Biomedical subjects

W Somerville

Publications and source records attributed to W Somerville.

At least 37 records · Page 2Linked to original sources

PubMed1979

Hypertension--going backwards or forwards?

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Aged↗

PubMed1979

Electrocardiographic changes resembling myocardial ischaemia in asymptomatic men with normal coronary arteriograms.

T wave and ST segment abnormalities in 20 asymptomatic men aged 18 to 55 were investigated because they were identical with myocardial ischaemic changes, and the professional livelihood of the subjects was jeopardised. Coronary arteriograms showed unobstructed arteries in all except one in whom a 50 per cent lesion of the left anterior descending artery was present. Left ventricular angiograms showed a normal contraction pattern, Ejection fractions were normal in 12 and increased in 8. Three characteristic electrocardiographic patterns were observed: flat or inverted T waves in leads II, III, aVF, and V4 to 6 designated type 1; deep T inversion particularly evident in leads V2 to 5 designated type 2, and minor ST segment depression in the inferior and lateral leads without T changes designated type 3. Characteristically, type 1 changes were temporarily suppressed by either beta-blockade or an overnight rest and were more abnormal in the standing position. Type 2 and 3 changes were relatively uninfluenced by these manoeuvres. Maximal treadmill exercise tests were positive in 6 and borderline or negative in 14. When repeated after oxprenolol all tests were negative. Echocardiograms showed asymmetric septal hypertrophy in 3 subjects (ratio of greater than 1.5 between ventricular septum and posterior left ventricular wall). After normalisation by an overnight rest, type 1 T wave abnormalities were reproduced by intravenous adrenaline infusion (0.024 to 0.18 microgram/kg/min) but not by noradrenaline or by adrenaline after prior administration of oxprenolol. When the T waves had remained deeply inverted before infusion despite rest (type 2) adrenaline infusion normalised them and again noradrenaline was without effect. This effect was also prevented by oxprenolol. Type 3 changes were uninfluenced by catecholamine infusion. Plasma catecholamine estimations suggest that catecholamine hypersecretion and hypersensitivity may both be relevant, particularly the latter. The apparent bimodal response of the ventricular myocardium to adrenaline infusion is not surprising since in vitro experiments suggest that reversal of T wave polarity in either direction may result from summation of changes in action potential duration in different parts of the heart. Such changes may be unimodal, that is both areas involved show lengthening or shortening of action potential duration, but by occurring at different rates may lead to a bimodal change in the differences in duration which generate the T wave.

Adolescent↗

PubMed1978

D. Evan Bedford.

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Cardiology↗

PubMed1977

Dennis Deuchar.

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Cardiology↗

PubMed1977

The use of "fresh" unstented homograft valves for replacement of the aortic valve: analysis of 6 1/2 years experience.

Between August 1969 and January 1976, 561 patients underwent homograft replacement of the aortic valve (AVR). Isolated AVR was performed in 339 patients, ranging in age between 18 months and 74 years. The valves were sterilized in antibiotic solution and preserved at 4 degrees C in tissue culture medium. There were 11 early deaths (3.2%) and 23 late deaths (6.8%). Actuarial analysis showed 88% survival at 5 years and 85% at 6 years. Valve failure occurred in 13 patients (3.8%) due to prolapse of one cusp in five patients (1.5%), infective endocarditis in three and degeneration of the graft in five (1.5%). Degenerative valve failure was encountered after the fourth year with an incidence of 3.5% of patients at risk, and occurred only in grafts from donors over the age of 70 years. Diastolic murmurs were present in 22% of patients followed up for more than one month and increased very slightly with time. The clinical result was judged to be good or excellent in approximately 90% of the surviving patients.

Adolescent↗

PubMed1974