Catheter Ablation Of Ventricular Tachycardia Research Articles

Early experience with mechanical hemodynamic support for catheter ablation of malignant ventricular tachycardia

Objective: To explore the role of mechanical hemodynamic support (MHS) in mapping and catheter ablation of patients with hemodynamically unstable ventricular tachycardia (VT), report single-center experience in a cohort of consecutive patients receiving VT ablation during MHS therapy, and provide evidence-based medical evidence for clinical practice. Methods: This was a retrospective cohort study. Patients with hemodynamically unstable VT who underwent catheter ablation with MHS at Beijing Anzhen Hospital, Capital Medical University between August 2021 and December 2023 were included. Patients were divided into rescue group and preventive group according to the purpose of treatment. Their demographic data, periprocedural details, and clinical outcomes were collected and analyzed. Results: A total of 15 patients with hemodynamically unstable VT were included (8 patients in the rescue group and 7 patients in the preventive group). The acute procedure was successful in all patients. One patient in the rescue group had surgical left ventricular assist device (LVAD) implantation, remaining 14 patients received extracorporeal membrane oxygenation (ECMO) for circulation support. ECMO decannulation was performed in 12 patients due to clinical and hemodynamic stability, of which 6 patients were decannulation immediately after surgery and the remaining patients were decannulation at 2.0 (2.5) d after surgery. Two patients in the rescue group died during the index admission due to refractory heart failure and cerebral hemorrhage. During a median follow-up of 30 d (1 d to 12 months), one patient with LVAD had one episode of ventricular fibrillation at 6 months after discharge, and no further episodes of ventricular fibrillation and/or VT occurred after treatment with antiarrhythmic drugs. No malignant ventricular arrhythmia occurred in the remaining 12 patients who were followed up. Conclusions: MHS contributes to the successful completion of mapping and catheter ablation in patients with hemodynamically unstable VT, providing desirable hemodynamic status for emergency and elective conditions.

Septal late enhancement by cardiac CT is associated with repeat ablation in nonischemic cardiomyopathy patients.

Scar substrate in nonischemic cardiomyopathy (NICM) patients is often difficult to identify. Advances in cardiac imaging, especially using late iodine-enhanced computed tomography (LIE-CT), allow better characterization of scars giving rise to ventricular tachycardia (VT). Currently, there are limited data on clinical correlates of CT-derived scar substrates in NICM. We sought assess the relationship between scar location on LIE-CT and outcomes after radiofrequency catheter ablation (RFCA) in NICM patients with VT. From 2020 to 2022, consecutive patients with NICM undergoing VT RFCA with integration of cardiac CT scar modeling (inHeart, Pessac, France) were included at two US tertiary care centers. The CT protocol included both arterial-enhanced imaging for anatomical modeling and LIE-CT for scar assessment. The distribution of substrate on CT was analyzed in relation to patient outcomes, with primary endpoints being VT recurrence and the need for repeat ablation procedure. Sixty patients were included (age 64 ± 12 years, 90% men). Over a median follow-up of 120 days (interquartile range [IQR]: 41-365), repeat ablation procedures were required in 32 (53%). VT recurrence occurred in 46 (77%), with a median time to recurrence of 40 days (IQR: 8-65). CT-derived total scar volume positively correlated with intrinsic QRS duration (r = .34, p = 0.008). Septal scar was found on CT in 34 (57%), and lateral scar in 40 (7%). On univariate logistic regression, septal scar was associated with increased odds of repeat ablation (odds ratio [OR]: 2.9 [1.0-8.4]; p = 0.046), while lateral scar was not (OR: 0.9 [0.3-2.7]; p = 0.855). Septal scar better predicted VT recurrence when compared to lateral scar, but neither were statistically significant (septal scar OR: 3.0 [0.9-10.7]; p = 0.078; lateral scar OR: 1.7 [0.5-5.9]; p = 0.391). In this tertiary care referral population, patients with NICM undergoing VT catheter ablation with septal LIE-CT have nearly threefold increased risk of need for repeat ablation.

Outcomes of Patients with Malignancy Undergoing Catheter Ablation for Ventricular Tachycardia in the United States

Outcomes of Patients with Malignancy Undergoing Catheter Ablation for Ventricular Tachycardia in the United States

Mortality in Recipients of Durable Left Ventricular Assist Devices Undergoing Ventricular Tachycardia Ablation.

