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Biomedical subjects

H Gardiner

Publications and source records attributed to H Gardiner.

11 recordsLinked to original sources
PubMed2001

Ventriculo-vascular interaction in the normal development of the fetal circulation.

OBJECTIVES: To examine cardiovascular physiology in the healthy fetus during normal development. DESIGN: Twenty normal fetuses were studied longitudinally from 20 weeks to term. Serial echocardiography was performed, and arterial and venous diameter pulse wave characteristics and aortic pulse wave propagation velocity (PWV) were examined in the thoracic descending aorta (AoD) and inferior caval vein (IVC) using an ultrasonic phase-locked echo-tracking system. Statistical analyses included ANOVA, paired t-test and logistic regression where appropriate. RESULTS: Aortic PWV, maximum incremental and late decremental velocities increased with gestation while the relative pulse amplitude decreased, reflecting falling distal impedance. There was a linear increase in cardiac preload and relative pulse amplitude in the IVC with gestation that correlated significantly with the presence of end-diastolic flow in the pulmonary artery and improvement in right ventricular diastolic function. CONCLUSIONS: Non-invasive concurrent assessment of preload, ventricular function and impedance are possible in the fetus and may prove useful in the longitudinal study of fetal adaptation to pathophysiological changes.

Aorta, Thoracic↗
PubMed2001

Ventriculovascular physiology of the growth-restricted fetus.

OBJECTIVES: To examine the mechanisms by which intrauterine growth restriction may influence later cardiovascular risk by comparing the ventriculovascular physiology of gestational age- and weight-matched growth-restricted and normal fetuses. DESIGN: A prospective longitudinal observational study of 20 normal fetuses studied from 20 weeks to term at monthly intervals was compared with a growth-restricted cohort examined in the interval between diagnosis and delivery. The last values before delivery of the growth-restricted cohort were compared with the normal cohort in two analyses matched for weight and for gestation. Arterial and venous vessel wall physiology and aortic pulse wave velocity were examined longitudinally in the thoracic descending aorta and inferior vena cava using an ultrasonic phase-locked echo-tracking system. Serial echocardiographic examinations were performed assessing structure, ventricular dimensions, function and Doppler flows. RESULTS: There was a linear increase in cardiac preload and relative pulse amplitude in the inferior vena cava with gestation. In normal fetuses, the aortic pulse wave velocity, maximum incremental and late decremental velocities increased with gestation whilst the relative pulse amplitude decreased reflecting falling distal impedance. In both age- and weight-matched analyses, the growth-restricted fetuses showed significantly reduced values reflecting the chronic fetal ventriculovascular responses to increased placental impedance. Pulse wave velocity increased with gestation and was significantly less in the growth-restricted cohort. CONCLUSIONS: Growth restriction is associated with abnormal ventriculovascular physiology that represents a successful adaptive response to raised placental impedance and reduction in wall stress as evidenced by the lower fetal pulse wave velocity in growth-restricted fetuses. However, whilst fetal adaptive mechanisms may aid survival they may result in cerebral and vascular abnormalities that prejudice later cardiovascular health.

Aorta, Thoracic↗
PubMed1998

Internal mammary artery to coronary artery bypass in paediatric cardiac surgery.

The internal mammary artery is regarded as the optimal conduit for coronary artery bypass grafting in adults. Use of this conduit in paediatric surgery is rare and has been reported mainly in patients with Kawasaki's disease. We report five patients who required internal mammary-coronary artery grafting due to adverse anatomical disposition of the coronary artery. In two cases an internal mammary graft was required during correction of transposition of the great arteries. The other cases involved correction of a left coronary artery arising anomalously from the pulmonary artery. Late angiography shows satisfactory growth and patency of the conduits.

Coronary Angiography↗
PubMed1995

Alagille syndrome: family studies.

Alagille syndrome (AGS) is one of the major forms of chronic liver disease in childhood with severe morbidity and a mortality of 10 to 20%. It is characterised by cholestasis of variable severity with paucity of interlobular bile ducts and anomalies of the cardiovascular system, skeleton, eyes, and face. Previous studies suggest a wide variation in the expression of the disease and a high incidence of new mutations. To determine more accurately the rate of new mutations and to develop criteria for detecting the disorder in parents we systematically investigated parents in 14 families with an affected child. Clinical examination was supplemented by liver function tests, echocardiography, radiographic examination of the spine and forearm, ophthalmological assessment, and chromosome analysis. Six parents had typical anomalies in two or more systems pointing to the presence of autosomal dominant inheritance. Systematic screening of parents for the features defined in this study should improve the accuracy of genetic counselling.

Abortion, Spontaneous↗
PubMed1986

Evaluation of febrile patients in Port Sudan, Sudan: isolation of dengue virus.

One hundred consecutive patients admitted to the Port Sudan Hospital with a temperature greater than or equal to 100 degrees F were evaluated. Enteric fever was diagnosed in 19 patients and malaria in 13. Virologic studies identified 21 cases of dengue infection. One dengue 1 and 17 dengue 2 infections were diagnosed by viral isolation. Three untyped dengue infections were identified serologically. The clinical presentation and course of patients infected with dengue virus were most consistent with classic dengue fever. There was no evidence of hemorrhagic phenomena or shock in any of the dengue-infected patients. Both dengue 1 and 2 must be considered causes of acute fever in East Africa.

Adolescent↗
PubMed1977

Mild high-renin essential hypertension. Neurogenic human hypertension?

To determine whether the elevated plasma renin activity in some cases of mild essential hypertension expresses sympathetic-nervous-system over-activity, we compared indexes of sympathetic activity in 16 patients with mild high-renin essential hypertension, 15 hypertensive patients with normal plasma renin activity and 20 normal subjects. Patients with elevated activity exhibited a raised plasma norepinephrine concentration (P less than 0.05), a greater fall in cardiac output with cardiac beta-adrenergic blockade by intravenous propranolol (P less than 0.01), reduction in total peripheral vascular resistance with alpha-adrenergic blockade produced by intravenous phentolamine (P less than 0.01), and reduction to normal of blood pressure by "total" autonomic blockade (atropine, propranolol and phentolamine). On psychometric testing, patients with high-renin hypertension, but not those with normal plasma renin activity, exhibited suppressed hostility (P less than 0.01), a behavioral pattern linked to increased sympathetic activity. The hypertension in these patients with high renin activity is neurogenic and possibly psychosomatic in origin.

Adolescent↗