Ability to remotely monitor atrial high-rate episodes using a single-chamber implantable cardioverter-defibrillator with a floating atrial sensing dipole

AIMS

To allow timely initiation of anticoagulation therapy for the prevention of stroke, the European guidelines on atrial fibrillation (AF) recommend remote monitoring (RM) of device-detected atrial high-rate episodes (AHREs) and progression of arrhythmia duration along pre-specified strata (6 min…<1 h, 1 h…<24 h, ≥ 24 h). We used the MATRIX registry data to assess the capability of a single-lead implantable cardioverter-defibrillator (ICD) with atrial sensing dipole (DX ICD system) to follow this recommendation in patients with standard indication for single-chamber ICD.

METHODS AND RESULTS

In 1841 DX ICD patients with daily automatic RM transmissions, electrograms of first device-detected AHREs per patient in each duration stratum were adjudicated, and the corresponding positive predictive values (PPVs) for the detections to be true atrial arrhythmia were calculated. Moreover, the incidence and progression of new-onset AF was assessed in 1451 patients with no AF history. A total of 610 AHREs ≥6 min were adjudicated. The PPV was 95.1% (271 of 285) for episodes 6min…<1 h, 99.6% (253/254) for episodes 1 h…<24 h, 100% (71/71) for episodes ≥24 h, or 97.5% for all episodes (595/610). The incidence of new-onset AF was 8.2% (119/1451), and in 31.1% of them (37/119), new-onset AF progressed to a higher duration stratum. Nearly 80% of new-onset AF patients had high CHA2DS2-VASc stroke risk, and 70% were not on anticoagulation therapy. Age was the only significant predictor of new-onset AF.

CONCLUSION

A 99.7% detection accuracy for AHRE ≥1 h in patients with DX ICD systems in combination with daily RM allows a reliable guideline-recommended screening for subclinical AF and monitoring of AF-duration progression.

A real‐world experience of subcutaneous and transvenous implantable cardiac defibrillators—comparison with the PRAETORIAN study

Background

Methods

Results

Conclusion

Rationale and study design of the MINERVA study: Multicentre Investigation of Novel Electrocardiogram Risk markers in Ventricular Arrhythmia prediction-UK multicentre collaboration

INTRODUCTION

The purpose of this study is to assess the ability of two new ECG markers (Regional Repolarisation Instability Index (R2I2) and Peak Electrical Restitution Slope) to predict sudden cardiac death (SCD) or ventricular arrhythmia (VA) events in patients with ischaemic cardiomyopathy undergoing implantation of an implantable cardioverter defibrillator for primary prevention indication.

METHODS AND ANALYSIS

Multicentre Investigation of Novel Electrocardiogram Risk markers in Ventricular Arrhythmia prediction is a prospective, open label, single blinded, multicentre observational study to establish the efficacy of two ECG biomarkers in predicting VA risk. 440 participants with ischaemic cardiomyopathy undergoing routine first time implantable cardioverter-defibrillator (ICD) implantation for primary prevention indication are currently being recruited. An electrophysiological (EP) study is performed using a non-invasive programmed electrical stimulation protocol via the implanted device. All participants will undergo the EP study hence no randomisation is required. Participants will be followed up over a minimum of 18 months and up to 3 years. The first patient was recruited in August 2016 and the study will be completed at the final participant follow-up visit. The primary endpoint is ventricular fibrillation or sustained ventricular tachycardia >200 beats/min as recorded by the ICD. The secondary endpoint is SCD. Analysis of the ECG data obtained during the EP study will be performed by the core lab where blinding of patient health status and endpoints will be maintained.

ETHICS AND DISSEMINATION

Ethical approval has been granted by Research Ethics Committees Northern Ireland (reference no. 16/NI/0069). The results will inform the design of a definitive Randomised Controlled Trial (RCT). Dissemination will include peer reviewed journal articles reporting the qualitative and quantitative results, as well as presentations at conferences and lay summaries.

TRIAL REGISTRATION NUMBER

NCT03022487.

