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Biomedical subjects

K R Bloom

Publications and source records attributed to K R Bloom.

32 records · Page 2Linked to original sources
PubMed1978

Truncal or aortic valve stenosis in functionally single arterial trunk. A clinical, hemodynamic and pathologic study of six cases.

Stenosis of the semilunar valve in the presence of a functionally single arterial trunk is uncommon. Three patients with truncus arteriosus, two with tetralogy of Fallot and pulmonary atresia and one with pulmonary atresia and intact septum were diagnosed as having stenosis of the truncal or aortic valve on the basis of clinical, echocardiographic, hemodynamic and angiocardiographic findings. Echocardiograms consistently showed multiple diastolic closure lines and abnormal semilunar valves in addition to the aortic override in five patients and hypoplastic right ventricle in the patient with pulmonary atresia and intact septum. Peak systolic gradients between the left ventricle and truncus (or aorta) at cardiac catheterization ranged from 20 to 47 mm Hg. Retrograde aortography confirmed a domed and stenotic semilunar valve. Cyanosis was progressive in the three patients with pulmonary atresia. Two patients had arterial anastomosis, and one had a right ventricle-pulmonary arterial graft in addition to aortic valvotomy. One of the three patients with truncus arteriosus underwent complete repair in addition to truncal valvotomy but he died in the post-operative period. The other two patients with truncus arteriosus died of intractable congestive cardiac failure before surgical intervention. It is suggested that the presence of semilunar valve stenosis in these patients adversely affects the prognosis. The myocardium is already jeopardized as a result of hypoxia in pulmonary atresia and left ventricular diastolic overload in patients with truncus arteriosus. The added burden of semilunar valve stenosis may further compromise the functional status of the myocardium.

Angiocardiography↗
PubMed1978

Nonstructural heart disease in the newborn. Observations during one year in a perinatal service.

One-third of 327 newborn infants referred to the perinatal service of the Hospital for Sick Children during 1975 with suspected cardiopulmonary disorders proved to have nonstructural heart disease. Most of these were term infants with transient tachypnoea or cyanosis who recovered. A history of fetal distress or difficult delivery was commonly associated. The haemodynamic disorder for most was a delay in the normal progress of the transitional circulation. Evidence of myocardial ischaemia was present in 40%, and about half of these developed congestive heart failure. Aids to diagnosis of the ischaemic complication included echocardiography and myocardial perfusion scanning. For a small proportion specific metabolic disturbances, myocarditis, or dysrhythmia seemed the primary cause but even for these there were reasonable grounds to suspect a prenatal origin. Current general supportive measures were of value in treatment.

Arrhythmias, Cardiac↗
PubMed1978

Aortic stenosis in children. Experience with echocardiographic prediction of severity.

Fifty-six children with aortic stenosis were investigated both by echocardiography and cardiac catheterization. The ratio of end-systolic wall thickness (Ws) to internal diameter (LVES) across the minor axis of the LV as determined by echocardiography and multiplied by a factor of 245 predicts left ventricular pressure (r = 0.83). Subtracting the arm systolic blood pressure from the predicted intraventricular systolic pressure (PISP) gives a predicted systolic pressure gradient (r = 0.91). The technique is found to be useful for both initial and sequential noninvasive assessment of aortic stenosis with normal LV function irrespective of the level of obstruction. It is shown to apply equally well to wide range of LV pressures, is independent of volume load, and is useful in predicting small gradients. Some common problems encountered with the measurements are examined in detail.

Adolescent↗
PubMed1978

The reliability and practicality of single crystal echocardiography in the evaluation of single ventricle. Angiographic and pathological correlates.

