尖端扭转型室性心动过速(附八例分析)

本文分析八例伴Q—T间期延长的尖端扭转型室速(TdP),即长QT综合征(LQTS)。均为女性患者,平均年龄69岁。病因均为冠心病,其中合并慢性肺心病1例、Ⅲ度及Ⅱ度二型房室传导阻滞4例、低血钾5例、乙胺碘呋酮作用伴低血钾1例、频发室性早搏7例。治疗为去除诱因,治疗原发病,补充氯化钾、滴注异丙肾上腺素加快心率。硫酸镁静注能迅速中止TdP,心脏起搏是安全有效的治疗方法。结合文献对TdP的发病机理、病因及分类进行讨论。     

Experimental study on the mechanism of sex difference in the risk of torsade de pointes

Torsadedepointes (TdP )isaformofpolymorphicventriculartachycardia (VT)accompaniedbyaprolongedQTinterval FemalesareathigherriskofdevelopingTdP ,especiallyinresponsetodrugsordiseasesthatcanprolongtheQTinterval 1 3　Thequestionofwhyfemalesareathigherriskhasarousedgreatinterest ExperimentsonthistopichavefocusedontheQTintervalaswomennaturallyhavealongerQTintervalthanmen 4 　Buttheresultsofpastexperimentshavebeeninconsistent,5,6 　andthemechanismsoffemalepredominanceinTdPremainunclear Itiskno…     

QT hysteresis in long-QT syndrome children with exercise testing

Background Congenital long QT syndrome (LQTS) is an inherited ion channel disorder resulting in abnormal cardiac repolarization that can cause syncope and sudden death associated with a prolonged rate-corrected QT interval and polymorphic ventricular tachycardia. Several studies in adults showed that LQTS patients have altered QT adaptation to heart rate changes compared with normal subjects which forming a “hysteresis loop” in the QT-circle length plot. This study was to observe the QT interval changing during exercise testing in children long QT syndrome (LQTS) patients, explore the new diagnosis methods of LQTS. Methods The subjects were divided into 3 groups according to 1993 LQTS diagnostic criteria. Group 1: LQTS group (n=17) who scored > or = 4 points indicating definite LQTS. Group 2: Middle group (n=16), patients who have prolonged QT interval but scored 1.5 to 3.5. Group 3: Normal control group (n=18). The average age of all study population is (12.3±5.8) years. No case had beta-adrenergic antagonists administration before exercise testing. All subjects were underwent tread mill exercise testing and electrocardiograph in whole exercise testing and recovery were recorded. QT and heart rate changing during whole exercise testing period were recorded. △QT, the QT interval at 1, 2, 4, 6 minutes into recovery subtract from the QT interval at a similar heart rate during exercise, were calculated.Results In all three groups, QT intervals were shortening with the increasing of heart rate, but QTc had no significant change. △QT at 1 minute ((45±11) ms), 2 minutes ((37±15) ms), 4 minutes ((23±12) ms) into recovery in LQTS group were significantly greater than that of the other two groups (P<0.05, P<0.01, P<0.01, respectively). There was no △QT significant difference between middle group and normal control group at recovery time. During the recovery phase in LQTS group, the QT interval remained shortened despite a decelerating heart rate, forming a hysteresis “loop” in the curve relating the QT interval to the cycle length．Conclusions In children LQTS patients, there is significant QT hysteresis loop in the relation of QT interval with heart rate during recovery of exercise testing, which could be useful to the early diagnosis for LQTS.     

