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Biomedical subjects

L Swan

Publications and source records attributed to L Swan.

17 recordsLinked to original sources
PubMed2000

Exercise prescription in adults with congenital heart disease: a long way to go.

OBJECTIVE: To determine if appropriate advice had been given to adults with congenital heart disease regarding safe and effective exercise, and to assess pre-existing misconceptions of the potential benefits and dangers of exercise. DESIGN: An anonymous self assessment questionnaire. SETTING: A tertiary referral clinic. PATIENTS: 99 adults (57 men, 42 women) with congenital heart disease, mean age 25.6 years. MAIN OUTCOME MEASURES: The extent and nature of exercise advice given over previous years; a measure of current activity level compared with the American Heart Association recommendations; and an assessment of exercise limiting symptoms and a description of barriers to further exercise. RESULTS: 44% of the cohort assumed all exercise was safe despite their cardiac disease. A health care professional had only raised the issue of specific exercise advice in 28 cases. Of those given instruction it was more common to receive prohibitive advice (30%) than to be encouraged to take more exercise (19%). Despite this 61% were involved in some form of at least light exercise. The most prevalent barriers to exercise were current symptoms (32.3%), lack of interest in exercise (24.2%), and health fears (16.1%). CONCLUSIONS: The education of adults with congenital heart disease regarding exercise and its potential benefits and limitations is suboptimal even in a specialist clinic.

Adolescent↗
PubMed1999

Hemodynamic and coronary effects of intravenous eletriptan, a 5HT1B/1D-receptor agonist.

OBJECTIVE: To investigate the systemic, pulmonary, and coronary artery effects of eletriptan, a new 5HT1B/1D-agonist in patients undergoing cardiac catheterization. METHODS: Ten patients (two men and eight women) without significant obstructive coronary artery disease were administered 3.33 microg/kg/min intravenous eletriptan after they were given a placebo infusion of 0.9% saline solution. Serial measurements of right heart and systemic pressures were taken at 5-minute intervals during placebo infusion, eletriptan infusion, and a 30-minute postinfusion period. Cardiac output by the thermodilution technique and coronary angiography were performed every 15 minutes. Quantitative coronary angiography was carried out to measure coronary artery dimensions. RESULTS: A small but statistically significant increase in occluded wedge pressure (7.4 versus 8.8 mm Hg; 95% confidence interval [CI], 0.74, 2.51; P < .01), right atrial pressure (5.3 versus 6.1 mm Hg; 95% CI, 0.0, 1.4; P < .05), and mean pulmonary artery pressure (13.2 versus 14.6 mm Hg; 95% CI, 0.0, 2.7; P = .05) was observed during the eletriptan infusion compared with placebo. A statistically significant increase in systemic vascular resistance (1256 versus 1519 dyne/sec/cm(-5); 95% CI, 126, 398; P < .01) and pulmonary vascular resistance (76.4 versus 100.8 dyne/sec/cm(-5); 95% CI, 1.9, 46.9; P < .05) was observed in the period after drug infusion. No overall effect was observed on the coronary arteries, although a segmental right coronary artery constriction developed in one patient, possibly as a result of catheter-induced spasm. CONCLUSIONS: Eletriptan, a 5HT1B/1D-agonist effective in migraine, causes no significant coronary artery constriction in patients without significant obstructive coronary artery disease. This finding may reflect a relative selectivity for the 5HT1D-receptor subtype.

Adult↗
PubMed1999

The haemodynamic effect of the 5HT1 agonist BMS-180048: a class effect of triptans?

AIMS: To investigate the effects of an intravenous infusion of BMS-180048, a novel 5HT1-like agonist, on the systemic, pulmonary and coronary circulations in patients undergoing diagnostic cardiac catheterisation. METHODS: Ten patients (mean age 55 years (range 41-65)) were studied during diagnostic cardiac catheterisation. The haemodynamic response to an intravenous (i.v.) infusion for 30 min of BMS-180048 (0.56 mg kg(-1) h(-1) for 10 min and 0.39 mg kg(-1) h(-1) for 20 min) was assessed via a 7F Swan Ganz catheter and thermodilution cardiac output system. Quantitative coronary angiography was performed at 10 min intervals. RESULTS: BMS-180048 caused a significant increase in systemic arterial systolic blood pressure (rise of 32.5 mmHg, 95% CI 24,44.5) P=0.009), pulmonary artery systolic (12.2 mmHg, 95% CI 6.8,18.5; P=0.009) and diastolic pressures (8.5 mmHg, 95% CI 5.0,13.8; P=0.009), right atrial pressure (4 mmHg, 95% CI 1.5,5.2; P=0.013) and pulmonary capillary wedge pressure (9.5 mmHg 95% CI 5.2,14.0; P=0.09). There was no significant change in cardiac output (0.1 l min(-1), 95% CI -0.17,0.57, P>0.05). Mean coronary artery diameter in the proximal coronary segments decreased by 0.73 mm (95% CI -1.22,-0.15; P=0.03) at 35 min. The corresponding reduction in middle segments was 0.26 mm (95% CI -0.395,-0.08; P=0.02). There was a non-significant trend to constriction in the most distal segments of 0.28 mm (95% CI -0.68,0.015); P=0.06). One patient experienced chest pain with ECG changes suggestive of ischaemia. CONCLUSIONS: BMS-180048 displayed a cardiovascular profile similar to that previously reported for sumatriptan. These changes appear to reflect a class effect of these agents.

