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Biomedical subjects

P T Wilmshurst

Publications and source records attributed to P T Wilmshurst.

At least 19 recordsLinked to original sources

Restrictive and hypertrophic cardiomyopathies in Noonan syndrome: the overlap syndromes.

A woman with Noonan syndrome had clinical and haemodynamic features of restrictive cardiomyopathy. There was no ventricular hypertrophy on echocardiography but myocardial biopsies showed myocyte hypertrophy without pathological disarray. This case illustrates the overlap of the cardiac phenotypes of Noonan syndrome, restrictive cardiomyopathy, and hypertrophic cardiomyopathy.

Adolescent

Critical illness poly-neuropathy following severe hyperpyrexia.

Two patients developed critical illness polyneuropathy after severe hyperpyrexia. Fever was secondary to a phaeochromocytoma in one patient and sepsis in the other. These observations suggest that high fever may be one possible aetiology of critical illness polyneuropathy.

Adrenal Gland Neoplasms

Effects of a patent foramen ovale on arterial saturation during exercise and on cardiovascular responses to deep breathing, Valsalva manoeuvre, and passive tilt: relation to history of decompression illness in divers.

OBJECTIVE: To determine whether the presence of a patent foramen ovale could result in significant arterial desaturation and affect the responses of heart rate and blood pressure to physiological manoeuvres and to determine whether responses differed between those with and those without prior clinical events associated with a patent foramen ovale. DESIGN: Blind controlled study. SETTING: Teaching hospital. PATIENTS: Divers with a large patent foramen ovale shown by contrast echocardiography and divided into those who had neurological decompression illness that started within 30 minutes of surfacing (group 1), those who had no history of decompression illness (group 2), and age and sex matched control divers who had no evidence of intracardiac shunts (group 3). MAIN OUTCOME MEASURES: The change in percentage haemoglobin oxygen saturation during treadmill exercise and the response of heart rate and blood pressure to physiological manoeuvres. RESULTS: There were no significant differences between the three groups but two divers in group 1 showed clinically important desaturation during exercise and unusual blood pressure and heart rate responses to passive tilt. These divers were notable for having the greatest number of episodes and the most severe single episode of spinal cord decompression illness. CONCLUSION: A large patent foramen ovale may be associated with clinically significant arterial desaturation and unusual responses of heart rate and blood pressure in some healthy subjects.

Arteries

Cerebral perfusion deficits in divers with neurological decompression illness.

Cerebral perfusion deficits detected by injection of 99Tcm-hexamethylpropyleneamine oxime (HMPAO) and single photon emission tomography is said to correlate well with clinical findings in divers with neurological decompression illness. We studied 12 divers. Six had residual cerebral signs (group 1) and six had no residual cerebral symptoms or signs (group 2). Perfusion deficits were as common in group 2 as in group 1. The site of the deficit did not correlate well with either the neurological findings at presentation or the residual clinical signs after treatment. The data suggest that claims that HMPAO scanning correlates with clinical findings and can be used for patients management were incorrect.

Cerebrovascular Disorders

Effect of aortic valve replacement on syncope in patients with aortic stenosis.

OBJECTIVE: To determine the role of exertion as a precipitating factor in syncope in patients with aortic stenosis. DESIGN: Follow up for at least one year after aortic valve replacement. SETTING: Regional cardiac centre. PATIENTS: Consecutive patients who underwent aortic valve replacement for aortic stenosis and who had a history of syncope and no other clinically significant cardiac lesion were recruited during a five year period. METHODS: Patients were interviewed to determine the characteristics of syncope and were divided into those in whom syncope was consistently related to exertion (group 1, 26 patients) and those in whom it was not (group 2, 13 patients). Recurrence of syncope after valve replacement was determined at visits to the clinic. RESULTS: Groups 1 and 2 did not differ significantly with respect to valve area, age, or sex. In 13 of the 26 patients in group 1 syncope was preceded by angina despite the absence of coronary artery disease, but none of the 13 patients in group 2 had angina. After valve replacement none of group 1 and eight of the 13 patients in group 2 had recurrence of syncope (p < 0.01). CONCLUSION: When patients with aortic stenosis experience syncope unrelated to exertion, the symptom is usually unrelated to the valve disease and another cause should be sought.

Aged

Histoplasma endocarditis on a stenosed aortic valve presenting as dysphagia and weight loss.

A 40-year-old man with aortic stenosis and disseminated histoplasmosis did not respond to treatment with itraconazole. Though there was no haemodynamic deterioration, valvar regurgitation, or embolic phenomena a presumptive diagnosis of infective endocarditis was made. This was confirmed at aortic valve replacement. Antifungal treatment was continued for 18 months after valve replacement and serological tests for Histoplasma became progressively more negative during a three year follow up.

