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Biomedical subjects

C G MacArthur

Publications and source records attributed to C G MacArthur.

16 recordsLinked to original sources
PubMed1984

The relationship of myocarditis to dilated cardiomyopathy.

Three patients with congestive cardiomyopathy are reported in whom high neutralizing antibody titres to Coxsackie B viruses were detected. At post-mortem examination, all three had histologically demonstrable chronic inflammation of the myocardium. The hearts of ten patients dying in cardiac failure due to other causes showed no comparable inflammatory infiltration. This provides further evidence that Coxsackie B viral myocarditis is involved in the pathogenesis of some cases of dilated cardiomyopathy. One patient also had pulmonary veno-occlusive disease. This has been reported in association with myocarditis once previously in an infant. A viral aetiology has been postulated. It seems likely in this patient to have also been due to a Coxsackie B virus.

Adolescent↗
PubMed1984

Right ventricular dilated cardiomyopathy.

Fourteen patients with predominantly right sided dilated cardiomyopathy were studied, of whom five died suddenly. The condition is characterised by male preponderance, syncope, ventricular tachycardia, which typically has a left bundle branch block pattern on the surface electrocardiogram, and right heart failure. The diagnosis should be considered in patients presenting with otherwise unexplained ventricular tachycardia or syncope; the diagnosis may be readily missed because of the nonspecific nature or absence of signs.

Adolescent↗
PubMed1982

Measurement of lung water in dog lobes using inhaled C15O2 and injected H215O.

Indicator-dilution analysis was used in a recirculation-free isolated dog lobe preparation to compare an inhaled water tracer (C15O2) and an injected water tracer (H215O) with direct weighing as a measure of total lung water. Residue detection (counting over the lung) was compared with outflow detection (counting over the venous effluent). With outflow detection, inhaled C15O2 measured 74% and injected H215O 90% of the gravimetric lung water. In hemodynamic edema, the increase in lung water measured by residue detection of both tracers correlated well with increases in weight (r = 0.92, slope = 1.03). However, outflow detection of both tracers underestimated the lung water increase by 53% in edema (r = 0.88, slope = 0.47). Thus, in edema, equilibration of both tracers within the lung water volume is rapid, but clearance from the lung is delayed because slowly clearing water pools develop. The errors caused by inhomogeneity of perfusion distribution were investigated after pulmonary arterial injection of 34-, 50-, and 175-micrometers spheres. For the same lung weight, C15O2 transit was delayed and H215O transit accelerated greatly by the 175-micrometers spheres and slightly by the 50-micrometers spheres.

Animals↗
PubMed1981

The effect of hydralazine on arrhythmias in congestive cardiomyopathy.

We studied 12 patients with congestive cardiomyopathy who were given 75 mg hydralazine daily for 2 wk and 150 mg hydralazine daily for another 2 wk. Two 24-h ambulatory ECG recordings in a control period and two in each hydralazine period were performed and analysed. It was found that hydralazine therapy in congestive cardiomyopathy does not significantly increase or decrease the occurrence of ventricular or supraventricular arrhythmias.

Adult↗
PubMed1980

The use of radioisotopes to measure regional lung water.

A new technique for measuring regional lung water is described. The technique involves single-breath inhalation of C15O2 and 11CO2, with monitoring by external scintillation counters of lung clearance during breathhold. Preliminary studies in anaesthetised dogs and in isolated dog lungs, which validade the technique, are briefly presented. The results show a good correlation with directly measured lung water in non-oedematous lungs, but a tendence to overestimate lung water in the presence of oedema. The potential value of this non-invasive technique for sensitively detecting early pulmonary oedema in man is discussed.

Animals↗
PubMed1979

Antibodies to Coxsackie B viruses in congestive cardiomyopathy.

Fifty patients with congestive cardiomyopathy have been studied for evidence of previous Coxsackie B virus infection and compared with age- and sex-matched controls who had been admitted to hospital for investigation of other cardiac diseases. High neutralisation titres (greater than or equal to 1024) to Coxsackie B viruses were more common among the controls. On subdividing the patients according to their length of symptomatic history before study, high titres were more common only in those with a short history (less than or equal to 1 year). High titres were more common when there had been a febrile illness at the onset of symptoms. Endomyocardial biopsies of 18 patients disclosed no evidence of myocarditis, or, in 12 cases, of viral involvement. Although the evidence remains circumstantial, these results support the theory that Coxsackie B viruses may cause congestive cardiomyopathy and encourage further research into the mechanisms of myocardial cell damage by these visuses.

Adult↗
PubMed1979

Ventilatory function in the Eisenmenger syndrome.

Ventilatory function and carbon monoxide transfer factor were studied in nine adult patients with post-tricuspid intracardiac defects and the Eisenmenger syndrome. A consistent mild defect of ventilatory function was found, with raised residual volume and closing capacity and reduction of other lung volumes and maximal expiratory flows. Maximal expiratory flow was particularly reduced at low lung volumes. One of the four subjects in whom pressure-volume studies were performed showed loss of normal elastic recoil at low lung volumes. A significant poorly ventilated space was excluded since the volume of distribution of helium during a 10 second breath-hold at full inspiration was close to plethysmographically measured total lung capacity. Carbon monoxide transfer factor, after correction for haemoglobin concentration, was 77% of predicted normal values. Sequential assessment of carbon monoxide transfer factor might be useful in the early diagnosis of pulmonary vascular disease in infants with large intracardiac defects, since it is likely to be raised early due to high pulmonary blood flow and will fall with the development of pulmonary vascular disease.

Adult↗
PubMed1977

Endobronchial lipoma: a review with four cases.

Endobronchial lipomas are rare benign tumours which can cause irreversible pulmonary damage unless removed early. The clinical features and treatment of four cases are reviewed in the light of the previous literature. The histogenesis of these tumours and their relationship to hamartomas are discussed. The treatment of choice in most cases is bronchoscopic excision.

Adipose Tissue↗
PubMed1977

Hypertensive pulmonary vascular disease in children. Detection by radioactive nitrogen (13N) inhalation and injection.

Regional lung function has been studied in 16 children with intracardiac shunts and a variety of associated cardiac anomalies using radioactive nitrogen (13N) and a gamma camera-computer system. The distribution and washout of inhaled 13N were usually normal. The distribution of intravenously injected 13N was often abnormal and could be related to local anatomy. The most important finding was delayed clearance by ventilation of intravenously injected 13N in children with an abnormally raised pulmonary/systemic vascular resistance ratio (Rp/Rs) at cardiac catheterisation. The regional localisation of this ventilation-perfusion imbalance could be related in several children to the probable distribution of hypertensive pulmonary vascular disease, predicted either from local anatomy shown at cardiac catheterisation or from the abnormal distribution of pulmonary perfusion. Abnormalities present on breathing air may be partially reversed on breathing 100 per cent oxygen.

Child↗
PubMed1976

Measurement of regional pulmonary oedema in man using radioactive water (H215O).

Regional extravascular lung water (rELW) has been measured in normal subjects and in patients with left heart diseases using a double-indicator dilution technique and external counting over the chest. Gamma-emitting radioisotopes were injected intravenously, 113Inm as a vascular non-duffusible indicator, and H215O as a freely diffusible indicator. Time activity curves were then recorded over the upper and lower zones of the lung in the supine position with external probes. rELW per unit of blood volume and rELW per unit of blood flow were increased in patients with raised left atrial pressure even in the presence of radiologically clear lung fields. There was a uniform distribution of these ratios between upper and lower zones in normals, whereas in patients rELW was preferentially distributed in the lower zones.

Blood Flow Velocity↗