OUP accepted manuscript

Aims

To report 5-year outcomes of EFFORTLESS registry patients with early generation subcutaneous implantable cardioverter-defibrillator (S-ICD) devices.

Methods and results

Kaplan–Meier, trend and multivariable analyses were performed for mortality and late (years 2–5) complications, appropriate shock (AS) and inappropriate shock (IAS) rates. Nine hundred and eighty-four of 994 enrolled patients with diverse diagnoses (28% female, 48 ± 17 years, body mass index 27 ± 6 kg/m², ejection fraction 43 ± 18%) underwent S-ICD implantation. Median follow-up was 5.1 years (interquartile range 4.7–5.5 years). All-cause mortality was 9.3% (95% confidence interval 7.2–11.3%) at 5 years; 703 patients remained in follow-up on study completion, 171 withdrew including 87 (8.8%) with device explanted, and 65 (6.6%) lost to follow-up. Of the explants, only 20 (2.0%) patients needed a transvenous device for pacing indications. First and final shock efficacy for discrete ventricular arrhythmias was consistent at 90% and 98%, respectively, with storm episode final shock efficacy at 95.2%. Time to therapy remained unaltered. Overall 1- and 5-year complication rates were 8.9% and 15.2%, respectively. Early complications did not predict later complications. There were no structural lead failures. Inappropriate shock rates at 1 and 5 years were 8.7% and 16.9%, respectively. Self-terminating inappropriately sensed episodes predicted late IAS. Predictors of late AS included self-terminating appropriately sensed episodes and earlier AS.

Conclusion

In this diverse S-ICD registry population, spontaneous shock efficacy was consistently high over 5 years. Very few patients underwent S-ICD replacement with a transvenous device for pacing indications. Treated and self-terminating arrhythmic episodes predict future shock events, which should encourage more personalized device optimization.

Ultrasound Probe Pose Classification for Task Recognition in Central Venous Catheterization

Central Line Tutor is a system that facilitates real-time feedback during training for central venous catheterization. One limitation of Central Line Tutor is its reliance on expensive, cumbersome electromagnetic tracking to facilitate various training aids, including ultrasound task identification and segmentation of neck vasculature. The purpose of this study is to validate deep learning methods for vessel segmentation and ultrasound pose classification in order to mitigate the system's reliance on electromagnetic tracking. A large dataset of segmented and classified ultrasound images was generated from participant data captured using Central Line Tutor. A U-Net architecture was used to perform vessel segmentation, while a shallow Convolutional Neural Network (CNN) architecture was designed to classify the pose of the ultrasound probe. A second classifier architecture was also tested that used the U-Net output as the CNN input. The mean testing set Intersect over Union score for U-Net cross-validation was 0.746 ± 0.052. The mean test set classification accuracy for the CNN was 92.0% ± 3.0, while the U-Net + CNN achieved 92.7% ± 2.1%. This study highlights the potential for deep learning on ultrasound images to replace the current electromagnetic tracking-based methods for vessel segmentation and ultrasound pose classification, and represents an important step towards removing the electromagnetic tracker altogether. Removing the need for an external tracking system would significantly reduce the cost of Central Line Tutor and make it far more accessible to the medical trainees that would benefit from it most.

Management and cleanup of legacy radium-contaminated sites in the United States

The hazards associated with radium-containing materials were largely unknown when they were first introduced into household and other products over a century ago. Radium was also originally thought to have beneficial health properties, leading to confusion amongst the public about the safety of radium in household products and food items. When the adverse health effects associated with radium were discovered and became well known, radium products became unpopular and were prohibited in some countries. In the United States, after the hazards associated with radium became known, radium was first regulated by individual states in the late 1920s and early 1930s. Later, the US Nuclear Regulatory Commission (NRC) was given a role in the regulation of discrete sources of radium with the passage of the Energy Policy Act of 2005. After passage of the Act, the NRC began to systematically identify sites around the country where radium was used and reached out to site owners to determine whether existing radium contamination could pose a risk to public health and safety and the environment. The NRC devised a graded approach in response to its new regulatory responsibilities to address potential public health and safety issues at legacy radium sites. By September 2019, the NRC had dispositioned all the sites that were identified as having potential contamination from historical radium within its regulatory purview in non-Agreement States. The staff worked with site owners and federal, state and local officials, as needed, to properly disposition the sites to ensure that each site either meets the applicable criteria for unrestricted use or has controls in place to limit access during remediation so that no site poses an unacceptable risk to public health and safety and the environment.

