Objective:Accurate measurement of QT interval,the ventricular action potential from depolarization to repolarization,is important for the early detection of Long QT syndrome.The most effective QT correction(QTc)formul...Objective:Accurate measurement of QT interval,the ventricular action potential from depolarization to repolarization,is important for the early detection of Long QT syndrome.The most effective QT correction(QTc)formula has yet to be determined in the pediatric population,although it has intrinsically greater extremes in heart rate(HR)and is more susceptible to errors in measurement.The authors of this study compare six dif-ferent QTc methods(Bazett,Fridericia,Framingham,Hodges,Rautaharju,and a computer algorithm utilizing the Bazett formula)for consistency against variations in HR and RR interval.Methods:Descriptive Retrospective Study.We included participants from a pediatric cardiology practice of a community hospital who had an ECG performed in 2017.All participants were healthy patients with no past medical history and no regular med-ications.Results:ECGs from 95 participants from one month to 21 years of age(mean 9.7 years)were included with a mean HR of 91 beats per minute(bpm).The two-sample paired t-test or Wilcoxon signed-rank test assessed for any difference between QTc methods.A statistically significant difference was observed between every combination of two QTc formulae.The Spearman’s rank correlation analysis explored the QTc/HR and QTc/RR relationships for each formula.Fridericia method was most independent of HR and RR with the lowest absolute value of correlation coefficients.Bazett and Computer had moderate correlations,while Framingham and Rautaharju exhibited strong correlations.Correlations were positive for Bazett and Computer,reflecting results from prior studies demonstrating an over-correction of Bazett at higher HRs.In the linear QTc/HR regression analysis,Bazett had the slope closest to zero,although Computer,Hodges,and Fridericia had comparable values.Alternatively,Fridericia had the linear QTc/RR regression coefficient closest to zero.The Bland-Altman method assessed for bias and the limits of agreement between correction formulae.Bazett and Computer exhibited good agreement with minimal bias along with Framingham and Rautaharju.To account for a possible skewed distri-bution of QT,all the above analyses were also performed excluding the top and bottom 2%of data as sorted by heart rate ranges(N=90).Results from this data set were consistent with those derived from all participants(N=95).Conclusions:Overall,the Fridericia correction method provided the best rate correction in our pedia-tric study cohort.展开更多
Background PD(PD)is associated with a twofold increase in the risk of death especially sudden death.A predisposing factor for cardiac sudden death is prolongation of the QT interval.This study evaluated the potential ...Background PD(PD)is associated with a twofold increase in the risk of death especially sudden death.A predisposing factor for cardiac sudden death is prolongation of the QT interval.This study evaluated the potential association between QT interval and PD.Methods A systematic search was conducted of Medline and EMBASE using the search terms“PD”AND“QT interval”OR“Cardiac Repolarization”to identify articles.Results Seven studies with persons with PD(n=981)and control groups were identified.There was a significant difference in QT interval comparing patients with PD and persons without PD.The odds ratio showed a significant(P<0.001)2.6-fold(random effect)greater QTc prolongation in PD compared to control.Overall,there was a significantly longer QT in patients with PD than controls of 10.7±2.8 ms.Data analysis did not show much publication bias.Focusing only on studies that related the QT interval to the severity of PD as assessed by Hoehn–Yahr classification(n=6),there was a significant(P=0.004)overall correlation between QT interval and the severity of PD.There was little publication bias.The data directly examining patients with PD taking any drug than might prolong QT do not support an association between these mediations and QT prolongation.Conclusion Individuals with PD have a longer QT interval than individuals without PD.The QT interval is associated with a greater severity of PD and a greater probability of developing more severe PD.The QT interval should be considered in assessment of PD and possibly as a target for the treatment of PD.展开更多
嵌入式GUI(Graphical User Interface)为嵌入式系统提供了一种应用于特殊场合的人机交互接口(Man-Machine Inter-face)。由于嵌入式系统本身的硬件资源有限,要求嵌入式GUI具有高度可移植性和可裁剪性,以适应不同的硬件条件和使用需求。...嵌入式GUI(Graphical User Interface)为嵌入式系统提供了一种应用于特殊场合的人机交互接口(Man-Machine Inter-face)。由于嵌入式系统本身的硬件资源有限,要求嵌入式GUI具有高度可移植性和可裁剪性,以适应不同的硬件条件和使用需求。首先介绍嵌入式Linux GUI目前的发展状况及各自的特点,然后针对目前主流的嵌入式GUI系统——Qt/Embedded,阐述其图形引擎的实现。最后,结合三星公司S3C2410的开发板,实现了一种嵌入式GUI系统在具体平台上的应用。展开更多
基金This study was reviewed and approved by the New York-Presbyterian Brooklyn Methodist Hospital Institutional Review Committee.The study follows the guidelines outlined in the Declaration of Helsinki.
