Vaginal Mucositis in Measles

Background: Measles (rubeola), a common childhood exanthema, occurs infrequently in adults. Vaginal mucositis in association with measles is not commonly described

Sympathetic activation, ventricular repolarization and Ikrblockade: Implications for the antifibrillatory efficacy of potassium channel blocking agents

AbstractObjectives. The aim of the present study was to test, in vivo and in vitro, the influence of adrenergic activation on action potential prolongation induced by the potassium channel blocking agent d-sotalol.Background. d-Sotalol is not effective against myocardial ischemia-dependent ventricular fibrillation in the presence of elevated sympathetic activity. Most potassium channel blockers, such as d-sotalol, affect only one of the two components of Ik(Ikr) but not the other (Iks). Iksis activated by isoproterenol. An unopposed activation of Iksmight account for the loss of anti-fibrillatory effect by d-sotalol in conditions of high sympathetic activity.Methods. In nine anesthetized dogs we tested at constant heart rate (160 to 220 beats/min) the influences of left stellate ganglion stimulation on the monophasic action potential prolongation induced by d-sotalol. In two groups of isolated guinea pig ventricular myocytes we tested the effect of isoproterenol (10−9mol/liter) on the action potential duration at five pacing rates (from 0.5 to 2., Hz) in the absence (n = 6) and in the presence (n = 8) of d-sotalol.Results. In control conditions, both in vivo and in vitro, adrenergic stimulation did not significantly change action potential duration. d-Sotalol prolonged both monophasic action potential duration in dogs and action potential duration of guinea pig ventricular myocytes by 19% to 24%. Adrenergic activation, either left stellate ganglion stimulation in vivo or isoproterenol in vitro, reduced by 40% to 60% the prolongation of action potential duration produced by d-sotalol.Conclusions. Sympathetic activation counteracts the effects of potassium channel blockers on the duration of repolarization and may impair their primary antifibrillatory mechanism. An intriguing clinical implication is that potassium channel blockers may not offer effective protection from malignant ischemic arrhythmias that occur in a setting of elevated sympathetic activity

Effectiveness and limitations of β-blocker therapy in congenital long-QT syndrome

Background—β-blockers are routinely prescribed in congenital long-QT syndrome (LQTS), but the effectiveness and limitations of β-blockers in this disorder have not been evaluated. Methods and Results—The study population comprised 869 LQTS patients treated with β-blockers. Effectiveness of β-blockers was analyzed during matched periods before and after starting β-blocker therapy, and by survivorship methods to determine factors associated with cardiac events while on prescribed β-blockers. After initiation of β-blockers, there was a significant (P<0.001) reduction in the rate of cardiac events in probands (0.97±1.42 to 0.31±0.86 events per year) and in affected family members (0.26±0.84 to 0.15±0.69 events per year) during 5-year matched periods. On-therapy survivorship analyses revealed that patients with cardiac symptoms before β-blockers (n=598) had a hazard ratio of 5.8 (95% CI, 3.7 to 9.1) for recurrent cardiac events (syncope, aborted cardiac arrest, or death) during β-blocker therapy compared with ..

CaV1.2 Calcium Channel Dysfunction Causes a Multisystem Disorder Including Arrhythmia and Autism

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Long QT Syndrome and Pregnancy

ObjectivesThis study was designed to investigate the clinical course of women with long QT syndrome (LQTS) throughout their potential childbearing years.BackgroundOnly limited data exist regarding the risks associated with pregnancy in women with LQTS.MethodsThe risk of experiencing an adverse cardiac event, including syncope, aborted cardiac arrest, and sudden death, during and after pregnancy was analyzed for women who had their first birth from 1980 to 2003 (n = 391). Time-dependent Kaplan-Meier and Cox proportional hazard methods were used to evaluate the risk of cardiac events during different peripartum periods.ResultsCompared with a time period before a woman’s first conception, the pregnancy time was associated with a reduced risk of cardiac events (hazard ratio [HR] 0.28, 95% confidence interval [CI] 0.10 to 0.76, p = 0.01), whereas the 9-month postpartum time had an increased risk (HR 2.7, 95% CI 1.8 to 4.3, p < 0.001). After the 9-month postpartum period, the risk was similar to the period before the first conception (HR 0.91, 95% CI 0.55 to 1.5, p = 0.70). Genotype analysis (n = 153) showed that women with the LQT2 genotype were more likely to experience a cardiac event than women with the LQT1 or LQT3 genotype. The cardiac event risk during the high-risk postpartum period was reduced among women using beta-blocker therapy (HR 0.34, 95% CI 0.14 to 0.84, p = 0.02).ConclusionsWomen with LQTS have a reduced risk for cardiac events during pregnancy, but an increased risk during the 9-month postpartum period, especially among women with the LQT2 genotype. Beta-blockers were associated with a reduction in cardiac events during the high-risk postpartum time period

Risk Factors for Recurrent Syncope and Subsequent Fatal or Near-Fatal Events in Children and Adolescents With Long QT Syndrome

