Biomedical subjects

A N Sulke

Publications and source records attributed to A N Sulke.

10 recordsLinked to original sources

PubMed1992

The effect of atrio-ventricular delay programming in patients with DDDR pacemakers.

Modern DDDR (dual chamber universal, rate responsive) pacemakers are complex, hugely capable devices incorporating new features that theoretically should enhance haemodynamics and therefore quality of life. Ten patients (mean age 48 years) with chronotropic incompetence and high grade A-V block had activity sensing DDDR devices implanted and underwent a randomized double-blind crossover assessment of rate responsive and different fixed atrio-ventricular delay (AVD) settings during 2 weeks of out-of-hospital activity in DDDR mode. Subjective assessment showed improved 'general wellbeing' and preference for 175 ms rate responsive AVD (P less than 0.01) or 125 ms fixed AVD (P less than 0.05). The longest fixed AVD setting (250 ms) was least acceptable and had increased symptom prevalence (P less than 0.02). Perceived exercise capacity and exercise treadmill tolerance was not significantly different at any setting in DDDR mode but was less in DDD mode. Echocardiographically derived stroke distance was greater at 125 ms AVD than 250 ms at 100 b.min-1 (P less than 0.05) but did not differ at slower heart rates at any AVD. Colour Doppler assessed mitral and tricuspid regurgitation was greatest at 250 ms AVD at all heart rates but did not correlate with increased symptomatology. Stroke distance evaluated from the mitral inflow velocity profile allows improved AVD programming during DDDR pacing. Rate adaptive A-V delay is a useful feature during DDDR pacing.

Adolescent↗

PubMed1991

Patent foramina ovale in elderly stroke patients.

Fifty elderly patients who had suffered cerebrovascular incidents from no obvious cause and 33 age-matched controls were investigated for the presence of a patent foramen ovale by contrast 2-dimensional echocardiography at rest and after the Valsalva manoeuvre. Right-to-left shunting was found in only one patient and in none of the controls. This finding is in contradistinction to young adult stroke patients in whom the prevalence of a haemodynamically significant patent foramina ovale is high. Paradoxical embolism is an uncommon cause of stroke in the elderly.

Aged↗

PubMed1991

Open access exercise electrocardiography: a service to improve management of ischaemic heart disease by general practitioners.

An initial study of the use of open access exercise electrocardiography by general practitioners (GPs) in South East Kent showed that patient selection and interpretation of test results was frequently incorrect. After issuing guidelines, modifying the request form and instituting registrar review of all requests, significant improvements in both referral pattern, result interpretation and patient management have resulted. Forty-nine GPs requested 110 exercise tests during 1988/89. Twelve per cent were not undertaken after discussion with the referring practitioner. Eighty-four per cent of those tested would have been referred to the district general hospital cardiology outpatient department in the absence of open access exercise electrocardiography service. Six per cent of patients were referred directly for invasive investigation. Thirty-five per cent were referred to the district general hospital cardiology outpatient department, whilst 42% were spared hospital referral based on the result of the investigation. Better use of the modified service was suggested by: referral of fewer patients with non-cardiac chest pains (P = 0.002); more patients with a moderate pre-test probability of ischaemic heart disease (P less than 0.05); fewer inappropriate requests (P less than 0.01); and fewer inappropriately undertaken tests (P less than 0.001) than in the previous study. All patients with strongly positive test results were appropriately managed. Open access exercise electrocardiography in the format investigated is potentially a cost-effective and useful tool to improve diagnosis and management of heart disease by GPs.

Adolescent↗

PubMed1991

Which pacemaker?

Explore the source record for details and available documents.

Bradycardia↗

PubMed1990

Acceleration of conduction within an accessory pathway with propafenone.

We describe a case of dangerous acceleration of conduction through an accessory pathway produced by the Class IC agent propafenone during routine electrophysiological study of a patient with Wolff-Parkinson-White syndrome. This pro-arrhythmic effect has not previously been described with this drug. Propafenone is now being more widely used since the publication of the preliminary results of the CAST Study in the U.S.A.

Adult↗

PubMed1990

Supraventricular tachycardia control with Tachylog II: long-term follow-up.

