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Biomedical subjects

K R Bloom

Publications and source records attributed to K R Bloom.

At least 19 recordsLinked to original sources
PubMed1994

Spontaneous conversion of supraventricular tachycardia followed by electromechanical dissociation.

We present this case to emphasize the potentially fatal outcome of supraventricular tachycardia in infancy, particularly if it has been undiagnosed for several days. Certainly, careful monitoring needs to take place during any attempt at cardioversion or any other noxious stimulation of the patient. Bicarbonate therapy should be provided if metabolic acidosis is present. Restoration of sinus rhythm may not guarantee an immediate return of normal cardiac function.

Heart Arrest↗
PubMed1989

Primary pericardial sarcoma in a neonate.

A 9-day-old infant was found to have an undifferentiated pericardial sarcoma. Despite intensive surgery and chemotherapy, the child died of progressive disease. This is the first report to our knowledge of a primary pericardial sarcoma in a newborn.

Echocardiography↗
PubMed1981

A comprehensive scoring system for evaluating Noonan syndrome.

A multidisciplinary team assessed 23 patients with various manifestations of the Noonan syndrome, including pulmonary valve stenosis (with leaflet dysplasia), "typical" facial appearance (including hypertelorism, epicanthic folds, flat nasal bridge, and apparently low-set ears), short stature, and mental retardation. Seven patients had a family history of the syndrome. A comprehensive scoring system was devised on the basis of frequency and severity of manifestations and results of invasive and noninvasive tests in these patients and those reported in the literature. The scoring system was condensed into a score card for clinical use and validated by "blind" application to patients with isolated pulmonary valve stenosis or suspected Noonan syndrome. Use of a scoring system to diagnose a syndrome for which there is no specific diagnostic test facilitates accuracy and decreases observer bias. In the case of unusual congenital disorders it is particularly valuable for a pediatrician in general practice.

Adolescent↗
PubMed1981

Atrial septal aneurysm: a cause for midsystolic click. Report of a case and review of the literature.

A patient who was evaluated for a midsystolic click was found to have an aneurysm of the atrial septum as an isolated anomaly. Bulging of this aneurysm into the right atrium was associated with the production of the click. Echo-, phono-, and angiocardiographic features are presented, with a review of the literature on atrial septal aneurysms. These aneurysms, although rare, should be considered in the differential diagnosis of patients with midsystolic click.

Adult↗
PubMed1980

Hemodynamic responses to supine exercise in children with left-sided cardiac disease.

Exercise, a physiologic stress, has been used in adults to unmask abnormalities of left ventricular hemodynamics not detectable at rest. Similar data in children are not available. An evaluation was made of the feasibility, safety and value of a graded upright and supine ergometer stress test to assess exercise hemodynamics during cardiac catheterization in 21 children with left-sided cardiac disease. The catheterization technique involved the simultaneous recording of intracardiac and great vessel pressures, thermodilution cardiac index and M mode echocardiograms of the left ventricular cavity. The method appears practical and safe. Although hemodynamic responses varied among clinical groups, the lack of control data currently prevents assessment of the value of this technique for long-term management.

Adolescent↗
PubMed1980

Comparative echocardiographic features of conditions presenting with symptomatic pulmonary hypertension and right ventricular hypertrophy in early infancy.

Echocardiographic dimensions in infants (less than 2 months) with pulmonary hypertension, associated with coarctation of the aorta in 21, total anomalous venous return in 10, and left-to-right shunts in 14 were compared with 10 infants with respiratory distress syndrome, seven with transient tachypnoea of the newborn, 20 normal children, and with each other. Distinguishing features of total anomalous pulmonary venous return were very significantly lower left atrial and left ventricular dimensions. Right ventricular enlargement was maximal in patients with coarctation of the aorta and total anomalous pulmonary venous return. Left ventricular end-diastolic dimension in coarctation of the aorta was not significantly different from normal but the left ventricular end-systolic dimension was significantly lower, suggesting a hypercontractile left ventricle. Similar findings were observed in patients with left-to-right shunts. M-mode echocardiograms are hence valuable in differentiating conditions which may present with intractable congestive cardiac failure in the newborn and also distinguishing them from common respiratory disease of the neonate.

Cardiomegaly↗
PubMed1980

Assessment of left ventricular contractility during supine exercise in children with left-sided cardiac disease.

