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Biomedical subjects

J S Child

Publications and source records attributed to J S Child.

At least 73 records · Page 4Linked to original sources
PubMed1986

Cardiac involvement in Friedreich's ataxia: a clinical study of 75 patients.

To establish the prevalence and to characterize the types of cardiac involvement in Friedreich's ataxia, 75 consecutive patients (39 male and 36 female), aged 10 to 66 years (mean 24) were prospectively studied. Electrocardiograms were performed in all patients, vectorcardiograms in 34 and echocardiograms in 58. Electrocardiographic and vectorcardiographic abnormalities occurred in 69 (92%) of the 75 patients. Electrocardiograms revealed ST-T wave abnormalities in 79%, right axis deviation in 40%, short PR interval in 24%, abnormal R wave in lead V1 in 20%, abnormal inferolateral Q waves in 14% and left ventricular hypertrophy (voltage and repolarization criteria) in 16%. Echocardiograms revealed concentric left ventricular hypertrophy in 11%, asymmetric septal hypertrophy in 9% and globally decreased left ventricular function in 7%. Progression from a normal echocardiogram to concentric left ventricular hypertrophy, asymmetric septal hypertrophy or globally decreased left ventricular function was identified in one patient in each category, although the study was not designed for longitudinal follow-up. Two patients died, and necropsy revealed in both a minimally dilated but flabby left ventricle. On the basis of electrocardiographic and vectorcardiographic and echocardiographic data, 95% of patients had one or more disorders. The most common abnormality was segmental myocardial "dystrophy" (electrocardiographic QRS initial force abnormalities), but global left ventricular hypokinesia occurred more often than previously recognized.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1986

Renal function and urate metabolism in late survivors with cyanotic congenital heart disease.

Diminished glomerular filtration rate, proteinuria, and large hypercellular congested glomeruli with segmental sclerosis are found in late survivors with cyanotic congenital heart disease (CCHD). Hyperuricemia is common, acute gouty arthritis is less common than uric acid levels would predict, and overt tophaceous deposits of uric acid are exceptional. The role of the kidney in causing the basic biochemical disturbances, and the relative importance of impaired urate excretion vs urate overproduction have not been established. Accordingly, we reviewed the courses of two index patients and prospectively studied eight additional CCHD patients from 28 years to 46 years old with mean hematocrits of (62 +/- 10%). Plasma creatinine concentration was normal (0.9 +/- 0.1 mg/dl) yet glomerular filtration rate was mildly reduced to 93 +/- 14 ml/min as measured by creatinine clearance and to 81 +/- 6 ml/min as measured by 111In DTPA. Three patients had significant proteinuria and one was nephrotic. Plasma uric acid concentration was high in all but one (8.2 +/- 2.1 mg/dl), mean 24 hr uric acid excretion was normal (564 +/- 221 mg), and fractional uric acid excretion was relatively low (6.3 +/- 2.6%). The two patients with highest plasma uric acid levels (12.0 and 10.2 mg/dl) had the lowest fractional excretions (2.8% and 4.0%). Both of these patients had diminished capacity to excrete a water load (38% and 27%/4 hr) and to maximally concentrate urine (520 and 635 mOsm/kg after water deprivation and vasopressin). In conclusion, high plasma uric acid levels in late survivors with CCHD are secondary to inappropriately low fractional uric acid excretion, not to urate overproduction.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Regional perfusion, glucose metabolism, and wall motion in patients with chronic electrocardiographic Q wave infarctions: evidence for persistence of viable tissue in some infarct regions by positron emission tomography.

Positron-emission tomography with 13N-ammonia and 18F-2-deoxyglucose was used to assess regional perfusion and glucose utilization in 31 chronic electrocardiographic Q wave regions in 20 patients. With previously published criteria, regions of infarction were identified by a concordant reduction in regional perfusion and glucose utilization, and regions of ischemia were identified by preservation of glucose utilization in regions of diminished perfusion. Only 10 of the 31 regions (32%) exhibited myocardial infarction tomographically. In contrast, positron tomography revealed ischemia in six regions (20%) and was normal in 15 regions (48%). Even when Q wave regions were reassigned and consolidated to enhance the specificity of the electrocardiogram, uptake of 18F-2-deoxyglucose was noted in the majority (54%) of the regions. Neither electrocardiographic ST-T changes nor severity of associated wall motion abnormality reliably distinguished tomographically identified regions of ischemia from infarction. Thus positron tomography reveals evidence of persistent tissue metabolism in a high proportion of chronic electrocardiographic Q wave regions, and commonly used clinical tests do not reliably distinguish hypoperfused but viable regions from tomographically defined regions of myocardial infarction.