Ten patients aged 16-63 years (mean 36.3) had the Siemens P56T "Tachylog II" pacemaker implanted for treatment of drug refractory supraventricular tachycardia. The pacemaker incorporates a noninvasive electrophysiological study (EPS) facility and a sophisticated Holter function combined with a unique "learning" self-search antitachycardia algorithm. The Holter reveals that new tachycardias arise that are not previously detected at conventional EPS. The number of stimuli in the initiation sequences during noninvasive EPS proved highly variable, however, termination sequences remained constant in the long term. There was variability of timing of stimuli in the long term that was significantly greater for "new" tachycardias than for "original" arrhythmias. Long-term follow-up (at 1 month, 6 months, and 1 year) have shown that 90% of patients have good tachycardia control without the need for drugs. All patients confirm the acceptability of this pacemaker for control of their arrhythmias in the long term.

Adolescent↗

PubMed1990

Comparison of the normal sinus node with seven types of rate responsive pacemaker during everyday activity.

The heart rate response of 59 patients aged 17-79 years implanted with seven different types of rate responsive pacemakers was evaluated during graded exercise treadmill testing and during standardised daily activities. The heart rate response in patients with pacemakers was compared with the chronotropic response in 20 healthy controls of similar age and sex distribution who performed identical protocols. All pacemaker types adequately simulated the control heart rate response during the graded exercise treadmill test except during the early stages of exercise. However, during everyday activities, the response of ventricular rate responsive (VVIR) pacemakers was varied. Activity sensing systems rapidly overresponded to staircase descent, to changes in walking speed, and to suitcase lifting with the pacemaker arm, and these systems did not respond to mental stress. "Physiological" sensors (QT and minute ventilation units) responded slowly to rapid changes in physiological demand. The QT pacemaker patients did respond to mental stress but showed a paradoxical increase in rate during the recovery phases of burst exercise protocols such as staircase ascent/descent and walking deceleration. Dual chamber pacemakers in VDD, DDD, and DDDR modes most closely simulated the normal chronotropic response during everyday activities. Graded exercise treadmill testing, in isolation, may not be the best way to asses or program the heart rate response in patients with the heart rate adaptive pacemakers because changes in heart rate during everyday activities may deviate considerably from the normal sinus response despite satisfactory simulation of the normal chronotropic response during treadmill testing.

Adolescent↗

PubMed1990

Open access exercise electrocardiography: does it improve the management of cardiovascular disease in the community?

In this study the use of exercise electrocardiography, by 47 general practitioners in South East Kent has been evaluated. Of 110 consecutive requests the majority (88%) were for diagnostic purposes, while only 7% were for prognostic assessment. Many of those referred were young or had non-cardiac chest pain and in 59% of cases the test result was unlikely to alter the clinical assessment of the probability of ischaemic heart disease (IHD). The test result influenced patient management in 85% of cases. Only 15% of patients were subsequently referred to the district general hospital although all had been considered for referral prior to the test. Although referral for invasive investigation of six patients was expedited by the provision of stress testing, in five patients general practitioners failed to consider any further investigation despite the patient having a strongly positive test. General practitioners use exercise electrocardiography primarily to exclude IHD in patients at low risk and provide reassurance. They rarely use the test as a means to guide management of those with known or probable IHD.

Cardiovascular Diseases↗

PubMed1985

Variation in natural killer activity in peripheral blood during the menstrual cycle.

Natural killer activity was measured sequentially in normal female volunteers through their menstrual cycle. During the periovulatory period there was a significant fall in natural killer activity compared with in normal male volunteers. This variation was not apparent in women taking oral contraception. Cytotoxic activity was not related to oestradiol concentrations in individual women. The data support an interaction between immunological activity and sex hormones over the normal physiological range and would account for the described reduction in natural killer activity in pooled blood from female blood donors.

Adult↗

PubMed1985

Hormonal modulation of human natural killer cell activity in vitro.

This study investigates the effect of steroid and polypeptide hormones on human NK cell activity in vitro. Solutions of hormones were incubated with normal peripheral blood cells in a 4 h cytotoxic assay against the NK-sensitive erythromyeloid cell line K562. The steroid hormones oestradiol, progesterone and testosterone did not exhibit a significant effect on K562 lysis at concentrations within the normal physiological range. HCG and LH, however, had a marked effect on NK activity, the latter at concentrations within the range observed in normal menstruating females.

Adult↗