Substrate-based catheter ablation of epicardial ventricular tachycardia related to an anomalous coronary artery

Delayed enhancement magnetic resonance imaging is known for its ability to identify scarred myocardial tissue. This case report describes the use of MR imaging to define the location and transmural extent of infarcted tissue in a 45-year-old woman with an anomalous right coronary artery and hemodynamically unstable ventricular tachycardia. By demonstrating a predominantly epicardial infarct, MR imaging indicated that the pericardial approach was necessary for successful substrate-based ventricular tachycardia ablation.     

Predicting arrhythmia recurrence following catheter ablation for ventricular tachycardia using late gadolinium enhancement magnetic resonance imaging: Implications of varying scar ranges

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Percutaneous epicardial ablation reverses ventricular tachycardia mediated cardiomyopathy

We report on the case of an 18-year-old girl with asymptomatic incessant ventricular tachycardia. Initial attempts at endocardial ablation failed and she was monitored until her cardiac function deteriorated. A percutaneous epicardial approach with electroanatomical mapping was then used which successfully terminated the tachycardia. Left ventricular size and function subsequently returned to normal. This case demonstrates that percutaneous epicardial ablation of ventricular tachycardia is safe and feasible in young patients and highlights the importance of recognising this at an early stage.     

特发性左心室流出道心外膜侧室性心动过速

目的报道9例经电生理检查证实的特发性左心室流出道心外膜侧室性心动过速(室速)的体表心电图及电生理检查特点.方法男性5例,女性4例,年龄15～58岁,6例为运动诱发的持续性室速,3例为运动诱发的非持续性室速.结果室速时,9例体表心电图QRS波全部呈现右束支阻滞图形(8例胸前导联V1-V6呈现高R波),Ⅱ、Ⅲ、aVF导联为高R波,Ⅰ、aVL导联为QS波.电生理检查,右心室和左心室心内膜标测未发现最早心室激动点,在较早心室心内膜激动处的心内电图多呈现起始部低幅电位,提示远场电位.心室内起搏标测未发现与室速体表心电图12导联QRS波形态相同的起搏点.8例通过心脏静脉系统标测发现最早的心室激动点[体表心电图最早QRS波前15～50ms,平均(32±12)ms]和完全或近乎完全的起搏标测位于心大静脉的远端1例、心前间隔静脉的近端7例.1例患者在左心室流出道消融成功,1例患者在心大静脉远端血管内消融成功.其他患者在右心室和/或左心室内消融失败.结论心脏静脉标测可以鉴别出特发性左心室流出道心外膜侧室速.     

Efficacy and safety of combined endocardial/epicardial catheter ablation for ventricular tachycardia in Chagas disease: A randomized controlled study

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Value of high-density endocardial and epicardial mapping for catheter ablation of hemodynamically unstable ventricular tachycardia

BACKGROUND: Percutaneous epicardial mapping has been used for ablation of recurrent ventricular tachycardia (VT). OBJECTIVES: The purpose of this study was to use a combined epicardial and endocardial mapping strategy to delineate the myocardial substrate for recurrent VT in both ischemic (n = 12) and nonischemic cardiomyopathy (n = 8), and to define the role of epicardial ablation. METHODS: Electroanatomic mapping was performed in 20 patients. High-density voltage maps were obtained by acquiring both endocardial and epicardial electrograms. Electrograms derived from six patients with structurally normal hearts were used as controls. A total of 26 VTs were targeted in the 20 patients. RESULTS: Most VTs (23/26 [88.5%]) were hemodynamically unstable. In patients with ischemic cardiomyopathy, the extent of endocardial scar was greater than epicardial scar. A definable pattern of scar could not be demonstrated in nonischemic cardiomyopathy. Pathologic examination of explanted hearts in two patients with nonischemic cardiomyopathy demonstrated that low-voltage areas were not always predictive of scarred myocardium. A substrate-based approach was used for catheter ablation. Catheter ablation was performed on the endocardium in all patients; additional epicardial delivery of radiofrequency energy was required in 8 (40%) of 20 patients for successful ablation. During follow-up (12 +/- 4 months), 15 (75%) of 20 patients have been arrhythmia-free. CONCLUSION: Patients with ischemic cardiomyopathy tend to have a larger endocardial than epicardial scar. Use of epicardial and endocardial electroanatomic mapping to define the full extent of myocardial scars allows successful catheter ablation in patients with hemodynamically unstable VTs.     