文摘Objective:Accurate measurement of QT interval,the ventricular action potential from depolarization to repolarization,is important for the early detection of Long QT syndrome.The most effective QT correction(QTc)formula has yet to be determined in the pediatric population,although it has intrinsically greater extremes in heart rate(HR)and is more susceptible to errors in measurement.The authors of this study compare six dif-ferent QTc methods(Bazett,Fridericia,Framingham,Hodges,Rautaharju,and a computer algorithm utilizing the Bazett formula)for consistency against variations in HR and RR interval.Methods:Descriptive Retrospective Study.We included participants from a pediatric cardiology practice of a community hospital who had an ECG performed in 2017.All participants were healthy patients with no past medical history and no regular med-ications.Results:ECGs from 95 participants from one month to 21 years of age(mean 9.7 years)were included with a mean HR of 91 beats per minute(bpm).The two-sample paired t-test or Wilcoxon signed-rank test assessed for any difference between QTc methods.A statistically significant difference was observed between every combination of two QTc formulae.The Spearman’s rank correlation analysis explored the QTc/HR and QTc/RR relationships for each formula.Fridericia method was most independent of HR and RR with the lowest absolute value of correlation coefficients.Bazett and Computer had moderate correlations,while Framingham and Rautaharju exhibited strong correlations.Correlations were positive for Bazett and Computer,reflecting results from prior studies demonstrating an over-correction of Bazett at higher HRs.In the linear QTc/HR regression analysis,Bazett had the slope closest to zero,although Computer,Hodges,and Fridericia had comparable values.Alternatively,Fridericia had the linear QTc/RR regression coefficient closest to zero.The Bland-Altman method assessed for bias and the limits of agreement between correction formulae.Bazett and Computer exhibited good agreement with minimal bias along with Framingham and Rautaharju.To account for a possible skewed distri-bution of QT,all the above analyses were also performed excluding the top and bottom 2%of data as sorted by heart rate ranges(N=90).Results from this data set were consistent with those derived from all participants(N=95).Conclusions:Overall,the Fridericia correction method provided the best rate correction in our pedia-tric study cohort.
文摘Background PD(PD)is associated with a twofold increase in the risk of death especially sudden death.A predisposing factor for cardiac sudden death is prolongation of the QT interval.This study evaluated the potential association between QT interval and PD.Methods A systematic search was conducted of Medline and EMBASE using the search terms“PD”AND“QT interval”OR“Cardiac Repolarization”to identify articles.Results Seven studies with persons with PD(n=981)and control groups were identified.There was a significant difference in QT interval comparing patients with PD and persons without PD.The odds ratio showed a significant(P<0.001)2.6-fold(random effect)greater QTc prolongation in PD compared to control.Overall,there was a significantly longer QT in patients with PD than controls of 10.7±2.8 ms.Data analysis did not show much publication bias.Focusing only on studies that related the QT interval to the severity of PD as assessed by Hoehn–Yahr classification(n=6),there was a significant(P=0.004)overall correlation between QT interval and the severity of PD.There was little publication bias.The data directly examining patients with PD taking any drug than might prolong QT do not support an association between these mediations and QT prolongation.Conclusion Individuals with PD have a longer QT interval than individuals without PD.The QT interval is associated with a greater severity of PD and a greater probability of developing more severe PD.The QT interval should be considered in assessment of PD and possibly as a target for the treatment of PD.
文摘嵌入式GUI(Graphical User Interface)为嵌入式系统提供了一种应用于特殊场合的人机交互接口(Man-Machine Inter-face)。由于嵌入式系统本身的硬件资源有限,要求嵌入式GUI具有高度可移植性和可裁剪性,以适应不同的硬件条件和使用需求。首先介绍嵌入式Linux GUI目前的发展状况及各自的特点,然后针对目前主流的嵌入式GUI系统——Qt/Embedded,阐述其图形引擎的实现。最后,结合三星公司S3C2410的开发板,实现了一种嵌入式GUI系统在具体平台上的应用。
