Percutaneous laser-assisted coronary angioplasty.
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Anesthesia, Local↗
Biomedical subjects
D I Tayler
Publications and source records attributed to D I Tayler.
Percutaneous laser thermal angioplasty: initial clinical results with a laser probe in total peripheral artery occlusions.
A metal-tipped laser fibre was used during percutaneous angioplasty of femoral/popliteal or iliac artery occlusions in 56 patients. Primary success was achieved in 50 (89%) of these total occlusions, providing a channel for subsequent balloon dilatation. Before the procedure, 18 lesions had been judged untreatable by conventional angioplasty and four of the six failures were in these. Complications directly attributable to the laser probe were one case of vessel perforation and two cases of entry into vessel walls; these had no sequelae. Other acute complications were a distal thrombosis in a non-heparinised patient, requiring local streptokinase treatment, and two reocclusions and one transient peripheral embolic episode in the first 24 hours. The laser probe technique has potential for increasing the proportion of patients suitable for angioplasty.
Aged↗
Laser-assisted percutaneous angioplasty: initial clinical experience in peripheral arteries.
Experimental and animal studies have shown that laser energy can vaporize intra-vascular thrombus and atheroma, suggesting that it may have a role in percutaneous angioplasty. Argon laser energy transmitted via a flexible fibre introduced through a percutaneous catheter was used in 15 patients undergoing balloon angioplasty of femoral or popliteal arteries. Of four stenoses, laser alone produced improvement of the lumen in two. Of 11 occlusions some degree of clearance of the lumen was achieved by laser in eight prior to balloon dilatation. Extravasation of contrast medium indicating wall perforation occurred in two patients, without clinical sequelae. No other complications, such as embolism, arterial spasm or toxic effects were observed. There was one acute re-occlusion, almost certainly not related to the use of laser. There have been no late complications. The ability of laser to influence favourably vascular occlusion is confirmed, but technical advances are necessary to avoid vessel wall perforation consistently and to improve the production of an adequate lumen before its potential can be fully realized.
Angioplasty, Balloon↗
Percutaneous laser angioplasty. Initial clinical experience.
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Angioplasty, Balloon↗
Artefactual ST segment abnormalities due to electrocardiograph design.
Specifications recommended for electrocardiographs omit any reference to phase characteristics and place undue emphasis on an extended amplitude response. This does not, however, ensure faithful reproduction of the electrocardiogram and may result in less effective attenuation of unwanted noise than can be achieved with modern filters. The separate effects of phase and amplitude response on electrocardiographic signals were compared, and it was shown that distortion of the electrocardiogram by equipment with an inadequate phase response may cause changes resembling those seen in ischaemic heart disease. Case reports are presented in which distortion produced by commercial equipment impeded diagnosis. Specifications recommended as standard for electrocardiographs should be modified to include phase response and allow greater attenuation of frequencies below 0.5 Hz.
Adult↗
Single lead atrial synchronised pacing in patients with cardiogenic shock after acute myocardial infarction.
A pacing system requiring only a single lead was used to establish atrial synchronised pacing in eight patients with complete atrioventricular block and cardiogenic shock following acute myocardial infarction. Spontaneous atrial activity was sensed through electrodes positioned on the pacing lead and used to trigger ventricular demand pacing. A normal atrioventricular relation could be established in each of these critically ill patients without the complexity of inserting and finding a stable position for an additional atrial sensing lead. Atrial synchronised pacing at the spontaneous sinus rate had distinct haemodynamic advantages compared with conventional ventricular pacing at 100 beats/min. Mean cardiac output for the group was 3.3 1/min with atrial synchronised pacing compared with 2.6 1/min with conventional pacing, a significant difference of 27%. Peak systolic pressure averaged respectively 91 and 73 mm Hg in the two pacing modes. With conventional ventricular pacing a pronounced phasic alteration in blood pressure was observed, dependent on the altering relation of the paced beats to spontaneous atrial activity. Atrial synchronised pacing abolished this effect and resulted in a stable blood pressure at or above the peak pressure achieved with conventional pacing. Atrial synchronised pacing with a single lead system can be established rapidly. This mode of pacing has appreciable and significant haemodynamic superiority over conventional ventricular pacing in patients with cardiogenic shock and atrioventricular block following acute myocardial infarction.
Aged↗
Five hundred patients with myocardial infarction monitored within one hour of symptoms.
Of 2886 patients monitored during acute myocardial infarction, 500 were observed within one hour of the onset of symptoms. Half of the early admission group were admitted in response to emergency 999 calls and 435 of them travelled in resuscitation ambulances, where surveillance for arrhythmias was instituted. Pulmonary oedema occurred in 130 patients (26%), cardiogenic shock supervened in 60 (12%), and 115 (23%) died in hospital. Ventricular fibrillation was observed in 98 patients (20%). Forty two of them survived to be discharged, including 20 of the 24 with primary fibrillation which had occurred first in hospital. In only one case did primary ventricular fibrillation occur after the first 10 hours of onset of illness. Sinus bradycardia, atrial fibrillation, ventricular tachycardia, and ventricular fibrillation were all observed more frequently in patients admitted within one hour after the onset of symptoms than in those admitted later. An element of selection is inevitable when early admission is encouraged by the existence of a resuscitation ambulance system; this will depend in part on the early recognition of risk and the geographical location of the attack. These factors may bias the group towards relatively high risk. Nevertheless, prompt admission after myocardial infarction should improve survival by permitting successful management both of ventricular fibrillation and of other arrhythmias which may influence short term and long term prognosis.
Aged↗
A simple pacemaker inhibitor.
A design for a simple easy to use pacemaker inhibitor is described. The unit enables a pacemaker patient's native rhythm to be displayed even if the rate is less than the pacemaker's demand setting.
Biomedical Engineering↗