Exercise stresses the cardiovascular system and causes it to use its reserve capacities. Exercise assessment may unmask abnormalities of left ventricular contractility not suspected from or detected by resting measurements. We have studied the following indices of left ventricular contractility in 21 children with left-sided congenital heart disease: maximum dP/dt, Vmax, Vpm, Vcf, and peak meridional wall stress. Studies were performed in the supine posture at rest, and at 25 per cent, and 50 per cent of a predetermined maximal upright workload on a bicycle ergometer. The method of measurement used simultaneous high fidelity catheter pressure tracings and M-mode echocardiography. There were no complications and the technique appeared practical and safe. The measurements of contractility differentiated patients with left ventricular volume or pressure overload from each other and from patients with either volume plus pressure overload, or myocardial dysfunction. These measurements can be used to measure the functional reserve capacity of patients with left-sided lesions, and may be useful in follow-up studies, especially before and after operation.

Adolescent↗
PubMed1980

Right ventricular volume determinations in 18 patients with pulmonary atresia and intact ventricular septum. Analysis of factors influencing right ventricular growth.

Right ventricular growth was assessed angiocardiographically in 18 patients with pulmonary atresia, intact ventricular septum, and hypoplastic and hypertensive right ventricle. A variety of surgical procedures were performed. In only 12 patients (66.7%) was right ventricular-pulmonary artery continuity achieved (group 1). Nine of these 12 patients persisted with systemic or suprasystemic right ventricular pressures. Among the six patients in whom right ventricular-pulmonary artery continuity was not achieved (group 2), all maintained suprasystemic right ventricular pressures. Right ventricular growth was assessed in groups 1 and 2. The patients were also subdivided according to the qualitative degree of tricuspid regurgitation as determined angiocardiographically on right ventricular cineangiocardiograms at the preoperative catheter study. Right ventricular growth to normal levels as evidenced by change in right ventricular end-diastolic volume was rarely observed in group 2 patients. Among the four patients with severe tricuspid regurgitation and a large tricuspid valve, right ventricular growth to normal levels was achieved whether they were in group 1 or group 2. Right ventricular growth is thus predicated on numerous morphologic factors in these patients. However, reconstitution of right ventricular-pulmonary artery continuity and a nonobstructive tricuspid valve are probably two of the more important factors.

Aging↗
PubMed1980

Noninvasive assessment of left ventricular function related to serum digoxin levels in neonates.

Eighteen neonates in heart failure were investigated to assess whether high or low serum digoxin levels had differing effects on left ventricular function as determined by systolic time intervals obtained by echocardiography. Nine patients had digoxin levels of 1.99 +/- 0.35 ng/ml (group 1). Nine others had levels of 3.62 +/- 0.95 ng/ml (group 2). Systolic time intervals were obtained by echocardiography before and at 5 days after digoxin and correlated with serum levels. The heart rate, preejection period (PEP), left ventricular ejection time (LVET), electromechanical systole (QS2) and the PEP/LVET ratio were measured. LVET and electromechanical systole were indexed. These measurements were analyzed and the two groups were compared using Student's t test. The clinical improvement in both groups was similar and no difference in ECG changes were noted. Therapy with digoxin produced changes in heart rate and systolic time intervals in both groups. Both showed significant shortening of electromechanical systole index; group 1 significantly shortened the LVET index and PEP/LVET ratio, whereas group 2 significantly shortened the PEP. Statistical analysis comparing the two groups showed no difference between them. Digoxin produces measurable changes in the indices of left ventricular function. The magnitude of these changes suggests no therapeutic advantage to the higher levels.

Digoxin↗
PubMed1979

Echocardiographic recognition of atrioventricular valve stenosis associated with endocardial cushion defect: pathologic and surgical correlates.

The association of either mitral or tricuspid stenosis with endocardial cushion defects has been well recognized pathologically but is infrequenctly diagnosed clinically. M mode echocardiographic features such as markedly disproportionate ventricular size, abnormal mitral or tricuspid diastolic echoes or failure to define adequately an atrioventricular (A-V) valve are strongly suggestive of associated stenosis of that valve. In this study mitral stenosis in association with endocardial cushion defect was correctly diagnosed in four of five patients. In the fifth patient (the first seen) the condition was easily diagnosed retrospectively. Tricuspid stenosis was similarly diagnosed prospectively in three of four patients. Significant stenosis was not overlooked or misdiagnosed in any patient with an endocardial cushion defect. Significant stenosis of an A-V valve in association with endocardial cushion defect carries a high mortality. It is important to recognize the combined lesion clinically because infants with it are not suitable for total surgical correction. Palliative surgical procedures with aggressive medical therapy probably offer the infant the best chance of surviving until ventricular growth may render corrective surgery feasible.

