Ventricular Tachycardia Ablation Procedures Research Articles

Regional Strain by Cardiac Magnetic Resonance Imaging Improves Detection of Right Ventricular Scar Compared With Late Gadolinium Enhancement on a Multimodality Scar Evaluation in Patients With Arrhythmogenic Right Ventricular Cardiomyopathy.

Arrhythmogenic right ventricular cardiomyopathy is an inherited cardiomyopathy characterized by fibrofatty replacement of right ventricular myocardium resulting in reentrant ventricular tachycardia (VT). Cardiac magnetic resonance imaging (CMR) can noninvasively measure regional abnormalities using tissue-tracking strain as well as late gadolinium enhancement (LGE). In this study, we examine arrhythmogenic substrate using regional CMR strain, LGE, and electroanatomic mapping (EAM) in arrhythmogenic right ventricular cardiomyopathy patients presenting for VT ablation. Twenty-one patients underwent right ventricular endocardial EAM, whereas 17 underwent epicardial EAM, to detect dense scar (<0.5 mV) as well as CMR study within 12 months. Quantitative regional strain analysis was performed in all 21 patients, although the presence of LGE was visually examined in 17 patients. Strain was lower in segments with dense scar on endocardial and epicardial EAM (-9.7±4.1 versus -7.3±4.0, and -9.8±2.8 versus -7.6±3.8; P<0.05), in segments with LGE scar (-9.9±4.4 versus -6.0±3.6; P=0.001), and at VT culprit sites (-7.4±3.7 versus -10.1±4.1; P<0.001), compared with the rest of right ventricular. On patient-clustered analysis, a unit increase in strain was associated with 21% and 18% decreased odds of scar on endocardial and epicardial EAM, respectively, 17% decreased odds of colocalizing VT culprit site, and 43% decreased odds of scar on LGE-CMR ( P<0.05 for all). LGE and EAM demonstrated poor agreement with κ=0.18 (endocardial, n=17) and κ=0.06 (epicardial, n=13). Only 8 (15%) VT termination sites exhibited LGE. Regional myocardial strain on cine CMR improves detection of arrhythmogenic VT substrate compared with LGE. This may enhance diagnostic accuracy of CMR in arrhythmogenic right ventricular cardiomyopathy without the need for invasive procedures and facilitate the planning of VT ablation procedures.

Contemporary Tools and Techniques for Substrate Ablation of Ventricular Tachycardia in Structural Heart Disease.

As we have witnessed in other arenas of catheter-based therapeutics, ventricular tachycardia (VT) ablation has become increasingly anatomical in its execution. Multi-modality imaging provides anatomical detail in substrate characterization, which is often complex in nonischemic cardiomyopathy patients. Patients with intramural, intraseptal, and epicardial substrates provide challenges in delivering effective ablation to the critical arrhythmia substrate due to the depth of origin or the presence of adjacent critical structures. Novel ablation techniques such as simultaneous unipolar or bipolar ablation can be useful to achieve greater lesion depth, though at the expense of increasing collateral damage. Disruptive technologies like stereotactic radioablation may provide a tailored approach to these complex patients while minimizing procedural risk. Substrate ablation is a cornerstone of the contemporary VT ablation procedure, and recent data suggest that it is as effective and more efficient that conventional activation guided ablation. A number of specific targets and techniques for substrate ablation have been described, and all have shown a fairly high success in achieving their acute procedural endpoint. Substrate ablation also provides a novel and reproducible procedural endpoint, which may add predictive value for VT recurrence beyond conventional programmed stimulation. Extrapolation of outcome data to nonischemic phenotypes requires caution given both the variability in substrate nonischemic distribution and the underrepresentation of these patients in previous trials.

Cardiac Imaging in Patients With Ventricular Tachycardia.

