高血压病左室肥厚与QTc离散度关系的研究

目的 探讨高血压病病左室肥厚（ＬＶＨ）与非在室肥厚（ＮＬＶＨ）患者ＱＴｃｄ的关系及临床意义。方法 用分层抽样法测定１０３例原发性高血压病患者住院首次１２导联心电图ＱＴｃ离散度（ＱＴｃｄ）其中合并ＬＶＨ患者５７例，合并ＮＬＶＨ患者４６例，并与２０例健康人作对照，结果 ＱＴｃｄＬＶＨ组分别与ＮＬＶＨ组，对照组比较均有非常显著性差异（Ｐ〈０．０１）ＮＬＶＨ组与对照组比较无显著性差异（Ｐ〉０．０５）。结论     

围绝经期及其前后妇女QTcd离散度的研究

目的探讨绝经后妇女冠心病及心血管事件发生率升高的相关机制.方法分别测量42例围绝经期前健康妇女(Ⅰ组,平均年龄41.40±0.92岁)、43例围绝经期健康妇女(Ⅱ组,平均年龄45.5±4.32岁)、40例绝经后健康妇女(Ⅲ组,平均年龄51.45±7.26岁)的校正QT离散度(QTcd)和性激素(SH)水平,研究其变化规律和相互关系.结果绝经后妇女的QTcd与围绝经期前妇女的QTcd相比略有延长,尚无显著性差异;而围绝经期妇女的QTcd与围绝经期前妇女的QTcd相比延长明显,有显著性差异.结论围绝经期妇女SH紊乱导致心肌电不稳定性增高,是除了脂代谢异常之外的导致冠心病发病率升高及心血管事件发生率升高的机制之一.     

我院住院患者应用胺碘酮对QTc间期的影响

摘 要 目的:评估胺碘酮对住院患者QT/ QTc间期的影响及药品不良反应。方法：纳入2014年1～6月上海浦东新区公利医院心内科使用胺碘酮的住院患者共59例,记录患者一般情况和合并用药等信息,观察应用胺碘酮注射液或胺碘酮片剂后心率、QT间期、QTc间期的变化,以及在用药期间发生药品不良反应。结果：用药后患者的平均心率、QT间期和QTc间期较用药前显著减慢(P<0.01)。59例患者中,12例用药后QTc＞500 ms,5例患者用药后△QTc＞50 ms且 QTc＜500 ms。研究中,共有8例合并使用一种或多种可延长QT间期的药物,包括左氧氟沙星（4例）,阿奇霉素（3例）,氟哌噻吨美利曲辛（1例）,多潘立酮（1例）。32例应用胺碘酮注射液患者中有3例发生注射部位反应,用药中未出现与胺碘酮相关的心律失常[包括尖端扭转性室速(Tdp）]。结论：住院患者应用胺碘酮后QT间期、QTc间期均会不同程度延长,对于用药后QTc＞500 ms、△QTc＞50 ms或合并使用其他可延长QT间期药物的患者,Tdp发生风险增加,应及时调整胺碘酮用药方案并严密监测心电图,避免恶性心律失常事件的发生。     

QT延长与高血压合并心房颤动导管射频消融术后复发的相关性分析

目的 探讨高血压合并阵发性心房颤动患者的QTc是否与心房颤动导管射频消融术后复发相关.方法 回顾性分析201 1年1月至2012年12月在北京安贞医院第1次行导管射频消融术的高血压合并阵发性心房颤动心功能正常患者242例,将纳入患者按疾病复发情况分为复发组（98例）和未复发组（144例）,收集术前心电图和其他临床资料,术后定期随访.结果 随访（17±9）个月,98例患者（40.0％）心房颤动导管消融术后复发.与未复发组相比,复发组QTc明显延长[（429±26） ms比（419 ±23） ms]（P=0.004）.复发组的左心房前后径较未复发组明显增大[（41±6）mm比（38±5）mm]（P=0.003）.QTc与心率存在明显的相关性（r=0.162,P=0.011）.长QTc组（n=53）的导管消融术后心房颤动复发率明显较正常QTc组（n=165）和短QTC组（n=24）高（P =0.001、P=0.069）;左心房直径＜38.3 mm组与左心房直径≥38.3 mm组消融术后心房颤动复发率比较,左心房增大与导管消融术后复发相关（P=0.017）.多因素Cox回归分析表明QTc和左心房前后径是心房颤动复发的独立危险因素（QTc：风险比=2.361,95％置信区间：1.353 ～4.121,P=0.003;左心房前后径：风险比=1.795,95％置信区间：1.041 ～3.094,P=0.035）.长QT患者心房颤动复发的风险比为2.361（95％置信区间：1.353 ～4.121,P=0.003）.与左心房前后径单独预测术后复发相比,左心房前后径和QTc联合能更好地预测心房颤动导管消融术后复发.结论 QT延长是高血压合并心房颤动导管消融复发的独立危险因素.     

Ipragliflozin Does Not Prolong QTc Interval in Healthy Male and Female Subjects: A Phase I Study

Background

Ipragliflozin, a potent, selective sodium glucose cotransporter 2 inhibitor, is in development for the treatment of type 2 diabetes mellitus. The International Conference on Harmonisation recommends that the safety investigation of new drugs include characterization of each agent’s effects on the QT/QTc interval.