Left ventricular assist device (LVAD) recipients have a higher incidence of ventricular tachycardia (VT). However, the role of VT ablation in this population is not well-established. This single-center retrospective cohort study sought to examine the impact of post-LVAD implant VT ablation on survival. This retrospective study examined a cohort of patients that underwent LVAD implantation at Baylor St. Luke's Medical Center and Texas Heart Institute between January 2011 and January 2021. All-cause estimated mortality was compared across LVAD recipients based on the incidence of VT, timing of VT onset, and the occurrence and timing of VT ablation utilizing Kaplan-Meier survival analysis and Cox proportional hazards models. Post-implant VT occurred in 53% of 575 LVAD recipients. Higher mortality was seen among patients with post-implant VT within a year of implantation (HR: 1.62 [95%CI: 1.15-2.27]). Among this cohort, patients who were treated with a catheter ablation had superior survival compared with patients treated with medical therapy alone for the 45months following VT onset (HR: 0.48 [95%CI: 0.26-0.89]). Moreover, performance of an ablation in this population aligned mortality rates with those who did not experience post-implant VT (HR: 1.18 [95%CI: 0.71-1.98]). VT occurrence within 1 year of LVAD implantation was associated with worse survival. However, performance of VT ablation in this population was correlated with improved survival compared with medical management alone. Among patients with refractory VT, catheter ablation aligned survival with other LVAD participants without post-implant VT. Catheter ablation of VT is associated with improved survival in LVAD recipients, but further prospective randomized studies are needed to compare VT ablation to medical management in LVAD recipients.

Preprocedural imaging with cardiac computed tomography for endo-epicardial ventricular tachycardia ablation

BackgroundStudies evaluating the systematic use of cardiac computed tomography (CCT) for the preprocedural assessment of myocardial fibrosis are limited. Their implementation in the electrophysiology workflow has not been extensively described. ObjectiveThis study aimed to explore the degree of concordance between CCT and electroanatomic mapping (EAM) for the evaluation of cardiac fibrosis in patients undergoing endo-epicardial ventricular tachycardia (VT) ablation. MethodsFrom November 2017 to December 2021, patients undergoing endo-epicardial VT catheter ablation with CCT as the only source of preprocedural scar assessment were prospectively enrolled. After image integration, myocardial fibrosis detected with CCT was compared with low-voltage areas identified by endo-epicardial EAM. Postprocedural VT recurrences of this approach were evaluated after at least 1 year of follow-up. ResultsThe study enrolled 35 patients (mean age, 60.7 ± 13.2 years; 94.2% male). The most common underlying arrhythmic substrate was dilated cardiomyopathy (48.6%). CCT was employed for contraindications to cardiac magnetic resonance, such as unstable VTs (31.4%) or nonconditional implantable cardioverter-defibrillators (28.6%), but also for patients’ and operators’ preferences (14.3%–25.7%). Myocardial fibrosis was correctly identified by CCT and EAM, with strong agreement between these techniques both overall (Cohen κ for agreement, 0.933) and in per-segment analysis (κ ranging from 0.796 to 1.0). Ischemic patients showed the best correlation (κ = 1.000), whereas myocarditis showed the worst (κ = 0.750). After a median follow-up of 14 (12–24) months, 1-year freedom from recurrences was achieved in 74.3% patients; overall freedom from recurrences was 60.0%. ConclusionA CCT-based preprocedural assessment before VT ablation is feasible, showing high diagnostic concordance with EAM in detecting myocardial fibrosis.

Road-Map to Epicardial Approach for Catheter Ablation of Ventricular Tachycardia in Structural Heart Disease: Results From a 10-Year Tertiary-Center Experience.

Epicardial approach in ventricular tachycardia (VT) ablation is still regarded as a second-step strategy, due to the risk of complications. We evaluated the frequency that epicardial ablation targets were identified and ablation performed following pericardial access compared with unnecessary pericardial access for different VT causes and potential markers of epicardial VT. All VT ablation procedures including epicardial approach over a 10-year period were included. First-line epicardial approach was indicated in arrhythmogenic right ventricular cardiomyopathy (ARVC) and postmyocarditis VT; in patients with idiopathic dilated cardiomyopathy (IDCM) and postmyocardial infarction, indications resulted from available imaging techniques or 12-lead VT morphology. The epicardial approach was considered useful if epicardial ablation was performed after epicardial mapping. Feasibility, complications, and long-term outcome were reported. Four hundred and eighty-eight subjects with a median age of 60 years (interquartile range, 47-65) and of left ventricle ejection fraction 41% (interquartile range, 30-55) underwent 626 epicardial VT ablations. Percutaneous access had a success rate of 92.2% and a complication rate of 3.6%. Overall, epicardial approach was, respectively, indicated to 11.8% of postmyocardial infarction patients, 49.5% in IDCM, 94% in myocarditis, and 90.7% in ARVC. Epicardial ablation at the first ablation attempt was performed in 9.3% of postmyocardial infarction patients, 28.8% in IDCM, 86.5% in myocarditis, and 81.3% in patients with ARVC. In first-line epicardial group, ARVC and myocarditis showed the highest odds for epicardial ablation (OR, 4.057 [95% CI, 1.299-8.937]; P=0.007; OR, 3.971 [95% CI, 1.376-11.465]; P=0.005, respectively). IDCM independently predicted unnecessary epicardial approach (OR, 2.7 [95% CI, 1.7-4.3]; P<0.001). After a follow-up of 41 months (interquartile range, 19-64), patients with IDCM experienced higher rate of recurrences and mortality compared with other causes. Epicardial approach is integral part of ablation armamentarium regardless of the VT cause, with high feasibility and low complication rate in experienced centers. Our data support its use at first ablation attempt in VTs related to ARVC and myocarditis.

