Negative participation of the left posterior fascicle in the reentry circuit of verapamil-sensitive idiopathic left ventricular tachycardia

Left posterior fascicle and idiopathic Left VT. The left posterior fascicle may be a bystander of the circuit of verapamil-sensitive idiopathic left ventricular tachycardia. During ventricular tachycardia (VT), 3 sequences of potentials were seen at the left posterior septum: diastolic Purkinje potentials propagating from base to apex and presystolic left posterior fascicular potentials and systolic left ventricular (LV) myocardial potentials propagating in the reverse direction. Selective capture of the left posterior fascicle by the sinus beat did not affect the VT cycle length. Entrainment pacing revealed that the retrograde limb of the circuit was not the left posterior fascicle, but the LV myocardium.     

Demonstration of the reentrant circuit of verapamil-sensitive idiopathic left ventricular tachycardia: direct evidence for macroreentry as the underlying mechanism

The exact reentrant circuit of verapamil-sensitive idiopathic left ventricular tachycardia (ILVT) remains unclear. This case report demonstrates the reentrant circuit of ILVT. A 20-pole electrode catheter was placed along the left posterior fascicle during electrophysiologic study. ILVT was reproducibly induced by programmed ventricular stimulation. During the tachycardia, sequential diastolic potentials bridging the entire diastolic period were observed in the recordings from the electrodes positioned from left ventricular mid-septum to inferoapical septum. The slow conduction zone appeared to be composed of a false tendon in this patient. Entrainment of the ILVT from the right ventricular outflow tract at a different pacing cycle length revealed that a dominant conduction delay occurred at the proximal site of the slow conduction zone. Entrainment studies from several sites on the left ventricular septum confirmed that these sites where sequential electrical activity was recorded were included within the reentrant circuit. However, the left posterior fascicle itself seemed to be a bystander. This report provides the direct evidence of macroreentry as the underlying mechanism of this ILVT, adjacent to the left posterior fascicle.     

Identification of an epicardial slow conduction channel using ripple mapping in ablation of postinfarct ventricular tachycardia

An 82‐year‐old man underwent redo catheter ablation of ventricular tachycardia (VT) after anterior infarction. A ripple mapping conducting channel (RMCC) was identified within the anterior scar in the left ventricular epicardium during sinus rhythm. Along the RMCC, delayed potentials during sinus rhythm, a good pace map with a long stimulus to the QRS interval, and mid‐diastolic potentials during VT were recorded, and epicardial ablation at this site eliminated the VT. These findings suggested that the RMCC in the epicardial scar served as a critical isthmus of the postinfarct VT, and ablation targeting the RMCC was effective.     

Quantitative analysis of the duration of slow conduction in the reentrant circuit of ventricular tachycardia after myocardial infarction

Background: Few data are available to define the circuits in ventricular tachycardia (VT) after myocardial infarction and the conduction time (CT) through the zone of slow conduction (SCZ). This study assessed the CT of the SCZ and identified different reentrant circuits. Methods: During VTs, concealed entrainment (CE) was attempted. The SCZ was identified by a difference between postpacing interval (PPI) and VT cycle length (VTcl) ≤30 ms. Since the CT in the normally conducting part of the VT circuit is constant during VT and CE, a CE site within the reentrant circuit with (S‐QRS)/PPI ≥ 50% was classified as an inner reentry in which the entire circuit was within the scar, and a CE site with (S‐QRS)/PPI < 50% as a common reentry in which part of the circuit was within the scar and part out of the scar. Results: CE was achieved in 20 VTs (12 patients). Six VTs (30%) with a (S‐QRS)/PPI ≥50% were classified as inner reentry and 14 VTs (70%) with a (S‐QRS)/PPI <50% during CE mapping as common reentry. The EG‐QRS interval (308 ± 73 ms vs 109 ± 59 ms, P < 0.0001) was significantly longer and the incidence of systolic potentials higher (4/6 vs 0/12, P < 0.001) in the inner reentry group. For the 14 VTs with a common reetry, the CT of the SCZ was 348 ± 73 ms, while the CT in the normal area was 135 ± 50 ms. Conclusion: According to the proposed classification, 30% of VTs after myocardial infarction had an entire reentrant circuit within the scar. In VTs with a common reentrant circuit, the CT of the SCZ is approximately four times longer than the CT in the normal area, accounting for more than 70% of VTcl.     