Adult↗
PubMed1986

Dynamics of oxygen uptake during exercise in adults with cyanotic congenital heart disease.

The dynamic increase in oxygen uptake (VO2) at the start of exercise reflects the circulatory adjustments to metabolic changes induced by the exercise. Because VO2 measured at the lungs is the product of pulmonary blood flow and arteriovenous oxygen difference, pathologic conditions affecting the capacity of these factors to change would be expected to alter VO2 kinetics. To determine whether measurement of VO2 kinetics can detect conditions in which the pulmonary blood flow response to exercise is abnormal, VO2 was measured, breath-by-breath, during the transition from rest to exercise in 13 adults with cyanotic congenital heart disease (central venoarterial shunting) and in nine normal subjects. The increase in VO2 above baseline during the first 20 sec of exercise (phase I), reflecting the immediate increase in pulmonary blood flow, was diminished in the patients compared with that in normal subjects (14.8 +/- 10.9 vs. 49.8 +/- 19.2 ml of oxygen) (p less than .001). The patients' phase I responses correlated with their reported physical activity tolerance (p less than .01). In addition, the second phase of the VO2 response kinetics was prolonged in patients compared with normal subjects (half-time = 63 +/- 13 vs 15 +/- 13 sec) (p less than .001). We conclude that striking disturbances in VO2 kinetics occur in patients with cyanotic congenital heart disease and that these measurements provide a useful noninvasive means of evaluating the degree to which the increase in pulmonary blood flow is constrained in response to exercise.

Adult↗
PubMed1986

Identification of impaired metabolic reserve by atrial pacing in patients with significant coronary artery stenosis.

We investigated myocardial 11C-palmitate clearance kinetics at a resting heart rate (control) and during pacing using positron-emission tomography in 10 patients with significant coronary artery stenosis (greater than 70%) and evidence of exercise-induced ischemia. Serial 11C-palmitate images acquired at control and during pacing revealed biexponential myocardial 11C clearance both in myocardium supplied by a stenotic coronary artery (myocardium "at risk") and in myocardium supplied by a normal coronary artery (normal myocardium). At control, the average rate of myocardial 11C clearance from the early rapid curve component (the clearance half-time) was similar in normal myocardium and in that at risk (22.2 +/- 5.2 vs 21.0 +/- 5.4 min, NS), as was the amount of myocardial 11C activity at the end of the early rapid phase (residual fraction 56.3 +/- 7.2% vs 54.7 +/- 7.3%, NS). Thus, myocardial clearance was homogeneous at control, suggesting a similar rate and amount of 11C-palmitate oxidation in normal myocardium and in that at risk. Pacing shortened clearance half-times and decreased residual fraction in both normal myocardium and that at risk compared with control. However, clearance half-times were 17% longer and residual fractions 14% higher in myocardium at risk compared with normal myocardium (p less than .005 and p less than .01, respectively). Therefore, during pacing myocardial 11C clearance became heterogeneous, suggesting impaired 11C-palmitate oxidation in myocardium at risk compared with normal myocardium. Increased substrate utilization in response to increased workload can be thought of as a measure of metabolic reserve. Our data suggest metabolic reserve for free fatty acid oxidation is impaired in myocardium supplied by a significantly stenosed coronary artery and that this impairment can be detected by analysis of myocardial 11C-palmitate clearance.

Adult↗
PubMed1984

Incidence and significance of early pericardial effusions after cardiac surgery.