Ventricular tachycardia (VT) is a major cause of sudden cardiac death. The majority of malignant VTs occur in patients with structural heart disease. Multimodality imaging techniques play an integral role in determining the underlying etiology and prognostic significance of VT. In recent years, advances in imaging technology have enabled characterization of the structural arrhythmogenic substrate in patients with VT with increasing precision. In parallel with these advances, the role of cardiac imaging has expanded from a largely diagnostic tool to an adjunctive tool to guide interventional approaches for treatment of VT. Invasive and noninvasive imaging techniques, often used in combination, have made it possible to integrate structural and electrophysiological information during VT ablation procedures. An important area of current development is the use of noninvasive imaging techniques based on body surface electrocardiographic mapping to elucidate the mechanisms of VT. In the future, these techniques may provide a priori information on mechanisms of VT in patients undergoing interventional procedures. This review provides an overview of the role of cardiac imaging in patients with VT.

Utility of high density multielectrode mapping during ablation of scar-related ventricular tachycardia

Multielectrode mapping catheters (MEMC) allow the performance of high resolution and density maps but the utility of these catheters in ventricular tachycardia (VT) ablation procedures has not been yet widely described. We sought to evaluate the utility of a MEMC during scar-related VT ablation procedures. Eighty-five consecutive scar-related VT ablation procedures were performed in 81patients. In the first 26 procedures, a standard 3.5-mm tip linear catheter was employed for endocardial/epicardial mapping (control group). In the following 59 procedures mapping was performed with a MEMC (study group). Procedural time, LV endocardial and epicardial mapping time, complications and ablation outcomes were compared. The use of the MEMC resulted in a significant shortening of the endocardial and epicardial mapping times (38 ± 15 minutes vs. 56 ± 24 minutes for endocardial LV mapping in the study and control group, respectively, P=0.001; and 28 ± 9 minutes vs 41 ± 16 minutes, for epicardial mapping, P=0.011) as well as the total procedural time (177 ± 53 minutes vs. 206 ± 50 minutes, respectively, P=0.02). The mapping density was also significantly increased in the study group (mean endocardial LV points: 2,143 ± 1,419 vs. 485 ± 174, for the study and control group, respectively, P<0.0001), specially within the scar area (49.6 ± 34 points/cm2 vs. 8.4 ± 4.6 points/cm2 , P<0.001). No differences in acute and long-term follow-up outcomes were observed. High-density multielectrode mapping is associated with a significant reduction of procedural and mapping times and a significant increase of mapping density without affecting outcomes in patients with scar-related VT.

P812Clinical validation of automatic local activation time annotation during idiopathic ventricular tachycardia ablation procedures

P812Clinical validation of automatic local activation time annotation during idiopathic ventricular tachycardia ablation procedures

Association of preprocedural cardiac magnetic resonance imaging with outcomes of ventricular tachycardia ablation in patients with idiopathic dilated cardiomyopathy

Knowledge of complex arrhythmogenic substrates can help plan ventricular tachycardia (VT) ablation in patients with idiopathic dilated cardiomyopathy (DCM). The purpose of this study was to assess whether preprocedural late gadolinium enhancement magnetic resonance imaging (LGE-MRI) can improve ablation outcomes in DCM. Consecutive patients (N = 96) with idiopathic DCM underwent VT ablation with open-irrigated catheters (2006-2016). Before 2012, LGE-MRI was not performed at our institution in patients with implanted devices, but it has been performed routinely in all patients after implementation of a new MRI protocol in 2012. We retrospectively compared acute and long-term outcomes of initial VT ablation procedures in patients with (n = 41) and those without (n = 55) preprocedural LGE-MRI. Procedural outcome was classified as successful if VT was not inducible postablation. The 2 groups had a similar mean age and ejection fraction, comorbidities, and frequency of epicardial ablation. Preablation LGE-MRI was independently associated with improved procedural success (63% vs 24%) by logistic regression analysis (adjusted odds ratio [OR] 7.86, P <.001). This result was consistent even when patients with nondiagnostic MRIs due to artifact were included in the imaging group (OR 4.87, P = .005). Preablation imaging was also associated with improved survival free of the composite endpoint of VT recurrence, heart transplantation, or death, which was met by 11 (27%) and 33 (60%) patients in the imaging and no imaging groups, respectively, after median 7.6 months of follow-up (unadjusted log-rank P = .02). However, there was no association with long-term outcomes after adjustment for other covariates. Preprocedural imaging with LGE-MRI may be associated with improved outcomes of VT ablation in DCM.