ObjectivesWe aimed to identify risk factors for recurrent syncope in children and adolescents with congenital long QT syndrome (LQTS).BackgroundData regarding risk assessment in LQTS after the occurrence of the first syncope episode are limited.MethodsThe Prentice-Williams-Peterson conditional gap time model was used to identify risk factors for recurrent syncope from birth through age 20 years among 1,648 patients from the International Long QT Syndrome Registry.ResultsMultivariate analysis demonstrated that corrected QT interval (QTc) duration (≥500 ms) was a significant predictor of a first syncope episode (hazard ratio: 2.16), whereas QTc effect was attenuated when the end points of the second, third, and fourth syncope episodes were evaluated (hazard ratios: 1.29, 0.99, 0.90, respectively; p < 0.001 for the null hypothesis that all 4 hazard ratios are identical). A genotype-specific subanalysis showed that during childhood (0 to 12 years), males with LQTS type 1 had the highest rate of a first syncope episode (p = 0.001) but exhibited similar rates of subsequent events as other genotype-sex subsets (p = 0.63). In contrast, in the age range of 13 to 20 years, long QT syndrome type 2 females experienced the highest rate of both first and subsequent syncope events (p < 0.001 and p = 0.01, respectively). Patients who experienced ≥1 episodes of syncope had a 6- to 12-fold (p < 0.001 for all) increase in the risk of subsequent fatal/near-fatal events independently of QTc duration. Beta-blocker therapy was associated with a significant reduction in the risk of recurrent syncope and subsequent fatal/near-fatal events.ConclusionsChildren and adolescents who present after an episode of syncope should be considered to be at a high risk of the development of subsequent syncope episodes and fatal/near-fatal events regardless of QTc duration

Genotype-Phenotype Correlation in the Long-QT Syndrome

Background —The congenital long-QT syndrome (LQTS) is caused by mutations on several genes, all of which encode cardiac ion channels. The progressive understanding of the electrophysiological consequences of these mutations opens unforeseen possibilities for genotype-phenotype correlation studies. Preliminary observations suggested that the conditions ("triggers") associated with cardiac events may in large part be gene specific. Methods and Results —We identified 670 LQTS patients of known genotype (LQT1, n=371; LQT2, n=234; LQT3, n=65) who had symptoms (syncope, cardiac arrest, sudden death) and examined whether 3 specific triggers (exercise, emotion, and sleep/rest without arousal) differed according to genotype. LQT1 patients experienced the majority of their events (62%) during exercise, and only 3% occurred during rest/sleep. These percentages were almost reversed among LQT2 and LQT3 patients, who were less likely to have events during exercise (13%) and more likely to have events during rest/sleep (29% and 39%). Lethal and nonlethal events followed the same pattern. Corrected QT interval did not differ among LQT1, LQT2, and LQT3 patients (498, 497, and 506 ms, respectively). The percent of patients who were free of recurrence with β-blocker therapy was higher and the death rate was lower among LQT1 patients (81% and 4%, respectively) than among LQT2 (59% and 4%, respectively) and LQT3 (50% and 17%, respectively) patients. Conclusions —Life-threatening arrhythmias in LQTS patients tend to occur under specific circumstances in a gene-specific manner. These data allow new insights into the mechanisms that relate the electrophysiological consequences of mutations on specific genes to clinical manifestations and offer the possibility of complementing traditional therapy with gene-specific approaches

K0s K0s Final State in Two-Photon Collisions and Implications for Glueballs

The K0s K0s final state in two-photon collisions is studied with the L3 detector at LEP. The mass spectrum is dominated by the formation of the f_2'(1525) tensor meson in the helicity-two state with a two-photon width times the branching ratio into K Kbar of 76 +- 6 +- 11 eV. A clear signal for the formation of the f_J(1710) is observed and it is found to be dominated by the spin-two helicity-two state. No resonance is observed in the mass region around 2.2 GeV and an upper limit of 1.4 eV at 95% C.L. is derived for the two-photon width times the branching ratio into K0s K0s for the glueball candidate xi(2230)

The masses of satellites in GAMA galaxy groups from 100 square degrees of KiDS weak lensing data

We use the first 100 deg2 of overlap between the Kilo-Degree Survey and the Galaxy And Mass Assembly survey to determine the average galaxy halo mass of ∼10 000 spectroscopically confirmed satellite galaxies in massive (M > 1013 h−1 M⊙) galaxy groups. Separating the sample as a function of projected distance to the group centre, we jointly model the satellites and their host groups with Navarro–Frenk–White density profiles, fully accounting for the data covariance. The probed satellite galaxies in these groups have total masses log 〈Msub/(h−1 M⊙)〉 ≈ 11.7–12.2 consistent across group-centric distance within the errorbars. Given their typical stellar masses, log 〈M⋆, sat/(h−2 M⊙)〉 ∼ 10.5, such total masses imply stellar mass fractions of 〈M⋆, sat〉/〈Msub〉 ≈ 0.04 h−1. The average subhalo hosting these satellite galaxies has a mass Msub ∼ 0.015Mhost independent of host halo mass, in broad agreement with the expectations of structure formation in a Λ cold dark matter universe.Publisher PDFPeer reviewe