窦性心律下非接触式标测指导线性消融治疗特发性左心室室性心动过速

目的 大多数特发性左心室室性心动过速(ILVT)是起源于左后分支(LPF)浦肯野纤维网的折返性心动过速,因而利用非接触式标测系统在窦性心律下标测LPF并经其导航系统指导线性消融治疗ILVT是可行的,现介绍此方法的安全性和有效性。方法 6例患者,1例既往接受3次射频导管消融术,临床呈无休止发作;1例为常规消融术后1个月复发;4例为常规首次接受射频导管消融术患者。其中男性5例,女性1例,平均年龄15～58(34.00±16.26)岁。常规电生理检查明确ILVT诊断后,将球囊电极导管经股动脉逆行送入至左心室心尖部,构建几何构形后建立窦性心律的等电位图。结果 窦性冲动沿希氏束向下传导,在间隔中部不到心尖处激动局部间隔心肌并很快激动整个左心室。局部虚拟电图显示,在间隔部激动的每个QRS波前均有高频、低幅的电位,该电位与QRS波之间的距离随激动的推移而逐渐缩短;心室激动爆发点处的局部电图呈QS型。在心室激动爆发点上方1 cm处于LPF区域作垂直于LPF激动方向的线性消融,消融后所有患者均出现不同程度的左后分支阻滞图形,线性消融的平均放电次数为4～8(5.66±1.50)次,消融完毕后心动过速均不能诱发。平均随访7～13(10.00±2.76)个月,所有患者均无心动过速复发。结论 窦性心律下标测LPF并指导线性消融治疗ILVT不仅安全有效     

左室特发性室性心动过速常规方法消融困难的线性消融

目的:探讨在常规方法消融困难的左室特发性室性心动过速（ILVT）患者中室间隔左室面线性消融的有效性。方法: 18例术中不能诱发持续性心动过速或发作时不能耐受患者,进行室间隔左室面心尖到心底部连线的前1/3～1/2区域,在窦性心律下首先标到蒲肯野氏纤维电位（PP）,向下至室间隔与左室下壁交界、向上至前后间隔中线进行线性消融,术后门诊或电话随访。结果: 所有患者术后即刻均未能诱发出ILVT。随访3~35（23±13）个月,3例/18例（17%）复发,远期成功率达83%,无1例发生永久性的并发症。结论: 对于术中不能诱发持续性心动过速或发作时不能耐受的ILVT患者,室间隔左室面线性消融安全有效,可以作为补救性消融措施。     

Mechanism of ventricular tachycardia in a patient with double-outlet left ventricle

We report the case of ventricular tachycardia (VT) ablation procedure in a patient with history of surgically repaired double-outlet left ventricle. The electrophysiology procedure revealed a re-entry pattern between the right-ventricle to main-pulmonary-artery conduit and the tricuspid annulus. The re-entrant mechanism was most likely promoted by a fibrous remodeling of this area, related to the surgical repair. This case is the first to describe a re-entry mechanism between fixed anatomical barriers in a repaired right ventricle of a double-outlet left ventricle. A pace mapping technique was used to highlight the VT isthmus.     

Magnetic electroanatomic mapping of an atrial tachycardia requiring ablation within the coronary sinus

We describe a focal atrial tachycardia (AT) originating from the region of the inferoposterior mitral annulus in which ablation at the site of earliest endocardial activation during AT was unsuccessful. Three-dimensional electroanatomic mapping identified the earliest atrial activation within the coronary sinus. Radiofrequency energy delivered at this site within the CS terminated this tachycardia without any complications, suggesting an origin within the CS. To our knowledge, this is the first time a three-dimensional, high-density activation map of such a tachycardia has been reported.     