1154Clinical validation of automatic local activation time annotation during idiopathic ventricular tachycardia ablation procedures

1154Clinical validation of automatic local activation time annotation during idiopathic ventricular tachycardia ablation procedures

Myocardial wall thinning predicts transmural substrate in patients with scar-related ventricular tachycardia

Scar-related ventricular tachycardia (VT) arises from specific substrate according to etiology. The purpose of this study was to evaluate the relationship between wall thinning (WT) on multidetector computed tomography (MDCT) and local abnormal ventricular activity (LAVA) in patients with ischemic cardiomyopathy (ICM), postmyocarditis (PMC), and dilated cardiomyopathy (DCM). Forty-two patients (40 male, age 58 ± 13 years, 22 ICM, 11 PMC, 9 DCM) underwent MDCT before a combined endo-/epicardial VT ablation procedure. WT (<5 mm) and severe wall thinning (SWT) (<2 mm) area on MDCT were compared to the prevalence of endo-/epicardial LAVA during sinus rhythm. WT and SWT were found on MDCT in 36 (86%) and 20 (48%) with 42 ± 37 cm2 and 26 ± 24 cm2, respectively. SWT was frequently detected in ICM (ICM 77% vs PMC 27% vs DCM 0%, P <.001). LAVA were frequently observed on the endocardium in ICM and on the epicardium in PMC. Endo-/epicardial facing LAVA were frequently found within SWT areas (91% in <2 mm, 9% in 2-5 mm, and 0% in >5 mm, P < .001). In SWT areas, the presence of endocardial LAVA in ICM and epicardial LAVA in PMC predicted opposite facing LAVA with sensitivity and specificity of 78% and 48% and 79% and 98%, respectively. SWT predicted epicardial LAVA in ICM and endocardial LAVA in PMC with sensitivity and specificity of 89% and 100%, and 100% and 100%, respectively. SWT is frequently found in ICM and PMC but is not common in DCM. SWT predicts LAVA on the opposite side of the wall (epicardial in ICM and endocardial in PMC), indicating transmural VT substrate. MDCT is useful for identifying VT substrate and helpful for understanding the mechanisms of the location of VT substrate domain.

Elucidation of hidden slow conduction by double ventricular extrastimuli: a method for further arrhythmic substrate identification in ventricular tachycardia ablation procedures.

Identification of local abnormal electrograms (EGMs) during ventricular tachycardia substrate ablation (VTSA) is challenging when they are hidden within the far-field signal. This study analyses whether the response to a double ventricular extrastimulus during substrate mapping could identify slow conducting areas that are hidden during sinus rhythm. Consecutive patients (n = 37) undergoing VTSA were prospectively included. Bipolar EGMs with >3 deflections and duration <133 ms were considered as potential hidden slow conduction EGMs (HSC-EGM) if located within/surrounding the scar area. Whenever a potential HSC-EGM was identified, a double ventricular extrastimulus was delivered. If the local potential delayed, it was annotated as HSC-EGM. The incidence of HSC-EGM in core, border-zone, and normal-voltage regions was determined. Ablation was delivered at conducting channel entrances and HSC-EGMs. VT inducibility after VTSA obtained was compared with data from a historic control group. 2417 EGMs were analyzed. 575 (23.7%) qualified as potential HSC-EGM, and 198 of them were tagged as HSC-EGMs. Scars in patients with HSC-EGMs (n = 21, 56.7%) were smaller (35.424.7 vs 67.639.1 cm2; P = 0.006) and more heterogeneous (core/scar area ratio 0.250.2 vs 0.450.19; P = 0.02). 28.8% of HSC-EGMs were located in normal-voltage tissue; 81.3% were targeted for ablation. Patients undergoing VTSA incorporating HSC analysis needed less radiofrequency time (17.411 vs 2310.7 minutes; P = 0.016) and had a lower rate of VT inducibility after VTSA than the historic controls (24.3% vs 50%; P = 0.018). Ventricular tachycardia substrate ablation incorporating HSC analysis allowed further arrhythmic substrate identification (especially in normal-voltage areas) and reduced RF time and VT inducibility after VTSA.

