双源CT精确判断的室间隔起搏患者心电图变化特征

目的结合数字减影血管造影(DSA)图像以及双源CT精确判定室间隔起搏部位,分析体表心电图变化特征。方法 57例植入起搏器患者,术中经DSA图像定位提示起搏导线植入右室间隔部,术后行双源CT确定导线精确位置,分析明确植入到室间隔不同部位及游离壁的起搏心电图特征。结果游离壁12例(21.1%);间隔45例(78.9%)。游离壁起搏的QRS波时限显著宽于高位间隔起搏(150±15 ms vs 121±26 ms,P<0.05);高位间隔起搏Ⅲ导联R波振幅(RⅢ)明显大于低位间隔起搏(1.10±0.55 mV vs-0.27±0.12 mV,P<0.05);高位间隔起搏者44.4%Ⅰ导联出现q波或QS,中位间隔36.8%,低位和游离壁均为0;代表游离壁起搏的肢体导联切迹发生率没有明显差异。结论室间隔起搏心电图往往表现为窄QRS波,I导联形态多变,高位间隔起搏时RⅢ较高。     

急性下壁心肌梗死aVR导联QRS波的形态分析

目的探讨下壁心肌梗死时心电图aVR导联QRS波群形态的改变。方法分析89例急性下壁心肌梗死患者心梗前、后以及1年后的心电图和100例经冠状动脉造影证实的无冠心病患者的心电图,分析aVR导联QRS波群形态的变化。结果急性下壁心肌梗死前和无冠心病患者的心电图aVR导联QRS波群多呈q(Q)r型(89.2%),少数呈QS型(10.8%);下壁心肌梗死后及1年后心电图aVR导联QRS波群多呈rs(S)型(86.21%),少数呈QS型(12.77%),极少数呈Qr型(1.02%)。结论下壁心肌梗死后心电图aVR导联QRS波群多呈r(sS)型。     

急性下壁心肌梗死心电图aVR导联ST段压低的临床意义

目的:评价急性下壁心肌梗死(MI)患者心电图aVR导联ST段压低的临床意义。方法:43例急性下壁MI患者根据有无aVR导联ST段压低分为2组,并分析其临床情况。结果:ST段压低组肌酸激酶及肌酸激酶同工酶峰值浓度明显高于非ST段压低组[(47.25±25.42)∶(25.50±15.46)mmol/L,P<0.01;(2.82±1.99)∶(1.80±0.86)mmol/L,P<0.05,ST段压低组患者并发后壁MI比例亦明显高于非ST段压低组(56%∶9%,P<0.01)。结论:急性下壁MI心电图aVR导联ST段压低提示梗死面积较大,累及下侧壁或后壁;且有助于并发后壁MI的诊断。     

心电图aVR导联变化对严重左主干狭窄病变的诊断意义

【】 目的 探讨冠状动脉左主干慢性严重狭窄病变的心电图特点。方法 单中心前展性连续选取典型心绞痛发作时12导联心电图aVR导联ST段抬高≥1mm,其他导联ST段压低或不抬高者作为研究对象,心绞痛缓解后aVR导联ST段抬高≥1mm恢复到等电位线。符合这一标准者共计76例住院急性冠脉综合症患者。依冠状动脉造影结果,分析左主干病变特点和其他冠状动脉病变特征。目测狭窄程度≥70%,为严重左主干狭窄病变。结果 单纯左主干严重狭窄54例(54/76, 71.1%),左主干病变 前降支近端近开口病变6例(6/76,7.9%);单纯左回旋支狭窄3例(3/76,3.9%); 其他复杂三支血管病变13例(13/76,17.1%)。冠状动脉正常者为零。左主干严重狭窄患者,aVR导联ST段抬高比非左主干患者更明显(0.25±0.10mV vs 0. 20±0.11mV, P<0.001); ST段压低导联多见于II III aVF和V3-V6导联,左主干严重狭窄患者,ST压低导联ST段压低程度比非左主干患者更明显(p<0.001)。这一特点诊断左主干严重狭窄的敏感性为72.7%, 假阳性54.4%,特异性45.4%,符合率61.9%。     