Adult↗
PubMed1999

Effects of subcutaneous naratriptan on systemic and pulmonary haemodynamics and coronary artery diameter in humans.

Naratriptan, an effective antimigraine agent, is a selective 5-hydroxytryptamine (5-HT1 )-receptor agonist with a pharmacologic profile similar to that of sumatriptan. The object of this study was to assess the haemodynamic effects of naratriptan in a clinical model previously applied to sumatriptan. Cardiac haemodynamics and coronary artery diameter were measured at baseline and after subcutaneous injections of placebo and naratriptan (1.5 mg, s.c.) in 10 patients undergoing diagnostic cardiac catheterisation. No statistically significant change in mean coronary artery diameter was observed after naratriptan [95% confidence interval (CI), -0.27-0.11 mm: p = 0.37]. Naratriptan injection was associated with statistically significant increases in systolic arterial pressure (95% CI, 7.6-22.0 mm Hg; p = 0.0015), total systemic vascular resistance (95% CI, 74-253 dyn/s/cc; p = 0.003), pulmonary artery systolic pressure (95% CI, 2.0-6.9 mm Hg; p = 0.003), pulmonary vascular resistance (95% CI, 3-34 dyn/s/cc; p = 0.025), and pulmonary artery wedge pressure (95% CI, 1.9-2.4 mm Hg; p = 0.009). Naratriptan, a selective 5-HT1-receptor agonist, caused a vasopressor response in the systemic and pulmonary arterial circulations but was not associated with coronary artery vasoconstriction.

Adult↗
PubMed1999

Familial pattern of corticosteroids and their metabolism in adult human subjects--the Scottish Adult Twin Study.

Corticosteroids are important in the regulation of normal physiology and are key factors in regulating cardiovascular physiology and disease, the development of which is known to have a genetic component. However, there is little information on the extent to which plasma and urine steroid levels are determined by familial and genetic factors. We have examined basal and ACTH-stimulated plasma steroid levels and 24-h corticosteroid metabolite excretion rates in 146 pairs of adult twins [75 monozygotic (MZ); 71 dizygotic (DZ)]. Intraclass correlation coefficients were measured for all variables; several plasma steroid measurements were strongly related in both (MZ) and (DZ) twins, consistent with a familial pattern. These included basal levels of 11-deoxycortisol and aldosterone. ACTH-stimulated plasma aldosterone levels were also significantly correlated, to a significant degree, in both MZ and DZ twins. The index of 11beta-hydroxysteroid dehydrogenase activity (tetrahydrocortisol + allotetrahydrocortisol/tetrahydrocortisone) and of the more specific index of activity of the type 2 isoform of this enzyme (urine free cortisol/cortisone) also correlated, to a similar degree, in DZ and MZ twins. In contrast, for the basal and ACTH-stimulated plasma concentrations and 24-h urine excretion rates of several corticosteroids, there was evidence of significant heritability (H2), in that correlation in MZ twins was greater than in DZ. For example, basal plasma corticosterone concentrations (B) (H2 = 0.44), basal and stimulated 11-deoxycorticosterone concentrations (DOC) (H2 = 0.44 and 0.41, respectively), stimulated 11-deoxycortisol concentrations (H2 = 0.53), and the index of 11beta-hydroxylase activity DOC/B (H2 = 0.49) were all significantly heritable. For the urinary variables, 24-h tetrahydrodeoxycortisol (H2 = 0.59) and free aldosterone (H2 = 0.56) were significantly heritable. Our data provide the first evidence that plasma and urine levels of important glucocorticoids and mineralocorticoids show a strong familial pattern, and in some instances, there is evidence of a genetic component to this. This suggests that corticosteroids have a plausible role in essential hypertension that has a similar heritable component.

11-beta-Hydroxysteroid Dehydrogenases↗
PubMed1999

Multiple system atrophy.

Multiple system atrophy is a neurological disorder that has gone unrecognized for too long due to its involvement across multiple regions of the central nervous system. This disorder is finally being unveiled through increased reporting in the scientific literature. Further research will enhance our understanding of this disease and lead to more effective treatment regimens as well as an improved quality of life for patients with MSA.

Algorithms↗
PubMed1998

Outcomes of transposition of the great arteries in the ear of atrial inflow correction.