Screening Nitrate in Forages with a Test Strip: Collaborative Study

A collaborative study was conducted for screening nitrate in forages with a commercially available test strip. The method involves extracting a finely ground sample with deionized water. The test strip is dipped in the sample extract. The color of the reaction zone on the test strip changes from white to pink or purple depending on the nitrate concentration in sample extract. The nitrate present in the extract is determined by comparing the color of the test strip to the color scale on the test strip container. Six blind quintuplicates of forage samples were analyzed by 20 collaborators. Nitrate concentrations in forage samples tested ranged from &lt;1000 ppm nitrate to &gt;10 000 ppm nitrate on dry matter basis. Each collaborator was asked to assign each sample to one of the 4 following nitrate concentration ranges: (1) &lt;1000 ppm, (2) 1000 to 5000 ppm, (3)&gt;5000 ppm to 10 000 ppm, and (4) &gt;10 000 ppm. Nineteen of 20 collaborators reported results. Results from 2 laboratories were rejected as outliers by inspection and χ2 test. Sensitivity rates (p+) ranged from 0.965 to 0.998, with standard errors of 0.006 to 0.16. Specificity rates (p−) ranged from 0.991 to 0.997 for the 4 ranges, with standard errors of 0.003 to 0.006. False-positive rates (pf+) ranged from 0.006 to 0.046, with standard errors of 0.006 to 0.025. False-negative rates (pf−) ranged from 0.003 to 0.007, with standard errors of 0.003 to 0.006. Screening nitrate in forages with a test strip has been adopted first action by AOAC INTERNATIONAL.

Quality of life, depression, and anxiety in patients with a subcutaneous versus transvenous defibrillator system

BACKGROUND

Use of the subcutaneous implantable defibrillator (S-ICD) has increased because the device received US Food and Drug Administration approval in 2012, but we still know little about whether the quality of life (QoL) of patients with an S-ICD versus a transvenous ICD (TV-ICD) is comparable. We compared S-ICD patients with TV-ICD patients on QoL, depression, and anxiety up to 12 months' follow-up.

METHODS

A matched cohort of S-ICD (N = 167) and TV-ICD patients (N = 167) completed measures on QoL, depression, anxiety, and personality at baseline, 3, 6, and 12 months post implant. Data were analyzed using multivariable modeling with repeated measures.

RESULTS

In adjusted analyses, we found no statistically significant differences between cohorts on physical and mental QoL and depression (all Ps > .05), while S-ICD patients reported lower anxiety than TV-ICD patients (P = 0.0007). Both cohorts experienced improvements in physical and mental QoL and symptoms of depression and anxiety over time (all Ps < .001), primarily between implant and 3 months. These improvements were similar for both cohorts with respect to physical and mental QoL and anxiety (Ps > .05), while S-ICD patients experienced greater reductions in depressive symptoms (P = .0317).

CONCLUSION

The QoL and depression levels were similar in patients with an S-ICD and a TV-ICD up to 12 months' follow-up, while S-ICD patients reported lower anxiety levels and a greater reduction in depression over time as compared to TV-ICD patients. This knowledge may be important for patients and clinicians, if the indication for implantation allows both the S-ICD and the TV-ICD, making a choice possible.