巨大Epsilon波致心律失常性右室心肌病临床和心电图特点

目的总结心电图表现为巨大Epsilon波致心律失常右室心肌病(ARVC)患者的临床和心电图特点。方法分析本院于2011年1月至2014年12月收治的12导联心电图示巨大Epsilon波ARVC患者的临床和心电图特点。通过查询Medline、CNKI、VIP和万方数据库等总结该心电图特征ARVC患者的特点。结果 5例患者中男性4例。首发症状均为心悸、头昏。发作时心电图为右室起源室性心动过速。心脏超声示右室扩大;右室壁变薄,可见小凹。心电图V_1导联QRS呈"M"型;巨大Epsilon波振幅为(0.37±0.16)mV,振幅与S波比值为1.20±0.23;持续时间为(90±12.75)ms,持续时间与QRS波相比为0.60±0.06。文献报道5例患者均为男性。临床表现为心悸,晕厥发作。心电图V_1导联QRS均呈rsR′,Fontain导联、心向量和晚电位证实该R′波为Epsilon波。V_1导联Epsilon波振幅为(0.52±0.35)mV,振幅与S波比值为1.18±0.74;持续时间(96.0±11.4)ms,持续时间与QRS波相比为0.65±0.08。结论临床上巨大Epsilon波ARVC患者少见,右室激动延缓,心律失常发生率高。     

起源于三尖瓣环非间隔部位的房性心动过速体表心电图特点及射频消融治疗

目的报道起源于三尖瓣环非间隔部位的房性心动过速(简称房速)体表心电图特点及射频消融结果。方法13例房速均被证实起源于三尖瓣环非间隔部位并射频消融成功。影像学消融靶点位于三尖瓣环,局部电图可见A波和V波,且A∶V<2,V波的振幅>0.5 mV。结果9例消融成功部位位于三尖瓣环下侧壁,4例位于三尖瓣环上侧壁,靶点局部A波激动时间领先体表心电图P波起点41±15 ms,AV比值0.5±0.4。三尖瓣环下侧壁起源的房速P波特点:Ⅰ、aVL、aVR导联P波正向,Ⅱ、Ⅲ、aVF导联P波负向,V1～V6导联P波负向。三尖瓣环上侧壁起源的房速P波特点:Ⅰ、aVL导联P波正向,aVR导联P波负向或呈等电位线,Ⅱ、Ⅲ、aVF导联P波低幅正向波或呈等电位线,V1导联负向,胸前导联由右向左P波逐渐移行为正向。结论三尖瓣环非间隔部位是右房房速的一个重要起源点,其体表心电图有明确特征。     

26例致心律失常右室心肌病的临床和心电图特点分析

目的:探讨致心律失常右室心肌病(ARVC)的临床和心电图特点。方法:收集、查阅1993～2003年 上海市中山医院心内科26例诊断为ARVC的入院病例资料,分析其窦性心律和(或)室性心动过速发作时的常 规体表心电图各项参数,并作统计分析。结果:26例ARVC病例中,入院年龄为13～70(37.7±15.1)岁,首发症 状年龄为8～55(33.2±13.9)岁;13例(50%)有晕厥发作史。25例常规心电图检查中有11例(44.0%)发现Ep silon波,多见于右侧胸导联(V1～3),部分病例可出现于Ⅱ、Ⅲ和aVF导联,其中1例在大多数导联上均可见Epsi lon波;8例(33.3%)右侧胸导联可见T波倒置。右侧胸导联的平均QRS间期(QRS1=V1+V2+V3间期的平 均值)为0.1～0.22(0.13±0.030)s,左侧胸导联的平均QRS时间(QRS2=V4+V5+V6间期的平均值)为0.08 ～0.18(0.11±0.02)s(P<0.01),QRS1/QRS2为1.2±0.2(1.0～1.9),其中16例(61.5%)两者之比≥1.2。4 例出现肢体导联低电压,3例出现完全性右束支传导阻滞,类右束支、左前分支、左后分支和室内传导阻滞各1 例,1例在aVF导联出现显著的T波电交替。结论:心电图中Epsilon波和右胸导联QRS间期延长,有助于诊断 ARVC。     

