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Biomedical subjects

E Sowton

Publications and source records attributed to E Sowton.

At least 109 records · Page 6Linked to original sources
PubMed1979

Cold pressor test in detection of coronary heart-disease and cardiomyopathy using technetium-99m gated blood-pool imaging.

50 normotensive subjects (22 controls with no cardiac disease, 24 patients with coronary heart-disease, and 4 with early cardiomyopathy) were investigated with gated cardiac blood-pool scintigraphy before and during cold pressor stimulation. The controls had no change or a significant rise (p less than 0.005) in left ventricular ejection fraction and preserved normal myocardial-wall motion, whereas patients with coronary-artery disease or cardiomyopathy had a significant fall (p less than 0.001) in left ventricular ejection fraction and many developed abnormal regional wall motion despite the absence of angina pectoris. Cold pressor gated cardiac blood-pool studies were more sensitive than single-lead exercise electrocardiography (p = 0.03) in the detection of patients with severe coronary-artery disease without previous myocardial infarction.

Adolescent↗
PubMed1977

Assessment of ventricular elements of mitral valve by left ventriculography.

In the left ventriculogram in the right anterior oblique projection the plane of the mitral valve is seen in profile and the papillary muscle shadows are outlined. The distance from the middle of the papillary muscles to the plane of the mitral valve during systole was used to assess the average length of the chordae tendineae, and the area of the papillary muscle shadows was measured as an index of hypertrophy in a series of hearts with mitral valve disease. Valvar mitral stenosis is characterised by slight reduction in the length of chordae tendineae and more hypertrophy of the papillary muscles, while in subvalvar mitral stenosis there is more shortening of the chordae tendineae and less papillary muscle hypertrophy. Valvotomy may lengthen the chordae tendineae in subvalvar mitral stenosis. In rheumatic mitral regurgitation length of chordae tendineae and papillary muscle size were normal. The measurements were not useful in assessing non-rheumatic mitral regurgitation.

Anthropometry↗
PubMed1977

Acute coronary insufficiency. Review of 46 patients.

Forty-six patients admitted with acute coronary insufficiency are reviewed. All were investigated by coronary angiography; 4 had normal coronary arteries and are included in this study; the remainder had a distribution of coronary artery disease similar to other angina patients. The clinical and angiographic findings, management, and subsequent course of the other 42 patients are presented. Fourteen patients (33%) in whom rest pain persisted after 48 hours underwent emergency coronary angiography, with 3 deaths; of the surviving 11 who had acute saphenous vein bypass grafting, 2 died at operation and 3 had perioperative myocardial infarctions. Seventeen patients (41%) who initially improved required surgery within 6 months because of symptoms. Eleven patients (26%) were not operated on. It is concluded that acute coronary insufficiency is best managed initially by intensive medical therapy but a high proportion will require surgery later because of disabling angina. Early investigation and surgery are associated with a high mortality and incidence of myocardial infarction. Survivors of surgery are symptomatically improved and there is a low incidence of late infarction and death.

Acute Disease↗
PubMed1976

Use of cardiac pacemakers in Britain.

In Britain during 1975 cardiac pacemakers were implanted at the rate of 56 new patients per million population. This is about one-third the rate for other Western countries but still represents an increase of 150% since 1972. Six-thousand generators were used, and apparatus worth about 2m pounds was implanted. Over 90% of the initial implantations were by the transvenous route, and the mortality from this operation was only 0-3%. Electrode repositioning was needed in 10% of cases. The average age of patients at the time of first implantation was 70. Most patients with pacemakers were able to obtain driving licenses and insurance; only 10% had to pay an additional premium. There is no evidence from insurance comparnies that such patients have an increased risk of accidents. Patients who wished to undertake paid employment almost always did so, often in their previous job. About 80% of the patients were able to increase or maintain their leisure activities at the same level of effort as before pacing became necessary. The number of implantations may be expected to increase by about three times over the next five years.

Adolescent↗
PubMed1976

Clinical features and follow-up of patients with angina and normal coronary arteries.

The clinical findings in 45 patients with angina and normal coronary arteries are reviewed. The primary site, radiation, and character of the pain were typical of angina but the pain was atypical in its relation to stress, frequency of occurrence, relief with rest, and response to nitroglycerin. 22 had abnormal electrocardiograms with evidence of past myocardial infarction in 3. 5 had abnormal exercise tests. During a two-year follow up period there were no further myocardial infarctions and anginal pain either disappeared or improved in 73%. It is concluded that patients with angina and normal coronary arteries can often be distinguished clinically and that they have a good prognosis.

Adult↗
PubMed1976

Pacing techniques in the management of supraventricular tachycardias. Part 2. An implanted atrial synchronous pacemaker with a short atrioventricular delay for the prevention of paroxysmal supraventricular tachycardias.

An implanted atrial synchronous pacemaker with an atrioventricular delay of 30 msec is described. This pacemaker was implanted into a patient with paroxysmal supraventricular tachycardia due to an intra AV nodal reciprocal mechanism. The pacemaker was able to trigger from atrial potentials following atrial premature beats down to a coupling time of 300 msec. Following each triggering atrial potential, a ventricular stimulus was applied 30 msec later thereby producing a ventricular premature beat in response to each sinus beat or each atrial premature beat. Retrograde conduction from this atrial premature beat blocked the re-entry mechanism within the AV node and prevented the initiation of tachycardia. A detailed discussion on all parameters of function of this pacemaker is presented.