A Comparison of the Quality of Life of Patients With an Entirely Subcutaneous Implantable Defibrillator System Versus a Transvenous System (from the EFFORTLESS S-ICD Quality of Life Substudy)

The first clinical results from the Evaluation of Factors Impacting Clinical Outcome and Cost Effectiveness of the subcutaneous implantable cardioverter defibrillator (EFFORTLESS S-ICD) Registry on the entirely S-ICD system are promising, but the impact of the S-ICD system on patients' quality of life (QoL) is not known. We evaluated the QoL of patients with an S-ICD against an unrelated cohort with a transvenous (TV)-ICD system during 6 months of follow-up. Consecutively implanted patients with an S-ICD system were matched with patients with a TV-ICD system on a priori selected variables including baseline QoL. QoL was measured with the Short-Form Health Survey at baseline, 3, and 6 months after implant and compared using multivariable modeling with repeated measures. Patients with an S-ICD (n = 167) versus a TV-ICD system (n = 167) did not differ significantly on physical (p = 0.8157) and mental QoL scores (p = 0.9080) across baseline, 3, and 6 months after implantation in adjusted analyses. The evolution in physical (p = 0.0503) and mental scores (p = 0.3772) during follow-up was similar for both cohorts, as indicated by the nonsignificant interaction effect for ICD system by time. Both patients with an S-ICD system and a TV-ICD system experienced significant improvements in physical and mental QoL between time of implant and 3 months (both p's <0.0001) and between time of implant and 6 months (both p's <0.0001) but not between 3 and 6 months (both p's >0.05). In conclusion, these first results show that the QoL of patients with an S-ICD versus TV-ICD system is similar and that patients with either system experience improvements in QoL on the short term.

Minimizing right ventricular pacing in pacemaker patients with intact and compromised atrioventricular conduction : Results from the EVITA Trial

INTRODUCTION

Unnecessary ventricular pacing is associated with increased morbidity and mortality. Over the years different algorithms have been developed to reduce right ventricular pacing.

OBJECTIVES

Goal of the present study was to test the efficacy of the ventricular intrinsic preference (VIP) algorithm in patients with atrioventricular intact (AVi) and atrioventricular compromised (AVc) AV-conduction.

METHODS

Evaluation of VIP feature in pacemaker patients (EVITA) was a multicenter, prospective, randomized trial (Trials.gov Identifier: NCT00366158). In total, 389 patients were randomized to AVc group: n = 140/132 VIP OFF/VIP On, AVi group: n = 54/63 VIP OFF/VIP ON). One-month post-implantation AV conduction testing (AVc: PR/AR interval > 210 ms) was performed. Follow-up visits occurred 6 and 12 months after DDD-pacemaker implantation.

RESULTS

In AVi and AVc-patients initiation of the VIP feature significantly reduced incidence of ventricular pacing (AVi: 53 ± 38 vs. 9 ± 21%, p = 0.0001; AVc: 79 ± 31 vs. 28 ± 35%, p = 0.0001). DDD-pacemaker implantation per se significantly reduced incidence of AF in VIP ON (AVi 27 vs. 0%, p < 0.0001; AVc 29 vs. 3%, p < 0.0001) and VIP OFF patients (AVi 43 vs. 4%, p < 0.0001; AVc 33 vs. 3, p < 0.0001), without significant differences between VIP ON and OFF groups (p > 0.05). In the AVc group activation of VIP significantly reduced incidence of adverse events (AE). All-cause mortality was not significantly different in VIP ON (n = 5) and VIP OFF (n = 4, p > 0.05) patients.

CONCLUSION

AV search hysteresis (VIP) markedly reduces ventricular pacing both in patients with normal AV conduction and in patients with prolonged PR interval or intermittent AV block.

Worldwide experience with a totally subcutaneous implantable defibrillator: early results from the EFFORTLESS S-ICD Registry

Aims

The totally subcutaneous implantable-defibrillator (S-ICD) is a new alternative to the conventional transvenous ICD system to minimize intravascular lead complications. There are limited data describing the long-term performance of the S-ICD. This paper presents the first large international patient population collected as part of the EFFORTLESS S-ICD Registry.

