Mohanan Nair Krishna Kumar, Thajudeen Anees, Namboodiri Narayanan, Valaparambil Ajitkumar
Department of Cardiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum -11, Kerala, India.
Department of Cardiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum -11, Kerala, India.
Indian Pacing Electrophysiol J. 2017 Mar-Apr;17(2):58-62. doi: 10.1016/j.ipej.2017.01.004. Epub 2017 Jan 20.
A 30year old patient presented to us with recurrent episodes of palpitation and documented tachycardia. In all his presentations a wide QRS tachycardia was recorded. The baseline ECG showed pre excitation. The 12 lead ECG of the tachycardia and the baseline ECG is shown in Fig. 1A. During EP study the patient had baseline pre excitation and the HV interval was 16 ms. A duo-decapolar halo (HL) catheter was used to map right atrium and a decapolar coronary sinus (CS) catheter was used to map coronary sinus. In addition a His bundle and right ventricular (RV) quadripolar catheters were used. The delta wave morphology was suggestive of a posteroseptal pathway. Ventricular pacing from RV apex showing central decremental conduction with ventriculo-atrial Wenkebach at 290 ms. Ventricular extrastimulation also showed decremental conduction and VA block at S1 S2 of 400,240. The intra cardiac recording of tachycardia and its initiation is shown in Fig. 1B. Pacing from lateral RA (HL 5, 6 electrodes) showed progressive pre excitation with extrastimulation and induction of tachycardia. The QRS morphology was same as the patient's clinical tachycardia and the tachycardia cycle length (TCL) was 304 ms. An atrial entrainment protocol showed entrainment with the same QRS morphology while pacing from right atrium. The VA interval of the first return cycle was the same as the subsequent VA intervals. A ventricular entrainment protocol showed V-A-V response and post pacing interval of 414 ms. An atrial extra systole was given from the mid CS electrodes (CS 5, 6) - the effect is shown in Fig. 3. In sinus rhythm a parahisian pacing manoeuvre was done as shown in Fig. 4A. What is the mechanism of the tachycardia and what are the pathways involved?
一名30岁患者因反复发作心悸且记录到心动过速前来就诊。在他所有的发病情况中，均记录到宽QRS心动过速。基线心电图显示预激。心动过速的12导联心电图和基线心电图见图1A。在电生理研究期间，患者有基线预激，HV间期为16毫秒。使用双极十极环状（HL）导管标测右心房，使用十极冠状窦（CS）导管标测冠状窦。此外，还使用了希氏束和右心室（RV）四极导管。δ波形态提示为后间隔旁道。从右心室心尖部进行心室起搏显示，在290毫秒时出现中心递减传导及室房文氏现象。心室期外刺激在S1S2为400、240时也显示递减传导及室房阻滞。心动过速及其起始的心内记录见图1B。从右心房外侧（HL 5、6电极）起搏显示，期外刺激时预激逐渐加重并诱发心动过速。QRS形态与患者临床心动过速相同，心动过速周期长度（TCL）为304毫秒。心房拖带方案显示，从右心房起搏时拖带且QRS形态相同。第一个回波周期的室房间期与随后的室房间期相同。心室拖带方案显示V-A-V反应，起搏后间期为414毫秒。从中部冠状窦电极（CS 5、6）给予心房期前收缩——其效应见图3。在窦性心律时，进行了如图4A所示的希氏束旁起搏操作。心动过速的机制是什么，涉及哪些旁道？
