查看“︁QT间期”︁的源代码

{{Infobox medical intervention
 | Name        = QT间期
 | Image       = File:QT interval.jpg
 | Caption     = [[心电图]]显示用切线法计算的 QT 间期
 | ICD10       = R94.31
 | ICD9        = 89.52
 | MeshID      = D004562
 | MedlinePlus = 003868
 | OtherCodes  =
}}
'''QT间期'''是描述[[心电图]]波形中，[[Q波]]开始到[[T波]]结束的时间，該電位變化時間近似于从[[心室]]开始收缩到结束舒张的时间<ref name="eurekaselect">{{Cite journal |last=Postema |first=Pieter G. |last2=Wilde |first2=Arthur A. M. |date=2014-08 |title=The measurement of the QT interval |url=http://www.eurekaselect.com/article/60490 |journal=Current Cardiology Reviews |volume=10 |issue=3 |doi=10.2174/1573403x10666140514103612 |issn=1875-6557 |pmc=4040880 |pmid=24827793 |access-date=2022-06-20 |archive-date=2022-08-02 |archive-url=https://web.archive.org/web/20220802125558/http://www.eurekaselect.com/article/60490 |dead-url=no }}</ref>。QT间期過長或過短可能代表[[心律失常|心律异常]]和[[心搏停止|心源性猝死]]的风险較高。<ref name="eurekaselect" />可能造成QT间期异常的原因包含[[遗传学|遗传疾病]]（如[[长QT综合症]]）、<ref>{{Cite web |title=Long QT syndrome - Symptoms and causes |url=https://www.mayoclinic.org/diseases-conditions/long-qt-syndrome/symptoms-causes/syc-20352518 |website=Mayo Clinic |language=en |access-date=2022-06-20 |archive-date=2022-07-26 |archive-url=https://web.archive.org/web/20220726032426/https://www.mayoclinic.org/diseases-conditions/long-qt-syndrome/symptoms-causes/syc-20352518 |dead-url=no }}</ref>药物（如[[索他洛尔]]或[[替洛利生]]）、血液[[電解質不平衡|電解質失衡]]（如[[低钾血症]]）或[[内分泌疾病|激素失衡]]（如[[甲状腺机能低下症|甲状腺功能减退症]]）等。<ref>{{Cite journal |last=Nachimuthu |first=Senthil |last2=Assar |first2=Manish D. |last3=Schussler |first3=Jeffrey M. |date=2012-10 |title=Drug-induced QT interval prolongation: mechanisms and clinical management |url=https://journals.sagepub.com/doi/10.1177/2042098612454283 |journal=Therapeutic Advances in Drug Safety |volume=3 |issue=5 |doi=10.1177/2042098612454283 |issn=2042-0986 |pmc=4110870 |pmid=25083239 |access-date=2022-06-20 |archive-date=2022-08-03 |archive-url=https://web.archive.org/web/20220803145742/https://journals.sagepub.com/doi/10.1177/2042098612454283 |dead-url=no }}</ref>

