Thakur R K, Klein G J, Sivaram C A, Zardini M, Schleinkofer D E, Nakagawa H, Yee R, Jackman W M
Arrhythmia Service, University Hospital, London, Canada.
Circulation. 1996 Feb 1;93(3):497-501. doi: 10.1161/01.cir.93.3.497.
Idiopathic left ventricular tachycardia (ILVT) characterized by QRS complexes with right bundle-branch block (RBBB) morphology and left axis deviation is a distinct clinical syndrome that also demonstrates a characteristic response to verapamil and inducibility from the atrium in patients without structural heart disease. A false tendon has been described in the left ventricle in a patient with ILVT in whom surgical resection of the false tendon resulted in cure. We hypothesized that the false tendon is responsible for the genesis of similar ventricular tachycardia (VT) in others.
We performed transthoracic (TTE) and/or transesophageal (TEE) two-dimensional echocardiograms in 15 patients undergoing catheter ablation for ILVT. There were 12 men and 3 women (mean age, 31 +/- 12 years, with average symptom duration of 11 +/- 9 years). The mean VT cycle length was 360 +/- 70 ms, and all had RBBB morphology with left axis deviation. Cardiac chamber sizes, left ventricular wall thickness, and wall motion were normal in all ILVT patients. TTE and/or TEE demonstrated a false tendon extending from the posteroinferior left ventricular free wall to the left ventricular septum in all ILVT patients. The false tendons were thick (> or = 2 mm maximal thickness) in 5 patients and thin (< 2 mm maximal thickness) in 10 patients. We compared ILVT patients with a control group of 671 consecutive patients referred for echocardiography for other reasons. The mean age for the control group was 42 years. A false tendon was seen in the left ventricle in 34 of 671 (5%). In the control group patients with a false tendon, 2 patients had a history of VT (left bundle-branch block morphology) and 1 had ventricular fibrillation. The false tendons in the control patients were also oriented transversely across the ventricular cavity but were somewhat thinner (< 2 mm maximal thickness in 32 of 34 patients). Catheter ablation with the use of radiofrequency and/or direct current applied to the posteroapical septum resulted in cure in 14 of 15 patients.
A false tendon extending from the posteroinferior left ventricle to the septum is a consistent finding in patients with ILVT and probably is responsible for this unique arrhythmia. The mechanism by which the false tendon precipitates tachycardia is speculative, but possibilities include conduction through the false tendon or by producing stretch in the Purkinje fiber network on the interventricular septum.
特发性左心室心动过速（ILVT）以QRS波群呈右束支传导阻滞（RBBB）形态及电轴左偏为特征，是一种独特的临床综合征，在无结构性心脏病的患者中，其对维拉帕米也有特征性反应且可从心房诱发。曾有一名ILVT患者的左心室中发现了一条假腱索，该患者接受假腱索手术切除后得以治愈。我们推测假腱索是其他患者发生类似室性心动过速（VT）的原因。
我们对15例接受ILVT导管消融术的患者进行了经胸（TTE）和/或经食管（TEE）二维超声心动图检查。其中男性12例，女性3例（平均年龄31±12岁，平均症状持续时间11±9年）。VT平均周长为360±70毫秒，所有患者的QRS波群均呈RBBB形态且电轴左偏。所有ILVT患者的心脏腔室大小、左心室壁厚度及室壁运动均正常。TTE和/或TEE显示，所有ILVT患者均有一条假腱索从左心室后壁下份延伸至左心室间隔。5例患者的假腱索较厚（最大厚度≥2毫米），10例患者的假腱索较薄（最大厚度<2毫米）。我们将ILVT患者与671例因其他原因接受超声心动图检查的连续患者组成的对照组进行了比较。对照组的平均年龄为42岁。671例中有34例（5%）在左心室中发现假腱索。在对照组中有假腱索的患者中，2例有VT病史（左束支传导阻滞形态），1例有室颤病史。对照组患者的假腱索也横向穿过心室腔，但稍薄一些（34例中有32例最大厚度<2毫米）。对15例患者中的14例，采用射频和/或直流电对后心尖间隔进行导管消融后治愈。
从左心室后壁下份延伸至间隔的假腱索在ILVT患者中是一个一致的发现，可能是这种独特心律失常的原因。假腱索引发心动过速的机制尚属推测，但可能的机制包括通过假腱索传导或通过使室间隔上的浦肯野纤维网产生牵张。