阻塞性睡眠呼吸暂停低通气综合征患者昼夜心室复极参数变化研究

背景阻塞性睡眠呼吸暂停低通气综合征（OSAHS）是一种常见的睡眠呼吸疾病,越来越多的研究表明OSAHS与心血管疾病具有显著相关性,是心律失常、高血压、冠心病等心血管疾病的独立危险因素,但其具体机制仍未完全阐明。相关证据表明,Tp-e间期、QT间期和Tp-e/QT等心室复极参数可能与心律失常甚至心源性猝死有关。然而截止到目前,对OSAHS相关心律失常及心电参数变化的研究相对较少。目的研究OSAHS患者昼夜心室复极参数变化。方法选取2020年6月至2021年7月在郑州大学第一附属医院接受多导睡眠监测、符合纳入及排除标准的OSAHS患者159例,并根据疾病的严重程度进一步分为轻-中度OSAHS组（78例）与重度OSAHS组（81例）;选取51例未患疾病的健康者为对照组。测量并计算所有参与者的日间和夜间Tp-e间期、QT间期、Tp-e/QT。结果对照组与轻-中度OSAHS组、重度OSAHS组之间的日间Tp-e间期、夜间Tp-e间期、日间Tp-e/QT、夜间Tp-e/QT比较,差异均有统计学意义（P<0.05）。日间Tp-e间期、夜间Tp-e间期、日间Tp-e/QT、夜间Tp-e/QT在三组间有逐渐延长的趋势（P<0.05）;三组日间及夜间QT间期比较,差异无统计学意义（P>0.05）。OSAHS患者日间静息状态及夜间阻塞性呼吸暂停期的Tp-e间期、QT间期、Tp-e/QT比较,差异均有统计学意义（P<0.05）;夜间阻塞性呼吸暂停期的Tp-e间期、QT间期、Tp-e/QT均较日间静息状态有所延长,差异有统计学意义（P<0.05）。OSAHS患者夜间Tp-e间期（rs=0.221,P=0.005）、夜间Tp-e/QT（rs=0.298,P<0.001）均与AHI呈正相关。结论OSAHS患者夜间阻塞性呼吸暂停期心室复极参数较日间静息状态下延长,昼夜变化显著,为今后OSAHS合并心律失常的研究提供了新的思路。     

冠心病合并2型糖尿病患者Tp-e间期与Tp-e/QT比值的研究

目的探讨2型糖尿病合并冠心病患者QT间期、Tp-e间期和Tp-e/QT检测的临床价值。方法随机选取冠心病合并2型糖尿病50例,分别与年龄、性别与之匹配的体检组、2型糖尿病、冠心病患者各50例进行比较,分别测量四组V4导联QT间期、Tp-e间期、计算Tp-e/QT。结果 (1)冠心病合并2型糖尿病组与体检组对比QT间期、Tp-e间期和Tp-e/QT比值差异有统计学意义(P0.05)。(2)冠心病合并2型糖尿病组与2型糖尿病组、冠心病组对比,Tp-e间期和Tp-e/QT比值均显著高,差异有统计学意义(P0.05)。(3)冠心病合并2型糖尿病组与冠心病组、2型糖尿病组比较,QT间期差异无统计学意义(P0.05)。结论 Tp-e间期与Tp-e/QT比值比QT间期在预测室性心律失常更有价值;Tp-e间期和Tp-e/QT可作为冠心病合并2型糖尿病患者发生恶性心律失常的预测指标。     

获得性长QT间期综合征新理念

获得性长QT间期综合症（1ong QT yndrome,LQTS）伴发的尖端扭转室性心动过速（torsa de depointes,TdP）是一种具有潜在致命性的恶性心律失常,多见于住院患者,是院内心源性猝死的重要原因之一。2010年美国及中国提出专家共识,强调临床各科医师均应加强对获得性LQTS的认识,掌握心电图特点和危险因素,及时采取有效的防范措施,减少院内心脏恶性事件的发生。     

