggested to be an indicator of small artery properties, was similar in both groups. CTTI was strongly related to systolic pressure (r=0.81), integrated mean arterial pressure (r=0.83), and systolic pressure-heart rate product (r=0.85) and was less strongly related to diastolic (r=0.71) or pulse pressure (r=0.57). Weak correlations were observed between CTTI and measured compliance-related variables, which also showed absent or weak correlations among themselves. We conclude that the weak relationships among BP and compliance-related variables could be due to intrinsic differences in the properties of large and small arteries, theoretical methodological weaknesses, measurement artifacts, or intrinsic hemodynamic differences of the sitting position. At present, compliance-related variables provide little additional advantage over cuff BP in the office estimation of cardiac work. (+info)
Cardiac auscultatory recording database: delivering heart sounds through the Internet.
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The clinical skill of cardiac auscultation, while known to be sensitive, specific, and inexpensive in screening for cardiac disease among children, has recently been shown to be deficient among residents in training. This decline in clinical skill is partly due to the difficulty in teaching auscultation. Standardization, depth, and breadth of experience has been difficult to reproduce for students due to time constraints and the impracticality of examining large numbers of patients with cardiac pathology. We have developed a web-based multimedia platform that delivers complete heart sound recordings from over 800 different patients seen at the Johns Hopkins Outpatient Pediatric Cardiology Clinic. The database represents more than twenty significant cardiac lesions as well as normal and innocent murmurs. Each patient record is complete with a gold standard echo for diagnostic confirmation and a gold standard auscultatory assessment provided by a pediatric cardiology attending. (+info)