Echocardiography (echo) is frequently performed postoperatively to evaluate patients suspected of having cardiac tamponade or pericarditis. The overall incidence and significance of echocardiographic pericardial effusions (PE) early after cardiac surgery are unknown. Therefore, M-mode and 2-dimensional (2-D) echo were used to study 39 stable patients 4 to 10 days after cardiac surgery. Twenty-two patients (56%) had unequivocal moderate-to-large PEs. PEs were identified on serial chest x-rays in only 6 patients. PEs were significantly more common after heavy postoperative bleeding, and occurred in 16 of 19 patients with more than 500 ml of total chest tube output; only 6 of 20 patients with chest tube output less than 500 ml had PE. There was no correlation of PE by echo with pericardial friction rubs, chest pain or atrial arrhythmias. Elevated erythrocyte sedimentation rate did not correlate with PE by echo or clinical pericarditis. In 1 of 22 patients with PE, tamponade developed, and the patient required reoperation on day 5; the other 21 were discharged without related therapy. Thus, early postoperative PEs are common and related to postoperative bleeding. Because they do not correlate with symptoms of pericarditis and rarely lead to tamponade, their identification is usually of limited clinical significance.

Adult↗
PubMed1984

Primary hemochromatosis: anatomic and physiologic characteristics of the cardiac ventricles and their response to phlebotomy.

M-mode and 2-dimensional echocardiography and gated equilibrium blood pool imaging (rest and exercise) were used in 10 patients with primary hemochromatosis to characterize the spectrum of pathophysiologic abnormalities of the cardiac ventricles and to determine the response to chronic therapeutic phlebotomy. Dilated and restrictive cardiomyopathic patterns were identified in 1 patient each, but our data do not permit conclusions on when in the natural history a given pattern becomes overt. On entry into study, 3 patients had normal ventricles and 7 had ventricular abnormalities on echocardiography and blood pool angiography. In 2 of the latter patients, biventricular dysfunction and increased left ventricular (LV) mass normalized after phlebotomy; 1 patient achieved a normal LV response to exercise. Of the 4 patients with isolated abnormal LV ejection fraction responses to exercise, the EF normalized in 2 after phlebotomy. In 1 patient, isolated right ventricular enlargement and dysfunction (echocardiographic and radionuclide imaging) normalized after phlebotomy. Thus, primary hemochromatosis can effect LV and RV size and function; clinically occult cardiac involvement can be identified by echocardiography and equilibrium blood pool imaging; therapeutic phlebotomy can ameliorate or reverse the deleterious effects of excess cardiac iron deposition which appears to exert its harm, at least in part, by a mechanism other than irreversible connective tissue replacement.

Adult↗
PubMed1984

Cardiac hypertrophy and function in master endurance runners and sprinters.

Cardiac enlargement with increased left ventricular mass is a recognized adaptive response to intensive physical conditioning. There have been few reports regarding cardiac hypertrophy and function in the middle-aged or older athlete. Accordingly, we studied 9 male Masters Track endurance distance runners (E) (mean age 54 yr) and 13 male Masters Track sprinters (S) (mean age 47 yr) by M-mode echocardiography, systolic time intervals, and maximal treadmill stress testing with direct measurement of maximal O2 consumption (VO2max). Left ventricular mass (LVM) index for E (154.0 +/- 27.4 g/m2; mean +/- SD) was greater than for S (127.1 +/- 15.9 g/m2) (P less than 0.05). LVM index was greater for both groups compared with age-range matched controls (N = 111.7 +/- 23.8 g/m2) (P less than 0.02). VO2max was greater in E (54 +/- 12 ml X kg-1 X min-1) than S (47 +/- 7 ml X kg-1 X min-1) (P less than 0.05) despite the younger age of S (P less than 0.05); both E and S had greater VO2max than predicted for nonathletic males of equivalent age. There was no significant linear relationship for LVM index and VO2max in the athletes. Left ventricular function at rest was normal. Thus, in well-trained older (greater than or equal to 40 yr) male distance runners and sprinters VO2max and LVM index are greater in E than S, and each greater than in controls, resting left ventricular function is normal, as judged by fractional shortening and systolic time intervals, and the degree of hypertrophy (LVM index) does not directly correlate with aerobic capacity (VO2max).

Adaptation, Physiological↗
PubMed1984

Systemic venous and pulmonary arterial flow patterns after Fontan's procedure for tricuspid atresia or single ventricle.

