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规则心律变化背后的机制是什么 来自书心剑律 00:00 04:59 English audio presented by Dr.Ethan（杜先锋） 素材来源： JOSEPHSON AND WELLENS ECG LESSONS Heart Rhythm 2019, 16 (3) :486-488 Let's enjoy the English learning in the EP world！ 病 例 简 介 Brief introduction 患者女性，41岁，既往“突发心悸3年”，每次持续数分钟后可自行停止，近两月来发作较前频繁，心电图如图1所示。 The ECG shown in Figure 1 was recorded in a 41-yearwoman with a 3-year history of palpitations of sudden onset, which lasted a few minutes and terminated spontaneously. The frequency of those episodes had increased during the past 2 months.
Figure 1: 12lead electrocardiogram showing a change from a regular rhythm with a narrow QRS to a much faster regular rhythm with left bundle branch block. Lowvoltage P waves seem to be located between 2 narrow QRS complexes. 1、图1左侧记录的窄QRS波为何种心律？ 1、What kind of narrow QRS rhythm is present on the left side of the recording? 2、图1右侧记录的宽QRS波为何种节律？ 2、What kind of wide QRS rhythm is present on the right? 3、窄QRS波和宽QRS波心律之间是否存在共同的心动过速机制？ 3、Is there a common tachycardia mechanism between the narrow and the wide QRS rhythm? 讨 论 Discussions 1. 房波在心率90次/分的窄QRS波心律时难以识别。P波在Ⅱ、Ⅲ 、aVF导联中，呈负向、窄且低平；在V2-V6导联中，P波似乎位于T波终末。图中未见窦性心律。观察窄QRS波显示：在其末端存在负向房波与前面提及低平的房波极性一致，并精确地位于2个QRS波之间。如果判断正确，房室呈2:1关系。 1. During the narrowQRSrhythm, which has a rate of 90/min, atrial activity is difficult to identify. P waves, which are narrow and low in voltage and negative in leads II, III, aVF, and V2–V6 seem to be present at the end of the T wave. No sinus rhythm is present. Examination of the narrow QRS complexes reveals a negative deflection at their end with the same polarity as the low-voltage atrial deflections described earlier, exactly between 2 QRS complexes. If correct, there are 2 atrial deflections with 1 QRS complex. 2. 在该心电图的中间段，心律变为180次/分的宽QRS波心动过速。其QRS波的宽度为130ms伴左束支传导阻滞（LBBB）图形。心动过速时P波无法识别，但根据QRS波的形态和宽度，提示室上速伴LBBB。 2. In the middle of the tracing, the rhythm changes into a wide QRS tachycardia with a rate of 180/min. The QRS is 130 ms wide and has a left bundle branch block (LBBB) configuration. No P waves can be identified during the tachycardia, but QRS configuration and width suggest a supraventricular tachycardia with LBBB. 3. 结合以上两点的讨论，发现宽QRS波心动过速的频率恰好是窄QRS波的2倍。在窄QRS波心动过速中，房波与QRS波的间期固定。故P波和QRS波之间存在固定的2:1的关系。基于P波的形态，考虑有2种诊断可能： 3. Combining the findings described in 1 and 2, we note that the wide QRS tachycardia has exactly twice the rate of the episode with the narrow QRS. In view of the fixed distance between the atrial deflections and the QRS when the QRS is narrow, we conclude that, at that time, a fixed 2:1 relation between P waves and QRS was present. Two possible diagnoses should be considered in view of the Pwave configuration： A. 低位房速，起源靠近房间隔，先以2:1房室传导，后转变为1:1房室传导伴LBBB。 A. Low atrial tachycardia, with an origin close to the interatrial septum with 2:1 AV conduction to the ventricle changing to 1:1 AV conduction with LBBB. B. 房室结折返性心动过速（AVNRT），先以1:1传导至心房，并以2:1传导至心室，后变为1:1传导至心室伴LBBB。 B. Atrioventricular nodal reentrant tachycardia(AVNRT),initially with 1:1 conduction to the atrium and 2:1 conduction to the ventricle, changing to 1:1 conduction to the ventricle with LBBB. B的可能性较大，因为在窄QRS波心动过速发作时，P波恰好精确位于2个QRS波之间，该诊断在电生理检查中得到了证实（图2）。可见前传His电图与逆传的房波间期为60ms，为典型慢-快AVNRT间期。1:1传导至心室时出现LBBB，可能是因为第3相束支阻滞或是左束支被逆行侵入所致。该患者接受导管射频消融行房室结慢径改良。 Possibility B is favored because of the P location exactly between 2 QRS complexes during the episode with a narrow QRS. That diagnosis was confirmed during electrophysiologic study (Figure 2). Note that the distance between the anterograde Hisbundle electrogram and the retrograde atrial deflection measures 60 ms, a typical time interval in slow/fast AVNRT. The LBBB during 1:1 conduction to the ventricle can be the result of either phase 3 bundle branch block or retrograde invasion into the left bundle branch. Therapy consisted of radiofrequency catheter ablation of the slow AV nodal pathway.
Figure 2. 12lead electrocardiogram with 3 intracardiac registrations, from proximal and distal coronary sinus and His bundle, during the change from a narrow QRS to a wide QRS with doubling in rate. Note that during the 2:1 AV relation, the Hisbundle electrogram is located before the atrial electrogram, indicating impulse formation in the AV node with retrograde conduction to the atrium. 审 校：杜先锋 编 译：傅国华 编 辑：方任远 书心剑律｜心律最前沿 |
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