Periprocedural acute haemodynamic decompensation during substrate-based ablation of scar-related ventricular tachycardia: a rare and unpredictable event.

Patients with structural heart disease (SHD) undergoing catheter ablation (CA) for ventricular tachycardia (VT) are at considerable risk of periprocedural complications, including acute haemodynamic decompensation (AHD). The PAINESD score was proposed to predict the risk of AHD. The goal of this study was to validate the PAINESD score using the retrospective analysis of data from a large-volume heart centre. Patients who had their first radiofrequency CA for SHD-related VT between August 2006 and December 2020 were included in the study. Procedures were mainly performed under conscious sedation. Substrate mapping/ablation was performed primarily during spontaneous rhythm or right ventricular pacing. A purposely established institutional registry for complications of invasive procedures was used to collect all periprocedural complications that were subsequently adjudicated using the source medical records. Acute haemodynamic decompensation triggered by CA procedure was defined as intraprocedural or early post-procedural (<12 h) development of acute pulmonary oedema or refractory hypotension requiring urgent intervention. The study cohort consisted of 1124 patients (age, 63 ± 13 years; males, 87%; ischaemic cardiomyopathy, 67%; electrical storm, 25%; New York Heart Association Class, 2.0 ± 1.0; left ventricular ejection fraction, 34 ± 12%; diabetes mellitus, 31%; chronic obstructive pulmonary disease, 12%). Their PAINESD score was 11.4 ± 6.6 (median, 12; interquartile range, 6-17). Acute haemodynamic decompensation complicated the CA procedure in 13/1124 = 1.2% patients and was not predicted by PAINESD score with AHD rates of 0.3, 1.8, and 1.1% in subgroups by previously published PAINESD terciles (<9, 9-14, and >14). However, the PAINESD score strongly predicted mortality during the follow-up. Primarily substrate-based CA of SHD-related VT performed under conscious sedation is associated with a substantially lower rate of AHD than previously reported. The PAINESD score did not predict these events. The application of the PAINESD score to the selection of patients for pre-emptive mechanical circulatory support should be reconsidered.

Prevalence of atrial fibrillation and/or atrial flutter in multicenter randomized controlled trials for catheter ablation of ventricular tachycardia in structural heart disease: A meta-analysis

Prevalence of atrial fibrillation and/or atrial flutter in multicenter randomized controlled trials for catheter ablation of ventricular tachycardia in structural heart disease: A meta-analysis

Wavefront curvature analysis derived from preprocedural imaging can identify the critical isthmus in patients with postinfarcted ventricular tachycardia

BackgroundWhere activation wavefront curvature is convexly shaped, functional conduction block can occur. ObjectiveThe purpose of this study was to determine whether left ventricular (LV) wall thickness determined from contrast-enhanced computed tomography (CT) is useful in localizing such areas in clinical postinfarction reentrant ventricular tachycardia (VT). MethodsWe evaluated data from 6 patients who underwent catheter ablation for postinfarction VT. CT imaging with inHEART processing was conducted 1–3 days before electrophysiological (EP) study to determine LV wall thickness (T). Activation wavefront curvature was approximated as ΔT/T, where ΔT represents wall thickness change. During EP study, bipolar LV VT electrograms were acquired using a high-density mapping catheter, and activation times were determined. Maps of T, ΔT/T, and VT activation were subsequently compared using statistical analyses. ResultsTwo of 6 cases exhibited dual circuit morphologies, resulting in a total of 8 VT morphologies analyzed. The LV wall near the VT isthmus location tended to be thin, on the order of a few hundred micrometers. Regions of largest ΔT/T partially coincided with the lateral isthmus boundaries where electrical conduction block occurred during VT. ΔT/T at the boundaries, measured from imaging, was significantly larger compared to values at the isthmus midline and to the global LV mean value (P <.001). ConclusionWavefront curvature measured by ΔT/T and caused by source–sink mismatch is dependent on ventricular wall thickness. Areas of high wavefront curvature partly coincide with and may be helpful in locating the VT isthmus in infarct border zones using preprocedural imaging analysis.