Despite increasing use of Fontan or modified Fontan repairs, the comparative hemodynamic efficacy of different types of connections are unresolved. Accordingly, we undertook a prospective study designed to determine postoperative flow patterns after Fontan's operation. Seven subjects had tricuspid atresia and eight had single ventricle. Ages ranged from 5 to 38 years (mean 16.4). Ten subjects had nonvalved right atrial-to-pulmonary arterial connection, and four had nonvalved right atrial-to-right ventricular communication. A valved conduit established continuity between the right atrium and right ventricle in one subject. Doppler flow profiles were recorded in the pulmonary artery and in the superior and inferior venae cavae of each. A reference electrocardiogram was used for timing purposes. In 14 patients, forward flow in the pulmonary artery was biphasic. Flow began at the end of the T wave (early ventricular diastole), peaked at or before the P wave (atrial systole), and returned to baseline by the peak of the R wave. Forward flow recommenced at the peak of the R wave (ventricular systole) and returned to baseline at the end of the T wave. Flow in the superior vena cava varied, and could not be recorded in three subjects. Between the end of the P wave and peak of the R wave (atrial systole) flow was reversed in eight, absent in three, and forward in one patient. Forward flow occurred between the peak of the R wave and the end of the T wave and was either continuous or biphasic. Fourteen patients had adequate studies of inferior vena cava flow; reversed flow during atrial systole occurred in 10 subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1983

Aortic valve systolic flutter as a screening test for severe aortic stenosis.

Previous efforts using M-mode echocardiography or 2-dimensional (2-D) echocardiography have not consistently separated patients with and without significant aortic stenosis (AS). We postulated that an aortic valve sufficiently pliant to produce systolic flutter on M-mode echocardiography could exclude significant AS and reviewed the M-mode echocardiograms of 50 consecutive patients (mean age 59 years) catheterized for presumed AS; 2-D echocardiography was also performed in 18 of 50 patients (36%). In 40 of 50 patients (80%) the aortic valve cusps were easily identified on M-mode echocardiography: 19 of 40 (48%) had systolic flutter with a mean aortic valve gradient of 4 +/- 8 mm Hg (mean +/- standard deviation [SD]) and an aortic valve area of 2.8 +/- 0.4 cm2; 21 of 40 (52%) had no systolic flutter with a mean aortic valve gradient of 55 +/- 19 mm Hg and an aortic valve area of 0.7 +/- 0.3 cm2. In the 10 of 50 patients (20%) in whom aortic valve cusps were not clearly identified, the mean aortic valve gradient was 50 +/- 24 mm Hg and the aortic valve area 0.8 +/- 0.4 cm2. Systolic flutter was not seen with an aortic valve gradient greater than 30 mm Hg or an aortic valve area less than 1 cm2. Aortic valve systolic opening by M-mode echocardiography or 2-D echocardiography did not accurately predict the severity of AS. Thus, aortic valve systolic flutter seen on M-mode echocardiography is strong evidence against significant AS, but the absence of systolic flutter does not allow reliable prediction of the severity of AS. The finding of systolic flutter by M-mode echocardiography may be a useful screening test in patients presumed to have AS.

Aortic Valve↗
PubMed1983

Angled interventricular septum on echocardiography: anatomic anomaly or technical artifact?

An acutely angled interventricular septum has been reported to constitute a distinct two-dimensional echocardiographic geometric pattern that may permit a false M-mode echocardiographic recording of asymmetric septal hypertrophy. In light of experience suggesting that the angle between the aortic root and interventricular septum varied with the intercostal space of the transducer, 45 subjects were prospectively studied by two-dimensional and M-mode echocardiography. Parasternal long- and short-axis views were obtained from two to four intercostal spaces in each subject. Two-dimensional echographic cursor-generated M-mode echocardiograms were obtained from the long-axis views; interventricular septal and left ventricular posterior wall thickness was measured from both the two-dimensional and M-mode echocardiograms. On two-dimensional echocardiography, the angle between the aortic root and septum became more acute as a progressively lower intercostal space was used (p less than 0.001). Although no change in septal thickness was apparent, the septal thickness significantly increased as a progressively lower intercostal space was used. On M-mode echocardiography, 21 subjects (47%) demonstrated asymmetric septal hypertrophy (septal/posterior wall thickness ratio greater than 1.3) from at least one intercostal space, but this was confirmed by the two-dimensional technique in only 4 subjects (9%). Thus, a two-dimensional echocardiographic recording of an angled interventricular septum can be produced by positioning the transducer in a low intercostal space, and caution must be used in the interpretation of asymmetric septal hypertrophy on M-mode echocardiograms. Two-dimensional echocardiography is a useful means of identifying subjects with apparent asymmetric septal hypertrophy that often may be the result of a technical artifact.