经皮球囊二尖瓣成形术治疗风湿性心脏病二尖瓣狭窄对P波离散度的影响

目的 探讨经皮球囊二尖瓣成形术(PBMV)治疗风湿性心脏病二尖瓣狭窄对P波离散度的影响.方法选择风湿性心脏病二尖瓣狭窄并成功行PBMV术患者.术前窦性心律,术后维持窦性心律6个月以上,共95例,男21例,女74例,年龄18～57岁(37.5±7.9岁).所有患者均测量PBMV前、后12导联同步心电图P波宽度,计算最宽P波(P_(max))、最窄P波(P_(min))并取两者差的平均值,即为P波离散度(Pd),Pd=P_(max)-P_(min)(最大P波宽度-最小P波宽度);所有患者均测量PBMV前、后心电图Ⅱ导联P波高度;所有患者均测量PBMV前、后心电图V_1导联测得的心房终东电压(Ptf-V_1).结果 PBMV术前、术后患者,年龄、心率、左室舒张期内径、右室舒张期内径和左室射血分数(EF)无统计学差异.PBMV术后左房内径(41.86±5.46mm)比术前(44.48±5.60mm)显著缩小(P<0.01);术后P_(max)(113.33±14.92ms)比术前P_(max)(116.85±15.68ms)显著缩小(P<0.01);术后Pd(29.05±14.56ms)比术前Pd(32.83±12.87ms)显著缩小(P<0.05);术后P波高(0.14±0.05mV)比术前(0.18±0.07mV)显著缩小(P<0.01);术后Ptf-V_1(-0.020±0.019mm·s)比术前(-0.037±0.033mm·s)显著缩小(P<0.01).结论PBMV对心房间的传导的时间及振幅有明显作用,应用这些无创性电生理指标对判定PBMV的预后可能会有一     

正常人与右室肥大患者的U波特征

对100例正常人(NP)、60例右室肥大(RVH)、30例单纯性右束支传导阻滞(RBBB)和35例RVH伴RBBB患者的U波进行分析。发现NP组U波特点:1.除aVR导联外U波均直立;2.U波振幅范围-0.02-0.12mV:3.U波时限0.17±0.02s(0.14-0.22s);4.U波外形起始部较快速、终末部较缓慢;5.Ta-Ua间期0.19±0.02s(0.16-0.24s)。而RVH、RVH+RBBB组Ⅰ、aVL、V_5导联U波振幅较NP组高,V_1、aVR导联较NP组低或倒置加深(P<0.05-0.01)。其中V_1导联U波倒置和V_5导联U波≥0.04mV与RVH有较好的相关性。但RBBB组除V_1导联U波振幅外各参数与NP组无明显差异(P>0.05)。提出U波与机械-电反馈作用相关。     