Radiofrequency catheter ablation guided by noncontact mapping of ventricular tachycardia originating from an idiopathic left ventricular aneurysm

Idiopathic left ventricular aneurysm and diverticulum is known to be an arrhythmogenic substrate associated to ventricular tachyarrhythmias, generally based on a reentry mechanism. A case of a young woman affected by a monomorphic ventricular tachycardia, refractory to medical treatment, originating from an aneurysm of the membranous interventricular septum is reported. The left ventricular aneurysm was well characterized by multislice computed tomography and left ventricular angiography. Because of the nonsustained and poorly tolerated nature of the target arrhythmia, a noncontact mapping system was used to guide radiofrequency catheter ablation, allowing the elaboration of a three-dimensional activation map of the left ventricle on the basis of a ventricular tachycardia single beat. The procedure was acutely successful, and the patient remained free of ventricular tachycardia recurrences without antiarrhythmic drugs during a subsequent 6-month follow-up period. This is the first report of a successful radiofrequency catheter ablation guided by noncontact mapping system of a ventricular tachycardia originating from an idiopathic left ventricular aneurysm. This nonfluoroscopic mapping method allows a reliable reconstruction of the spatial relationships between the left ventricular main cavity and the aneurysm and can be safely and effectively used to map the ventricular tachycardia and guide the ablation procedure, particularly when conventional mapping is not indicated or not effective because of nonsustained or not-tolerated characters of ventricular tachycardia.     

射频消融左后分支治疗维拉帕米敏感性特发性室性心动过速

目的报道消融左后分支治疗左室特发性室性心动过速(简称室速)。方法对57例维拉帕米敏感性左室特发性室速患者进行电生理检查及射频消融,以窦性心律时产生左后分支阻滞和/或室速不再被诱发作为消融成功终点。结果57例中41例室速诱发条件稳定(71.9%),9例诱发条件不稳定(15.8%),7例不能被诱发(12.3%),所有患者均达消融成功终点。术后全部患者体表心电图Ⅰ导联出现R波降低,S波加深,呈rS形态或RS形态,Ⅱ、Ⅲ、aVF导联出现小q波,或在原有q波基础上加深,R波振幅明显增高,呈qR形态,额面电轴度数显著增加(54.06°±38.24°vs 90.55°±7.88°,P<0.001)。27例出现完全性左后分支阻滞改变(47.4%),30例为不完全性左后分支阻滞(52.6%)。1例1年后室速再发,左后分支阻滞消失,重复消融直至再次出现左后分支阻滞,术后室速未有再发。结论射频消融产生左后分支阻滞可作为左室特发性室速的消融成功终点,尤其适用于不易被常规电生理检查诱发的患者。     

非接触式标测指导特发性左心室室性心动过速的射频消融

目的　虽然采用传统标测技术指导特发性左心室室性心动过速 (idiopathicleftventriculartachycardia ,ILVT)射频消融的效果较满意 ,但临床上仍存在一些疑难或复发病例。为此 ,我们使用非接触式标测技术指导ILVT的射频消融。方法　共 13例患者 ,均为男性 ,平均年龄 (31 0± 14 3)岁 ,其中8例既往共接受 15次射频消融术。将EnSite电极导管置于左心室心尖部以获取心内膜等电位图 ,并使用其导航功能指导消融。结果　 13例患者均诱发并标测到ILVT ,其中 5例起源于室间隔中下部 ;3例起源于心尖部 ;3例起源于室间隔中上部 ,2例起源于主动脉根部。全部ILVT均在EnSite标测到的最早激动处消融成功 ,其中 ,有 9例ILVT在EnSite滤波设置为 8Hz时 ,在心内膜等电位图上最早激动部位可见峡部状狭窄区 ,此处消融均一次成功。仅 3例VT于消融靶点处有浦肯野电位。平均X线暴露时间 (2 6± 12 )min。随访 (13 0± 6 2 )个月 ,1例患者有VT复发 ,但心电图和EnSite标测显示为另一起源 ,再次消融成功。结论　心内非接触式标测技术有望提高ILVT尤其是复杂和疑难病例导管消融治疗的成功率。建议使用 8Hz做为目前版本下ILVT标测的标准滤波参数。     

Human histopathology of electroanatomic mapping after cooled-tip radiofrequency ablation to treat ventricular tachycardia in remote myocardial infarction