Adult

Primary restrictive cardiomyopathy: clinical and pathologic characteristics.

Twenty-four patients with restrictive cardiomyopathy were identified at St. Thomas' Hospital during a 17-year period. All had endomyocardial biopsy, but in two patients the biopsy specimens were small and nondiagnostic. Seven patients had amyloidosis and five had other specific heart muscle diseases. The remaining 10 patients with primary restrictive cardiomyopathy had myocyte hypertrophy or interstitial fibrosis, or both. Patients with primary restrictive cardiomyopathy presented earlier but survived longer after presentation than did those with amyloidosis. In each group, survival after cardiac catheterization was related to cardiac index but not to filling pressures. Primary restrictive cardiomyopathy was associated with complete heart block in four patients, two of whom had skeletal myopathy. One had a family history of dominantly inherited skeletal myopathy. Primary restrictive cardiomyopathy was present in a mother and daughter. Two other patients had a family history of heart failure, sudden death or complete heart block, alone or in combination, at a young age. Restrictive hemodynamics and complete heart block were present in patients even in the absence of significant fibrosis. The data suggest that primary restrictive cardiomyopathy may be a distinct myopathy with dominant inheritance and incomplete penetrance that is expressed morphologically as myocyte hypertrophy and interstitial fibrosis. Skeletal myopathy may be associated with the cardiomyopathy.

Adolescent

Infective endocarditis, rheumatoid factor, and anticardiolipin antibodies.

Serum samples from 22 patients with infective endocarditis were analysed for the presence of antibodies to cardiolipin, false positive Venereal Disease Research Laboratory (VDRL) test, and rheumatoid factor in order to determine the prevalence of anticardiolipin antibodies, their level, and to ascertain whether there was any correlation with the presence of rheumatoid factor. Although the latex test was positive in 10/22 (45%) patients, anticardiolipin antibodies, usually of a low level, were raised in only four (18%), and the VDRL test was positive in two patients in whom other antibodies were negative. These results show a clear discordance between these three tests, indicating that B cell production of these antibodies is separate and distinct. As with other infections which result in anticardiolipin antibody production, no thrombotic events were encountered.

Autoantibodies

Relation between interatrial shunts and decompression sickness in divers.

The prevalence of right-to-left interatrial shunts was determined by contrast echocardiography in a blind comparison of 61 divers who had had decompression sickness, divided into four predetermined clinical subgroups, and a control group of 63 who had not. The prevalence of shunt was 15/63 in the controls and did not differ significantly in 24 divers with onset of neurological symptoms more than 30 minutes after surfacing (4/24) or 6 with joint pain only (1/6). In divers who had neurological symptoms within 30 minutes of surfacing the prevalence of shunt was 19/29, significantly higher. Rashes soon after surfacing were related to shunts but late rashes were not.

Decompression Sickness

Cold-induced pulmonary oedema in scuba divers and swimmers and subsequent development of hypertension.

The effect of cold and/or a raised partial pressure of oxygen was examined in eleven people with no demonstrable cardiac abnormality but who had pulmonary oedema when scuba diving or surface swimming, and in ten normal divers. These stimuli induced pathological vasoconstriction in the pulmonary oedema group, nine of whom also showed signs of cardiac decompensation when so stimulated. The pulmonary oedema patients have been followed-up for an average of 8 years. Seven have become hypertensive. Except for the onset of lone atrial fibrillation in one normotensive female diver and development of Raynaud's phenomenon in a normotensive man, there have been no cardiovascular events and no deaths.

Acute Disease

Effects of verapamil on haemodynamic function and myocardial metabolism in patients with hypertrophic cardiomyopathy.

The effect of 20 mg dose of intravenous verapamil was studied over a range of heart rates in 12 patients with hypertrophic cardiomyopathy. Six patients had an appreciable left ventricular outflow tract gradient and six did not. The drug reduced myocardial oxygen consumption in proportion to a reduction in the development of left ventricular pressure. The negative inotropic effect of verapamil was counteracted by the drug's non-specific vasodilator activity, so that cardiac index was unaltered at any heart rate and as a result myocardial efficiency was unaffected by the drug. Verapamil did not consistently alter myocardial metabolism. Some patients showed improvement in anaerobic myocardial metabolism after verapamil but an equal number showed impairment of lactate metabolism. It was not possible to predict from clinical features, echocardiographic findings, or haemodynamic variables measured before administration of verapamil which patients would demonstrate haemodynamic or metabolic improvement after the drug. In this short term study no mechanism was demonstrated by which patients with hypertrophic cardiomyopathy might obtain a consistent improvement from treatment with verapamil.

Adolescent