心电图对右心室流出道室性早搏消融结果的预测价值

目的 了解体表心电图对右心室流出道室性早搏(室早)消融结果的预测价值.方法 收集2002年1月～2007年3月室性早搏发作时心电图V1导联QRS波均呈左束支阻滞(LBBB)形态的无明显器质性心脏病患者72例,按射频消融治疗结果分为成功组和对照组,其中成功组63例,对照组9例(失败4例、复发5例),分析两组体表心电图12导联R波幅度、R波时限、S波时限、QRS时限,V2导联R波时限占QRS时限的百分比、胸前导联R波移行导联、V1导联R/S的比值、V1导联R波缺失、aVL和aVR比例(Qs或rS幅度)、I导联R波单相、I和aVL导联Qs波以及起搏时12导联心电图与自然发作室早心电图图形相同的导联数,比较两组患者心电图的特点.结果 胸前导联移行导联在≥V3成功率较高,≤V2很难成功(P=0.002),V1导联R波缺失预示成功率高(P=0.011),V2导联R波时限占QRS时限的百分比大于30%更易成功(P=0.025),两组体表心电图的aVL:aVR(QS或rS的幅度比),aVL导联Qs形态和起搏时12导联心电图与自然发作室早心电图图形相同的导联数有显著差异性(P《0.05),12导联R波幅度、R波时限、S波时限、QRS时限等参数中仅Ⅱ导联的S波时限有显著性差异(P=0.027),其他指标未达到统计学意义(P》0.05).结论 术前分析心电图有助于临床医生选择合适室早患者作为消融对象,以降低失败风险,提高成功率.     

Effect of limb lead electrodes location on ECG and localization of idiopathic outflow tract tachycardia: a prospective study

Role of ECG in Localization of OT‐VT. Background: Different kinds of the surface ECG limb electrode positions may affect the limb lead vector and therefore the accuracy of the 12‐lead ECG in localization of outflow tract ventricular tachycardia (OTVT). This study was intended to evaluate and compare the accuracy of the standard and the modified 12‐lead ECG for localization of OTVT using the current published criteria. Methods and Results: Twenty consecutive patients (10 men, mean age, 51.6 ± 13.4 years) with OT‐VT were included. A standard ECG with the distal placement of the limb lead electrodes and a modified ECG with the limb electrodes placed on the torso were recorded during the OT‐VT and were used for localization by 2 electrophysiologists who were blinded to the successful ablation site to compare the accuracy of the 2 ECGs. The R wave amplitude during OT‐VT in lead I of the standard 12‐lead ECG was significantly higher compared to the modified surface ECG (0.225 ± 0.145 mV vs 0.139 ± 0.111 mV, P = 0.032). The S wave in aVR during OT‐VT was significantly more negative compared to the modified surface ECG (?0.682 ± 0.182 mV vs ?0.527 ± 0.228 mV, P = 0.017). The rate of accurate localization of the successful ablation sites in the anterior versus posterior outflow tract by the 2 observers using standard ECG (70% and 80%) were higher compared to modified ECG (50% and 60%, P = 0.042). Conclusion: The R wave amplitude in lead I and the depth of the S wave amplitude in lead aVR of the standard surface ECG during OT‐VT is significantly larger compared to the modified surface ECG. As the QRS morphology of the OT‐VT is usually the first clue to the possible site of successful ablation, the standard 12‐lead ECG should be used for more accurate localization of the origin of the OT‐VT. (J Cardiovasc Electrophysiol, Vol. 22, pp. 886‐891, August 2011)     

经CT定位不同部位间隔起搏的心电图特征分析

目的 探讨不同间隔部位起搏的体表心电图特征.方法 观察31例永久性心脏起搏器间隔起搏患者体表心电图特征,使用64排双源CT精确定位起搏导线在间隔部的具体位置,比较不同位置间隔起搏的心电图参数变化.结果 ①仅根据X线植入的起搏导线,起搏导线误置于前壁的占12.9%.②前壁起搏的QRS间期（148±19）ms,宽于高位间隔起搏QRS间期（118±24）ms（P＜0.05）.③中位间隔起搏QRS波群移行6.00±0.76,晚于高位间隔（4.13±1.56）和低位间隔（3.75±2.99）（均P＜0.05）.④高位间隔起搏RIII（1.11±0.70）mV,大于低位间隔起搏RⅢ（0.038±0.075）mV（P＜0.05）.⑤高位间隔起搏（46.7%）及中位间隔起搏（37.3%）I出现q波或QS的比例有多于前壁起搏的趋势.结论经CT定位不同部位间隔起搏的体表心电图存在明显不同,一些参数有助于判断导线位置.     

