Mini-electrodes help identifying hidden slow conduction during ventricular tachycardia substrate ablation

A 69-year-old male with dilated non-ischemic cardiomyopathy and history of sustained monomorphic VT (SMVT) underwent an unsuccessful VT substrate ablation due to the proximity of the earliest activation site to the conduction system. A second attempt was performed using an ablation catheter with mini-electrodes (ME) and multiple extrastimuli to unveil hidden slow conduction (HSC) sites, allowing the performance of a successful ablation. No SMVT was induced thereafter.ME-obtained electrograms permit to accurately localize areas of HSC sites within ventricular tachycardia (VT) substrates. In our case, this allowed safe ablation during sinus rhythm to eliminate the VT substrate.     

Postinfarct ventricular tachycardia substrate: Characterization and ablation of conduction channels using ripple mapping

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Idiopathic fascicular left ventricular tachycardia: Linear ablation lesion strategy for noninducible or nonsustained tachycardia

BACKGROUND: Idiopathic "fascicular" left ventricular tachycardia (IFLVT) is frequently not inducible or nonsustained at the time of planned catheter ablation. The mechanism of the arrhythmia has been suggested to be reentry involving a sizable area of the LV inferior septum extending from base toward the apex. OBJECTIVE: We tested the ability of a series of radiofrequency lesions delivered in a linear fashion to the inferior-mid septum to control ventricular tachycardia not amenable to standard mapping ablation strategies. METHODS: Programmed stimulation both at baseline state and with isoproterenol after heart rate was increased by at least 25% was performed in all patients. The patients included in the study were either non-inducible or only had brief nonsustained VT not amenable to "traditional" mapping. A detailed electroanatomic map of the LV was performed in sinus rhythm. The location of the linear lesion along the inferior septum was guided by the presence of Purkinje potentials, with pacemapping as an additional guide. A linear lesion was placed perpendicular to the long axis of the ventricle approximately midway from the base to the apex in the region of the mid to mid-inferior septum. Radiofrequency lesions were delivered using a 4mm tip catheter at 50 Watts and 52 degrees for 60-90 seconds. RESULTS: Of 122 consecutive patients who underwent ablation of idiopathic VT from 1999 to 2003, 15 had IFLVT based on standard diagnostic criteria. Six of the 15 patients (40%) had nonsustained or no inducible VT in the EP lab. The number of RF lesions ranged from 7 to 15 (mean 9). The length of the effective linear lesion ranged from 1.2 to 2.2 cm (mean 1.7 cm). Development of left posterior fascicular block was noted in two of the six patients. However, despite the absence of development of left posterior fascicular block in the other four patients, no VT or premature ventricular beats could be induced after ablation using the same provocation maneuvers as performed in the baseline state. No spontaneous arrhythmias occurred during follow-up to 16 +/- 8 months (range 6 to 30 months). CONCLUSION: In patients with difficult to induce or nonsustained VT with the typical right bundle branch block pattern and a superiorly directed axis on 12-lead ECG, RF energy ablation delivered in a linear fashion approximately midway to two thirds toward the apex along the mid to inferior septum and perpendicular to the plane of the septum is safe and effective for VT control.     

Minimal and deep sedation during ablation of ventricular tachycardia

Background

Catheter ablation is a curative treatment option for ventricular premature contractions (VPC) and ventricular tachycardia (VT). Procedures require different sedation levels, depending on duration, ablation approach and patient characteristics. The aim of our study was to evaluate feasibility of minimal and deep sedation for ablation of VPC/VT.

Methods

Patients underwent catheter ablation of VPC/VT under minimal or deep sedation. Events of hypotension, hypoxia, bradycardia, procedural complications and VT inducibility were compared between the groups.

Results

120 patients were included. In 42 patients (53.6 ± 17.1 years, 47.6% male) ablation was performed under minimal sedation with midazolam, and in 78 patients (54.2 ± 17.5 years, 67.9% male) ablation was performed under deep sedation with propofol/midazolam. There were significantly fewer patients with idiopathic VT (62.8 vs. 88.1%, p = 0.011) in the deep sedation group, LVEF was significantly lower (47 ± 14.4 vs. 53.1 ± 11.7) and the procedure duration was significantly longer (201.9 ± 85.9 vs. 137.9 ± 98.7). No significant differences in procedural complications or sedation related events (hypotension: 0 vs. 3.8%, p = 0.2, no hypoxia, no bradycardia) were detected.

Conclusions

Minimal sedation and deep sedation are both feasible during VPC/VT ablation procedures. Propofol does not increase complications even in a collective with pre-existing impairment of LVEF. Adequate monitoring and trained personnel should be present.     

Epicardial ablation of syncopal ventricular tachycardia. Utility of the electrocardiogram.

We describe the case of a young man with syncopal ventricular tachycardia, normal left ventricular ejection fraction, normal coronary arteries, and a left ventricular aneurysm. The ECG during tachycardia suggested an epicardial origin. The arrhythmia was successfully treated using a non-surgical transthoracic epicardial approach.     

