1,120 research outputs found
Exciton-polariton emission from organic semiconductor optical waveguides
We photo-excite slab polymer waveguides doped with J-aggregating dye
molecules and measure the leaky emission from strongly coupled waveguide
exciton polariton modes at room temperature. We show that the momentum of the
waveguide exciton polaritons can be controlled by modifying the thickness of
the excitonic waveguide. Non-resonantly pumped excitons in the slab excitonic
waveguide decay into transverse electric and transverse magnetic strongly
coupled exciton waveguide modes with radial symmetry. These leak to cones of
light with radial and azimuthal polarizations
Ablation of atrial fibrillation: awaiting the new paradigm**Editorials published in the Journal of the American College of Cardiologyreflect the views of the authors and do not necessarily represent the views of JACCor the American College of Cardiology.
Why Should We Care About CARE-HF?
Previous trials of cardiac resynchronization therapy (CRT) have suggested that this therapy can significantly improve functional class and exercise capacity during short-term follow-up. The impact of this therapy on morbidity and mortality has only recently been reported. The Cardiac Resynchronization-Heart Failure (CARE-HF) study has definitively shown that CRT significantly reduces mortality (36%, p < 0.002) in patients with NYHA functional class III and IV heart failure and ventricular dyssynchrony. This study also shows that CRT reverses ventricular remodeling and improves myocardial performance progressively for at least 18 months. In heart failure patients, the CARE-HF and Comparison of Medical Therapy, Pacing, and Defibrillation in Heart Failure (COMPANION) (the earlier major morbidity/mortality trial) studies together show the unequivocal benefit for CRT therapy and CRT therapy with back-up defibrillation to significantly reduce mortality and hospitalization compared with optimal medical therapy. Both studies suggest the benefit of adding the implantable cardiac defibrillator to CRT devices, as over one-third of deaths in the CRT-pacemaker arm of both the COMPANION and CARE-HF studies were sudden
Peritoneal mesothelioma in a young woman: Case report of radiopathologic findings and review of the literature
Peritoneal mesothelioma is a rare diagnosis most often seen in middle-aged men and exceedingly rarely in individuals in their teens and twenties. Diagnosis is often delayed secondary to nonspecific presenting symptoms and a misconception that there must be a history of asbestos exposure to garner such a diagnosis. Here, we present the case of a 21 year-old female with a histologically confirmed diagnosis of peritoneal mesothelioma and review the key radiologic and histologic findings of this rare diagnosis
Permanent His Bundle Pacing: Electrophysiological and Echocardiographic Observations From Long-Term Follow-Up
Background
Permanent His bundle pacing (HBP) is a physiological alternative to right ventricular pacing. It is not known whether HBP can cause His-Purkinje conduction (HPC) disease. The aim of our study is to assess His bundle capture and its effect on left ventricular (LV) function in long-term follow-up and to determine HPC at the time of pulse generator change (GC) in patients with chronic HBP.
Methods
HB electrograms were recorded from the pacing lead at implant and GC. HBP QRS duration (QRSd), His-ventricular (HV) intervals, and HB pacing thresholds at GC were compared with implant measurements. HPC was assessed by pacing at cycle lengths of 700 ms, 600 ms, and 500 ms at GC. LV internal diameters, ejection fraction (EF), and valve dysfunction at baseline were compared with echocardiography during follow-up.
Results
GC was performed in 20 patients (men 13; age 74 ± 14 years) with HBP at 70 ± 24 months postimplant. HV intervals remained unchanged from initial implant (44 ± 4 ms vs 45 ± 4 ms). During HBP at 700 ms, 600 ms, and 500 ms (n = 17), consistent 1:1 HPC was present. HBP QRSd remained unchanged during follow-up (117 ± 20 ms vs 118 ± 23 ms). HBP threshold at implant and GC was 1.9 ± 1.1 V and 2.5 ± 1.2 V @ 0.5 ms. Despite high pacing burden (77 ± 13%), there was no significant change in LVEF (50 ± 14% at implant) during follow-up (55 ± 6%, P = 0.06).