Methods and results

The EFFORTLESS S-ICD Registry is a non-randomized, standard of care, multicentre Registry designed to collect long-term, system-related, clinical, and patient reported outcome data from S-ICD implanted patients since June 2009. Follow-up data are systematically collected over 60-month post-implant including Quality of Life. The study population of 472 patients of which 241 (51%) were enrolled prospectively has a mean follow-up duration of 558 days (range 13–1342 days, median 498 days), 72% male, mean age of 49 ± 18 years (range 9–88 years), 42% mean left ventricular ejection fraction. Complication-free rates were 97 and 94%, at 30 and 360 days, respectively. Three hundred and seventeen spontaneous episodes were recorded in 85 patients during the follow-up period. Of these episodes, 169 (53%) received therapy, 93 being for Ventricular Tachycardia/Fibrillation (VT/VF). One patient died of recurrent VF and severe bradycardia. Regarding discrete VT/VF episodes, first shock conversion efficacy was 88% with 100% overall successful clinical conversion after a maximum of five shocks. The 360-day inappropriate shock rate was 7% with the vast majority occurring for oversensing (62/73 episodes), primarily of cardiac signals (94% of oversensed episodes).

Conclusion

The first large cohort of real-world data from an International patient S-ICD population demonstrates appropriate system performance with clinical event rates and inappropriate shock rates comparable with those reported for conventional ICDs. Clinical trial registration URL: http://www.clinicaltrials.gov. Unique identifier NCT01085435.

Long-term fracture rates seen with continued ibandronate treatment: pooled analysis of DIVA and MOBILE long-term extension studies

Ibandronate reduces the risk of vertebral and non-vertebral fractures versus placebo in postmenopausal women with osteoporosis. This analysis, in which fractures were reported as safety events, showed that long-term use of ibandronate was associated with low fracture rates over 5 years of treatment.

INTRODUCTION

A previous post-hoc meta-analysis of 2-3 year studies found that ibandronate regimens with annual cumulative exposure (ACE) of ≥10.8 mg reduced the risk of vertebral and nonvertebral fractures (NVFs) versus placebo in postmenopausal women. This post-hoc analysis used individual patient data from the 2-year monthly oral ibandronate in ladies (MOBILE) and dosing intravenous administration (DIVA) studies, including the 3-year long-term extensions (LTEs), to assess fracture risk in patients treated with ibandronate for 5 years.

METHODS

Patients treated for 2 years in MOBILE with monthly oral ibandronate 150 mg (n = 176) and in DIVA with IV ibandronate every 2 months 2 mg (n = 253) or quarterly 3 mg (n = 263) who continued on the same regimens for 3 additional years in the LTEs were included. Three-year placebo data (n = 1,924) were obtained from the ibandronate osteoporosis vertebral fracture trial in North America and Europe (BONE) and IV Fracture Prevention trials. The primary endpoint was clinical fracture rate; clinical fracture data were collected as adverse events. Time to fracture was analyzed using Kaplan-Meier and statistical analysis was conducted using the log-rank test. All clinical fractures included all NVFs and symptomatic vertebral fractures.

RESULTS

For ibandronate regimens with ACE ≥10.8 mg, time to fracture was significantly longer for all clinical fractures, NVFs, and clinical vertebral fractures versus placebo (P = 0.005). For all fracture types, the rate of fracture appeared stable during the 5-year treatment period.

CONCLUSION

In women with postmenopausal osteoporosis, continuous treatment with ibandronate over 5 years results in low sustained clinical fracture rate.

N-Acetylcysteine inhibits platelet-monocyte conjugation in patients with type 2 diabetes with depleted intraplatelet glutathione: a randomised controlled trial

AIMS/HYPOTHESIS

The aim of this study was to determine whether oral dosing with N-acetylcysteine (NAC) increases intraplatelet levels of the antioxidant, glutathione (GSH), and reduces platelet-monocyte conjugation in blood from patients with type 2 diabetes.