Outcomes of Combined Endocardial-Epicardial Ablation Compared With Endocardial Ablation Alone in Patients Who Undergo Epicardial Access

Percutaneous epicardial access (EpiAcc) is used in an attempt to improve outcomes of ablation. We aim to report our experience in EpiAcc for management of symptomatic ventricular premature complexes (VPC) and ventricular tachycardia (VT). All patients from January 2004 to July 2014 who underwent EpiAcc as part of a VPC or VT ablation procedure were included. Outcomes between those with endocardial-only (Gp1) and endocardial/epicardial (Gp2) ablation and those for VPC and VT ablation were compared. EpiAcc for VPC or VT ablation was attempted in 173 patients; 10 patients were excluded because of failure of access (n= 7) or no ablation performed (n= 3). Of the remaining 163, 131 patients (80.4%) had undergone previous endocardial ablation. Mean age was 53.7 ± 15.7years; 115 (71%) were men. VT ablation was the indication in 105 patients (64%). The underlying substrate was predominately nonischemic cardiomyopathy (49.1%). Epicardial ablation was performed in 115 (70.6%). Procedural and clinical success was obtained in 92.0% and 69.9% of patients, respectively, with no difference between Gp1 and Gp2. Those who underwent VPC ablation had superior clinical outcomes at 1-year follow-up. EpiAcc is feasible in almost all patients with no previous cardiac surgery and permits acute procedural success in >90% of patients, most of whom had failed previous ablation. However, epicardial ablation was not delivered in 1/3 of patients. Epicardial mapping may be helpful as in the absence of an appropriate epicardial site for ablation, and focus can be shifted to more detailed endocardial mapping and ablation.

218-04: Substrate Ablation Before or After Ventricular Tachycardia Induction and Ablation. A Randomized Study

Background: Ventricular tachycardia (VT) induction and mapping as the first step in VT ablation procedures remains standard practice. However, the role and the optimal sequence of VT induction and ablation when combined with substrate ablation during procedures remains unclear. Methods and Results: Forty-eight consecutive patients with structural heart disease and clinical VTs were included and randomized to a simplified substrate ablation procedure with scar dechanneling as the first step (group 1, n = 24) or standard procedure with VT induction and ablation followed by scar dechanneling afterwards (group 2, n = 24). Thirty-eight patients had coronary artery disease, 10 non-ischemic cardiomyopathy and 1 arrhythmogenic right ventricular dysplasia. Prior to substrate ablation, 32 VTs were induced and targeted for ablation in 23 patients of the group 2. Procedure time (209 ± 70 min. vs. 262 ± 63 min., P = 0.009), fluoroscopy time (14 ± 6 min. vs. 21 ± 9 min, P = 0.005) and the need for electrical cardioversion (25% vs 54%, P = 0.039) were lower in group 1. After substrate ablation, 16 (66%) patients from group 1 and 12 (50%) from group 2 were non-inducible (P = 0.242). After residual inducible-VT ablation the percentage of patients with acute procedure success was 87.5% in group 1 and 70.8% in group 2 (P = 0.155). There were no differences in VT recurrence rate between groups during a mean follow-up of 22 ± 14 months (log rank P= 0.557). Conclusion: VT induction and mapping prior to substrate ablation prolongs the procedure, radiation exposure and the need for of electrical cardioversion; without benefit in terms of acute and long-term outcomes.

Substrate modification or ventricular tachycardia induction, mapping, and ablation as the first step? A randomized study

