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Biomedical subjects

G Sloman

Publications and source records attributed to G Sloman.

At least 37 records · Page 2Linked to original sources
PubMed1980

Prospective angiographic assessment of factors affecting early patency of saphenous vein-coronary artery bypass grafts.

Between November 1977 and September 1978, early post-operative angiography was performed in 50 of 53 consecutive patients undergoing coronary artery bypass surgery. An average of 2.4 grafts per patient were applied. The overall patency rate was 82% and was not affected by the degree of proximal native vessel stenosis. Grafts to circumflex marginal vessels had a significantly lower (P < 0.05) patency rate (72%) than grafts to the left anterior descending (84%) and its diagonal branches (85%), or to the right coronary artery (90%). Ten single grafts were applied and all were patent. Forty-nine of the 50 patients had at least one patent graft. Fifty-three per cent of the grafts were considered of excellent quality and 25% patent but of fair quality only. There was a 100% patency rate for vessels of 2 mm diameter or more, which is significantly better (P < 0.01) than for vessels of 1-2 mm diameter (78%) or for vessels of less than 1 mm diameter (50%). There was a suggestion of a lower patency rate (74%) for vessels with evidence of distal disease, compared with vessels without such disease (85%). An assessment of the overall quality of the recipient vessel was made, taking both diameter and disease into account. This showed improved results for better quality vessels in terms of graft patency (P < 0.1) and graft quality (P < 0.05).

Coronary Angiography↗
PubMed1980

Effects of quinidine and disopyramide on serum digoxin concentrations.

Although quinidine and digoxin are frequently given together, it has only recently become apparent that serum digoxin concentration may rise during quinidine treatment. A prospective study was performed to compare the effects of quinidine and disopyramide in patients receiving maintenance digoxin therapy. During quinidine administration serum digoxin concentration rose by more than 50% in seven of nine patients (the mean concentration rising from 1.43 +/- 0.20 to 2.61 +/- 0.43 nmol/l, P < 0.005). During the disopyramide treatment a small rise in serum digoxin was noted (mean 1.3 +/- 0.16 to 1.5 +/- 0.19 nmol/l, P < 0.05). We suggest that digoxin doses should be reduced immediately prior to commencing quinidine therapy in patients already receiving adequate maintenance digoxin, and patients should be followed carefully for evidence of digoxin toxicity. Disopyramide appears a suitable alternative anti-arrhythmic drug to quinidine in patients on maintenance digoxin.

Adult↗
PubMed1980

The small-tined pacemaker lead--absence of dislodgement.

The Medtronic 6961 unipolar transvenous ventricular lead has four symmetrically placed, small tines that protrude backward just proximal to the tip, and are designed to become entrapped beneath or between right ventricular trabeculae. One hundred leads were implanted. Initially, the leads were more difficult to position at the right ventricular apex as the tines tended to anchor on intracardiac structures. This was overcome by rotating the lead. The time of negotiating the lead from right atrium to right ventricular apex averaged 3.1 minutes for all leads. The first 20 procedures averaged 4.2 minutes and the last 20 averaged 2.1 minutes. In this latter group, 11 of the 20 passages took 60 seconds or less. Once adequate positioning was obtained, the lead was retracted using slight tension to demonstrate tip entrapment. There were no lead dislodgements. Eight deaths occurred following institution of pacing and lead dislodgement was not detected in any of these cases. Four patients had complications associated with pacing, two transient diaphragmatic pacing not requiring reoperation, one right ventricular perforation and one raised threshold with intermittent failure of pacing without lead perforation or dislodgement. Because of the absence of dislodgement, this lead appears to have significant advantages over conventional leads.

Electrodes, Implanted↗
PubMed1980

The refurbished pulse generator.