Action Potentials↗
PubMed1976

Left main stem coronary artery disease. Retrospective review of 26 patients treated surgically or medically.

The clinical, angiographic, exercise testing, operative, and follow-up data of 26 patients found at angiography to have left main stem coronary artery stenosis, defined as a reduction in the lumen diameter of 50% or more, are reviewed. There was a high incidence of significant proximal stenosis in the branches of the left main stem. No clinical features were found to distinguish patients with left main stem stenosis. All patients were considered for saphenous vein bypass grafting, selection being based upon the severity of symptoms, left ventricular function, and suitability of the coronary vessels for grafting. Two patients died within 24 hours of coronary angiography. Nine patients were operated on with no mortality. There has been one late cardiac death during a mean follow-up time of 13 months. All patients were symptomatically improved with a significant (P less than 0-01) increase in exercise ability postoperatively. Fifteen patients were not operated on. Six of these patients were regarded as operable but surgery was deferred; five have died at a mean time of 7-2 months. Five of the nine patients regarded as inoperable have died at a mean follow-up time of 14-8 months. The five non-surgical survivors remain symptomatic with no significant change in exercise ability. Recently reported surgical and medical series of patients with left main stem stenosis are reviewed.

Angiography↗
PubMed1976

Assessment of metoprolol, a cardioselective beta-blocking agent, during chronic therapy in patients with angina pectoris.

Ten patients with typical angina pectoris and without hypertension, congestive heart failure or other disease were treated with alternating four-week courses of metoprolol (alpha beta1 cardioselective beta-blocking agent), propranolol and placebo. Midway through each four-week period, drug dosage was doubled; thus, regimes were metoprolol, 150 and 300 mg/day, propranolol, 120 and 240 mg per day and placebo, 3 and 6 tablets per day. Serum concentrations of metoprolol increased with increasing dosage in a proportion very similar to that seen with propranolol. Statistically significant reductions in angina frequency/nitroglycerin consumption, and statistically significant increases in total work performed on a bicycle ergometer, were found with both active compounds when compared with placebo. No significant differences were noted between the two active compounds. Though most patients showed greatest improvement on the higher of the two drug dosages, three patients with metoprolol and two with propranolol responded best on the lower dose regime. Both compounds reduced heart rate at rest and during exercise. Neither reduced arterial pressure at rest, but both reduced arterial pressure during exercise. It is concluded that metoprolol is as effective as propranolol in the reduction of angina attacks and improvement in exercise tolerance during chronic therapy in patients with uncomplicated angina pectoris. It is now appropriate to study the effects of metoprolol in patients with coronary artery disease in whom the harmful effects of non-selective beta-blockade heretofore have precluded optimal therapy with beta-blocking drugs.

Adult↗
PubMed1975

Effect of new beta-adrenergic blocking agent, Atenolol (Tenormin), on pain frequency, trinitrin consumption, and exercise ability.

In 11 patients with severe angina pectoris a new beta-blocking drug, atenolol (Tenormin; I.C.I.66082), was found in a double-blind randomized trial to reduce significantly the frequency of anginal attacks (P less than 0-001) and the amount of trinitrin consumed (P less than 0-03) in comparison with practolol and placebo. There was no significant improvement in the patients' ability to exercise on the bicycle ergometer.

Administration, Oral↗
PubMed1975

Pacing techniques in the management of supraventricular tachycardias. Part 1. The use of high frequency stimulation (HFS) in the management of paroxysmal supraventricular tachycardia.

Using techniques for programmed electrical stimulation of the heart, seven patients with paroxysmal supraventricular tachycardia have been studied and shown to have a reciprocal mechanism as the most likely basis for the tachycardia. In four patients it was found that the tachycardia could be terminated by single right atrial premature beats and in three patients two right atrial premature beats were required. A variable zone for tachycardia termination was found when single or double stimuli were used and so a system for introducing high frequency stimuli at 100 or 1000 stimuli/sec for a given duration is described. Using this system a wider range of the cardiac cycle could be covered, thereby increasing the likelihood of producing correctly timed premature beats. The results of using this system are presented and its practical usage discussed.

Adult↗
PubMed1975

Problems concerning assessment of anatomical site of accessory pathway in Wolff-Parkinson-White syndrome.

Twp patients with type B WPW syndrome and reciprocal tachycardias have been studied using intracardiac electrograms and programmed electrical stimulation of the heart. One patient, who had a right-sided accessory pathway giving the surface electrocardiographic appearances of type B WPW syndrome, was shown to have an additional left-sided accessory pathway as occurs in type A WPW syndrome. This concealed left-sided atrioventricular connexion formed the retrograde pathway during reciprocal tachycardia. In the second patient the appearances of type B WPW syndrome were shown to be caused by an accessory pathway between the atrial septum and the right side of the interventricular septum rather than an accessory pathway in the right atrioventricular groove. The significance of these findings when considering surgical interruption of an accessory atrioventricular conduction pathway is discussed.

Adult↗
PubMed1975

Fate of coronary collateral circulation after aorto-coronary saphenous vein bypass grafts.

The pre- and postoperative patterns of coronary artery collateral circulation have been studied in 34 patients who had saphenous vein bypass grafting. When the graft remained patent homocoronary collaterals could not be visualized after operation, but new intercoronary anastomoses frequently developed to other diseased arteries. When the graft and the bypassed artery were both obstructed there was a high incidence (5 out of 11) of myocardial infarction despite good preoperative collaterals.

Aorta, Thoracic↗