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
许多广泛使用的药物都可能导致QT间期/QTc延长,继而引起尖端扭转型室性心动过速(torsade de pointes,TdP)等心律失常,后者可能会进一步恶化为心室颤动,甚至造成心脏性猝死。因此,为了预防和降低药源性QT间期延长和TdP的风险,对危险因素...许多广泛使用的药物都可能导致QT间期/QTc延长,继而引起尖端扭转型室性心动过速(torsade de pointes,TdP)等心律失常,后者可能会进一步恶化为心室颤动,甚至造成心脏性猝死。因此,为了预防和降低药源性QT间期延长和TdP的风险,对危险因素的发现、预警和纠正至关重要。近年来,临床已开始应用决策支持系统等预警策略,通过识别多种风险因素预测QT间期/QTc延长和警示TdP高风险人群。本文总结了可引起长QT间期和TdP风险的药物及相关危险因素,并归纳现有的预警措施,期望为暴露于相关风险的患者管理提供参考。展开更多
垂体前叶功能减退行低血糖兴奋试验19例,检测身高、体重、BMI、血压、血糖、血脂、尿酸、血钾、血钠、甲功、动态皮质醇、ACTH、心电图。对比分析患者低血糖发作前及低血糖发生时QT间期,QTc的变化。结果:垂体前叶功能减退患者低血糖发...垂体前叶功能减退行低血糖兴奋试验19例,检测身高、体重、BMI、血压、血糖、血脂、尿酸、血钾、血钠、甲功、动态皮质醇、ACTH、心电图。对比分析患者低血糖发作前及低血糖发生时QT间期,QTc的变化。结果:垂体前叶功能减退患者低血糖发生前后QT间期(393.8±27.93 vs 396.2±35.93)无统计学差异,QTc(420.0±26.48 vs 443.7±38.36,P=0.0059)有统计学差异。结论:垂体前叶功能减退患者低血糖时QTc明显延迟,提示垂体前叶功能减退患者低血糖时的心血管事件,可能与缺乏糖皮质激素对心脏的调节作用有关。展开更多
目的探讨肝硬化患者QTc间期及QT离散度(QTd)变化的机制与临床意义。方法116例肝硬化患者与50例对照组行同步12导联心电图,测定QTc及QTd,同时检测凝血酶原活动度(PTA)、白蛋白(Alb)、总胆红素(TBil),观察腹水和肝性脑病情况。结果肝硬化...目的探讨肝硬化患者QTc间期及QT离散度(QTd)变化的机制与临床意义。方法116例肝硬化患者与50例对照组行同步12导联心电图,测定QTc及QTd,同时检测凝血酶原活动度(PTA)、白蛋白(Alb)、总胆红素(TBil),观察腹水和肝性脑病情况。结果肝硬化组的QTc延长发生率显著高于对照组(41.4%vs 4.0%,P<0.01),肝硬化组QTd显著高于对照组(48.7±18.6ms vs 34.6±11.1ms,P<0.05),QTc延长的发生率与Child分级、TBil、腹水量呈正相关,与PTA、Alb、肝性脑病无相关性。结论肝硬化患者QTc延长及QTd增加是多因素共同作用的结果,QTc延长及QTd增加是引起室性心律失常的常见诱因,可能也是肝硬化患者出现猝死的原因之一。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.
文摘许多广泛使用的药物都可能导致QT间期/QTc延长,继而引起尖端扭转型室性心动过速(torsade de pointes,TdP)等心律失常,后者可能会进一步恶化为心室颤动,甚至造成心脏性猝死。因此,为了预防和降低药源性QT间期延长和TdP的风险,对危险因素的发现、预警和纠正至关重要。近年来,临床已开始应用决策支持系统等预警策略,通过识别多种风险因素预测QT间期/QTc延长和警示TdP高风险人群。本文总结了可引起长QT间期和TdP风险的药物及相关危险因素,并归纳现有的预警措施,期望为暴露于相关风险的患者管理提供参考。
文摘垂体前叶功能减退行低血糖兴奋试验19例,检测身高、体重、BMI、血压、血糖、血脂、尿酸、血钾、血钠、甲功、动态皮质醇、ACTH、心电图。对比分析患者低血糖发作前及低血糖发生时QT间期,QTc的变化。结果:垂体前叶功能减退患者低血糖发生前后QT间期(393.8±27.93 vs 396.2±35.93)无统计学差异,QTc(420.0±26.48 vs 443.7±38.36,P=0.0059)有统计学差异。结论:垂体前叶功能减退患者低血糖时QTc明显延迟,提示垂体前叶功能减退患者低血糖时的心血管事件,可能与缺乏糖皮质激素对心脏的调节作用有关。
文摘目的探讨肝硬化患者QTc间期及QT离散度(QTd)变化的机制与临床意义。方法116例肝硬化患者与50例对照组行同步12导联心电图,测定QTc及QTd,同时检测凝血酶原活动度(PTA)、白蛋白(Alb)、总胆红素(TBil),观察腹水和肝性脑病情况。结果肝硬化组的QTc延长发生率显著高于对照组(41.4%vs 4.0%,P<0.01),肝硬化组QTd显著高于对照组(48.7±18.6ms vs 34.6±11.1ms,P<0.05),QTc延长的发生率与Child分级、TBil、腹水量呈正相关,与PTA、Alb、肝性脑病无相关性。结论肝硬化患者QTc延长及QTd增加是多因素共同作用的结果,QTc延长及QTd增加是引起室性心律失常的常见诱因,可能也是肝硬化患者出现猝死的原因之一。
