High-Resolution Mapping and Successful Ablation of Purkinje Ectopy–Triggered Ventricular Fibrillation Storm

Catheter ablation is recognized as a central therapeutic option in treating patients with drug-refractory, scar-related monomorphic ventricular tachycardia (VT). Catheter ablation also has a role in selected cases of polymorphic VT (PMVT) and/or ventricular fibrillation (VF). Rarely, premature ventricular contractions (PVCs) originating from the Purkinje network can induce PMVT/VF. Although not completely elucidated, the electrophysiologic mechanisms behind this lethal arrhythmia have generally been thought to be related to abnormal automaticity and triggered activity. Ablation of the triggering PVCs can prevent VF recurrence and is potentially lifesavin

Pacemaker implantation in small hospitals: complication rates comparable to larger centres

Some countries have a demography that makes it necessary to maintain relatively small pacemaker centres. We wanted to assess the quality of pacemaker surgery in two such hospitals. Through patient records we gathered information on ∼535 consecutive primary pacemaker implantations in two small pacemaker centres with 30 and 80 annual operations, respectively. All patients were followed for 3 years. All complications documented in the patient records were registered. Furthermore, we performed a non-systematic literature search comparing our data with reports from major centres published over the last 10 years.We found 72 complications in 64 (12.0%) of the patients, the most common being bleeding, lead failure, and pneumothorax. If minor bleedings without any consequences for the patients are excluded, the number of complications was 46 in 40 patients (7.5%). We had to reoperate on 5.2% of the patients. There was no statistically significant difference in complication rates between the two hospitals. Education candidates generated statistically significant more complications than experienced doctors (13.7 vs. 7.1%, P < 0.05). There are no generally accepted norms of complication rates in pacemaker surgery. However, we found no indications that our centres have a rate of complications that is unacceptably high

Changes in Parkinson's disease sleep symptoms and daytime somnolence after bilateral subthalamic deep brain stimulation in Parkinson's disease

AbstractIntroduction: Deep brain stimulation (DBS) markedly improves motor function in advanced Parkinson’s disease (PD), but its effect on sleep is less clear. Patients and methods: Forty PD patients who had subthalamic DBS (STN-DBS) were identified from an on-going non-motor naturalistic longitudinal study (NILS). All patients were followed up for at least 6 months, 26 patients had a 1 year follow-up. A total PDSS score of 100 or less, a score in any PDSS-item of 6 or less, and a Epworth score of 10 or more were classified as being significant. Results: Forty-five percent of patients reported significant improvement in the total PDSS score at 6 months, and 35% at 12 months. In terms of magnitude, the total PDSS score at 6 months was significantly improved from baseline while the improvement at 12 months was not statistically significant. The most frequently reported improvements were overall sleep quality and maintenance of sleep. Some patients reported worsening of the total PDSS score. More than half of the patients reporting daytime sleepiness at baseline had persistent sleepiness at 6 and 12 months. The mean Epworth Score did not improve because a significant number of patients without sleepiness at baseline reported new-onset sleepiness at 6 and 12 months. Neither medication changes nor motor improvement were consistently related to sleep changes after DBS. Conclusion: Subthalamic DBS is associated with a statistically and clinically significant, but variable, improvement in sleep as measured by the PDSS. The most frequent improvements were better overall sleep quality and better sleep maintenance.</jats:p

Rate-equation calculations of the current flow through two-site molecular device and DNA-based junction

Here we present the calculations of incoherent current flowing through the two-site molecular device as well as the DNA-based junction within the rate-equation approach. Few interesting phenomena are discussed in detail. Structural asymmetry of two-site molecule results in rectification effect, which can be neutralized by asymmetric voltage drop at the molecule-metal contacts due to coupling asymmetry. The results received for poly(dG)-poly(dC) DNA molecule reveal the coupling- and temperature-independent saturation effect of the current at high voltages, where for short chains we establish the inverse square distance dependence. Besides, we document the shift of the conductance peak in the direction to higher voltages due to the temperature decrease.Comment: 12 pages, 6 figure

Does Sleep Really Influence Face Recognition Memory?

Mounting evidence implicates sleep in the consolidation of various kinds of memories. We investigated the effect of sleep on memory for face identity, a declarative form of memory that is indispensable for nearly all social interaction. In the acquisition phase, observers viewed faces that they were required to remember over a variable retention period (0–36 hours). In the test phase, observers viewed intermixed old and new faces and judged seeing each before. Participants were classified according to acquisition and test times into seven groups. Memory strength (d′) and response bias (c) were evaluated. Substantial time spent awake (12 hours or more) during the retention period impaired face recognition memory evaluated at test, whereas sleep per se during the retention period did little to enhance the memory. Wakefulness during retention also led to a tightening of the decision criterion. Our findings suggest that sleep passively and transiently shelters face recognition memory from waking interference (exposure) but does not actively aid in its long-term consolidation