Conclusions
HBP does not appear to cause new HPC abnormalities and is associated with stable HBP QRSd during long-term follow-up. Despite high pacing burden, HBP did not result in deterioration of left ventricular systolic function or cause new valve dysfunction
A comprehensive assessment of personality traits and psychosocial functioning in parents with bipolar disorder and their intimate partners
Background: Individuals with bipolar disorder (BD) often possess maladaptive traits and present with various difficulties in psychosocial functioning. However, little is known about the intimate partners of adults with bipolar disorder (BD) and how mental illnesses other than BD within couples may further complicate the picture. Such knowledge is needed to inform both couple and family interventions.
Methods: Participants were parents whose children were enrolled in a prospective study: 55 with BD and their partners, and 47 healthy control couples. All completed diagnostic interviews, and questionnaires describing personality traits, negative life events, coping skills, social support, marital adjustment and inter-partner verbal aggression. Parents with BD and healthy control parents were compared, as were the intimate partners. A series of exploratory analyses focused on the average measures within couples, with and without BD, and took account of comorbid personality disorders among those with BD and major depressive disorder among their partners.
Results: Intimate partners of adults with BD, relative to healthy control partners, presented with more mental disorders, higher neuroticism, lower extraversion, more emotion-focused coping, smaller social networks, less satisfaction with their social networks, and little, satisfying social contact. Additionally, they reported less consensus and satisfaction in their marital relationships, and engaged in more verbal aggression towards their partners. Participants with BD showed similar, more extreme, characteristics. Marital distress and verbal aggression were greatest among couples with an adult having BD and a comorbid personality disorder or a partner with major depressive disorder.
Conclusion: This study contributes to the literature by demonstrating that both parents with BD and their intimate
partners exhibit high levels of mental illness, maladaptive personality traits and psychosocial difficulties, thus limiting their partners’ ability to provide support and stability in the these high risk families. Moreover, mental illnesses other than BD may contribute to marital problems within couples. Some statistical analyses, particularly those involving comorbid conditions, were under-powered in this study. As clinical implications, the current study suggests that both individuals with BD and their partners could benefit from interventions aimed at lowering emotionality and verbal aggression, and increasing social support and effective coping skills
Characterization of health care utilization in patients receiving implantable cardioverter-defibrillator therapies: An analysis of the managed ventricular pacing trial.
BACKGROUND: Implantable cardioverter-defibrillators (ICDs) are effective in terminating lethal arrhythmias, but little is known about the degree of health care utilization (HCU) after ICD therapies.
OBJECTIVE: Using data from the managed ventricular pacing trial, we sought to identify the incidence and types of HCU in ICD patients after receiving ICD therapy (shocks or antitachycardia pacing [ATP]).
METHODS: We analyzed HCU events (ventricular tachyarrhythmia [VTA]-related, heart failure-related, ICD implant procedure-related, ICD system-related, or other) and their association with ICD therapies (shocked ventricular tachycardia episode, ATP-terminated ventricular tachycardia episode, and inappropriately shocked episode).
RESULTS: A total of 1879 HCUs occurred in 695 of 1030 subjects (80% primary prevention) and were classified as follows: 133 (7%) VTA-related, 373 (20%) heart failure-related, 97 (5%) implant procedure-related, 115 (6%) system-related, and 1160 (62%) other. Of 2113 treated VTA episodes, 1680 (80%) received ATP only and 433 (20%) received shocks. Stratifying VTA-related HCUs on the basis of the type of ICD therapy delivered, there were 25 HCUs per 100 shocked VTA episodes compared with 1 HCU per 100 ATP-terminated episodes. Inappropriate ICD shocks occurred in 8.7% of the subjects and were associated with 115 HCUs. The majority of HCUs (52%) began in the emergency department, and 66% of all HCUs resulted in hospitalization.
