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The aim of this research, which remains in progress, has been the examination of long-term psychological consequences for survivors of intensive care. Seventy-two patients were followed up for 1 year, after discharge from the Intensive Care Unit (ICU) at St James's University Hospital in Leeds. Major objectives of the study included assessment of patients' sense of well-being at specified intervals post-discharge, and identification of ICU-related variables which might influence psychological recovery. Psychometric assessments used were the General Health Questionnaire 28-item version, the Rosenberg Self-esteem Scale, and the Impact of Event scale. This paper describes findings from the research so far. An exploratory analysis of the data suggests that distinctions can be drawn among surviving patients with regard to psychological recovery, by way of variables such as type of illness, mode of admission and amount of recall. The work expands previous research into post-ICU psychology and quality of life, and should allow increased understanding of this patient group.

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Implantation of stents in selected patients improves outcome after coronary angioplasty. Newer antiplatelet regimes limit access site complications associated with stenting by the percutaneous femoral approach, but a substantial proportion of patients will require anticoagulant therapy for concomitant disease or will have peripheral vascular disease that prevents access from the leg. We investigated procedural success rates and outcome in consecutive patients undergoing elective stent implantation in our institution. In 73 patients who were receiving anticoagulation therapy and were stented by a direct approach to the left brachial artery, 98.6% of stents were successfully deployed, with a major vascular access site complication rate of 1.4%. Equipment consumption, procedural success rate, and fluoroscopy time were similar in patients stented by the direct brachial or percutaneous femoral approach. Where the percutaneous femoral approach is precluded or patients are anticoagulated, stent procedures can be successfully performed by the direct brachial approach with a low rate of access site complications, even when large-caliber guiding catheters are required.

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Manual slope programming in rate adaptive pacemakers can be time consuming. This may become worse with dual sensor devices. The remedy is to let the pacemaker automatically learn the slopes. Fast learning replaces initial manual slope programming. Daily learning is a continuous process to determine and optimize slopes during daily life. Both methods are known for a QT sensing pacemaker. Fast learning is known for other single sensor devices. The aim of this study was to follow daily learning in a QT and activity dual sensor pacemaker, starting with factory slope settings. Six patients were studied for about 8 weeks. The daily learning algorithm appeared to be effective, showing the desired regulation processes. It took 2-5 weeks to reach full rate response.

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Implantable defibrillators either monitor heart rate or use a probability density function to detect ventricular fibrillation/tachycardia. As a result, they are unable to discriminate sinus tachycardia and atrial arrhythmias from malignant ventricular rhythms. We have assessed high fidelity fiber-optic pressure recordings in the right atrium during cardiac arrhythmias in 23 patients (mean age 44 years, 11 females) undergoing electrophysiological study. The unfiltered pressure signal was amplified and recorded on paper. During sinus rhythm, a constant amplitude deflection occurred during atrial systole (a wave). A characteristic waveform pattern was observed during each of the studied tachyarrhythmias, which included atrial flutter and fibrillation, atrioventricular nodal reentrant tachycardia, atrioventricular reentrant tachycardia, and ventricular tachycardia with and without ventriculoatrial conduction. The waveform pattern allowed clear visual discrimination of the underlying arrhythmia. Mean atrial pressure was increased during all arrhythmias and did not allow discrimination of the nature of the tachycardia. High fidelity pressure recordings produced characteristic appearances for pattern recognition of each arrhythmia studied. They allowed determination of the temporal relation between electrical and mechanical cardiac events and may have potential in the detection and recognition of cardiac arrhythmias.

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Worldwide the majority of current proposals to release genetically modified organisms concern plants; most are for small changes in common crop plants and present little apparent hazard. However, there is much confusion about how plants become pests, and implausible risk factors are appearing in the literature and before committees. It is dangerous to estimate the risks from first principles because of the immaturity of plant population biology and the lack of empirical data. Regulatory agencies should concentrate on obtaining realistic assessment of hazards, and not attempt to balance notional benefits and disbenefits.