INTRODUCTION: Catheter ablation of ventricular tachycardia (VT) in remote myocardial infarction (MI) often requires excessive mapping procedures. Documentation of the electrical substrate via electrogram amplitude may help to identify regions of altered myocardium resembling exit areas of reentrant VTs. METHODS AND RESULTS: A patient with multiple symptomatic monomorphic VTs (biventricular ICD, remote MI) underwent electroanatomic substrate mapping (CARTOtrade mark) for VT ablation. Regions of scar (bipolar electrogram amplitudes or=1.5 mV), and "altered" myocardium (0.5-1.5 mV) were identified. Ablation was directed to regions with "altered" myocardium based on pace map correlation. After ablation the clinical VT did not reoccur. The patient died due to worsening of heart failure 7 days afterward. During postmortal evaluation specified sites of electroanatomic mapping were correlated to histopathological findings. Annotated scar areas were documented to consist of areas with massive fibrosis (>or=80% of mural composition). Ablations were found to span through regions with intermediate fibrosis (21-79%) mapped as "altered" myocardium. Ablation produced transmural coagulation necrosis of mesh-like fibrotic tissue with interspersed remnants of myocardial cells up to a maximum depth of 7.0 mm. Subendocardial intramural bleedings were universal findings 7 days after ablation. CONCLUSIONS: Electroanatomic substrate mapping for VT ablation sufficiently identified regions of scar and normal myocardium. Regions with bipolar electrogram amplitudes between 0.5 and 1.5 mV were found to correlate to areas of "intermediate" fibrosis (21-79%) with only remnant strands of myocardial cells and were identified as target region for ablation. Cooled-tip endocardial radiofrequency ablation lead to transmural coagulation necrosis up to a depth of 7.0 mm.     

Epicardial mapping and radiofrequency catheter ablation of ischemic ventricular tachycardia using a three-dimensional nonfluoroscopic mapping system

Endocardial radiofrequency catheter ablation of ischemic left ventricular tachycardia has been of variable success due to multiple factors. Two such factors include the location of the reentrant circuit in the deep myocardium or on the epicardial surface and the inherent limitations of fluoroscopy as a guide for target localization. We report a patient in whom successful epicardial mapping and radiofrequency catheter ablation of an ischemic left ventricular tachycardia was performed using pericardial access and the CARTO electroanatomic mapping system.     

儿童左心室特发性室性心动过速临床特点及射频消融治疗

目的:观察儿童左心室特发性室性心动过速(idiopathic left ventricular tachycardia ILVT)的临床特征和射频导管消融(radiofrequency catheter ablation RFCA)治疗的效果。方法:56例ILVT患儿行心内电生理检查和RFCA治疗,左心室特发性VT(ILVT)起自间隔部者以最早的P电位处为靶点,左心室流出道VT(LOT)和左前间隔来源的IVT,均以起搏与VT发作时12导联心电图QRS波,形态完全相同处或最早心室激动处为靶点。消融终点为程序刺激或静点异丙肾上腺素室速不被诱发。结果:RF-CA治疗ILVT的成功率为98.2%,复发率为5.5%。IVT起源部位分别位于左心室后间隔部47例,左前间隔3例,左心室流出道6例。结论:ILVT的RFCA成功率高,并发症少。     

电解剖标测消融左室特发性室性心动过速

目的报道三维电解剖标测指导下左室特发性室性心动过速(ILVT)的射频消融方法。方法4例经常规电生理标测消融失败的ILVT患者,应用三维电解剖(CARTO)标测指导确定消融部位。结果4例患者室性心动过速时CARTO标测的V波最早激动点在前中间隔,在此部位消融无效。以左后分支电位标测的最早激动点在左后间隔区域,在此部位消融终止所有ILVT,此成功部位距V波最早记录点1.0~2.0cm。随访1~7个月无复发。结论左后分支及其浦氏纤维是构成折返环的关键部位,也是射频消融的关键部位,并与折返的出口有一定距离。     

射频导管消融特发性左心室流出道室性心动过速

目的 探讨特发性左心室流出道室性心动过速(室速)心电图特点及射频导管消融结果。方法 对5例未发现器质性心脏病的左心室流出道室速患者行12导联心电图、动态心电图、心内电生理检查及射频导管消融治疗。结果5例患者心电图Ⅱ、Ⅲ、aVF导联呈R波；Ⅰ导联呈rs或QS波，振幅大于0．5mV；V1导联呈rs或RS波，胸前导联R波移行发生于V2～V3；aVR和aVL导联呈QS波，3例患者的消融靶点在左冠状窦口内，2例位于主动脉瓣下，随访6个月，无1例复发。结论 左心室流出道室速有特殊心电图表现，射频导管消融是首选的治疗措施。