Biomedical subjects

R J Wainwright

Publications and source records attributed to R J Wainwright.

7 recordsLinked to original sources

PubMed1991

Metastatic cardiac malignant fibrous histiocytoma presenting as right ventricular outflow tract obstruction.

An unusual case of metastatic disease of the right ventricle is described in a 74-year-old woman who had presented with a malignant fibrous histiocytoma of the right thigh previously treated with surgery and radiotherapy. Two years later she presented with signs and symptoms of tricuspid regurgitation and right ventricular outflow tract obstruction. The diagnosis of right ventricular tumor was made by echocardiographic and angiographic studies and confirmed on postmortem examination.

Aged↗

PubMed1991

Alcohol ablation of atrioventricular conduction.

Transcoronary ablation of atrioventricular conduction by dehydrated alcohol was attempted in 14 patients with refractory atrial arrhythmias. Alcohol (0.5 or 1.0 ml) was delivered after selective catheterisation of the atrioventricular nodal artery in the 10 patients in whom the artery could be identified by cineangiography. The other four patients underwent electrical ablation when the nodal artery could not be catheterised. Temporary atrioventricular block induced by dilute contrast and cold saline (0.9%) confirmed that the catheter was in the correct position before the alcohol was delivered. In all 10 patients complete atrioventricular block developed after alcohol ablation. The block persisted in all four patients given 1.0 ml alcohol but not in four of the six given 0.5 ml. The mean (SD) creatine kinase (MB fraction) at four to six hours after ablation was 76.5 (49.5) IU after 1.0 ml and 75.5 (43.1) IU after 0.5 ml alcohol (normal less than 20 IU). The overall success rate of alcohol ablation in the whole group on an "intention to treat" basis was 43%. The procedure was a technical success in six of the 10 patients in whom the nodal artery was identified. Transcoronary alcohol ablation of atrioventricular conduction should be considered in patients in whom electrical techniques have been unsuccessful.

Aged↗

PubMed1990

First-dose effects of enalapril and atenolol upon blood pressure and cerebral blood flow in patients with mild hypertension on diuretic therapy.

The present single-blind, randomised, cross-over, placebo-controlled study was set up to compare the first-dose effects upon blood pressure (BP) and cerebral blood flow (CBF, measured by Xenon inhalation) of a single oral dose of atenolol 50 mg and enalapril 5 mg in ten hypertensive patients receiving a thiazide diuretic. It was found that a) the timing and degree of fall in BP after the first dose of atenolol and enalapril on a diuretic background were similar and generally not associated with symptoms or a fall in CBF, and b) dizziness, which is sometimes associated with the first-dose effect of ACE inhibitors in hypertensives on diuretics, can occasionally occur accompanied by a substantial fall (43%) in CBF in the absence of marked falls in systolic blood pressure. It is suggested that the latter event may be linked to a disturbance of cerebral autoregulation in part dependent on localised renin-angiotensin systems.

Aged↗

PubMed1989

Electrical ablation of junctional tachycardias showing a long RP interval.

Transvenous catheter ablation of the anomalous pathway was attempted in seven patients with drug-resistant repetitive long RP tachycardias. The patients were aged 5.5-65 years (median 20 years) and had received from four to seven antiarrhythmic agents without effect. Electrophysiological studies confirmed the anomalous substrate for tachycardia in five patients but in two patients an intranodal mechanism could not be excluded. Discharges were delivered to the coronary sinus ostium or low right atrium close to the ostium using conventional defibrillators (three patients) or a modified device (four patients). Transient AV block was seen after six attempts progressing to permanent block in one patient. In no patient could enduring block in the retrograde limb of tachycardia be achieved, and tachycardia recurred in all patients in whom anterograde conduction remained intact. The failure of selective ablation techniques in long RP tachycardia may reflect the diversity of substrate anatomy or particular properties (anatomical or functional) of the pathway compared with the usual types of anomalous pathway.

Adolescent↗

PubMed1986

Detection of pathological tachycardia by analysis of electrogram morphology.

Pacemaker recognition of pathological tachycardia relies on heart rate analysis. This can lead to misdiagnosis when sinus tachycardia exceeds the preset tachycardia response trigger rate. We have explored a method for automatic tachycardia diagnosis by analysis of bipolar endocardial electrogram morphology. Electrograms were recorded from 11 patients (pts) during sinus rhythm and during a total of 20 abnormal rhythms: retrograde atrial depolarization from ventricular pacing in six patients; atrioventricular reentry tachycardia in five patients with intermittent left bundle branch block in one of those; AV nodal reentry tachycardia in five patients and ventricular tachycardia in three patients. Posture and respiration were varied during all rhythms except ventricular tachycardia. The electrograms were then digitized and converted to a form in which the amplitudes were proportional to the rates of change of the original electrogram (equivalent to a first time derivative); the derived signal was then analyzed by a new gradient pattern detection (GPD) program. Analysis of the processed atrial signals by GPD resulted in automatic recognition of abnormal rhythms from sinus rhythm in all cases except for one patient's retrograde atrial depolarization. At the ventricular level, GPD successfully distinguished all abnormal rhythms from sinus rhythm including recognition of left bundle branch block and varying degrees of preexcitation. Respiratory and postural variation did not affect the recognition process. We conclude that electrogram GPD has successfully and automatically detected a variety of arrhythmias which can be treated by implantable pulse generators and may, therefore, be a useful adjunct to heart rate analysis in future generations of such antitachycardia pacemakers.

Adolescent↗

PubMed1979

Cold-pressor test.

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Cold Temperature↗

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↗