== 测量 ==
QT间期最常在II导联中测量，用于评估系列心电图，I和V5导联是II导联的可比替代品。通常避免使用导联III、aVL和V1来测量QT间期。<ref>{{Cite journal |last=Panicker |first=Gopi Krishna |last2=Salvi |first2=Vaibhav |last3=Karnad |first3=Dilip R. |last4=Chakraborty |first4=Saikat |last5=Manohar |first5=Deepak |last6=Lokhandwala |first6=Yash |last7=Kothari |first7=Snehal |date=2014-03 |title=Drug-induced QT prolongation when QT interval is measured in each of the 12 ECG leads in men and women in a thorough QT study |url=https://www.sciencedirect.com/science/article/abs/pii/S0022073613005682?via%3Dihub |journal=Journal of Electrocardiology |volume=47 |issue=2 |doi=10.1016/j.jelectrocard.2013.11.004 |issn=1532-8430 |pmid=24388488 |access-date=2022-06-20 |archive-date=2022-07-02 |archive-url=https://web.archive.org/web/20220702225348/https://www.sciencedirect.com/science/article/abs/pii/S0022073613005682?via%3Dihub |dead-url=no }}</ref>QT间期的准确测量是主观的，因为T波的末端并不总是明确定义，通常会逐渐与基线融合。<ref>{{Cite journal |last=Panicker |first=Gopi Krishna |last2=Karnad |first2=Dilip R. |last3=Joshi |first3=Rajesh |last4=Shetty |first4=Sheetal |last5=Vyas |first5=Niraj |last6=Kothari |first6=Snehal |last7=Narula |first7=Dhiraj |date=2009-01 |title=Z-score for benchmarking reader competence in a central ECG laboratory |url=https://onlinelibrary.wiley.com/doi/epdf/10.1111/j.1542-474X.2008.00269.x |journal=Annals of Noninvasive Electrocardiology: The Official Journal of the International Society for Holter and Noninvasive Electrocardiology, Inc |volume=14 |issue=1 |doi=10.1111/j.1542-474X.2008.00269.x |issn=1542-474X |pmc=6932360 |pmid=19149789}}</ref>心电图复合波中的QT间期可以通过不同的方法手动测量，例如阈值法，其中T波的终点由T波的分量与等电基线合并的点或切线法确定，其中T波的终点由从最大下坡点处的T波外推到等电基线的切线的交点确定。<ref>{{Cite journal |last=Panicker |first=Gopi Krishna |last2=Karnad |first2=Dilip R. |last3=Natekar |first3=Mili |last4=Kothari |first4=Snehal |last5=Narula |first5=Dhiraj |last6=Lokhandwala |first6=Yash |date=2009-07 |title=Intra- and interreader variability in QT interval measurement by tangent and threshold methods in a central electrocardiogram laboratory |url=https://www.sciencedirect.com/science/article/abs/pii/S002207360900017X |journal=Journal of Electrocardiology |volume=42 |issue=4 |doi=10.1016/j.jelectrocard.2009.01.003 |issn=1532-8430 |pmid=19261293 |access-date=2022-06-20 |archive-date=2022-07-11 |archive-url=https://web.archive.org/web/20220711055449/https://www.sciencedirect.com/science/article/abs/pii/S002207360900017X |dead-url=no }}</ref>

随着具有同时12通道记录的数字心电图的可用性增加，QT测量也可以通过“叠加中位搏动”方法完成。在叠加中位心搏法中，为12条导联中的每条导联构建中位ECG复合波。12个中位心搏相互叠加，QT间期是从Q波的最早开始到T波的最新偏移量或从Q波开始的最大收敛点到T波偏移量测量的。<ref>{{Cite journal |last=Salvi |first=Vaibhav |last2=Karnad |first2=Dilip R. |last3=Panicker |first3=Gopi Krishna |last4=Natekar |first4=Mili |last5=Hingorani |first5=Pooja |last6=Kerkar |first6=Vaibhav |last7=Ramasamy |first7=Arumugam |last8=de Vries |first8=Michiel |last9=Zumbrunnen |first9=Troy |last10=Kothari |first10=Snehal |last11=Narula |first11=Dhiraj |date=2011-03 |title=Comparison of 5 methods of QT interval measurements on electrocardiograms from a thorough QT/QTc study: effect on assay sensitivity and categorical outliers |url=https://linkinghub.elsevier.com/retrieve/pii/S0022073610005686 |journal=Journal of Electrocardiology |volume=44 |issue=2 |doi=10.1016/j.jelectrocard.2010.11.010 |issn=1532-8430 |pmid=21238976 |access-date=2022-06-20 |archive-date=2022-06-18 |archive-url=https://web.archive.org/web/20220618144406/https://linkinghub.elsevier.com/retrieve/pii/S0022073610005686 |dead-url=no }}</ref>

== 心率校正 ==
QT间期随[[心率]]而变化，随着心率的增加，QT间期缩短。这些变化使得比较在不同心率下测量的QT间期变得更加困难。考虑到这一点，从而提高QT测量的可靠性，可以使用各种数学公式对QT间期进行心率（QTc）校正，该过程通常由现代心电图记录仪自动执行。