Characterization of ventricular tachycardia ablation in end-stage heart failure patients with left ventricular assist device (CHANNELED-Registry)

Abstract Background Left-ventricular-assist-devices (LVAD) are an established therapy for patients with end-stage heart failure. These patients are at high risk for ventricular tachycardia (VT) and ICD-shocks due to the arrhythmogenic substrate of the underlying cardiomyopathy itself and as the LVAD cannula might be arrhythmogenic, too. Purpose Data on catheter ablation of VT in LVAD patients are scarce and current evidence predominantly consists of case reports and small single-center series. This multicenter registry seeks to systematically assess the mechanism and origin of VA in LVAD patients and to evaluate procedural parameters and outcome of VT ablation in this special subset of patients. Methods Retrospective data of LVAD patients referred for VT ablation at 11 tertiary care centers between January 2017 and August 2023 were included in this multicenter registry. VT mechanisms, procedural data, clinical follow-up, and outcome were assessed. Results We report 49 patients (88% male, age 61±8 years) undergoing 51 ablation procedures included in this ongoing registry. The underlying cardiomyopathy was ischemic in 25/49 patients (51%) and nonischemic in 24/49 patients (49%) with a mean left ventricular ejection fraction of 21%±6% before LVAD implantation. Most catheter ablations were conducted after prior antiarrhythmic drug (AAD) treatment (15/51 on amiodarone, 13/51 on prior intensification of amiodarone treatment, 18/51 on prior combination of two or more AADs). A total of 75 VTs were targeted (39/51 transseptal, 3/51 retrograde aortic, 9/51 combined approaches) and 13/49 patients required VT ablation less than 1 month after LVAD implantation. Of the targeted VTs the majority (69%) were cardiomyopathy related and only 31% of the targeted VTs were related to the LVAD cannula. In 5/51 procedures access site complications and in 1/51 procedures a pericardial effusion occurred; one patient showed a post procedural oxygen desaturation; despite immediate intubation the patient deceased from hypoxic brain injury. No LVAD related complications were observed. A follow-up was available for 35/49 patients. During a median follow-up of 277 days (IQR 78-625 days), 5/35 patients were transplanted and 13/35 died. Patients died after a median time of 124 days (IQR 34-952 days) primarily from heart failure, sepsis, or intracranial bleeding. Of the remaining 17/35 patients, 7/17 patients were arrhythmia-free at a median follow-up of 212 days (IQR 78-639 days). Conclusion Although often chosen as last resort, catheter ablation of VT in LVAD patients is feasible and can be performed safely in this critically ill subset of heart failure patients in experienced centers. Intrinsic myocardial scar seems to be the dominant substrate in these patients but LVAD cannulae contribute to a significant number of VTs. In the presence of severely reduced LV function the VT recurrence remains high despite maximal therapy and prognosis of these patients is limited.

Left and right ventricular function measured by strain analysis predicts one-year mortality in ventricular tachycardia ablation patients with structural heart disease

Abstract Introduction Radiofrequency catheter ablation has become increasingly important in the management of scar-related ventricular tachycardia (VT). Wide range of clinical and procedural predictors of VT recurrence and mortality are described by previous studies. However, currently known echocardiographic predictors are mainly limited to conventional echo parameters. Speckle tracking echocardiography (STE) is a novel and promising method to evaluate systolic and diastolic function. STE derived parameters, such as global longitudinal strain (GLS), are proven predictors of mortality and arrhythmic events in heart diseases. Aims The aim of the present study was to assess whether STE derived parameters could be considered predictors of VT recurrence and mortality after catheter ablation of ventricular tachycardia in patients with structural heart disease. Methods We measured pre-ablation strain and strain rate parameters with speckle tracking. Left ventricular four-chamber longitudinal strain (LV4CLS), early diastolic strain rate (e’-sr), right ventricular free wall longitudinal strain (RVFWLS) and right ventricular four-chamber longitudinal strain (RV4CLS) were assessed in 73 cases. Patients were followed up for one year. Endpoints were VT recurrence, which was defined as either ICD recording of a sustained VT episode requiring therapy or an episode of sustained VT recorded on 12-lead ECG or CIED, and all-cause mortality. Results Univariate analysis using the Cox proportional hazard model revealed that only lower LVEF (HR: 0.52 [0.31-0.88], p=0.02) was associated with higher VT recurrence in the first year among the echocardiographic parameters. High LVEDD (HR: 3.9 [1.31-11.65], p=0.02), low TAPSE (HR: 0.52 [0.28-0.98], p=0.04), low LV4CLS (HR: 0.4 [0.19-0.83], p=0.01) and low RV4CLS (HR: 0.31 [0.13-0.72], p&amp;lt;0.01) were the predictors of 1-year mortality. Conclusion Strain parameters, especially right ventricular four-chamber longitudinal strain may supplement conventional echocardiographic parameters in the prediction of one-year mortality after catheter ablation in patients with structural heart disease. Further prospective clinical studies are necessary to verify the significance of strain parameters.