Value of lead aVR in the detection of significant left main coronary artery stenosis in acute coronary syndrome

BACKGROUND: Electrocardiographic lead aVR is usually ignored in patients with chest pain. ST segment elevation in aVR may have diagnostic value in patients with acute coronary syndrome (ACS) and significant stenosis or obstruction of the left main coronary artery (LMCAS), especially when accompanied by ST segment elevation in lead V(1). AIM: To asses the value of lead aVR and V1 for the detection of LMCAS in patients with ACS. METHODS: The study group consisted of 150 patients (mean age 60.6+/-9.5 years, range 33-78 years) with ACS, including 46 with LMCAS and 104 without LMCAS. ECG recordings obtained on admission were compared between these two groups. RESULTS: In patients with LMCAS, ST segment elevation in lead aVR was two times more frequent than in remaining patients (69.6% vs 34.6% p=0.0001) whereas there were no differences in lead V(1). Sensitivity of ST elevation in aVR in detection of LMCAS was 69.6%, specificity - 65.4%, positive predictive value - 47.1%, and negative predictive value - 82.9%. In patients with LMCAS, ST segment depression was significantly more often present in ECG leads other than aVR (45.6% vs 23.1% p<0.01). Patients with LMCAS more often had hypertension (95.6% vs 77.9% p<0.05) and three-vessel disease (78.3% vs 31.8%, p<0.0001). CONCLUSIONS: The assessment of lead aVR in patients with ACS may indicate LMCAS. Additional analysis of lead V(1) does not improve diagnostic accuracy.     

术中预防性应用艾司洛尔对高龄心肌缺血患者的心肌保护作用

目的研究术中预防性应用艾司洛尔对高龄心肌缺血患者的心肌保护作用。方法选取年龄75岁以上,符合美国麻醉医师协会(ASA)分级Ⅱ～Ⅳ级,拟于全身麻醉下行全髋关节置换术、股骨头置换术或股骨颈骨折切开/闭合复位内固定手术的心肌缺血患者30例,完全随机法分为观察组和对照组各15例。分别记录患者入手术室后、静脉泵注艾司洛尔后、神经阻滞后、诱导后、气管插管后、拔管后的心率(HR)、收缩压(SBP)、舒张压(DBP)、平均动脉压(MBP)、心率-收缩压乘积(RPP)、心电图ST段变化及心肌缺血发生率。结果观察组诱导、插管、拔管后HR[(66±7)次/min,(67±8)次/min,(70±16)次/min]明显低于相同时点对照组[(78±8)次/min,(73±10)次/min,(97±12)次/min,均为P<0.05];在麻醉期间(T1～5)观察组RPP(10 279±1833,8188±869,6970±805,6659±1420,9141±1763)均明显低于对照组(12 198±1825,9336±671,8598±1473,8091±1757,10 082±1396,均为P<0.05)。观察组心肌缺血发生率及持续时间、麻醉中尼卡地平总用量[0.07%,(90±0)min,(1.00±1.53)mg]均明显小于对照组[20.0%,(233±91)min,(2.00±1.52)mg,均为P<0.05]。麻醉结束时观察组ST段下移值明显低于患者入手术室时基础值[(-0.04±0.02)mV比(-0.08±0.05)mV,P<0.05],而对照组ST段较前差异无统计学意义[(-0.04±0.03)mV比(-0.03±0.02)mV,P>0.05]。结论术中预防性应用艾司洛尔可降低高龄心肌缺血患者全身麻醉时的心肌氧耗及心肌缺血发生率。     

aVR T波形态在评估急性冠状动脉综合征三支病变患者左心功能中的意义

目的 研究急性冠状动脉综合征(ACS)三支病变患者心电图aVR导联T波形态预测左心功能变化的意义.方法 160名冠状动脉造影明确的ACS三支病变患者按照入院心电图aVR导联T波形态分为T波直立组(72例)和T波倒置组(88例),比较两组一般资料、左心功能、冠状动脉病变及临床结局情况.结果 与T波倒置组比较,T波直立组左...     