Adolescent↗
PubMed1983

Atrial systolic notch on the interventricular septal echogram: an echocardiographic sign of constrictive pericarditis.

Interventricular septal motion during ventricular diastole was analyzed using M-mode echocardiography in 13 patients with constrictive pericarditis and 12 patients with restrictive cardiomyopathy. In seven of eight patients with constrictive pericarditis in sinus rhythm, an abnormal "atrial systolic" notch was observed consisting of abrupt initial posterior motion toward the left ventricle approximately at the middle of the P wave and subsequent anterior motion at the end of the P wave and termination before the R wave. This notch was absent during atrial premature beats that were recorded in two patients. The atrial systolic notch was not observed in any patient with restrictive cardiomyopathy. The septal notch in early ventricular diastole previously described in constrictive pericarditis was seen in 62% of patients with constrictive pericarditis and 25% of patients with restrictive cardiomyopathy. Thus, an abnormal atrial systolic notch may be an additional useful sign to differentiate constrictive pericarditis from restrictive cardiomyopathy. The mechanism may be related to transient late diastolic pressure gradients between both ventricles resulting from asynchrony of left and right atrial contractions.

Diastole↗
PubMed1983

From cyanotic infant to acyanotic adult - the odyssey of blue babies.

An edited summary of an Interdepartmental Conference arranged by the Department of Medicine of the UCLA School of Medicine, Los Angeles. Director of Conferences: William M. Pardridge, MD, Associate Professor of Medicine.In the past two decades we have witnessed the maturing of diagnostic and surgical skills in the management of congenital heart disease. Although longevity and quality of life have improved, cures are few; varying degrees of postoperative medical supervision are therefore needed. This new patient population of adults requiring long-term medical care continues to increase. Proper management of such patients can be taxing, requiring knowledge not only of the preoperative disease but also of the nature and effects of surgical intervention and of the presence, type and extent of late postoperative residua and sequelae. The tetralogy of Fallot is taken as a model because it is well known in both pediatric and adult medicine, because intracardiac repair includes a wide range of techniques and because postoperative residua and sequelae comprise a broad spectrum of patient care concerns.

Adult↗
PubMed1982

Pericardial disease in familial Mediterranean fever: an echocardiographic study.

We studied 30 randomly selected patients with familial Mediterranean fever (FMF) by M mode echocardiography to determine the frequency of pericardial involvement. There was no evidence of congestive heart failure, uremia, or any other illness known to be associated with pericardial disease in the study population. Eight of the 30 patients (27 percent) had echocardiographic evidence of pericardial disease. Two had pericardial effusions, two had pericardial thickening, and four either or both. Patients with pericardial involvement had a mean duration of FMF of 28.9 +/- 12.2 (SD) years vs 18.5 +/- 10.6 (SD) years for those without pericardial disease (P less than .02). We concluded that pericardial involvement is common in FMF and that its occurrence as detected by echocardiography increases with duration of illness.

Adolescent↗
PubMed1982

Mitral valve prolapse. Cross sectional and provocative M-mode echocardiography.

False-negative supine M-mode echocardiograms occur in some patients with proved mitral valve prolapse. To investigate further, we performed M-mode echocardiography (MME) during standing and after the inhalation of amyl nitrite in 17 patients (group 1) selected for auscultatory evidence of mitral valve prolapse (MVP) but negative supine MME. To validate the standing MME technique, eight patients with classic auscultatory MVP with positive supine MME for MVP (group 2) and 15 control subjects (group 3) were studied. Supine cross-sectional echocardiography (CSE) was compared to MME in all three groups. Standing MME elicited echocardiographic evidence of MVP in 14/17 (82 percent) of group 1--auscultatory evidence of MVP but negative supine MME; CSE demonstrated MVP in 8/13 (62 per cent) of the same patients. There was no clear advantage of the CSE long axis view over the CSE apical four chamber view in the diagnosis of MVP in these selected subjects; however, the two views were complementary. Amyl nitrite was ineffective in eliciting echocardiographic evidence of MVP.

Adult↗