Epicardial catheter ablation of ventricular tachycardia in patients of acm - from a university hospital report in switzerland

Abstract Background Arrhythmogenic left ventricular cardiomyopathy (ALVC) as a subtype of arrhythmogenic cardiomyopathy (ACM) is increasingly being recognized. Cardiac magnetic resonance (CMR) has emerged as the primary imaging modality for the diagnosis of ACM. In patients with right-dominant ACM (ARVC) and recurrent sustained ventricular tachycardia (VT), endocardial +/-epicardial ablation yields good clinical outcomes in the long-term. However, studies on VT ablation in ACM with LV involvement are scarce. Purpose We sought to investigate clinical outcomes of VT ablation in ACM patients with LV involvement. Methods The study included patients from the Zurich ACM Registry who met 2020 "Padua Criteria" for ACM and underwent VT ablation between January 2018 and July 2023. Epicardial ablation was performed in patients with recurrent sustained VT despite endocardial ablation, those lacking and endocardial substrate or if the ECG of the VT / substrate on CMR was suggestive of an epicardial origin. Catheter ablation was guided by activation/entrainment mapping for mappable VT, and pace mapping/voltage mapping during sinus rhythm for unmappable VT. Consecutive follow-up of all patients was performed according to our protocol. Results Twenty-one ACM patients underwent n=24 VT ablation procedures. Of those 20 patients, 6 patients (30%) had LV involvement on CMR. Eight (33%) patients underwent epicardial +/- endocardial ablation. Among patients receiving epicardial ablation, 3 patients (38%) had LV involvement. These three underwent a single ablation procedure, which was epicardial only. Total follow-up was 30 months (range 4-43). Three-month sustained VT/VF recurrence rates were 12% in the ACM group with LV involvement vs 25% in ACM without LV involvement. All patients with sustained VT/VF recurrence underwent repeat ablation via an epicardial approach within 3 months and were free of sustained VT/VF thereafter during a median follow-up of 12 months. One-year recurrence rate did not differ between ACM patients with LV involvement vs. without LV involvement (7.7% vs 8.3%, P＝0.117). Seven out of eight epicardial ablations achieved freedom from VT/VF after one-year follow-up. One ARVC patient with previous endocardial ablation had recurrent VT one month after epicardial ablation, which was free of VT after Flecainide combined with beta-blocker. No significant differences were found in the use of beta-blockers and antiarrhythmic drugs between both groups (ACM with LV involvement vs. without LV involvement) at baseline and during one-year follow-up. Conclusions Single or adjuvant epicardial substrate ablation of VT in arrhythmogenic cardiomyopathy is promising in terms of postprocedural VT free survival, especially in patients with left ventricular involvement demonstrated by CMR.Figure 1Figure 2

Catheter ablation of papillary muscle arrhythmias: procedural characteristics and long term outcome

Abstract Background Ventricular arrhythmias (VA) originating from the papillary muscles can occur both in patients with and without structural heart disease. Although catheter ablation is the treatment of choice, ablation success remains challenging and long-term outcomes for this origin of VA are still unsatisfactory. Methods and Results All patients undergoing catheter ablation for premature ventricular contractions or ventricular tachycardia between june 2009 and november 2022 were analyzed. 66 patients (26 female (39%), mean age 60±15 years) undergoing catheter ablation of VA originating from the papillary muscle were identified. 21/66 (32%) patients had a reduced or mildly reduced left ventricular ejection fraction at time of initial presentation. While mitral valve regurgitation was present in 32/66 (48%) patients, mitral valve prolapse was observed in only 2/66 (3%) patients. 6/66 (9%) patients presented with non-sustained ventricular tachycardia (VT) and 1/66 (2%) patient presented with sustainend VT prior to catheter ablation. 61/66 (92%) patients underwent ablation of PVCs of the left ventricular papillary muscles (22/66 (33%) patients anterolateral; 39 (59%) patients posteromedial). 5/66 patients underwent ablation of premature ventricular complex (PVC) originating from the papillary muscles of the right ventricle. In 13/66 (19.7%) patients only a retrograde approach was used, in 26/66 (39.5%) patients a retrograde and an additional transeptal approach and in only 10/66 (15.2%) patients solely a transeptal approach. Mean PVC QRS duration was 152.5 ± 3.5 msec. Ablation was acutely successful in 44/66 (67%) patients. Mean procedure time was 145.8 ± 63.7 minutes and mean number of radiofrequency applications was 21.3 ± 16.7 (25 to 55 Watts, 37764.2 ± 27824.1 Joules). Overall, procedural complications occurred in 4/66 (6%) patients Follow up data were obtained from Holter ECGs, review of medical records, patient consultation, or via structured follow-up within the prospective TRUST registry. All information was combined to assess recurrence of PVC/VT. Recurrence of VA originating from the papillary muscles occurred in 11/66 (17%) patients. 9/66 patients (14%) underwent re-ablation due to recurrence of VA originating from the papillary muscles after previous ablation procedures. Conclusion Catheter ablation of papillary muscle arrhythmias is associated with a single procedural success rate of 67% with a procedural complication rate of 6%. 14% of patients underwent re-ablation due to recurrence of papillary muscle arrhythmias.