垂体后叶素对妇科手术患者QT间期的影响

 目的 评估在妇科腹腔镜手术中,子宫肌壁注射垂体后叶素或催产素对患者QT间期的影响。方法 40例行子宫肌瘤手术的患者,ASAⅠ~Ⅱ级,年龄25~45岁,术前心电图均无异常。随机分为两组：A组（垂体后叶素组,n=20）,B组（催产素组,n=20）。均采用气管插管全身麻醉,分别于注射垂体后叶素或催产素前、注射后2、5、10、20、30 min行心电图检查,记录血压（blood pressure,BP）、心率（heart rate,HR）、QT间期,根据公式计算心率校正后的QT间期（QTc）。结果 子宫壁注射垂体后叶素2、5、10 min后QT间期显著延长（P<0.01）;催产素组QT间期有延长趋势,但无统计学意义（P>0.05）。结论 子宫壁注射垂体后叶素使患者QT间期显著延长,在临床应用中应引起重视。     

心房颤动对QT间期的影响

对30例房颤病人的50个心动每一QT间期与前一RR间期、平均QT与平均RR进行了相关性研究。结果表明:平均QT与平均RR呈线性相关,QT=169+0.253RR(P<0.001,r=0.892)。各心动的QT与前一RR也呈线性正相关,其平均回归斜率为0.081。每例各心动QT和前一RR的回归斜率与平均RR则呈线性负相关(r=-0.620,p<0.05)。30例的QT较同一平均心室率时窦性心律延长,除3例外其余仍在Lepeshkin报道正常范围,而平均QT与RR回归线高于Ahave报道的冠心病患者窦性心律的回归线。作者认为,QT间期不仅受病因、心室率的影响,而且受心律影响,故不宜单纯用Bazett公式纠正房颤病人(尤其在快速房颤时)的QT间期。     

Clarithromycin induced torsade de pointes

Background  Clarithromycin is a commonly used macrolide antibiotic. It is known to cause QT prolongation. Medication induced QT prolongation is a major risk factor for the development of torsade de pointes. Methods  A 79-year-old lady presented with frequent episodes of torsade de pointes following commencement of clarithromycin. This was noted to be in association with a prolongation of the QT interval. Conclusion  Knowledge of medications which prolong the QT interval is important to minimize the risk of ventricular arrhythmias, which may lead to sudden death. This is essential in patients with a congenitally long QT interval.     

阻塞性睡眠呼吸暂停低通气综合征对QTc间期的影响

目的:探讨阻塞性睡眠呼吸暂停低通气综合征（OSAHS）对QTc间期的影响。方法: 采用多导睡眠图(PSG)对98例患者进行监测;分为阻塞性睡眠呼吸暂停组66例和无睡眠呼吸暂停组32例,进行24 h动态心电图(DCG)检查,观察两组心率、QT间期、经心率校正的QT间期(QTc间期)及差异。结果:OSAHS组心率、QT间期、QTc间期分别是(76±10)次/分、(366±30)ms,(404±45)ms,非OSAHS组分别是(73±9)次/分、(342±31)ms,(374±26)ms,两组间QT,QTc比较, 差异有统计学意义(P<0.05)。结论: OSAHS组QT间期及QTc间期延长,提示OSAHS可能与心律失常和猝死有关。     

手汗症QT离散度改变与心脏自主神经关系探讨

目的探讨手汗症患者胸2-胸4（T2-4）Q—T离散度（QTd）变化与心脏自主神经的关系。方法用同步12导心电图测定112例手汗症患者交感神经链切断术前后R—R间期即心率（HR）、Q—T间期、最小QT间期（QTmin）、最大QT间期（QTmax）和经心率校正的QTmax（QTc—max）、QTmin（QTc—min）数值的变化进行对比分析。结果术后2—4dQT间期和R—R均较术前缩短,QTd延长,差异均有统计学意义（P〈0．01）。术后2—3年QT间期、R—R间期与术前无明显变化,差异无统计学意义（P〉0．05）。QT离散度较术前延长,存在明显相关性（P〈0．01）。结论手汗症患者T2-4交感神经链切断术后Q—T离散度（QTd）变化与交感神经有一定的相关性。     