Objective

The goal of this study was to assess the effect on cardiac repolarization (QTc interval) of repeated oral dosing of ipragliflozin at therapeutic (100 mg/d) and supratherapeutic (600 mg/d) levels in healthy subjects.

Methods

This was a double-blind, placebo- and active-controlled, 4-way crossover study. Subjects were randomized to 1 of 4 treatment sequences each including the following 4 treatments: placebo for 7 days; ipragliflozin 100 mg/d for 7 days; ipragliflozin 600 mg/d for 7 days; and active control moxifloxacin 400 mg on day 7 only. The primary assessment of QTc was based on Fridericia’s correction for heart rate (QTcF). Continuous 12-lead ECG interval extraction assessments were conducted on day 7. The least squares mean treatment difference from placebo and corresponding 2-sided 90% CIs were calculated for QTcF up to 14 hours postdose on treatment day 7. Ipragliflozin was deemed unlikely to have a clinically relevant effect on QTcF if the upper bound of the maximum treatment difference from placebo for ipragliflozin across all time points was < 10 ms. Assay sensitivity for QTcF interval prolongation was confirmed if the lower bound of the 2-sided 90% CIs for the mean moxifloxacin QTcF difference from placebo, determined at sampling time closest to average T_max, was > 5 ms.

Results

A total of 88 subjects were randomized to treatment (n = 22 per sequence; 10 males and 12 females). The largest upper bounds of the 90% CIs of mean treatment differences from placebo were 4.44 and 3.39 ms for ipragliflozin 600 and 100 mg, respectively, in all subjects, indicating no clinically relevant effect on QTcF interval. No specific effects were observed when the data were analyzed according to sex. No subject showed outlier QTcF intervals > 480 ms or a time-matched change from baseline > 60 ms. Moxifloxacin confirmed assay sensitivity for QTcF interval prolongation; the lower bound of the 2-sided 90% CIs at 3 hours postdose was 11.7 ms (> 5 ms).

Conclusions

No clinically meaningful QTc interval prolongation was observed in these healthy subjects who received ipragliflozin doses up to 600 mg/d for 7 days. ClinicalTrials.gov identifier: NCT01232413.     

冠状动脉旁路移植术对QT、QTc、JT离散度的影响

目的　探讨冠状动脉旁路移植术 (Coronary artery bypass graftings,CABG)对冠心病患者 QT间期离散度(QTd)、QTc离散度 (QTcd)及 JT离散度 (JTd)的影响。方法　测定 33例 CABG术前和术后的 QTd为 CABG组 ,并以 33例确诊为冠心病行冠状动脉造影 ,而暂未行 CABG手术和装支架的病人作对照组。结果　 1CABG前和对照组比较 QTd无显著增大 (P>0 .0 5 )。 2 CABG组术后病人的 QTd、QTcd及 JTd显著减小 (P<0 .0 5 )。 3对照组冠状动脉造影术后 QTd、QTcd及 JTd与术前比较 ,无明显改变 (P>0 .0 5 )。结论　 CABG能使 QTd、QTcd及 JTd减小     

Clinical and therapeutic aspects of congenital and acquired long QT syndrome.

The long QT syndrome is characterized by prolongation of the corrected QT (QTc) interval on the surface electrocardiogram. It is associated with precipitation of a polymorphic ventricular tachycardia, torsade de pointes, which may cause sudden death. The syndrome is a disorder of cardiac repolarization caused by the alterations in the transmembrane potassium and sodium currents. Six genetic loci for the congenital forms of the syndrome have been identified; sporadic cases occur because of spontaneous mutations. Acquired causes of the long QT syndrome include drugs, electrolyte imbalance, toxins, marked bradycardia, subarachnoid hemorrhage, stroke, myocardial ischemia, protein-sparing fasting, autonomic neuropathy, and human immunodeficiency virus disease. Clinical symptoms are the result of the precipitation of torsade de pointes and range from such minor symptoms as dizziness to syncope and sudden death. Short-term treatment is aimed at preventing the recurrences of torsade de pointes and includes intravenous magnesium and potassium administration, temporary cardiac pacing, and correction of electrolyte imbalance; rarely, intravenous isoproterenol is indicated. Long-term management includes use of beta-blockers, permanent pacemaker placement, and cardioverter-defibrillator implantation. Asymptomatic patients are treated if under the age of 40 years at the time of diagnosis.     

多巴酚丁胺负荷试验QTcd对冠心病的诊断价值

目的探讨多巴酚丁胺负荷试验前、后冠心病与非冠心病患者QTc散离度(QTcd)的变化,评估多巴酚丁胺负荷试验QTcd对冠心病的诊断价值。方法测量选择性冠脉造影证实的30例冠心病与20例非冠心病患者试验前、后QTcd值,并比较分析。结果冠心病组多巴酚丁胺负荷试验终点QTcd明显高于试验前QTcd(P<0.01),非冠心病组无明显差异(P>0.05)。多巴酚丁胺负荷试验终点QTcd≥55ms诊断冠心病的敏感性、特异性、准确性分别为83.3%、85%、84%,QTcd≥10ms(86.7%、85%、86%)高于传统试验ST段压低诊断冠心病的价值(56.7%、50%、54%)(P<0.05)。结论多巴酚丁胺负荷试验QTcd、QTcd可提高冠心病的诊断价值,是一种安全、简便、有效的无创检查方法。