OBJECTIVE: To examine long term morbidity and mortality following atrial inflow corrective procedures for transposition of the great arteries (TGA) and to investigate factors that influence morbidity and mortality. DESIGN: Retrospective cohort study from a single centre. SETTING: Cardiology and cardiothoracic surgical unit in a large tertiary referral centre. PATIENTS: All 130 patients who had TGA diagnosed between August 1972 and May 1988 and were considered suitable for atrial inflow correction; 109 of these underwent surgery (operative cohort: 84 Mustard operations and 25 Senning operations); 95 survived to hospital discharge (hospital surviving cohort). MAIN OUTCOME MEASURES: Death and cardiac events. RESULTS: There were relatively good long term results from atrial inflow correction for TGA with 5, 10, and 15 year survivals of 77.3%, 75.9%, and 71.3%. However, there was an appreciable incidence of late cardiac death and events, with 5, 10, and 15 year cardiac event-free survivals of 74.5%, 67.1%, and 39.6%. Supraventricular tachycardia was the only significant risk factor for late cardiac death (relative risk 8.72, 95% confidence interval, 2.86 to 26.64). Senning patients had better event-free survival (p = 0.04). CONCLUSIONS: Atrial inflow correction for TGA has a reasonably good 15 year survival (71.3%), but there is an appreciable incidence of late cardiac deaths and events (15 year event-free survival 39.6%). The Senning procedure is preferable to the Mustard procedure for cases unsuitable for arterial switching.

Adolescent↗
PubMed1997

The haematological management of patients with cyanotic congenital heart disease. A time for consensus?

AIMS: Recurrent venesection of patients with cyanotic congenital heart disease may be detrimental, with an increased risk of cerebrovascular events and symptomatic iron-deficiency. The aim of this study was to determine the venesection policies as practised in hospitals within a U.K. region and to determine if these policies followed current recommendations. METHODS AND RESULTS: Fifty-eight consultants (56% response rate) in cardiac specialties completed self-assessment questionnaires regarding the indications for and practice of venesection. Sixty-one percent of those responding were involved directly in the care of patients with cyanotic congenital heart disease and of these clinicians 97% used venesection. Indications for venesection varied, with 51% of those responding using an elevated haemoglobin per se (6.5-21.0 g. dl-1); 78% an elevated haematocrit (0.55-0.75) and 83% symptoms. Desired maintenance haemoglobin and haematocrit levels also varied greatly. Fifty percent of the consultants responding routinely screened their patients for iron deficiency and 23% felt there was no indication for investigating a low mean corpuscular volume. Only 18% of the policies described followed any evidence based principles. CONCLUSIONS: The practice of venesecting patients with congenital cyanotic heart disease varies greatly. Policies in many hospitals do not reflect the minimal benefits and considerable risks associated with recurrent venesection.

Cyanosis↗
PubMed1990

Outpatient use of prostaglandin gel for ripening of the cervix and induction of labor.

This case series reports the experience in a family practice center with the outpatient use of prostaglandin E2 (PGE2) gel in patients with a medical or obstetric indication for induction. A retrospective medical record review of a 15-month period was completed for 45 women receiving intravaginal PGE2 gel for cervical ripening before the induction of labor. A change in Bishop score was seen following application of the first gel in 21 women (54%). Six women (13%) had labor onset 1 to 16 hours after the initial gel placement, and an additional 19 women (42%) had labor onset within 48 hours of the final gel placement. Twenty-one women (47%) gave birth without the use of oxytocin, and only 11 women (24%) required oxytocin induction of labor. No significant differences were seen in type of delivery, delivery complications, or newborn outcome between categories of labor onset (spontaneous, PGE2 gel, oxytocin). Two complications followed gel insertions, one case of uterine hyperstimulation and one case of a brief episode of fetal bradycardia. Both women were identified within the monitoring period and subsequently were delivered of healthy term infants. This case series demonstrates the usefulness and lack of adverse effects of outpatient PGE2 gel as an adjunct in labor induction.

Administration, Intravaginal↗
PubMed1979

Effects of sex steroid hormones on arginine vasopressin in intact and castrated male and female rats.

In the present study we have examined the effects of androgens and estrogens on circulating arginine vasopressin (AVP). Adult male Wistar rats had serum AVP levels of 0.4 microU/ml. Two weeks after bilateral castration, AVP rose to 2.6 microU/ml, but daily testosterone administration (100 microgram/100 g BW) to the castrate males prevented the AVP increase (0.8 microU/ml). During a normal estrous cycle, adult female Wistar rats had AVP values of 0.6 microU/ml during diestrus, 4.6 microU/ml on the morning of proestrus, 1.3 microU/ml on the afternoon or proestrus, and 1.5 microU/ml on the day of estrus. These changes in AVP paralleled the presumed changes in serum estradiol. Two weeks after bilateral ovariectomy of the adult female rats, AVP was 1.4 microU/ml but daily estradiol injections (100 microgram/100 g BW) to the castrate females produced a rise of serum AVP to 5.0 microU/ml. The results suggest an androgen inhibition and an estrogen stimulation of serum AVP levels.

Animals↗