The role and optimal sequence of ventricular tachycardia (VT) induction, mapping, and ablation when combined with substrate modification is unclear. The purpose of this study was to test the benefits of starting the scar-related VT ablation procedure with substrate modification vs the standard protocol of VT induction, mapping, and ablation as the first step. Forty-eight consecutive patients with structural heart disease and clinical VTs were randomized to simplified substrate ablation procedure with scar dechanneling as the first step (group 1, n = 24) or standard procedure with VT induction, mapping, and ablation followed by scar dechanneling (group 2, n = 24). Procedure and fluoroscopy times, the need for external cardioversion, acute results, and VT recurrence during follow-up were compared between groups. Thirty-seven patients had ischemic cardiomyopathy, 10 nonischemic cardiomyopathy, and 1 arrhythmogenic cardiomyopathy. Before substrate ablation, 32 VTs were induced and targeted for ablation in 23 patients of group 2. Procedure time (209 ± 70 minutes vs 262 ± 63 minutes; P = .009), fluoroscopy time (14 ± 6 minutes vs 21± 9 minutes; P = .005), and electrical cardioversion (25% vs 54%; P = .039) were lower in group 1. After substrate ablation, 16 patients (66%) of group 1 and 12 patients (50%) of group 2 were noninducible (P = .242). End-procedure success (after residual inducible VT ablation) was achieved in 87.5% and 70.8% of patients, respectively (P = .155). There were no differences in VT recurrence rate between groups during a mean follow-up of 22 ± 14 months (log rank, P = .557). VT induction and mapping before substrate ablation prolongs the procedure, radiation exposure, and the need for electrical cardioversion without improving acute results and long-term ablation outcomes.

Safety and Feasibility of a Minimally Fluoroscopic Approach for Ventricular Tachycardia Ablation in Patients With Structural Heart Disease: Influence of the Ventricular Tachycardia Substrate.

We sought to evaluate the safety and feasibility of a minimally fluoroscopic approach using the CARTOUNIVU module during scar-related ventricular tachycardia (VT) ablation. Consecutive patients with structural heart disease undergoing VT ablation using the CARTOUNIVU module were prospectively included and classified depending on their VT substrate: (1) ischemic VT (IVT) and (2) nonischemic VT and depending on the presence of an epicardial access. Radiation exposure parameters and major and minor procedure-related complications were registered. A near-zero fluoroscopy exposure was defined as those procedures with an effective dose ≤1 mSv. A total of 44 VT ablation procedures were performed in 41 patients (22 IVT and 19 nonischemic VT). The use of the CARTOUNIVU module resulted in low levels of radiation exposure: median total fluoroscopy time and effective dose of 6.08 (1.51-12.36) minutes and 2.15 (0.58-8.22) mSv, respectively. Patients with IVT had lower radiation exposure than patients with nonischemic VT (total fluoroscopy time, 2.53 [1.22-11.22] versus 8.51 [5.55-17.34] minutes; P=0.016). Epicardial access was associated with significantly higher levels of radiation exposure. Complications occurred in 4.9% patients, none of them being related to the use of the image integration tool. A near-zero fluoroscopy ablation could be performed in 14 of 44 procedures (32%), 43% of IVT procedures, and 50% of procedures with endocardial access only. The use of the CARTOUNIVU module during scar-related VT ablation resulted in low levels of radiation exposure. A near-zero fluoroscopy approach can be achieved in up to half of the procedures, especially in IVT patients with endocardial ablation.

Nuclear Imaging Guidance for Ablation of Ventricular Arrhythmias.

Due to an increase in the number of patients with heart failure and ventricular arrhythmias, ventricular tachycardia ablation has a growing clinical role. Long-term success rates remain suboptimal and require creating a detailed electroanatomic map during the procedure to identify fibrotic areas responsible for arrhythmias. Nuclear imaging can identify areas of abnormal myocardial perfusion, metabolism, and innervation, which all may enhance our ability to identify ablation targets, thus decreasing procedure time and improving success rates. Myocardial scar, as assessed by single-photon emission computed tomography (SPECT) perfusion imaging, has been shown to correlate with abnormal areas found during electroanatomic mapping. Abnormal metabolism as identified by (18)fluorodeoxyglucose-positron-emission tomography (PET) imaging has been shown to predict successful ablation sites and help correct errors made in the creation of the electroanatomic map. Abnormal cardiac sympathetic innervation can be identified using the purpose (123)I-meta-iodobenzylguanidine SPECT imaging, which may help in identifying triggers that initiate ventricular tachycardia and also predict successful ablation sites within an otherwise normal myocardium. In conclusion, these imaging modalities can not only offer new insights into the pathophysiology of ventricular arrhythmias but also have the potential to improve outcomes from ventricular tachycardia ablation procedures.

Characteristics of Clinical and Induced Ventricular Tachycardia Throughout Multiple Ablation Procedures.