注射用磷丙泊酚钠在Ⅰ期临床耐受性试验中对健康受试者QT间期的影响

【摘要】 目的 探讨注射用磷丙泊酚钠（HX0507）在Ⅰ期临床耐受性试验中对健康受试者心电图QT间期的影响,了解其临床应用可能存在的风险。方法 将80例健康受试者顺序分配到13个剂量组。给药前记录基础心电图,并于给药后24 h内33个时点记录心电图。求得使用Fridericia公式和Bazett公式校正的QT间期,即QTcF（QTcF=QT/RR0.33）与QTcB（QTcB=QT/RR0.5）。以QTcF与基线值的差值（ΔQTcF）为主要目标变量分析HX0507对健康受试者QT间期的影响。结果 注射用磷丙泊酚钠在可能的临床常用剂量(3 mg/kg)和更大剂量(8～40 mg/kg)组给药后ΔQTcF均值在5.61～32.24 ms间,双侧90%可信区间上限在10.30～53.90 ms间。32例受试者出现了8种心电图相关的不良反应。结论 注射用磷丙泊酚钠在3 mg/kg和8～40 mg/kg剂量组对健康受试者QT间期有剂量相关性延长的趋势。     

射频消融对心率、QT间期及QT离散度的影响

目的 探讨导管射频消融术(RFCA)对心率、QT间期、QT离散度(QTd)的影响。方法 时比分析50例阵发性室上性心动过速(SVT)患者RFCA术前、术后的PP(RR)间期、QT间期、QTd变化。结果 RFCA术后PP(RR)间期明显缩短，心率加快；QT间期随心率加快而缩短；经心率校正后的QT间期、QTd与术前相比差异无显著性。结论 RFCA可导致窦性心率加快，对校正的QT间期、QTd无明显影响。     

Relationship between action potential duration of ventricular cells and heart rate in dog under natural breathing

Summary The ECG and transmembrane action potentials of the ventricular cells of 12 mongrel dogs at various heart rates under pentobarbital anesthesia and spontaneous breathing were simultaneously recorded. After statistical analysis of the records of 139 units, quantitative relationship between action potential durations (APDs) and heart rate, between QT intervals and heart rate, and between APD₉₀ and QT interval were recognized and regression equations were worked out by linear regression. The regression coefficients indicated that the relationship between APD₉₀, APD₅₀, QT interval and heart rate and that between APD₉₀ and QT interval were highly significant. In order to eliminate the effect of heart rate on APDs and QT interval, the correction formulas for heart rate on APDs and QT interval were worked out. After correction, the effect of heart rate on APDs and QT interval could be eliminated. This paper presents a practical method for the study of the effect of different agents on the APDs of ventricular cells and QT interval under spontaneous breathing.     

ECG series. Importance of QT interval in clinical practice

Long QT interval is an important finding that is often missed by electrocardiogram interpreters. Long QT syndrome (inherited and acquired) is a potentially lethal cardiac channelopathy that is frequently mistaken for epilepsy. We present a case of long QT syndrome with multiple cardiac arrests presenting as syncope and seizures. The long QTc interval was aggravated by hypomagnesaemia and drugs, including clarithromycin and levofloxacin. Multiple drugs can cause prolongation of the QT interval, and all physicians should bear this in mind when prescribing these drugs.     

儿童短QT间期综合征与恶性心律失常的预后研究

目的探讨儿童短QT间期综合征（SQTS）与恶性心律失常的预后意义。方法随机测量18例儿童常规12导联心电图（ECG）QTFridercia（QTfc）和QTNomogram（QTnc）间期,根据R-R间期（R-R）和心率（HR）计算QT间期校正值（QTFridercia、QTNomogram）。QTFridercia、QTNomogram间期≤300 ms为短QT间期,观察短QTFridercia、QTNomo-gram间期与恶性心律失常的关系。用奎尼丁、氟卡尼和除颤器（Implanted cardioverter-defibrillator）治疗观察其预后。结果 QTFridercia≤300 ms发生心律失常为100%,QTNomogram≤300 ms发生心律失常为100%;奎尼丁、氟卡尼可使QT间期值平均延长20 ms,减少恶性心律失常发生,P〈0.05。单用奎尼丁、氟卡尼治疗2年内心律失常发生率QT Fridercia44.44%,QTNomogram 44.44%;死亡率分别为11.11%、11.11%。除颤器治疗6例SQTS患者在2年的观察中无恶性心律失常发生和死亡率发生,P〈0.05。结论短QT间期与恶性心律失常有关;奎尼丁、氟卡尼能延长QT间期,可减少恶性心律失常发生;ICD能有效防止恶性心律失常的发生率和死亡率。     

