Search PubMed⌕ Search

Biomedical subjects

W B Strong

Publications and source records attributed to W B Strong.

At least 91 records · Page 5Linked to original sources
PubMed1984

Longitudinal exercise hemodynamics in children with sickle cell anemia.

To define further the natural history and causative factors in exercise-related cardiac dysfunction in children and adolescents with sickle cell anemia (SS), we studied the results of 74 patients' initial and follow-up exercise tests. The follow-up study was done one to three years after the first study in 36 children and four to seven years after initial testing in 38 children. Split-plot analysis of covariance did not show any temporal deterioration in exercise hemodynamic variables. Correlation analysis defined hemoglobin and hematocrit levels as critical determinants of cardiac functional reserve capacity in these patients. Several exercise ECG patterns, formerly considered abnormal in children with SS, are now considered to be variants of normal. Studies are presently in progress that should further define the nature and severity of the cardiac impairment during exercise in children with SS.

Adolescent↗
PubMed1984

Cardiac size and function in children with sickle cell anemia.

Cardiac size and function were studied echocardiographically in 124 children with sickle cell anemia. A group of 78 healthy black children served as control subjects. Sickle cell patients exhibited progressive chamber enlargement and progressively increasing left ventricular mass. Although contractility indices were normal, when the opposing influences of volume overload due to anemia and ventricular dysfunction were separated, abnormalities of systolic time intervals were identified. Left ventricular systolic time interval ratio and left ventricular preejection period were higher in the sickle cell group and became increasingly abnormal with growth, suggesting that left ventricular function deteriorated with time.

Adolescent↗
PubMed1984

Cardiovascular evaluation of the young athlete.

Heart murmurs and cardiovascular defects, elevated blood pressure, and arrhythmias cause considerable concern to many physicians evaluating or certifying students for competitive athletic participation. The purpose of this article is to present a practical approach to the evaluation and management of these problems.

Adolescent↗
PubMed1983

Exercise-induced cardiac dysfunction in sickle cell anemia. A radionuclide study.

Cardiac performance was studied by radionuclide angiography at rest and during exercise in 22 adolescents with sickle cell (SC) anemia and the results were compared with those in 12 control subjects. At rest, cardiac contractility was normal; cardiac output and end-diastolic volume were increased. At maximal exercise, heart rate, cardiac output response, and work capacity were reduced; the reduction was related to the degree of anemia. Left ventricular end-diastolic volume decreased with exercise most markedly in patients with ischemic exercise electrocardiograms. An abnormal ejection fraction response to exercise occurred in 4 patients; electrocardiographic signs of ischemia developed in all 4, and wall motion abnormalities in 2. Those patients who had electrocardiographic signs of ischemia had a significantly lower heart rate, ejection fraction, and cardiac output response to exercise, and a lower hematocrit level than subjects with normal results on exercise electrocardiography. The increase in cardiac output was not sufficient to maintain a normal level of exercise. The decrease in end-diastolic volume suggests that diastolic function was abnormal during exercise. Cardiac dysfunction was manifested by an abnormal ejection fraction response, wall motion abnormalities, and incomplete left ventricular filling during exercise.

Adolescent↗
PubMed1982

Responses to exercise in children with sickle cell trait.

To determine whether responses to exercise in children with sickle cell trait (AS) are different from those of normal children, we performed dynamic cycle ergometer stress testing in 48 children with AS, aged 4 to 21 years. We compared these data with those obtained from 184 healthy black children. No subject with AS demonstrated definite ischemia on the exercise ECG, but four (8.3%) had equivocal ischemia. Population statistics derived from Z score values showed that the subjects with AS had lower exercise values for heart rate and work load than the controls. The BP response to exercise was normal in subjects with AS. Since no ischemia or complications occurred, exercise in subjects with AS appears to be safe. Further studies are needed to define the mechanism for the impaired pulse rate and work load variables.

Adolescent↗
PubMed1982

Automated blood pressure measurement during ergometer exercise in children.

The measurement of systolic and diastolic blood pressure during exercise is often difficult to perform due to patient motion and environmental noise. We evaluated an automated system of blood pressure determination in 121 children undergoing cycle ergometer stress testing. The system (Critikon Model 1165) utilized acoustic transduction, with electrocardiogram gating and microprocessor signal filtering. One observer measured the blood pressure values from the same arm as the automated system; this observer was blinded to the readout of the system. The correlation coefficients for systolic blood pressure at rest, during exercise, and during recovery were all greater than 0.91, and improved with the use of a stethophone adapter. This system can eliminate intraobserver variation as well as the necessity for the technician or physician to direct attention away from the electrocardiogram and patient during stress testing.

Adolescent↗
PubMed1982

Exercise-induced ventricular tachycardia.

Exercise tests were done on all patients referred to us because of ventricular premature beats. Exercise-associated ventricular tachycardia was seen in three of these patients. Once therapy for the arrhythmia was begun in two patients, we performed serial exercise tests, attempting to provoke the arrhythmia again. In the third patients, who was pregnant, we advised against strenuous physical activity and will exercise her post partum to determine whether therapy is warranted. We have shown that exercise testing can be used successfully in unmasking ventricular arrhythmias not detectable on resting evaluation.

Adolescent↗
PubMed1982

Responses to ergometer exercise in a healthy biracial population of children.

To determine normal values for the exercise variables heart rate, blood pressure, maximal workload, physical working capacity index, J point displacement, and ST segment slope, we stress tested 405 healthy children. We analyzed the data for four body surface area-determined groups, to discover whether there were any racial differences between healthy white children and black children. There were numerous racial differences in blood pressure, maximal workload, and physical working capacity index; there were no differences in the heart rate values. The incidence of false-positive J point displacement was less than or equal to 3% when the PR isoelectric line method was used. The ST segment slope in healthy children was always greater than zero at maximal exercise. Thus, norms for exercise variables must be expressed in relation to both sex and race. The nomograms presented in this report provide an easy-to-use set of normative data for cycle ergometer stress testing in children.

Adolescent↗