METHODS

In this placebo-controlled randomised crossover study, the effect of oral NAC dosing on platelet-monocyte conjugation and intraplatelet GSH was investigated in patients with type 2 diabetes (eligibility criteria: men or post-menopausal women with well-controlled diabetes (HbA(1c) < 10%), not on aspirin or statins). Patients (n = 14; age range 43-79 years, HbA(1c) = 6.9 ± 0.9% [52.3 ± 10.3 mmol/mol]) visited the Highland Clinical Research Facility, Inverness, UK on day 0 and day 7 for each arm of the study. Blood was sampled before and 2 h after oral administration of placebo or NAC (1,200 mg) on day 0 and day 7. Patients received placebo or NAC capsules for once-daily dosing on the intervening days. The order of administration of NAC and placebo was allocated by a central office and all patients and research staff involved in the study were blinded to the allocation until after the study was complete and the data fully analysed. The primary outcome for the study was platelet-monocyte conjugation.

RESULTS

Oral NAC reduced platelet-monocyte conjugation (from 53.1 ± 4.5% to 42.5 ± 3.9%) at 2 h after administration and the effect was maintained after 7 days of dosing. Intraplatelet GSH was raised in individuals with depleted GSH and there was a negative correlation between baseline intraplatelet GSH and platelet-monocyte conjugation. There were no adverse events.

CONCLUSIONS/INTERPRETATION

The NAC-induced normalisation of intraplatelet GSH, coupled with a reduction in platelet-monocyte conjugation, suggests that NAC might help to reduce atherothrombotic risk in type 2 diabetes.

FUNDING

Chief Scientist Office (CZB/4/622), Scottish Funding Council, Highlands & Islands Enterprise and European Regional Development Fund.

TRIAL REGISTRATION

isrctn.org ISRCTN89304265.

Web-based training course for evaluating radiological dose assessment in NRC's license termination process

As part of the requirement for terminating the licenses of nuclear power plants or other nuclear facilities, license termination plans or decommissioning plans are submitted by the licensee to the U.S. Nuclear Regulatory Commission (NRC) for review and approval. Decommissioning plans generally refer to the decommissioning of nonreactor facilities, while license termination plans specifically refer to the decommissioning of nuclear reactor facilities. To provide a uniform and consistent review of dose modeling aspects of these plans and to address NRC-wide knowledge management issues, the NRC, in 2006, commissioned Argonne National Laboratory to develop a Web-based training course on reviewing radiological dose assessments for license termination. The course, which had first been developed in 2005 to target specific aspects of the review processes for license termination plans and decommissioning plans, evolved from a live classroom course into a Web-based training course in 2006. The objective of the Web-based training course is to train NRC staff members (who have various relevant job functions and are located at headquarters, regional offices, and site locations) to conduct an effective review of dose modeling in accordance with the latest NRC guidance, including NUREG-1757, Volumes 1 and 2. The exact size of the staff population who will receive the training has not yet been accurately determined but will depend on various factors such as the decommissioning activities at the NRC. This Web-based training course is designed to give NRC staff members modern, flexible access to training. To this end, the course is divided into 16 modules: 9 core modules that deal with basic topics, and 7 advanced modules that deal with complex issues or job-specific topics. The core and advanced modules are tailored to various NRC staff members with different job functions. The Web-based system uses the commercially available software Articulate, which incorporates audio, video, and animation in slide presentations and has glossary, document search, and Internet connectivity features. The training course has been implemented on an NRC system that allows staff members to register, select courses, track records, and self-administer quizzes.

Factors affecting reliability and confidence of DSM-III-R psychosis-related diagnosis

The relationships between interrater diagnostic reliability, confidence in diagnosis, DSM-III-R criteria ambiguity and case report data quality were examined in 20 case vignettes describing psychosis-related symptomatology. Each of seven diagnosticians made DSM-III-R diagnoses and gave confidence ratings for those diagnoses, as well as ratings on quality of data presented and clarity of diagnostic criteria for each vignette. As hypothesized, confidence ratings significantly predicted interrater diagnostic agreement. Clarity of DSM-III-R criteria positively correlated with both interrater reliability and confidence. Case report data quality correlated with diagnostic confidence but, contrary to the authors' hypothesis, did not correlate with interrater agreement. The authors conclude that confidence ratings may be useful indices of diagnostic reliability among experienced clinicians and suggest that the case report method allows for reliable diagnoses to be made.