=== 巴泽特公式 ===
最常用的QT校正公式是巴泽特公式（Bazett's formula），<ref>{{Cite journal |last=Bazett |first=H. C. |date=1997-04 |title=AN ANALYSIS OF THE TIME-RELATIONS OF ELECTROCARDIOGRAMS. |url=https://onlinelibrary.wiley.com/doi/10.1111/j.1542-474X.1997.tb00325.x |journal=Annals of Noninvasive Electrocardiology |language=en |volume=2 |issue=2 |doi=10.1111/j.1542-474X.1997.tb00325.x |issn=1082-720X |access-date=2022-06-20 |archive-date=2022-07-10 |archive-url=https://web.archive.org/web/20220710150657/https://onlinelibrary.wiley.com/doi/10.1111/j.1542-474X.1997.tb00325.x |dead-url=no }}</ref>該公式以得名自英國生理学家亨利·库斯伯特·巴泽特（Henry Cuthbert Bazett），<ref>{{Cite journal |last=Roguin |first=Ariel |date=2011-03 |title=Henry Cuthbert Bazett (1885-1950)--the man behind the QT interval correction formula |url=https://onlinelibrary.wiley.com/doi/10.1111/j.1540-8159.2010.02973.x |journal=Pacing and clinical electrophysiology: PACE |volume=34 |issue=3 |doi=10.1111/j.1540-8159.2010.02973.x |issn=1540-8159 |pmid=21091739 |access-date=2022-06-20 |archive-date=2022-07-08 |archive-url=https://web.archive.org/web/20220708145259/https://onlinelibrary.wiley.com/doi/10.1111/j.1540-8159.2010.02973.x |dead-url=no }}</ref>计算心率校正的QT间期（QTcB）。

巴泽特的公式是基于1920年的一项研究的观察结果。巴泽特的公式通常以返回QTc的形式给出，该QTc以量綱可疑的单位（秒的平方根）为单位。巴泽特公式的数学正确形式是：<math>QTc_B = {QT \over \sqrt{RR\over 1\text{ s}}}</math>

其中QTcB是针对心率校正的QT间期，RR是从一个QRS波群开始到下一个QRS波群开始的间隔。这个数学上正确的公式以与QT相同的单位返回QTc，通常为毫秒。<ref name="elsevier">{{Cite journal |last=Molnar |first=J. |last2=Weiss |first2=J. S. |last3=Rosenthal |first3=J. E. |date=1995-03-01 |title=The missing second: what is the correct unit for the Bazett corrected QT interval? |url=https://linkinghub.elsevier.com/retrieve/pii/S0002914999806031 |journal=The American Journal of Cardiology |volume=75 |issue=7 |doi=10.1016/s0002-9149(99)80603-1 |issn=0002-9149 |pmid=7864010 |access-date=2022-06-20 |archive-date=2020-08-06 |archive-url=https://web.archive.org/web/20200806191132/https://linkinghub.elsevier.com/retrieve/pii/S0002914999806031 |dead-url=no }}</ref>

在该公式的一些流行形式中，假设QT以毫秒为单位测量，而RR以秒为单位测量，通常从心率（HR）推导出为60/HR。因此，结果将以每平方根毫秒的秒数为单位。<ref name="wiley">{{Cite journal |last=Salvi |first=Vaibhav |last2=Karnad |first2=Dilip R. |last3=Panicker |first3=Gopi Krishna |last4=Kothari |first4=Snehal |date=2010-01 |title=Update on the evaluation of a new drug for effects on cardiac repolarization in humans: issues in early drug development |url=https://bpspubs.onlinelibrary.wiley.com/doi/10.1111/j.1476-5381.2009.00427.x |journal=British Journal of Pharmacology |volume=159 |issue=1 |doi=10.1111/j.1476-5381.2009.00427.x |issn=1476-5381 |pmc=2823350 |pmid=19775279 |access-date=2022-06-20 |archive-date=2022-07-04 |archive-url=https://web.archive.org/web/20220704180129/https://bpspubs.onlinelibrary.wiley.com/doi/10.1111/j.1476-5381.2009.00427.x |dead-url=no }}</ref>但是，使用此公式报告QTc会产生“关于测量原始QT和RR的单位的要求”。<ref name="elsevier" />

在这两种形式中，巴泽特的非线性QT校正公式通常被认为是不准确的，因为它在高心率时过度校正，而在低心率时校正不足。<ref name="wiley" />巴泽特校正公式是最适合新生儿的QT校正公式之一。<ref>{{Cite journal |last=Stramba-Badiale |first=Marco |last2=Karnad |first2=Dilip R. |last3=Goulene |first3=Karine M. |last4=Panicker |first4=Gopi Krishna |last5=Dagradi |first5=Federica |last6=Spazzolini |first6=Carla |last7=Kothari |first7=Snehal |last8=Lokhandwala |first8=Yash Y. |last9=Schwartz |first9=Peter J. |date=2018-08-14 |title=For neonatal ECG screening there is no reason to relinquish old Bazett's correction |url=https://academic.oup.com/eurheartj/article/39/31/2888/5025709 |journal=European Heart Journal |volume=39 |issue=31 |doi=10.1093/eurheartj/ehy284 |issn=1522-9645 |pmid=29860404 |access-date=2022-06-20 |archive-date=2022-06-20 |archive-url=https://web.archive.org/web/20220620123131/https://academic.oup.com/eurheartj/article/39/31/2888/5025709 |dead-url=no }}</ref>