CONCLUSION: For VTA-related HCUs, shocks are associated with a 25-fold increase in HCUs compared to VTAs treated by ATP only. Application of evidence-based strategies and automated device-based algorithms to reduce ICD shocks (higher rate cutoffs, use of ATP, and arrhythmia detection) may help reduce HCUs
Stress and selective attention : the impact of a stressful challenge on mood, cortisol, and the processing of emotional information
The studies presented in this thesis were designed to examine the unfolding of events when an individual is faced with a stressful challenge, by monitoring subjective mood, attention to emotional stimuli, and the hypothalamic-pituitary-adrenal (HPA) response to stress. It was hypothesized that participants would selectively attend to negative words (study 1) and pictures (study 2) following an aversive stressful experience, and that the attentional response to stress would mediate mood and HPA reactivity. Stress induction was achieved by means of a competitive Stroop task with monetary rewards where participants either repeatedly lost (negative stressor) or won (positive stressor) against a confederate. Participants then performed a spatial cueing task assessing attentional shifts towards and away from emotional and neutral stimuli. The results of these studies can be summarized by three major findings. Contrary to predictions, participants selectively avoided negatively-valenced pictures and words. This attentional avoidance response was associated with effective emotional and HPA regulation, suggesting that avoidance in this context may be adaptive as a coping response to stress. Second, stress-induced changes in processing efficiency or alertness, resulting in a wide-scope and flexible attentional style, were also observed, and this too may facilitate adaptive coping. Finally, participants with mild symptoms of depression and anxiety exhibited different patterns of response to stress than euthymic subjects, several characteristics of which may indicate a vulnerability to psychopathology. In effect, the results of these studies provide a possible model of how healthy participants cope with mild stress, and point to an attentional mechanism of emotion regulation that facilitates the maintenance of goal-directed behaviour
Vitamin C Intravenous Treatment In the Setting of Atrial Fibrillation Ablation: Results From the Randomized, Double-Blinded, Placebo-Controlled CITRIS-AF Pilot Study
BackgroundCatheter ablation is an effective treatment for atrial fibrillation (AF), but high levels of post-procedure inflammation predict adverse clinical events. Ascorbic acid (AA) has shown promise in reducing inflammation but is untested in this population. We sought to test the feasibility, safety, and preliminary effects on inflammatory biomarkers in the CITRIS-AF (Vitamin C Intravenous Treatment In the Setting of Atrial Fibrillation Ablation) pilot study.
Methods and ResultsPatients scheduled to undergo AF ablation (N=20) were randomized 1:1 to double-blinded treatment with AA (200 mg/kg divided over 24 hours) or placebo. C-reactive protein and interleukin-6 levels were obtained before the first infusion and repeated at 24 hours and 30 days. Pain levels within 24 hours and early recurrence of AF within 90 days were recorded. Median and interquartile range were aged 63 (56–70) years, 13 (65%) men, and 18 (90%) white. Baseline data were similar between the 2 groups except ejection fraction. Baseline C-reactive protein levels were 2.56 (1.47–5.87) mg/L and similar between groups (P=0.48). Change in C-reactive protein from baseline to 24 hours was +10.79 (+6.56–23.19) mg/L in the placebo group and +3.01 (+0.40–5.43) mg/L in the AA group (P=0.02). Conversely, change in interleukin-6 was numerically higher in the AA group, though not statistically significant (P=0.32). One patient in each arm developed pericarditis; no adverse events related to the infusions were seen. There were no significant differences between aggregated post-procedure pain levels within 24 hours or early recurrence of AF (both P\u3e0.05).
ConclusionsHigh-dose AA is safe and well tolerated at the time of AF ablation and may be associated with a blunted rise in C-reactive protein, although consistent findings were not seen in interleukin-6 levels. Further studies are needed to validate these findings and explore the potential benefit in improving clinically relevant outcomes
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