Aorta↗
PubMed1979

Transient myocardial ischemia of the newborn infant demonstrated by thallium myocardial imaging.

Five term and two premature newborn infants were referred for respiratory distress and congestive heart failure, and were found to have electrocardiographic Q or ST-T abnormalities suggesting ischemia. Echocardiographic and/or hemodynamic assessment excluded anatomic heart disease in six infants. In three infants, moderate or severe hemodynamic impairment within 36 hours of age was suggested by these studies. Myocardial perfusion images in all patients showed very poor myocardial uptake of thallium 201, compatible with global myocardial ischemia. Infants of similar age with myocarditis, or with congenital heart disease and congestive failure, had normal myocardial uptake. Rapid clinical improvement occurred within three to seven days. Two to five months later, all infants were well. Two had persistent electrocardiographic abnormalities but repeat thallium 201 imaging in six demonstrated almost normal myocardial uptake. These data provide further evidence that perinatal respiratory distress may be associated with myocardial dysfunction and congestive heart failure in some infants without anatomic heart disease, and suggest that myocardial dysfunction in these infants is associated with global myocardial ischemia, most of which is transient. The timing and nature of the insult causing the ischemia are unclear.

Coronary Disease↗
PubMed1979

Structural heart disease in the newborn. Changing profile: comparison of 1975 with 1965.

The earlier detection and investigation of babies with congenital structural heart disease has resulted in earlier treatment and better management of these patients. In 1965, at the Hospital for Sick Children, Toronto, 121 cases were assessed and treated; by 1975 this figure had risen to 226 cases. Few changes were noted in the incidence of the 10 most common malformations, except for the obvious increase in the incidence of patient ductus arteriosus due to survival of increasingly premature infants. The sick cardiac neonate was referred earlier in 1975, studied with newer non-invasive investigations, and, according to the severity of symptoms and signs, was sent sooner to cardiac catheterisation. 80% of babies presenting with cyanosis survived the first month and 60% of babies with congestive heart failure survived. With better surgery and perioperative care, the survival rate in the first month after surgery rose from 37% in 1965 to 70% in 1975.

Cardiac Catheterization↗
PubMed1979

Congenital absence of the pulmonary valve associated with imperforate membrane type of tricuspid atresia, right ventricular tensor apparatus and intact ventricular septum: a curious developmental complex.

We have presented the unique clinical and morphological features of 3 patients with an imperforate tricuspid valve and right ventricular tensor apparatus. Thus, despite valve tissue and apparatus, there was not a perforate atrioventricular connection. This most uncommon type of tricuspid atresia' was associated in all 3 cases with a congenitally absent pulmonary valve, an underdeveloped right ventricle, and a curious distortion of the ventricular septum. Indeed, 2 of these patients demonstrated severe disproportionate ventricular septal thickening, although histopathologic examination did not substantiate those features usually associated with a hypertrophic cardiomyopathy. Rather, microscopic examination revealed a sinusoidal malformation consisting of normal myocardial cells separated by branching ethothelial-lined channels which communicated with the right ventricular cavity. In addition, gross examination of these 3 specimens revealed an abnormally persistent right venous valve in 2, which subdivided the right atrium. Finally, these cases provide further evidence that the term 'tricuspid atresia' oversimplifies the observed morphological features.

Abnormalities, Multiple↗
PubMed1978

Echocardiography in adriamycin cardiotoxicity.

Twenty-six patients receiving adriamycin for osteogenic sarcoma had serial echocardiographic assessments of their left ventricular function. A statistically significant deterioration of function was noted throughout the course. Ventricular function tended to normalize in the period following cessation of adriamycin. The velocity of circumferential fibre shortening (Vcf) and ejection fraction (EF) were the best parameters. Sudden declines in these values resulted in us withholding therapy until the parameters again improved. Fatal congestive heart failure was seen in only one patient. Echocardiography thus provides the clinician with a valuable tool enabling one to improve the therapeutic usefulness of adriamycin by removing much of the uncertainty over the development of cardiotoxicity.

Adolescent↗