Optimal procedure endpoints of catheter ablation for ventricular tachycardia (VT) are not defined and multiple repeat procedures are sometimes required. However, there are few studies to compare the details of repeat procedures to the initial procedure. The aim of this study is to compare the characteristics of clinical and induced VT throughout multiple procedures and clarify their relations. Of 425 consecutive patients with structural heart disease who underwent catheter VT ablation, second, third and fourth procedures were performed in 101, 23, and 5 patients, respectively. Of 227 VTs that were induced during the second procedure, 68 (30%) VTs had previously been induced at the first procedure. In multivariable analysis, identification of an exit/isthmus site (HR = 0.29, P = 0.047), early termination of VT during radiofrequency application (HR 0.11, P = 0.037) and elimination of target VT at the end of first procedure (HR = 0.43, P = 0.036) were independently associated with noninducibility of the same VT at the second procedure. Over the course of multiple procedures the mean VT cycle length gradually lengthened (381 ± 107, 413 ± 111, 460 ± 124, 507 ± 99 milliseconds in first, second, third, and fourth procedure, respectively, P < 0.001) and more induced VTs became mappable (32%, 40%, 62%, and 70% in first, second, third, and fourth procedure, respectively, P < 0.001). Identification and ablation of VT exit/isthmus, early termination of VT during radiofrequency application and elimination of targeted VT are associated with absence of that VT during a repeat procedure, and recurrences are then mostly due to new VTs or other VTs that were not induced at the first procedure.

Abstract 16621: Clinical Results of Scar Related Ventricular Tachycardia Ablation Performed in a South America School Hospital

Introduction: Ventricular Tachycardia (VT) ablation is indicated in patients with recurrent episodes of VT or ICD shocks despite the use of AAD. Hypothesis: to evaluate the clinical characteristics and follow-up of patients that underwent scar related VT ablation in a school hospital in south america. Methods: We collected and analyzed data of all VT ablation performed in our institution between 2013 and 2014. Results: During the 2-year period we performed 107 scar related VT ablation procedures in 86 patients with an age of 56.7±14 years-old, most were male (70,9%). Sixty (56%) presented Chagas disease, 17 (16%) ischemic, 13 (12%) dilated, 12 (11%) RVAD and 5 (5%) other cardiomyopathies and the mean LV EF was 36.9±12.4%. The ablation was performed with CARTO in 60 (56,1%), Ensite 3 (2,8%) and EP only mapping in 44 (41,1%) procedures. Epicardial mapping was performed in 65 procedures (60,7%), most frequent in Chagas patients (81,7%;P&lt;0.001). There was complications in 6 (5,6%) procedures: one hemopericardium that open-chest surgery was necessary; two iliac artery dissection, both with conservative treatment; one complete AV block; one patient with refractory hypotension with the need of IABP and procedure interruption and one patient with late cardiac tamponade with the need of surgical drainage. In a median follow-up of 261 (Q1: 93 Q3: 479) days, 42 (40%) procedures presented recurrence in a median time of 40 (Q1: 7.5 Q3: 125) days. After the VT recurrence the ablation was repeated, and one patient underwent 4 ablation, 2 three ablations and 13 underwent two ablations. Following the last ablation, 61 (72.6%) patients remained free of VT recurrence (figure). Sixteen (19%) patients died in a median time of 34 (Q1: 14.75 Q3: 93) days following last ablation. Conclusion: Chagas disease was the most common cardiopathy in this population, where epicardial approach was frequently performed. After the last procedure, the majority of patients remained free of VT recurrence

Catheter ablation of idiopathic ventricular tachycardia without the use of fluoroscopy