Prediction of acute left main coronary artery obstruction by 12-lead electrocardiography. ST segment elevation in lead aVR with less ST segment elevation in lead V(1).

OBJECTIVES: We sought to determine the electrocardiographic (ECG) features associated with acute left main coronary artery (LMCA) obstruction. BACKGROUND: Prediction of LMCA obstruction is important with regard to selecting the appropriate treatment strategy, because acute LMCA obstruction usually causes severe hemodynamic deterioration, resulting in a less favorable prognosis. METHODS: We studied the admission 12-lead ECGs in 16 consecutive patients with acute LMCA obstruction (LMCA group), 46 patients with acute left anterior descending coronary artery (LAD) obstruction (LAD group) and 24 patients with acute right coronary artery (RCA) obstruction (RCA group). RESULTS: Lead aVR ST segment elevation (>0.05 mV) occurred with a significantly higher incidence in the LMCA group (88% [14/16]) than in the LAD (43% [20/46]) or RCA (8% [2/24]) groups. Lead aVR ST segment elevation was significantly higher in the LMCA group (0.16 +/- 0.13 mV) than in the LAD group (0.04 +/- 0.10 mV). Lead V(1) ST segment elevation was lower in the LMCA group (0.00 +/- 0.21 mV) than in the LAD group (0.14 +/- 0.11 mV). The finding of lead aVR ST segment elevation greater than or equal to lead V(1) ST segment elevation distinguished the LMCA group from the LAD group, with 81% sensitivity, 80% specificity and 81% accuracy. A ST segment shift in lead aVR and the inferior leads distinguished the LMCA group from the RCA group. In acute LMCA obstruction, death occurred more frequently in patients with higher ST segment elevation in lead aVR than in those with less severe elevation. CONCLUSIONS: Lead aVR ST segment elevation with less ST segment elevation in lead V(1) is an important predictor of acute LMCA obstruction. In acute LMCA obstruction, lead aVR ST segment elevation also contributes to predicting a patient's clinical outcome.     

aVR导联S T段抬高预测非S T段抬高型急性心肌梗死的临床价值

目的：探讨aVR导联ST段抬高对非ST段抬高型急性心肌梗死的预测价值。方法选取27例心电图改变为ST段压低≥0．1 mV伴aVR导联ST段抬高者作为观察组,另选50例ST段压低≥0．1 mV但不伴aVR导联ST段抬高者作为对照组,追踪观察2组非ST段抬高型急性心肌梗死的发生率。结果临床确诊为非 ST 段抬高型心肌梗死者观察组为7例（25．9％）,对照组为1例（2％）;2组比较差异有统计学意义（P＜0．05）。结论 aVR导联ST段抬高对非ST段抬高型急性心肌梗死具有一定的预测价值,临床应给予重视。     

Prognostic Significance of T‐Wave Amplitude in Lead aVR on the Admission Electrocardiography in Patients with Anterior Wall ST‐Elevation Myocardial Infarction Treated by Primary Percutaneous Intervention