With the advent of long-life lithium pulse generators, normally functioning pulse generators with a potential life of more than five years have been removed from patients and become available for re-implantation. Although pulse generator refurbishing is widely employed, the practice has not been accepted in the United States. At The Royal Melbourne Hospital, all lithium pulse generators removed because of patient death or other causes were washed in a quaternary ammonium compound and soaked in formaldehyde. Pulse generators were than electronically tested and, if within specification, were made available for re-implantation. Pulse generators were then washed under sterile conditions in distilled water and gas-sterilized with ethylene oxide. Between 1975 and 1978 (48 months), 600 pulse generators were implanted and 93 pulse generators removed. There were 56 deaths, 22 cases of pre-erosion, erosion, or infection and 15 elective removals either due to lead problems or impending power source depletion. Eight-three (89%) pulse generators were refurbished (14% of total implants). This included 12 pulse generators refurbished on two occasions. Ten pulse generators were returned to manufacturers, seven because of impending power source depletion, two with suspected electronic faults, and one with a damaged case. Two complications occurred in patients with refurbished pulse generators. An infective process present with the previous pulse generator spread to a new pocket. The other pulse generator was removed 35 months post second implantation because of impending power source depletion. Primary infection or unusual tissue reactions did not occur. Pulse generator refurbishing as described was found to be a safe and economic procedure.

Electric Power Supplies↗
PubMed1979

Predictors of reinfarction and sudden death in a high-risk group of acute myocardial infarction survivors.

75 patients aged under 70 years who had survived acute myocardial infarction complicated by both significant arrhythmias and cardiac failure were followed-up for 1 year in an attempt to identify features which suggest the likelihood of late death or reinfarction. Patients were carefully instructed in the identification and importance of possible prodromal symptoms and the availability of a mobile intensivecare ambulance service and a 24 h hospital control centre. Horizontal ST-segment depression or anginal pain on an exercise test done within 6 weeks of infarction was a useful predictor of late death. Routine twice weekly E.C.G. recordings taken by telephone transmitter at rest and after mild exertion resulted in the identification of significant arrhythmias in only 7 patients. 13 patients (17%) died, 5 of them instantaneously. 4 of the 13 patients and 22 of the 62 survivors reported "prodromal symptoms". Unreported prodromal symptoms were elicited retrospectively in 14 of the 62 survivors and from the relatives of 4 of the 13 patients who died. Thus, 35% of prodromal symptoms were not reported despite intensive patient education and counselling. The incidence of "prodromal symptoms" was no higher in patients who died than in those who did not die.

Acute Disease↗
PubMed1979

Mitral valve prolapse.

Mitral valve prolapse is a relatively common condition in the general population. The syndrome appears more common in females, and is often associated with a family history. Patients may be asymptomatic or may present with a variety of symptoms ranging from mild chest aches and anxiety to severe angina-like chest pain, palpitations and dizziness. The common auscultatory features include mid-systolic clicks and a late systolic murmur, either alone or in combination. The wide spectrum of symptoms and signs may be explained by ventriculovalvular disproportion, where either the ventricle is too small for the valve, or the valve is too large for the ventricle. The long-term prognosis is very good; severe mitral regurgitation can occasionally develop, but both sudden death and bacterial endocarditis are rare. No treatment is required for asymptomatic patients, beyond antibiotic cover for dental procedures and surgery.

Adolescent↗
PubMed1978

Electrophysiology of disopyramide in man.

The electrophysiological effects of an intravenous dose of disopyramide phosphate (2 mg per kg body weight) were studied in 17 patients. Studies were performed with the patients fasting, unpremedicated, and off all medication for three days. Blood samples for estimation of serum levels of disopyramide were collected in 15 of these patients. The effects of intravenous disopyramide were maximal at five minutes, less marked at 20 minutes, and largely gone by 30 minutes after administration of the drug. Sinus cycle length and corrected sinus node recovery time were shortened significantly. No index of atrioventricular nodal function was significantly changed. Both atrial and ventricular effective refractory periods were significantly prolonged. Further impairment of intraventricular conduction occurred in six patients with bundle branch block on electrocardiogram or prolonged HV interval. In one of two patients with Wolff-Parkinson-White syndrome, the bypass effective refractory period was prolonged. These electrophysiological changes are similar to quinidine and quinidine like drugs. It is recommended that disopyramide should be used cautiously in patients with evidence of His Purkinje system disease since it may lead to higher degrees of intraventricular block.

