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Biomedical subjects

R Hayward

Publications and source records attributed to R Hayward.

At least 109 records · Page 6Linked to original sources
PubMed1987

Effects of nifedipine on coronary perfusion; recent assessment by parametric digital subtraction.

The effects of nifedipine on myocardial perfusion abnormalities were investigated in 6 patients with left coronary artery disease using a digital angiographic method. Selective left coronary angiograms were digitized on-line into a 256 x 256 pixel matrix, approximately 20 ECG-gated end-diastolic frames being acquired during each coronary injection. After background subtraction, parametric analysis was undertaken, measuring sequential changes in contrast opacification against time. Isochrone maps were derived showing the distribution of times to attainment of peak contrast density throughout the left ventricle (the Tmax image) reflecting myocardial perfusion, and of times to arrival of half peak opacification (the T1/2max image) as an index of coronary flow. At basal heart rate (fixed by pacing) mean Tmax was attained in well supplied myocardium at the 7th cardiac cycle, and at the 9th cardiac cycle in the least perfused territory. Overdrive pacing reduced arrival times by 2-3 cycles, but inhomogeneity persisted. After sublingual nifedipine, contrast arrival was significantly accelerated by a mean of two cardiac cycles in poorly perfused regions, and by one cardiac cycle elsewhere. After nifedipine, overdrive pacing shortened Tmax and T1/2max most markedly in the least supplied territory. Results with this new technique indicate that nifedipine has beneficial effects on regional malperfusion in coronary disease.

Aged↗
PubMed1986

Use of monophasic action potential recordings during routine coronary-artery bypass surgery as an index of localised myocardial ischaemia.

In 8 patients undergoing routine coronary-artery bypass surgery, monophasic action potentials (MAPs) were measured by means of a hand-held pressure contact electrode to provide an index of local ischaemic changes. 4 patients received left internal mammary anastomoses (LIMA), and there were a total of 27 saphenous vein grafts (SVG). After completion of all grafts blood-flow to the myocardium was reduced for 90 s by means of different permutations of SVG and LIMA occlusion, either on or off bypass. In all patients MAPs indicated typical ischaemic changes. The high sensitivity of the method enables the study to be completed quickly and without hazard to the patient. The technique provides a new means to assess local ischaemia, the viability of specific areas of myocardium, and the efficiency of individual grafts during surgery.

Action Potentials↗
PubMed1986

Observations on the innervation of the sternomastoid muscle.

Nine out of fifteen cases having division of the spinal component of the accessory nerve and the upper cervical motor roots as treatment for spasmodic torticollis had residual movements in the sternomastoid of sufficient magnitude to make further surgery necessary before the muscle was effectively paralysed. These observations imply a more complex innervation for the muscle than is to be found in most anatomical texts.

Accessory Nerve↗
PubMed1986

Recurrent sterile meningitis caused by a pituitary abscess.

The case of a 21 year old woman who presented with recurrent sterile meningitis and bitemporal hemianopia is described. Computed tomographic scan showed a large low density ring enhancing lesion above and within the pituitary fossa which at operation and on histological examination was found to be compatible with an abscess. The visual field defect recovered completely and the scan appearances returned to normal postoperatively.

Abscess↗
PubMed1985

Primary intracranial histiocytic lymphoma with Langerhans' granules. A light microscopic and ultrastructural study.

An intracranial tumor classified as a histiocytic lymphoma was studied with light and electron microscopic examination and immunocytochemical methods. The characteristics of the malignant mononuclear phagocyte cells are described. The presence of some cells containing Langerhans' granules suggests differentiation towards a specialized cell of the mononuclear phagocyte system: the Langerhans' cell.

Adult↗
PubMed1985

Digital subtraction angiography in coronary artery bypass graft assessment: clinical applicability.

Application of electrocardiogram gated digital subtraction angiography to the assessment of coronary artery bypass graft function was studied one week to eight years after bypass operation in ten unselected patients with recurrent chest pain. For the digital method, contrast was injected into the ascending aorta via a 4 or 5 French gauge catheter. The results of this technique were compared with those of selective graft and coronary angiography in the same patients by two independent observers. Of twenty six grafts in the series, patency was confirmed in twenty one by both selective and digital angiography. The quality of graft run off, graded by each observer using a simple scoring system, demonstrated six points of inter observer disagreement when standard cineangiograms were used, compared with nine points of disagreement when digital images were used. Digital subtraction angiography provided useful graft visualisation, but was less good than conventional angiography at defining the native coronary circulation. The role of this promising new technique has yet to be established.

Aged↗
PubMed1983

Relationship between myocardial uptake and actions in heart failure of methyldigoxin.

1 Problems have been encountered in recent years in confirming useful benefit to patients with heart failure and sinus rhythm from acute exposure to digitalis glycosides, though effectiveness of these preparations upon cardiac contractile performance is indisputable. Undesired effects such as those upon systemic vascular resistance have been invoked to explain this. 2 Detailed haemodynamic responses have been studied by cardiac catheterisation in nine such patients for 30 min after intravenous methyldigoxin infusion. Myocardial glycoside uptake was simultaneously assessed. 3 Methyldigoxin uptake by the heart was rapid, passing its peak within 20 min, and was followed by substantial elution. 4 A small progressive and significant increase in cardiac output was observed, though left ventricular filling pressures were not significantly reduced after methyldigoxin. Cardiac contractile function as assessed by left ventricular maximum dP/dt, measured in six patients, showed consistent improvement.

Cardiac Catheterization↗