Background: T‐wave positivity in aVR lead patients with heart failure and anterior wall old ST‐segment elevation myocardial infarction (STEMI) are shown to have a higher frequency of cardiovascular mortality, although the effects on patients with STEMI treated with primary percutaneous coronary intervention (PCI) has not been investigated. In this study, we sought to determine the prognostic value of T wave in lead aVR on admission electrocardiography (ECG) for in‐hospital mortality in patients with anterior wall STEMI treated with primary PCI. Methods: After exclusion, 169 consecutive patients with anterior wall STEMI (mean age: 55 ± 12.9 years; 145 men) undergoing primary PCI were prospectively enrolled in this study. Patients were classified as a T‐wave positive (n = 53, group 1) or T‐wave negative (n = 116, group 2) in aVR based upon the admission ECG. All patients were evaluated with respect to clinical features, primary PCI findings, and in‐hospital clinical results. Results: T‐wave positive patients who received primary PCI were older, multivessel disease was significantly more frequent and the duration of the patient's hospital stay was longer than T‐wave negative patients. In‐hospital mortality tended to be higher in the group 1 when compared with group 2 (7.5% vs 1.7% respectively, P = 0.05). After adjusting the baseline characteristics, positive T wave remained an independent predictor of in hospital mortality (odds ratio: 4.41; 95% confidence interval 1.2–22.1, P = 0.05). Conclusions: T‐wave positivity in lead aVR among patients with an anterior wall STEMI treated with primary PCI is associated with an increase in hospital cardiovascular mortality.     

Electrocardiographic and electrophysiologic characteristics of ventricular tachycardia originating within the pulmonary artery

OBJECTIVES: We investigated the electrocardiographic (ECG) and electrophysiologic characteristics of ventricular tachycardia (VT) originating within the pulmonary artery (PA). BACKGROUND: Radiofrequency catheter ablation (RFCA) is routinely applied to the endocardial surface of the right ventricular outflow tract (RVOT) in patients with idiopathic VT of left bundle branch block morphology. It was recently reported that this arrhythmia may originate within the PA. METHODS: Activation mapping and ECG analysis were performed in 24 patients whose VTs or ventricular premature contractions (VPCs) were successfully ablated within the PA (PA group) and in 48 patients whose VTs or VPCs were successfully ablated from the endocardial surface of the RVOT (RV-end-OT group). RESULTS: R-wave amplitudes on inferior ECG leads, aVL/aVR ratio of Q-wave amplitude, and R/S ratio on lead V(2) were significantly larger in the PA group than in the RV-end-OT group. On intracardiac electrograms, atrial potentials were more frequently recorded in the PA group than in the RV-end-OT group (58% vs. 12%; p < 0.01). The amplitude of local ventricular potentials recorded during sinus rhythm within the PA was significantly lower than that recorded from the RV-end-OT (0.62 +/- 0.56 mV vs. 1.55 +/- 0.88 mV; p < 0.01). CONCLUSIONS: Ventricular tachycardia originating within the PA has different electrocardiographic and electrophysiologic characteristics from that originating from the RV-end-OT. When mapping the RVOT area, the catheter may be located within the PA if a low-voltage atrial or local ventricular potential of <1-mV amplitude is recorded. Heightened attention must be paid if RFCA is required within the PA.     

aVR 导联对急性心肌梗死中左主干病变的诊断意义

目的：通过分析急性心肌梗死患者12导联心电图,探讨心电图对左主干病变的诊断意义。方法对急性心肌梗死并行冠脉造影术的4914例患者进行分层随机抽样,根据造影结果,将样本分为左主干病变组及非左主干病变组。记录两组一般临床资料,盲法测量两组心电图,对比两组得出预测左主干病变的指标。结果二元 logistic 回归分析表明,aVR 导联 ST 段抬高≥0．05 mV（OR：8．160,P ＜0．05）是左主干病变的独立预测因子。联合 aVR 导联ST 段抬高≥0．05 mV、V4～V6导联 ST 段压低、≥5个导联 ST 段压低、aVF 导联低电压、QRS 波群时限＞100 ms 这5个无创性指标,可将确诊左主干病变的概率从25．19％提高到69．24％。5个心电图指标的阳性预测值分别为52．63％、32．73％、26．39％、16．22％和22．22％。结论心电图对急性心肌梗死中左主干病变的预测是可行的。aVR 导联 ST 段抬高≥0．05 mV 是预测左主干病变良好的心电图指标,联合多指标可提高心电图对左主干病变的诊断价值。