Long-term outcome after catheter ablation for fascicular ventricular tachycardia in a single high-volume center in Germany

Abstract Background Idiopathic Fascicular Ventricular Tachycardia (IFVT) accounts for less than 10% of all VTs and represents the most common idiopathic ventricular tachycardia of the left ventricle. This study reports on clinical and procedural characteristics and the long-term outcome of patients undergoing catheter ablation of premature ventricular complexes (PVC) and ventricular tachycardias (VTs) arising in proximity of the left ventricular conduction system. Methods and results This study includes 27 patients (17 male, 45 ± 17 years; 10 females, 50 ± 11 years) who underwent electrophysiological examinations at a tertiary ablation center over a period of 14 years (2009 to 2022). Follow-up was performed via regular Holter-ECGs and clinical evaluations, or via structured follow-up within the prospective TRUST registry. In 21/27 patients (77.8%), the left posterior fascicle (LPF) was involved in the IFVT. In 4 (14.8%) the left anterior fascicle (LAF) was involved and in 2 (7.4%) patients an origin in the upper septal (US) area was demonstrated. 22/27 (81.5%) patients had a preserved left ventricular ejection fraction (LVEF) and only 5 (18.5%) patients had a LVEF less than 50% at the time of presentation. 14/27 (51.9%) patients presented with PVC or non-sustained VTs with the following distribution: 10 (71.4%) originating from the LPF, 3 (21.4%) from the LAF and 1 (7.1%) from the US. 21/27 (77.8%) patients presented with sustained VTs: 16 (76.2%) arising from the LPF, 4 (19%) from the LAF and 1 (4.8%) from the US. However, only 2 (7.4%) patients presented in sustained VT at the beginning of the EP procedure. In 16 (59.3%) patients a sustained VT was induced during the EP study via isoprenaline and/or programmed ventricular stimulation. Mean QRS duration of the VT was 124.5 ± 14.6 msec. In 21 (77.7%) patients only a retrograde approach was used, in 3 (11.1%) patients a retrograde and an additional transeptal approach and in only 3 (11.1%) patients solely a transeptal approach. Mean number of radiofrequency applications was 11.8 ± 12.6 (30 to 40 Watts, 27545.6 ± 30524.4 Joules). FVT ablation was acutely successful in 24 patients (88.9%). In 2 patients (7.4%) no ablation was performed due to inability to induce VT under sedation. 3/27 patients (11.1%) underwent re-ablation due to FVT recurrence after previous ablation procedures. Moreover, 3 (11.1%) additional patients underwent repeated VT ablations during follow-up, but the arrhythmia originated from a different LV area. No procedure-related complication occurred. In 4 patients (14.8%) left fascicular posterior block was caused by ablation and in 3 (11.1%) patients a complete left bundle block. Mean procedure time was 130 ± 48.9 minutes. Conclusion Ablation of FVT in a tertiary ablation center is associated with a high single procedural success rate of 88.9% during long-term follow-up, with a mild risk of fascicular injury. 11.1% of patients underwent re-ablation due to FVT recurrence.

Manifestation of conduction block zones by substrate mapping evaluated under multidirectional pacing during ventricular tachycardia ablation