BackgroundCatheter ablation is the treatment of choice for many patients with idiopathic ventricular tachycardia (VT). Unfortunately, conventional catheter ablation is guided by fluoroscopy, which is associated with a small but definite radiation risk for patients and laboratory personnel. The aim of our study is to assess feasibility, success rate and safety of idiopathic VT ablation procedure performed without the use of fluoroscopy. MethodsNineteen consecutive patients undergoing idiopathic VT ablation at our institution have been included. The ablation procedures were performed under the guidance of electroanatomical mapping (EAM) system and intracardiac echocardiography (ICE). ResultsNineteen patients (mean age 38.7years) underwent ablation procedure for idiopathic VT. Twelve (63%) had outflow tract VT, 3 (18%) fascicular tachycardia, 2 (11%) peri-tricuspidal VT, 1 (5%) peri-mitral VT, and 1 (5%) lateral left free-wall VT. The mean procedural time was 170.2±45.7min. No fluoroscopy was used in any procedural phase. Acute success rate was 100%. No complication was documented in any patients. After a mean follow up of 18±4months, recurrences occurred in 2 patients. ConclusionsIn our preliminary experience idiopathic VT ablation without the use of fluoroscopy was feasible and safe, using a combination of EAM and ICE. Success rate was excellent with no complication.

Ventricular tachycardia ablation: a comprehensive review for anesthesiologists.

Percutaneous catheter ablation is being increasingly performed in patients with recurrent ventricular tachycardia (VT) unresponsive to medical treatment. Optimal management of patients requires careful consideration of the severity of the underlying cardiac disease, the anesthetic drug interactions, and the procedural technique during VT mapping and ablation. The goal is to choose an anesthetic technique that has the least effect on arrhythmogenicity, allowing reproducibility of the VT in the electrophysiology laboratory. Anesthetics can alter action potential and ventricular depolarization directly through their effects on ion channels and gap junctions, as well as indirectly via their effects on the autonomic nervous system. Furthermore, maintaining hemodynamic stability and monitoring for adequate end-organ perfusion are additional challenges. In this review, we provide a comprehensive update on the currently performed VT ablation procedures and their anesthetic considerations.

Contemporary Mapping Techniques of Complex Cardiac Arrhythmias - Identifying and Modifying the Arrhythmogenic Substrate.

Cardiac electrophysiology has moved a long way forward during recent decades in the comprehension and treatment of complex cardiac arrhythmias. Contemporary electroanatomical mapping systems, along with state-of-the-art technology in the manufacture of electrophysiology catheters and cardiac imaging modalities, have significantly enriched our armamentarium, enabling the implementation of various mapping strategies and techniques in electrophysiology procedures. Beyond conventional mapping strategies, ablation of complex fractionated electrograms and rotor ablation in atrial fibrillation ablation procedures, the identification and modification of the underlying arrhythmogenic substrate has emerged as a strategy that leads to improved outcomes. Arrhythmogenic substrate modification also has a major role in ventricular tachycardia ablation procedures. Optimisation of contact between tissue and catheter and image integration are a further step forward to augment our precision and effectiveness. Hybridisation of existing technologies with a reasonable cost should be our goal over the next few years.

Necessity of epicardial ablation for ventricular tachycardia after sequential endocardial approach

BackgroundCatheter ablation (CA) of ventricular tachycardia (VT) is an important treatment option in patients with structural heart disease (SHD) and implantable cardioverter defibrillator (ICD). A subset of patients requires epicardial CA for VT. ObjectiveThe purpose of the study was to assess the significance of epicardial CA in these patients after a systematic sequential endocardial approach. MethodsBetween January 2009 and October 2012 CA for VT was analyzed. A sequential CA approach guided by earliest ventricular activation, pacemap, entrainment and stimulus to QRS-interval analysis was used. Acute CA success was assessed by programmed ventricular stimulation. ICD interrogation and 24h-Holter ECG were used to evaluate long-term success. ResultsOne hundred sixty VT ablation procedures in 126 consecutive patients (114 men; age 65±12years) were performed. Endocardial CA succeeded in 250 (94%) out of 265 treated VT. For 15 (6%) VT an additional epicardial CA was performed and succeeded in 9 of these 15 VT. Long-term FU (25±18.2month) showed freedom of VT in 104 pts (82%) after 1.2±0.5 procedures, 11 (9%) suffered from repeated ICD shocks and 11 (9%) died due to worsening of heart failure. ConclusionsDespite a heterogenic substrate for VT in SHD, endocardial CA alone results in high acute success rates. In this study additional epicardial CA following a sequential endocardial mapping and CA approach was performed in 6% of VT.Thus, due to possible complications epicardial CA should only be considered if endocardial CA fails.