Adolescent↗
PubMed1978

The diagnosis of right ventricular perforation by an endocardial pacemaker electrode.

The diagnosis of right ventricular perforation by an endocardial pacemaker electrode should be suspected when failure of pacing occurs without electrode displacement. Although a number of changes occur on the standard electrocardiogram (ECG), none of these are diagnostic. The intracardiac electrogram performed during electrode withdrawal is not only diagnostic of perforation but can also aid in electrode positioning. Two case reports highlight these changes in the intracardiac electrogram. The first case also illustrates that, with electrode perforation, the ability to sense the intrinsic intracardiac electrical activity may be retained.

Aged↗
PubMed1978

Effect on survival after myocardial infarction of long-term treatment with phenytoin.

A prospective, randomised, open trial was performed in 150 patients to test for any beneficial effects on 2-year mortality of long-term antiarrhythmic therapy with phenytoin in patients with acute myocardial infarction. Patients were stratified according to age, sex, past history of myocardial infarction, and the presence of absence of electrical or mechanical complications in the course of acute infarction. They were then randomised to treatment or control groups (74 v. 76). The former received phenytoin in doses aimed at maintaining plasma phenytoin levels between 40 and 80 mumol/litre. All patients entered the study before discharge from the coronary care ward. Plasma phenytoin levels were in the therapeutic range in between 51 and 75 per cent of subjects at any follow up visit. There were 19 withdrawals from the treatment group, 10 of which were the result of side effects. There were 5 withdrawals from the control group. According to the original intention to treat, there were 18 deaths at 2 years in the treatment group and 14 deaths in the control group. There was no reduction in the incidence of instantaneous or sudden deaths. Deaths on treatment were not associated with a low phenytoin plasma level. Phenytoin treatment showed no beneficial effects on mortality and was associated with a high incidence of side effects.

Adult↗
PubMed1978

Effects of atrial fibrillation on prognosis of acute myocardial infarction.

Nine hundred and sixty-nine coronary care patients with acute myocardial infarction were followed for one year. Atrial fibrillation was documented in 107 patients. Compared with patients without atrial fibrillation, those with this arrhythmia were older, had clinically more severe infarction, and had a higher frequency of ventricular fibrillation or tachycardia, and right bundle-branch block. They had similar past histories of ischaemic heart disease and coronary risk factors. Patients with atrial fibrillation had a higher total mortality at 3 months and 12 months. The presence of atrial fibrillation was not associated with any significant increase in mortality within any decade of age or within any subgroup of clinical severity of infarction. The frequency of atrial fibrillation was similar in anterior and inferior infarction. Multiple episodes of atrial fibrillation occurred in 52 patients and episodes usually lasted for over 1 hour. In 50% of patients with single episode of atrial fibrillation the initial ventricular rate was greater than 120 beats per minute.

Acute Disease↗
PubMed1977

Changing patterns and mortality of acute myocardial infarction in a coronary care unit.

Three groups of patients who had been admitted to a coronary care unit with infarction at different periods since 1963 were reviewed to assess whether the outcome in such patients had improved over 12 years. There was a significant reduction in mortality among consecutive patients with mild or severe infarction between 1969-70 and 1974-5. Classifying the patients in all three groups according to their risk factors showed that for each risk factor mortality had decreased since 1963. The incidence of arrhythmias and conduction defects decreased between 1969-70 and 1974-5, and mortality among patients with each arrhythmia also fell. The reduction in mortality may reflect a changing pattern in the natural history of the disease as well as a benefit of improved treatment.

Adult↗
PubMed1977

Procaineamide blood levels after administration of a sustained-release preparation.

Procaineamide is now available as a sustained-release preparation. This preparation was administered in an eight-hourly regime to 26 patients, and therapeutic blood levels were obtained for the duration of the 56-hour study period in 20 patients. No side effects were observed. Inadequate blood levels may be predicted from a single blood level eight hours after the first dose, which could allow for dosage adjustment.

Arrhythmias, Cardiac↗