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The effects of DDD (fully automatic) and VVI (ventricular demand) pacing modes on exercise tolerance, symptom diary cards, and Holter monitoring were investigated in a randomised double blind crossover study of 16 patients who had had DDD pacemakers implanted because of frequent syncope. Eight patients presented with sick sinus syndrome and, with one exception, retrograde atrioventricular conduction and eight age and sex matched patients presented with 2:1 or complete atrioventricular block. Maximal symptom limited exercise in those with atrioventricular block was significantly higher after one month of DDD pacing than after VVI pacing. In those with sick sinus syndrome, however, maximal effort tolerance was not significantly different for the two pacing modes. In all but one patient with sick sinus syndrome sinus rhythm developed during exercise in VVI pacing. For both VVI and DDD modes maximal atrial rates were significantly lower in those with sick sinus syndrome. Palpitation and general wellbeing were significantly improved during DDD pacing in the eight patients with sick sinus syndrome. Shortness of breath was improved by DDD pacing in the eight patients with atrioventricular block but not in those with sick sinus syndrome. Holter monitoring showed that sick sinus syndrome patients remained in paced rhythm, either DDD or VVI, for most of the 24 hour period. DDD pacing was better than VVI pacing in sick sinus syndrome with retrograde atrioventricular conduction. Despite their ability to show sinus rhythm and inhibit their pacemakers on exercise patients with sick sinus syndrome are just as likely to have symptomatic benefit from DDD pacing as patients with atrioventricular block.

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Respiratory gas exchange on exercise was evaluated as a non-invasive method of assessing patients with heart failure. Twenty four men (age 28-72) with symptomatic chronic stable heart failure (New York Heart Association class II-III) and ten controls aged 36-70 were studied. During treadmill exercise oxygen consumption and carbon dioxide production were measured continuously by analysis of mixed expired gas with a computerised mass spectrometer. The anaerobic threshold was defined as the oxygen consumption at which carbon dioxide production increased disproportionately in relation to oxygen consumption. Oxygen consumption was stable at rest and increased on exercise, reaching a steady state within three minutes of any change in workload. The measurements of maximum oxygen consumption at the end of exercise and of anaerobic threshold were reproducible (retest reliability coefficients 90% and 91% respectively). There were significant differences in maximum oxygen consumption between functional classes. Similarly, there were significant differences in anaerobic threshold between classes, though there was considerable overlap. Measurement of oxygen consumption and anaerobic threshold provides an objective noninvasive assessment of patients with heart failure.

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Over a five-year period, hemodynamic exercise capacity studies and a randomized controlled trial have been performed in a total of 50 patients. DVI vs. VVI pacing showed an increase in stroke work index (P less than 0.005) and a fall in left ventricular filling pressure (P less than 0.05) in 17 patients. VDD/DDD pacing vs. VVI showed an exercise capacity benefit in 44 patients (P less than 0.01) including 8 patients with sinus node disease and a lower peak heart rate (P less than 0.02). Maintenance of benefit was also shown of VDD/DDD pacing in the longer term (13 months) vs. acute (P - NS). The controlled trial VDD/DDD vs. VVI showed benefit in shortness of breath (P less than 0.01) and general well being (P less than 0.01). It is concluded that atrial synchronous ventricular pacing (VDD/DDD) is the mode of choice in suitable patients.

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With the availability of reliable transvenous atrial leads and advances in electronic and battery technology, pacing for the restoration of the atrioventricular sequence has become practicable. This paper presents (1) a historical review of physiological cardiac pacing, and (2) a functional description of pacemakers currently available or in clinical validation. The indications and limitations of use for each is discussed on the basis of clinical experience in 176 patients. Predictions are made for future application of sophisticated pacemaker systems after the remaining clinical and technological barriers are overcome.

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