高血压不同左室构型患者QT间期离散度的研究

目的：研究高血压不同左室型患者QT间期离散的变化。方法：应用超声心动图计算左室重量指数（LVMI）和相对室壁厚度（RWT），按LVMI和RWT将左分为4种构型，对117例例原发性高血压病人的QT间期离散度进行研究，并以45例临床人作为对照组。结果：高血压组除正常构型外，其余QT间期离散度均大于对照组，而向心性肥厚和离心性肥厚组大于向心性重构组，向心性重构组大于正常构型组。QT间期离散度与LVMI正相关。结论：高血压不同左室构型患者QT间期离散度不同，随着LVMI增加QT间期离散度加大。     

司帕沙星和左氧氟沙星对豚鼠心电图QT间期的影响

目的:观察司帕沙星(sparfloxacin,SPX)和左氧氟沙星(levofloxacin,LVFX)对豚鼠心电图QT间期的影响。方法:豚鼠腹腔注射SPX和LVFX后,使用BL-410生理软件记录心电图Ⅱ导联中QT间期的变化。结果:SPX和LVFX引起的QT间期延长,具有剂量依赖性。当剂量为50 mg/kg时,SPX和LVFX均无明显的延长QT间期的作用;当剂量为100 mg/kg时,SPX引起QT间期延长,LVFX不引起QT间期延长;当剂量为200mg/kg时,SPX和LVFX均引起QT间期延长。结论:SPX和LVFX两种药物在低剂量时,都不表现心脏副作用,但随剂量增加,都有引起QT间期延长的潜在危险,两者相比,LVFX较为安全。     

司帕沙星和左氧氟沙星对豚鼠心电图QT间期的影响

目的：观察司帕沙星（sparfloxacin,SPX）和左氧氟沙星（1evofloxaein,LVFX）对豚鼠心电图QT间期的影响。方法：豚鼠腹腔注射不同剂量的SPX和LVFX后,使用BL-410生理软件记录心电图Ⅱ导联中QT间期的变化。结果：SPX和LVFX引起的QT间期延长,具有剂量依赖性,当剂量为50mg/kg时,SPX和LVFX均无明显的延长QT间期的作用;当剂量为100mg／kg时,SPX引起QT间期延长,LVFX不引起QT间期延长;当剂量为200mg／kg时,SPX和LVFX均引起QT间期延长。结论：SPX和LVFX2种药物在低剂量时都不表现心脏副作用,但随剂量增加,都有引起QT间期延长的潜在危险,两者相比。LVFX较为安全。     

原发性高血压患者Tp—Te间期和Tp-Te／QT比率的临床分析

目的：探讨原发性高血压患者Q—T间期、Tp—Te间期和Tp—Te／QT比率的临床意义。方法：随机抽取原发性高血压患者100例,并按1999年WHO／ISH高血压分类标准分为1、2、3级高血压,并与年龄性别相匹配的健康人100例作为对照观察,分别测量其V6导联Q-T间期与QTp间期,计算Tp—Te间期和Tp—Te／QT比率。结果：原发高血压组Tp—Te／QT比率和Tp—Te间期均高于对照组（P〈0．05）,而两组Q-T间期无差异（P〉0．05）。1、2和3级组间Tp—Te间期和Tp-Te／QT比率无差异（P〉0．05）。结论：血压不是导致Tp—Te间期与Tp-Te／QT比率增大的唯一因素。