Microelectrode voltage mapping for substrate assessment in catheter ablation of ventricular tachycardia: A dual-center experience

Introduction

The assessment of the ventricular myocardial substrate critically depends on the size of mapping electrodes, their orientation with respect to wavefront propagation, and interelectrode distance. We conducted a dual-center study to evaluate the impact of microelectrode mapping in patients undergoing catheter ablation (CA) of ventricular tachycardia (VT).

Methods

We included 21 consecutive patients (median age, 68 [12], 95% male) with structural heart disease undergoing CA for electrical storm (n = 14) or recurrent VT (n = 7) using the QDOT Micro catheter and a multipolar catheter (PentaRay, n = 9). The associations of peak-to-peak maximum standard bipolar (BV_c) and minibipolar (PentaRay, BV_p) with microbipolar (BV_μMax) voltages were respectively tested in sinus rhythm with mixed effect models. Furthermore, we compared the features of standard bipolar (BE) and microbipolar (μBE) electrograms in sinus rhythm at sites of termination with radiofrequency energy.

Results

BV_μMax was moderately associated with both BV_c (β = .85, p < .01) and BV_p (β = .56, p < .01). BV_μMax was 0.98 (95% CI: 0.93−1.04, p < .01) mV larger than corresponding BV_c, and 0.27 (95% CI: 0.16−0.37, p < .01) mV larger than matching BVp in sinus rhythm, with higher percentage differences in low voltage regions, leading to smaller endocardial dense scar (2.3 [2.7] vs. 12.1 [17] cm², p < .01) and border zone (3.2 [7.4] vs. 4.8 [20.1] cm², p = .03) regions in microbipolar maps compared to standard bipolar maps. Late potentials areas were nonsignificantly greater in microelectrode maps, compared to standard electrode maps. At sites of VT termination (n = 14), μBE were of higher amplitude (0.9 [0.8] vs. 0.4 [0.2] mV, p < .01), longer duration (117 [66] vs. 74 [38] ms, p < .01), and with greater number of peaks (4 [2] vs. 2 [1], p < .01) in sinus rhythm compared to BE.

Conclusion

microelectrode mapping is more sensitive than standard bipolar mapping in the identification of viable myocytes in SR, and may facilitate recognition of targets for CA.     

Late potentials abolition as an additional technique for reduction of arrhythmia recurrence in scar related ventricular tachycardia ablation

Late Potentials Ventricular Tachycardia Ablation . Rationale: To evaluate the efficacy of radiofrequency ventricular tachycardia (VT) ablation targeting complete late potential (LP) activity. Methods and Results: Sixty‐four consecutive patients (pts) with recurrent VTs and coronary artery disease or idiopathic dilated cardiomyopathy were evaluated. Fifty patients (47 male; 66.2 ± 10.1 years) had LPs at electroanatomical mapping; 35 patients had at least 1 VT inducible at basal programmed stimulation. After substrate mapping, radiofrequency ablation was performed with the endpoint of all LPs abolition. LPs could not be abolished in 5 patients despite extensive ablation, in 1 patient because of localization near an apical thrombus, and in 2 patients because of possible phrenic nerve injury. At the end of procedure, prevention of VT inducibility was achieved in 25 of 35 patients (71.4%) with previously inducible VT; VT was still inducible in 5 of 8 patients with incomplete LP abolition; and in 5 of 42 patients (16.1%) with complete LP abolition (P < 0.01). After a follow‐up of 13.4 ± 4.0 months, 10 patients (20.0%) had VT recurrences and one of them died after surgical VT ablation; VT recurrence was 9.5% in patients with LPs abolition (4/42 pts) and 75.0% (6/8 pts) in those with incomplete abolition [positive predictive value (PPV): 75%, negative predictive value (NPV): 90.4%, sensibility: 60.0%, and specificity: 95.0%, P < 0.0001); although it was 12.5% (5/40 pts) in patients without inducibility VT after the ablation, and 50% (5/10 pts) in those with inducible VT (PPV: 50%, NPV: 87.5%, sensitivity: 50.0%, and specificity: 87.5%, P = 0.008). Conclusions: LP abolition is an effective endpoint of VT ablation and its prognostic value compares favorably to that achieved by programmed electrical stimulation. (J Cardiovasc Electrophysiol, Vol. 23, pp. 621–627, June 2012)     