=== 弗里德里西亚公式 ===
弗里德里西亚提出了一种使用RR的立方根的替代校正公式<ref>{{Cite journal |last=Fridericia |first=L. S. |date=2003-10 |title=The duration of systole in an electrocardiogram in normal humans and in patients with heart disease. 1920 |url=https://pubmed.ncbi.nlm.nih.gov/14516292/ |journal=Annals of Noninvasive Electrocardiology: The Official Journal of the International Society for Holter and Noninvasive Electrocardiology, Inc |volume=8 |issue=4 |doi=10.1046/j.1542-474x.2003.08413.x |issn=1082-720X |pmc=7328879 |pmid=14516292 |access-date=2022-06-20 |archive-date=2022-07-10 |archive-url=https://web.archive.org/web/20220710144644/https://pubmed.ncbi.nlm.nih.gov/14516292/ |dead-url=no }}</ref>：<math>QTc_F = {QT \over \sqrt[3]{RR \over 1\text{ s}}}</math>

=== 萨吉公式 ===
弗雷明汉校正公式（Framingham correction），又稱為萨吉公式（Sagie's formula）。該公式源自於{{Le|弗雷明汉心脏研究|Framingham Heart Study}}，使用了超过5000名受试者的长期队列数据，被认为是一种更好的方法。<ref>{{Cite journal |last=Vandenberk |first=Bert |last2=Vandael |first2=Eline |last3=Robyns |first3=Tomas |last4=Vandenberghe |first4=Joris |last5=Garweg |first5=Christophe |last6=Foulon |first6=Veerle |last7=Ector |first7=Joris |last8=Willems |first8=Rik |date=2016-06-17 |title=Which QT Correction Formulae to Use for QT Monitoring? |url=https://www.ahajournals.org/doi/10.1161/JAHA.116.003264 |journal=Journal of the American Heart Association |volume=5 |issue=6 |doi=10.1161/JAHA.116.003264 |issn=2047-9980 |pmc=4937268 |pmid=27317349 |access-date=2022-06-20 |archive-date=2022-08-05 |archive-url=https://web.archive.org/web/20220805205712/https://www.ahajournals.org/doi/10.1161/JAHA.116.003264 |dead-url=no }}</ref><ref>{{Cite journal |last=Sagie |first=A. |last2=Larson |first2=M. G. |last3=Goldberg |first3=R. J. |last4=Bengtson |first4=J. R. |last5=Levy |first5=D. |date=1992-09-15 |title=An improved method for adjusting the QT interval for heart rate (the Framingham Heart Study) |url=https://www.ajconline.org/article/0002-9149(92)90562-D/pdf |journal=The American Journal of Cardiology |volume=70 |issue=7 |doi=10.1016/0002-9149(92)90562-d |issn=0002-9149 |pmid=1519533 |access-date=2022-06-20 |archive-date=2022-07-16 |archive-url=https://web.archive.org/web/20220716010533/https://www.ajconline.org/article/0002-9149(92)90562-D/pdf |dead-url=no }}</ref>

<math>QTlc = 1000\left(\frac{QT}{1000} + 0.154(1 - RR)\right)</math>

同样，这里QT和QTlc以毫秒为单位，而RR以秒为单位。

== 参见 ==
* [[心电图]]
* [[长QT综合症]]
* [[短QT综合征]]

== 参考文献 ==
{{Reflist|4}}

== 外部链接 ==
* {{Cite web |title=Corrected QT Interval (QTc) |url=https://www.mdcalc.com/corrected-qt-interval-qtc |website=MDCalc |language=en |access-date=2022-06-20 |archive-date=2022-01-20 |archive-url=https://web.archive.org/web/20220120175443/https://www.mdcalc.com/corrected-qt-interval-qtc |dead-url=no }}

{{心血管生理学}}

[[Category:心脏电生理学]]