第18课 罕见的束支传导阻滞

The electrocardiographic(Fig. 1) has been recorded from an asymptomatic 52-year-old woman free from organic heart disease,who was admitted to the outpatient department beacause a routine ECG had pointed out some abnormalities1: ①The QRS axis is at +90°, ②The QRS duration is 0.14 seconds, ③ The QRS configuration in the limb leads is suggestive of BBB, but it is hard to define, on the basis of these leads only, which type of BBB (right or left) is involved2.The wide S waves in leads I and aVL suggest at first glance an RBBB, whereas the QRS morphology in the inferior leads (monophasic R wave with secondary ST-T changes) is more consistent with an LBBB with relative right axis deviation, ④The chest leads further complicate the problem because lead V1 suggests an RBBB, whereas leads V5 and V6 are perfectly consistent with an LBBB, showing a monophasic R wave3, in addition, lead V5 shows ST-segment depression and negative T wave, typical of LBBB. It is worth noting that when the tracing was recorded, the correct placement of precordial electrodes was accurately checked, ⑤ Placement of precordial electrodes of leads V4,V5,and V6 2 intercostals spaces above restores4,in these leads, a QRS configuration suggestive of RBBB:small and relatively wide s waves appear and the T waves become positive.     

T电轴正常范围及与心室肥大,束支传导阻滞关系的初步探讨

为探索T电轴的正常范围及其临床意义,分析60例正常人、31例左束支传导阻滞、26例右束支传导阻滞、29例左心室肥大、18例左束文传导阻滞伴左心室肥大、33例右心室肥大和14例右束支传导阻滞伴右心室肥大患者的心电图T电轴.其结果分别为42.9°±21.9°、141.8°±70.7°、48.0°±31.2°、145.2°±58.6°、36.5°±38.0°、41.8°±22.5°和41.1°±22.0°,其中左束支传导阻滞和左束支传导阻滞伴左心室肥大与正常人T电轴范围差异有非常显著意义(P<0.01),而其余各组与正常人T电轴的差异无显著意义(P>0.05).提示60例正常人T电轴范围0°～±86°可作为正常T电轴的参考值,左束支传导阻滞是引起T电轴异常的原因之一.     

急性心肌梗死心电图误诊为右心室肥大1例

患者男性,48岁。因胸痛、晕厥倒地就诊入院,三年前即开始出现活动后胸闷,休息后可好转,未在意未治疗。入院心电图（图1A）示：窦性心律,频率117次/分。V1导联呈Rs型、V6导联呈rS型。R波电压明显较低,Ⅰ、Ⅱ、Ⅲ导联呈rS型,aVR呈qR型,电轴极度右偏呈无人区电轴。心电图诊断：①窦性心动过速;②右心室肥大。化验室检验：TnT0.997ng/ml,CK-MB32.77ng/ml,肌红蛋白82.3ng/ml。     

全麻诱导期间发生室颤复苏成功一例

患者，女、52岁，体重70千克，因右侧颌下腺肿物拟行肿物切除术。自诉既往无高血压、心脏病史。查体右侧颌下有一2×3cm肿物，与气管无粘连，不影响通气。ECG示：窦性心律，电轴左偏-28度。其他化验检查均呈阴性。术前1日测BP150/90mmHg，术前30分钟肌注鲁米那钠200mg，阿托品0.5mg。入手术室测BP180/95mmHg，     

宽QRS波群心动过速诊断中无人区心电轴的应用价值

宽QRS波群群心动过速的鉴别诊断一直是临床心电图学的一个热点。多数宽QRS波群心动过速是室性心动过速,但也可能是各种室上性心动过速伴     

无人区心电轴在鉴别宽QRS心动过速中的价值

宽QRS心动过速是指QRS宽度〉120ms，频率〉100次的一类心动过速。多见于室性心动过速，也可见于室上性心动过速伴室内差异性传导，或合并束支传导阻滞或预激综合征，是急诊科和心内科医生经常遇到的心律失常。发病急，病情重，需要快速加以鉴别，给出准确判断并及时予以处理。但在临床工作中，常常遇到的问题是各种鉴别诊断程序繁杂，不确定因素较多，快速指导性不够强，无人区心电轴是鉴别宽QRS心动过速的新方法。     

不完全性室内三分支阻滞1例

患者男性,73岁.临床诊断:冠心病.曾发生晕厥3次.12导联同步心电图示:P-P间距0.92s,频率65次/分,P-R间期0.26s,无QRS漏搏,P.v.向下,VS,6向上.R_(Ⅱ、Ⅲ、svF、V1)呈rsr'型,在V5,6导联呈RS 2,R/S < 1,QRS时限0.139,电轴左偏-88°.图1长Ⅱ导联为非同次记录.P-P间距0.69s,频率87次/分.P-R间期0.269,呈2: 1～3: 2下传,QRS时限0.13s,3: 1下传时,第2个下传的R波呈室内差异性传导.心电图诊断:①窦性心律;②不完全性室内三分支阻滞(完全性右束支阻滞,完全性左前分支阻滞,一度左后分支阻滞,频率增快时左后分支呈二度莫氏Ⅱ型阻滞).     

心电轴的测量方法

心电轴一般指的是平均QRS电轴（mean QRS axis）,它是心室除极过程中全部瞬间向量的综合（平均QRS向量）,借以说明心室在除极过程这一总时间内的平均电势方向和强度,它是空间性的,但心电图学中通常所指的是它投影在前额面上的心电轴。因此可以用心电图学中任何两个肢体导联的QRS波群的电压或面积计算出心电轴,一般采用平均心电轴于I导联正（左）侧段之间的角度来表示平均心电轴的偏移方向,除测定QRS波群电轴外,