Abstract Introduction Catheter ablation (CA) has proven to be effective therapy for ventricular tachycardia (VT) in patients with structural heart disease. However, activation mapping during VT is often limited in case of non-inducible, non-sustained or hemodynamically tolerable. It has been reported that a substrate-based approach for identifying conduction block and slow-conducting sites during sinus rhythm and ventricular pacing is promising strategies for CA. However, detailed analysis on the effectiveness of substrate mapping with multidirectional pacing to identify critical isthmus in unmappable VT have been lacking. Purpose The purpose of the present study was to evaluate the effectiveness of substrate mapping with multidirectional pacing in VT ablation. Methods From April 2022 to July 2023, 7 consecutive patients (4 men, age 62±9years) who underwent CA of VTs at our institute were enrolled. Isochronal late activation mapping (ILAM) was performed during sinus rhythm, right ventricular (RV) and left ventricular (LV) pacing. Cardiovascular magnetic resonance were performed in 3 of 7 cases to assess the distribution of myocardial late gadolinium enhancement. For catheter ablation, 2Fr electrode catheter was inserted into the anterior interventricular vein (AIV) at the distal site of the coronary sinus. LV pacing was performed using an electrode catheter placed in the AIV. ILAM were constructed by annotating the last deflection of each electrogram. Results In the 7 patients, 5 had ischemic cardiomyopathy and 2 had non-ischemic cardiomyopathy (Figure 1). During sinus rhythm, a deceleration zone (DZ) was identified in only 1 of 7 cases, consistent with linear conduction block. RV pacing demonstrated DZ in 3 of 7 cases. LV pacing revealed DZ in 6 of 7 cases, all of which had conduction blocks. U-shaped conduction blocks, which was not detectable in activation mapping during sinus rhythm, was newly identified in 29% of RV pacing, 71% of LV pacing. Combined RV and LV pacing unmasked the U-shaped conduction block in 86% of the cases. Only in case 7, activation mapping of VT with a cycle length of 470ms could be performed, and VT isthmus activation was observed in the area surrounded by the U-shaped conduction block (Figure 2). In other cases, the clinical VTs were unmappable because of the hemodynamic instability with tachycardia cycle length of approximately 300 milliseconds. Eventually, VTs became non-inducible in 3 of 5 cases in which induction was performed after the CA. During the follow-up period of 7±5 months, 6 of 7 cases remained free from any VT episodes. One patient showed small amount of pericardial effusion after CA. However, there were no life-threatening complications in any patients. Conclusion Substrate mapping using several different wavefront vectors in unstable VTs unveiled conduction block zones that might be potential ablation target sites for VT.Figure 1Figure 2

Catheter ablation versus antiarrhythmic drug therapy for sustained ventricular tachycardia in patients with hypertrophic cardiomyopathy.

Ventricular tachycardia (VT) is the primary cause of sudden cardiac death in patients with hypertrophic cardiomyopathy (HCM). However, the strategy for VT treatment in HCM patients remains unclear. This study is aimed to compare the effectiveness of catheter ablation versus antiarrhythmic drug (AAD) therapy for sustained VT in patients with HCM. A total of 28 HCM patients with sustained VT at 4 different centers between December 2012 and December 2021 were enrolled. Twelve underwent catheter ablation (ablation group) and sixteen received AAD therapy (AAD group). The primary outcome was VT recurrence during follow-up. Baseline characteristics were comparable between two groups. After a mean follow-up of 31.4 ± 17.5 months, the primary outcome occurred in 35.7% of the ablation group and 90.6% of the AAD group (hazard ratio [HR], 0.29 [95%CI, 0.10-0.89]; P = 0.021). No differences in hospital admission due to cardiovascular cause (25.0% vs. 71.0%; P = 0.138) and cardiovascular cause-related mortality/heart transplantation (9.1% vs. 50.6%; P = 0.551) were observed. However, there was a significant reduction in the composite endpoint of VT recurrence, hospital admission due to cardiovascular cause, cardiovascular cause-related mortality, or heart transplantation in ablation group as compared to that of AAD group (42.9% vs. 93.7%; HR, 0.34 [95% CI, 0.12-0.95]; P = 0.029). In HCM patients with sustained VT, catheter ablation reduced the VT recurrence, and the composite endpoint of VT recurrence, hospital admission due to cardiovascular cause, cardiovascular cause-related mortality, or heart transplantation as compared to AAD.

Efficacy of catheter ablation for ventricular tachycardia in ischemic cardiomyopathy patients without an ICD implantation

BackgroundThe implantable cardioverter-defibrillator (ICD) prevents sudden cardiac death in patients with ischemic cardiomyopathy (ICM). Catheter ablation has been shown to effectively reduce ventricular tachycardia (VT) recurrence, yet its efficacy in patients without an ICD implantation remains uncertain. ObjectiveWe aimed to investigate the outcomes of ablation for VT in patients with ICM without a backup ICD. MethodsPatients with ICM who received ablation for VT without an ICD implantation were included in this study. Ablation was guided by either activation mapping or substrate mapping. Endocardial ablation was the primary strategy; epicardial access was considered when endocardial ablation failed. The primary end point was VT recurrence during follow-up; secondary end points included cardiovascular rehospitalization, all-cause mortality, and a composite of these events. ResultsA total of 114 patients were included, with the mean age of 58.2 ± 11.1 years, 102 of whom (89.5%) were male. Twelve patients (10.5%) underwent endo-epicardial ablation, whereas the rest received endocardial ablation. With a median follow-up of 53.8 months (24.8–84.2 months), VT recurred in 45 patients (39.5%), and 6 patients (5.3%) died, including 2 sudden cardiac deaths. The recurrence rate of VT was significantly lower in patients undergoing endo-epicardial ablation than in those with endocardial ablation only (8.3% vs 43.1%; log-rank P = .032). After multivariate adjustment, epicardial ablation remained associated with a reduced risk of VT recurrence (hazard ratio, 0.14; 95% confidential interval, 0.02–0.98; P = .048). ConclusionPatients with ICM undergoing VT ablation without a backup ICD experienced a notably low rate of arrhythmic death. Most recurrences proved nonlethal.