A prospective clinical and echocardiographic diagnosis of single ventricle was made in 42 patients. Each was evaluated for the number of atrioventricular (A/V) valves, presence of an outflow chamber (OC), A/V valve-semilunar continuity, and orientation of the great arteries. Angiographic correlations were subsequently obtained in 40 and autopsies in 12. The overall diagnosis of single ventricle was substantiated in 39. Two other patients diagnosed as single ventricle by angiography were thought to have large ventricular septal defects on echocardiography. Tricuspid valve was interpreted as septum in one. The angiographic diagnosis of single ventricle was incorrect in another, correctly diagnosed by echocardiography and confirmed at pathology. The differential diagnosis also included A-V canal, L-transposition of the great arteries, double outlet right ventricle, and tricuspid atresia. This last condition has to be differentiated on clinical evidence. The echocardiograms were of particular value in determining the number of A/V valves. Two great arteries were demonstrated in 74% of patients and their relationship was correctly determined in 79% of these. Both imaging techniques agreed closely as to A/V valve-semilunar continuity and presence of an OC, but both showed some inaccuracies compared to pathological specimens. The echocardiogram helps both in planning catheterization and in evaluating the overall diagnosis.

Adolescent↗
PubMed1977

Echocardiographic evaluation of left-to-right shunt in ventricular septal defect and persistent ductus arteriosus.

Forty-five patients with either a ventricular septal defect or a persistent ductus arteriosus were assessed by echocardiography and cardiac catheterisation. Left atrial dimension was expressed either as a function of the body surface area (LAD cm per m2 BSA), or as a multiple of the aortic root dimension (LAD/AR), and was compared with the shunt size as determined by oximetry. A highly significant (P less than 0-001) regression relation was found for the group as a whole. A significant relation also existed for each individual group: ventricular septal defect, ventricular septal defect with pulmonary hypertension, and persistent ductus arteriosus. Regression equations were derived for the whole group. The value of echocardiography is in separating large from small shunts and in adding a dimension to the follow-up of the individual patient.

Adolescent↗
PubMed1976

Echocardiographic assessment of bicuspid aortic valves. Angiographic and pathological correlates.

Aortic root echocardiograms were recorded from 89 patients whose aortic valves had also been adequately defined by selective angiography or viewed surgically or at autopsy. The eccentricity index (E.I.) of the aortic leaflets was measured at the onset of diastole and an E.I. of 1.3 or greater was taken as abnormal. Of 31 patients with isolated nonobstruced or mildly obstructed bicuspid aortic valves (7 viewed previously at valvotomy and 24 diagnosed radiologically) 23 (74%) had an abnormal E.I. Varying eccentricity occurred in some of these patients. Central leaflet echoes (E.I. of 1.0 to 1.25) were present in the other eight patients. All 14 patients with nonobstructed tricuspid aortic valves had central echoes. Additional multilayered diastolic echoes were found in patients with bicuspid aortic valves as well as in two patients with abnormal tricuspid aortic valves. The valves of 13 patients with aortic stenosis or incompetence were viewed surgically and the E.I. was abnormal in all patients with a bicuspid aortic valve in this group. Aortic leaflet echo findings were not diagnostically helpful in ten patients with tetralogy of Fallot, one of whom had a normal E.I. with a surgically confirmed bicuspid aortic valve. Of 21 patients with VSD only one had a bicuspid aortic valve but six had an abnormal E.I. This false positive sign was related to a high membranous VSD, sometimes with aortic valve prolapse. It is concluded that an E.I. of greater than or equal to 1.3 in the absence of an associated VSD is diagnostic of a bicuspid aortic valve and can be expected to be found in approximately three-quarters of subjects with this abnormality.

Adolescent↗
PubMed1975

Epidemiology of rheumatic heart disease in black shcoolchildren of Soweto, Johannesburg.

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.

Adolescent↗
PubMed1975

The association of fixed and dynamic left ventricular outflow obstruction.

Twelve patients were investigated echocardiographically and angiographically and were shown to have severe fixed obstruction to the left ventricular outflow tract. Eight had valvular stenosis, and four had discrete subvalvular membranes. Two of the patients had additional dynamic obstruction of the left ventricular outflow tract. This was recognized preoperatively by echocardiography because of abnormal systolic motion of the mitral leaflet. At the time of definitive surgery for relief of the fixed obstruction, the additional dynamic obstruction was identified and treated, since persistent residual obstruction may lead to death in the immediate postoperative period or to long-term symptoms. The dynamic left ventricular outflow obstruction is probably a result of the hypertrophy produced by the fixed obstruction.

Adolescent↗