One-year follow-up of opiate injectors treated with oral methadone in a GP-centred programme

AIMS

To examine changes in drug-related behaviour in opiate-dependent injectors treated with oral methadone, in a shared care scheme where consumption of the daily dose is usually supervised by a community pharmacist.

DESIGN

One-year cohort study.

SETTING

Recruitment from the main routes into methadone prescribing in Glasgow during 1996: General Practitioner Drug Misuse Clinic Scheme and the Drug Problem Service.

PARTICIPANTS

Current opiate injectors entering methadone treatment.

FINDINGS

Among the 204 injectors recruited, 148 (73%) were re-interviewed at 6 months and 118 (58%) at both 6 and 12 months. Twenty-nine per cent of the cohort remained continuously on methadone for 12 months. In that group, over the 12-month period, self-reported daily opiate injecting reduced from 78% to 2%; overdose in the previous 6 months from 24% to 2%; mean daily drug spend from 50 Pounds to 4 Pounds; and mean monthly number of acquisitive crimes reduced from 13 to three. Assuming participants lost to follow-up were unchanged, significant improvements in the total cohort were seen in daily opiate injecting (from 80% at recruitment to 43% at 12 months), overdose (from 27% to 15%), mean daily drug spend (from 63 Pounds to 38 Pounds) and mean monthly number of acquisitive crimes (from 18 to 11). Discontinuation of treatment was mainly due to imprisonment (39%) or sanctions by the prescriber (33%).

CONCLUSION

Treatment of opiate-dependent drug injectors with methadone in a community-wide general practitioner-centred scheme, with supervised daily consumption, was associated with major beneficial change for a substantial proportion of patients.

Dopamine genes and ADHD

Family, twin, and adoption studies have documented a strong genetic basis for ADHD/HKD, but these studies do not identify specific genes linked to the disorder. Molecular genetic studies can identify allelic variations of specific genes that are functionally associated with ADHD/HKD, and dopamine genes have been the initial candidates based on the site of action of the stimulants drugs, which for a half century have provided the primary pharmacological treatment for ADHD/HKD. Two candidate dopamine genes have been investigated and reported to be associated with ADHD/HKD: the dopamine transporter (DAT1) gene [Cook et al., American Journal of Human Genetics 1995;56:993-998, Gill et al., Molecular Psychiatry 1997;2:311-313] and the dopamine receptor D4 (DRD4) gene [LaHoste et al., Molecular Psychiatry 1996;1:121-124: Smalley et al., 1998;3:427-430; Swanson et al., Molecular Psychiatry 1998;3:38-41]. Speculative hypotheses [Swanson and Castellanos, NIH Consensus Development Conference: Diagnosis and Treatment of Attention Deficit Hyperactivity Disorder, November 1998. p. 37-42] have suggested that specific alleles of these dopamine genes may alter dopamine transmission in the neural networks implicated in ADHD/HKD (e.g. that the 10-repeat allele of the DAT1 gene may be associated with hyperactive re-uptake of dopamine or that the 7-repeat allele of the DRD4 gene may be associated with a subsensitive postsynaptic receptor). These and other variants of the dopamine hypothesis of ADHD will be discussed.

Genetic locus heterogeneity in Lafora's progressive myoclonus epilepsy

In 1995, we mapped a gene for Lafora's progressive myoclonus epilepsy in chromosome 6q23-25. In 1997 and 1998, we reduced the size of the locus to 300 kb, and an international collaboration identified mutations in the protein tyrosine phosphatase gene. Here, we examine for heterogeneity through the admixture test in 22 families and estimate the proportion of linked families to be 75 to 85%. Extremely low posterior probabilities of linkage (Wi), exclusionary LOD scores, and haplotypes identify 4 families unlikely to be linked to chromosome 6q24.