Mapping for ventricular tachycardia

Mapping strategies for ventricular tachycardia (VT) have evolved significantly in the past 2 decades. This review discusses mapping techniques that can help in successful VT ablation. The electrocardiogram (ECG) remains a vital component of VT mapping and can help to identify the chamber of origin of VT. The ECG morphology of VT, however, is influenced by orientation of heart and location of the scar. Activation mapping during VT is an important technique that can help in further localization. Care has to be exercised to ensure that small signals are not ignored and far-field signals are recognized. Pace-mapping to mimic the VT is another way to map exit site for scar based reentrant VT or the site of origin of triggered and automatic VT in the absence of structural heart disease. For the latter group, this technique is widely used in determining the site of ablation. It is important to ensure a complete ECG match (12 out of 12 leads) of the pace-map to the clinical arrhythmia in these patients. In patients with structural heart disease, entrainment mapping remains the gold standard for defining the protected isthmus and other components of the VT circuit. Using this technique, successful ablation of reentrant VT can be achieved in 60–90% of patients. In order to perform entrainment mapping, the VT has to be hemodynamically tolerated; this is not the case in 25% of pts with scar based reentrant VT. The development of 3-dimensional mapping systems allows for more anatomically based linear ablation in patients with poorly tolerated uniform VT. Despite these advances, there are still about 10–20% VTs that cannot be ablated successfully with the above described techniques, especially in patients with structural heart disease. Other recent advances such as percutaneous closed chest epicardial mapping technique and cooled tip ablation catheter technology have the potential to enhance mapping and successful ablation of VT.     

Three dimensional epicardial mapping and ablation of recurrent non-ischaemic ventricular tachycardia

Radiofrequency ablation is a therapeutic option for recurrent ventricular tachycardia (VT) in both ischaemic and non-ischaemic subsets. Usually this is attempted by mapping endocardially; however, in some situations epicardial approach may be needed to access the VT circuit. We report two cases in which epicardial approach was used to successfully ablate the VT, when endocardial ablation was ineffective.     

Epicardial and subselective transcoronary chemical ablation of incessant ventricular tachycardia

Incessant ventricular tachycardia in patients with severely depressed ventricular function remains a major therapeutic challenge. Although alcohol ablation via the tachycardia related vessel has been shown to be an effective alternative, it might not be applicable in some cases due to anatomic limitations. In three patients with ischemic cardiomyopathy and incessant ventricular tachycardia no effective antiarrhythmic therapy could be found. Alcohol ablation was then attempted but the tachycardia related vessel could not be intubated. A subselective injection of alcohol into a more proximal segment of the coronary artery was then performed in two cases. In one patient as subselective injection was also not possible, the injection was performed epicardially after thoracotomy. Ablation was successful in all cases. In very selected cases of incessant ventricular tachycardia that have failed all other therapeutic interventions, alcohol ablation of the tachycardia can be performed using an epicardial or subselective transcoronary injection of alcohol. © 1993 Wiley-Liss, Inc.     

Image-based criteria to identify the presence of epicardial arrhythmogenic substrate in patients with transmural myocardial infarction

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