Active Arrhythmia Pattern: A Novel Predictor of ICD Shocks-A Subanalysis From the PARTITA Study.

In the PARTITA trial (Does Timing of Ventricular Tachycardia Ablation Affect Prognosis in Patients With an Implantable Cardioverter Defibrillator?), antitachycardia pacing (ATP) predicted the occurrence of implantable cardioverter defibrillator (ICD) shocks. Catheter ablation of ventricular tachycardia after the first shock reduced the risk of death or worsening heart failure. A threshold of ATPs that might warrant an ablation procedure before ICD shocks is unknown. Our aim was to identify a threshold of ATPs and clinical features that predict the occurrence of shocks and cardiovascular events. We analyzed data from 517 patients in phase A of the PARTITA study. We used classification and regression tree analysis to develop and test a risk stratification model based on arrhythmia patterns and clinical data to predict ICD shocks. Secondary end points were worsening heart failure and cardiovascular hospitalization. Classification and regression tree classified patients into 6 leaves by increasing shock probability. Patients treated with ≥5 ATPs in 6 months (active arrhythmia pattern) had the highest risk of ICD shocks (93% and 86%, training and testing samples, respectively). Patients without ATPs had the lowest (1% and 2%). Other predictors included left ventricle ejection fraction<35%, age of <60 years, and obesity. Survival analysis revealed a higher risk of worsening heart failure (hazard ratio, 5.45 [95% CI, 1.62-18.4]; P=0.006) and cardiovascular hospitalization (hazard ratio, 7.29 [95% CI, 3.66-14.5]; P<0.001) for patients with an active arrhythmia pattern compared with those without ATPs. Patients with an active arrhythmia pattern (≥5 ATPs in 6 months) are associated with an increased risk of ICD shocks, as well as heart failure hospitalization and cardiovascular hospitalization. These data suggest that additional treatments may be helpful to this high-risk group as a preventive strategy to reduce the incidence of major events. Further prospective randomized trials are needed to confirm the benefits of early ventricular tachycardia ablation in this setting.

Real World Data from Catheter Ablation of Ventricular Tachycardias and Premature Ventricular Complexes in a Tertiary Care Center.

Background: Catheter ablation in patients with ventricular arrhythmias (VA), such as ventricular tachycardias (VT) or frequent premature ventricular complexes (PVC), is increasingly considered an effective and safe therapy when performed in experienced centers. This study sought to determine acute success rates and complication rates of ablation procedures for patients with VA in a Swiss tertiary care center. Methods: All patients who underwent ablation therapy for VT and PVC at the University Heart Center in Zurich, Switzerland, between March 2012 and April 2017 were included in this analysis. Results: A total of 120 patients underwent catheter ablation for VT and PVC (69 and 51, respectively). Seventy percent of patients were male, and the mean age was 55.3 years. The most common indication for ablation was high PVC burden (47.5%), followed by paroxysmal VT (38.3%), ICD shocks (23.3%), incessant VT (12.5%), electrical storm (7.5%), and syncope (3.3%). Acute success rates for VT and PVC ablations were 94.2% and 92.2%, respectively. Rates for complications (including major and minor) for VT and PVC were 10.1% and 7.8%, respectively. Complications occurred only in patients with structural heart disease; no complications were noted in structurally normal hearts. Conclusions: Our results suggest that catheter ablation for VT and PVC has high acute success rates with a reasonable risk for complications in the setting of tertiary care centers, comparable to those reported in other studies.

Catheter Ablation of Ventricular Tachycardia in Ischemic Heart Disease: What Is Known and New Perspectives.

This review aims to evaluate current evidence regarding ventricular tachycardia ablation in patients with ischemic heart disease and explore novel approaches currently developing to improve procedural and long-term outcomes. Recently published trials (PARTITA, PAUSE-SCD, and SURVIVE-VT) have demonstrated the prognostic benefit of prophylactic ventricular tachycardia ablation compared to current clinical practice. Advanced cardiac imaging provides a valuable pre-procedural evaluation of the arrhythmogenic substrate, identifying ablation targets non-invasively. Advanced cardiac mapping techniques allow to better characterize arrhythmogenic substrate during ablation procedure. Emerging technologies like pulsed field ablation and ultra-low temperature cryoablation show promise in ventricular tachycardia ablation. Advancements in mapping techniques, ablation technologies, and pre-procedural cardiac imaging offer promise for improving ventricular tachycardia ablation outcomes in ischemic heart disease.