Directions of aetiologic research on attention deficit hyperactivity disorder

OBJECTIVE

The aim of this paper is to review and integrate recent literature on aetiological factors that have been postulated for attention deficit hyperactivity disorder (ADHD).

METHOD

Recent studies relating to perinatal brain damage, intra-uterine toxic effects, neurochemical, brain imaging and genetic studies are reviewed, and those considered most significant are discussed. Where possible, recent findings are integrated and directions of future research are suggested. Clinical implications are briefly discussed.

RESULTS

Perinatal studies indicate that children with a birth weight under 750 g may be disadvantaged for attentional skills. Magnetic resonance imaging (MRI) and steady state visually evoked potential studies show differences in prefrontal, caudate and parietal areas in ADHD children, suggesting right hemispheric dysfunction. Functional MRI studies hold promise in further elucidating attentional systems in the central nervous system that are involved in ADHD. Genetic studies suggest genes related to dopaminergic systems may be important.

CONCLUSIONS

Recent research on ADHD has made considerable advances, particularly in the areas of brain imaging and genetic studies. Genetic studies should provide further aetiological understandings of ADHD, leading to more targeted treatments.

Laparoscopic hernia repair in Leicester General Hospital: a prospective audit of 94 patients

Conventional hernia repair is effective in terms of cure but is associated with considerable postoperative pain and delay in return to normal activity. Laparoscopic repair has the potential to reduce pain and speed return to normal activity, but there have been few published reports of the outcome of this operation in the UK. We present a prospective audit of 94 patients who underwent laparoscopic repair. Of the 94 patients, 87 (92.6%) were male and 7 (7.4%) were female. Thirteen of the repairs were bilateral and 12 were recurrent. Two had to be converted to open repair. The mean operating time for unilateral repair was 56 min and for bilateral repair 98 min. Sixty-three patients (67%) were discharged within 24 h and 21 (22.4%) were discharged within 48 h. There were minor complications in 20 patients (21%), eight of whom (8.5%) developed a haematoma. The other minor complications included seromas (2), bruising at the site of the entry port (2), hyperaesthesia in the groin (2), port hernia (1), shoulder tip pain after surgery (3) and postoperative urinary retention (2). Nine (9.5%) patients claimed to have had no pain or discomfort at all; 35 (37.2%) were pain and discomfort free in 2 weeks. Thirty-two (34%) patients returned to normal activities in 2 weeks. With a median follow-up of 8 months 3 (3.2%) recurrences were noted. It is emphasised that this series represents a learning curve and that the operation is developmental. We are now restricting laparoscopic repair to recurrent and bilateral hernias where the technique offers particular advantages.

Laparoscopic cholecystectomy in Leicester: an audit of 555 patients

Laparoscopic techniques have revolutionised the surgical approach to cholecystectomy, even though there have been no published randomised controlled trials to demonstrate the safety of this approach. We present an audit of 555 patients offered laparoscopic cholecystectomy. In all, 54 patients (9.7%) were converted to an open procedure. Peroperative cholangiography (POC) was attempted in 190 cases (34.2%) and achieved in 141 (25.4%). Major complications occurred in 26 cases (4.7%) including 5 (0.9%) deaths, two of whom had major pre-existing morbidity. There was one common bile duct (CBD) injury (0.18%). There were 30 patients (5.4%) found to have CBD stones, 27 of which were cleared at ERCP, and three converted to open exploration. Cholecystectomy by any route is a major operation and we conclude that careful case selection remains imperative. However, morbidity is favourable compared with open cholecystectomy, and comparable with other reports using the laparoscopic technique. Our experience of CBD injury (0.18%) is also acceptable compared with the risk of injury during open cholecystectomy. There were 312 patients (56.2%) who did not undergo perioperative CBD imaging with ERCP or POC and three of these developed early symptomatic retained stones. This group requires further follow-up.