Intra-coronary guidewire mapping–A novel technique to guide ablation of human ventricular tachycardia

Hypothesis Endocardial catheter ablation of ventricular tachycardia (VT) may fail if originating from epicardial or intramural locations. We hypothesized that mapping could be achieved using an angioplasty guidewire in the coronary circulation, to guide trans-coronary ablation. Methods and results Six patients (2 male), 64 ± 14 years and previously unsuccessful endocardial VT ablation were studied. Using ECG and existing endocardial mapping data, a coronary artery supplying the predicted VT origin was selected. A 0.014-in angioplasty guidewire was advanced into branches of the artery and connected to an amplifier to record unipolar signals against an indifferent electrode within the inferior vena cava. An uninflated angioplasty balloon was advanced over the wire such that only the distal 5 mm was used for mapping. One VT per patient was mapped (CL 348 ± 102.1 ms). Diastolic potentials were recorded from all (77.7 ± 43.8 ms pre-QRS onset) and concealed entrainment demonstrated in 3. Pacemapping during sinus rhythm was used in the remainder due to failure of entrainment (n = 2) or degeneration to VF (n = 1). Following branch identification, cold saline injection causing VT termination was used for further confirmation. Five VTs were ablated using intra-coronary ethanol injection via the central lumen of the inflated over the wire balloon. The other was ablated using radiofrequency energy in a coronary vein adjacent to the target artery, which was too small for an angioplasty balloon. No complications or recurrence of ablated VT was seen over 19 ± 17 months of follow up. Conclusions Intracoronary guidewire mapping is a novel method of electrophysiological epicardial mapping to help guide trans-coronary VT ablation. Supporting Grants: British Heart Foundation Project Grant PG/2001030, London, UK     

Unique preferential conduction within the isolated septal substrate in a patient with ventricular tachycardia complicated with non-ischemic dilated cardiomyopathy

We describe the case of a 67-year-old woman with non-ischemic dilated cardiomyopathy who underwent successful radiofrequency catheter ablation for ventricular tachycardia (VT) originated from the isolated ventricular septal substrate. Pacemapping exhibited either left, identical to clinical VT, or right bundle branch block like wide QRS morphology. Time interval from the stimulus to QRS onset (St-QRS) was prolonged at the center of the substrate, while St-QRS at the border was shortened. Difference in the morphology of pacemapping was dependent on whether or not the pacing stimulus could propagate directly into the right ventricle due to the possible intramural conduction disturbance.     

Endocardial catheter ablation of ventricular tachycardia in patients with ventricular assist devices

BACKGROUND: The outcomes of patients with ventricular assist devices (VADs) who undergo catheter ablation for ventricular tachycardia (VT) have not been reported. OBJECTIVE: The purpose of this study was to assess the feasibility, safety, and efficacy of endocardial VT ablation in patients with VADs. METHODS: We retrospectively reviewed three cases at our institution where endocardial catheter ablation was performed in patients with VADs and incessant VT. RESULTS: Three patients with underlying cardiomyopathies and VADs underwent VT ablation for incessant VT refractory to multiple antiarrhythmic medications. In each case, VT was either eliminated or significantly ameliorated by catheter ablation. No procedure-related complications occurred. The hemodynamic stability afforded by the VAD played an important role in facilitating ablation in two of the cases. CONCLUSION: Catheter ablation for VT in VAD patients appears to be feasible, safe, and effective based on our initial experience. Several technical issues, such as decreases in ventricular volumes that can limit maneuverability of the ablation catheter and potential entrapment of the mapping catheter in the inflow cannula, need to be considered at the time of ablation.     

室性心动过速合并室上性心动过速的射频消融

目的报道7例室性心动过速（VT）合并室上性心动过速（sVT）的射频消融。方法7例患者男6例,女1例,平均年龄（21±9）岁。阵发性心动过速病史（3．7±2．0）年。术中心房和心室刺激诱发VT和SVT,并进行消融。结果7例患者心房或心室刺激能反复诱发和终止VT合并SVT。法洛四联症矫治术后右心室VT合并三尖瓣环峡部依赖性心房扑动（AFL）1例,其余6例均为维拉帕米敏感性左心室特发性室速（ILVT）,分别合并AFL1例,左后间隔旁路参与的顺向型房室折返性心动过速（AVRT）1例,冠状静脉窦口慢旁路参与的顺向型AVRT1例,慢慢型房室结折返性心动过速（AVNRT）1例,左侧游离壁旁路参与的顺向型AVRT2例。7例患者的两种心动过速均成功消融,所有患者消融术后随访2年,无一例VT或SVT复发。结论VT合并SVT并不少见,消融术中应放置必需的心腔内电极导管,完成详细电生理检查,避免漏诊。一次消融应根除两种疾病。     

射频消融治疗特发性室性心动过速疗效观察

目的 :评价射频消融术治疗特发性室性心动过速 (室速 )临床疗效。方法 :5 6例特发性室速患者中 ,34例左室特发性室速采用EPT小、中弯大头导管 (或Webstr小弯大头 ) ,在左室行激动顺序标测和消融 ,以P电位较QRS起点提前 2 0ms以上作为消融靶点。 2 2例右室流出道室速采用Webster加硬导管在右室流出道行起搏标测 ,以起搏时与心动过速时体表 12导联QRS形态完全相同或最接近处为消融靶点 ,成功标准为放电过程中心动过速终止且不能诱发。结果 :5 1例患者消融成功 ,成功率 91.1%。 34例左室特发性室速中 30例靶点位于左室间隔中下部 ,2例近左室心尖 ,1例左室流出道 ,1例位于间隔高位。 31例消融成功 ,1例失败 ,2例因导管到达间隔处机械刺激终止室速而不能再诱发 ,于终止室速处作为靶点射频消融 ,1例于术后第 2天、另 1例半年后室速复发。 2 2例右室流出道室速 ,16例位于流出道间隔侧 ,6例位于流出道游离侧壁。 19例起搏标测到与心动过速 12导联QRS形态完全相同靶点 ,1例形态接近 ,消融获成功。 2例未能诱发室速 ,射频消融 1个月心动过速重新出现 ,所有患者无并发症出现。结论 :射频消融术对特发性室速是一种安全有效的治疗方法 ,可作为首选治疗。电生理未诱发室速或机械刺激终止室速不宜尝试射频消融治疗。