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Background: Management of acute myocarditis (AM) patients experiencing ventricular arrhythmia (VA) during acute illness is controversial, especially regarding early implantable cardioverter-defibrillator (ICD) implantation., Objectives: The purpose of this study was to evaluate the prevalence of and find predictors for long-term sustained VA recurrence and overall mortality among AM patients with VA., Methods: This was a multicenter retrospective analysis of AM patients (verified by cardiac magnetic resonance imaging or myocardial biopsy) with documented VA during the acute illness ("initial VA"). Patients with history of myocardial infarction, heart failure, or VA were excluded. The study endpoint was a composite of sustained VA and overall mortality during follow-up., Results: The study included 69 AM patients with initial VA: sustained monomorphic ventricular tachycardia (MMVT) (n = 25), sustained polymorphic ventricular tachycardia (VT)/ventricular fibrillation (n = 13), and nonsustained VT (n = 31). Age was 44 ± 13 years, and 23 of 69 (33.3%) were women. During median follow-up of 5.5 years, 27 of 69 (39%) patients reached the composite endpoint including sustained VA (n = 24) and death (n = 11). Initial MMVT, predischarge left ventricular dysfunction (left ventricular ejection fraction <50%), and anteroseptal delayed enhancement on cardiac magnetic resonance imaging were significantly associated with the composite endpoint. On multivariable analysis, initial MMVT (HR: 5.17; 95% CI: 1.81-14.6; P = 0.001) and predischarge LV dysfunction (HR: 4.57; 95% CI: 1.83-11.5; P = 0.005) were independently associated with the composite endpoint. Using these 2 predictors, we could delineate subgroups with low (∼4%), medium (∼42%), and high (∼82%) 10-year incidence of composite endpoint., Conclusions: AM patients presenting with VA have high incidence of sustained VA recurrence and mortality posthospitalization. Initial MMVT and predischarge LV dysfunction are independently associated with VA recurrence and mortality. Implantable cardioverter-defibrillator implantation may be considered in such high-risk patients., Competing Interests: Funding Support and Author Disclosures This study was supported by Shaare Zedek Medical Center scientific grant number 18004723 including 20,000 Israeli Shekel (∼5000$), which was mainly used to pay for statistical analysis. The authors have reported that they have no relationships relevant to the contents of tis paper to disclose., (Copyright © 2024 American College of Cardiology Foundation. All rights reserved.)

Aims: Little is known about patients with right bundle branch block (RBBB)-ventricular tachycardia (VT) and arrhythmogenic cardiomyopathy (ACM). Our aims were: (i) to describe electrocardiogram (ECG) characteristics of sinus rhythm (SR) and VT; (ii) to correlate SR with RBBB-VT ECGs; and (iii) to compare VT ECGs with electro-anatomic mapping (EAM) data., Methods and Results: From the European Survey on ACM, 70 patients with spontaneous RBBB-VT were included. Putative left ventricular (LV) sites of origin (SOOs) were estimated with a VT-axis-derived methodology and confirmed by EAM data when available. Overall, 49 (70%) patients met definite Task Force Criteria. Low QRS voltage predominated in lateral leads (n = 37, 55%), but QRS fragmentation was more frequent in inferior leads (n = 15, 23%). T-wave inversion (TWI) was equally frequent in inferior (n = 28, 42%) and lateral (n = 27, 40%) leads. TWI in inferior leads was associated with reduced LV ejection fraction (LVEF; 46 ± 10 vs. 53 ± 8, P = 0.02). Regarding SOOs, the inferior wall harboured 31 (46%) SOOs, followed by the lateral wall (n = 17, 25%), the anterior wall (n = 15, 22%), and the septum (n = 4, 6%). EAM data were available for 16 patients and showed good concordance with the putative SOOs. In all patients with superior-axis RBBB-VT who underwent endo-epicardial VT activation mapping, VT originated from the LV., Conclusions: In patients with ACM and RBBB-VT, RBBB-VTs originated mainly from the inferior and lateral LV walls. SR depolarization and repolarization abnormalities were frequent and associated with underlying variants., (© The Author(s) 2023. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Verapamil-sensitive left fascicular monomorphic ventricular tachycardia (LF-VT) was first described ~4 decades ago. Our knowledge regarding this arrhythmia is evolving continuously. The current review aims to highlight up to date aspects of this arrhythmia focusing on its ECG recognition, new considerations of the reentrant circuit, ablation targets in inducible and non-inducible patients and the approach to LF-VT with multiform morphology., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background: Multiform fascicular tachycardia (FT) was recently described as a ventricular tachycardia (VT) that has a reentrant mechanism using multiple fascicular branches and produces alternate fascicular VT forms. Ablating the respective fascicle may cause a change in the reentrant circuit resulting in a change in morphology. Ablation of the septal fascicle is crucial for successful treatment., Objectives: To describe four cases of FT in which ablation induced a change in QRS morphologies and aggravated clinical course., Methods: Four out of 57 consecutive FT cases at three institutions were retrospectively analyzed and found to involve multiform FT. These cases underwent electrophysiological study, fascicular potential mapping, and electroanatomical mapping. All patients initially had FT with right bundle branch block (RBBB) and superior axis morphology., Results: Radiofrequency catheter ablation (RFCA) targeting the distal left posterior fascicle (LPF) resulted in a second VT with an RBBB-inferior axis morphology that sometimes became faster and/or incessant and/or verapamil-refractory in characteristics. RFCA in the upper septum abolished the second VT with no complications and uneventful long-term follow-up., Conclusions: The change in FT morphology during ablation may be associated with a change in clinical course when shifting from one route to another and may aggravate symptoms. Targeting of the proximal conduction system (such as bifurcation, LPF, left anterior fascicle, high septal/auxiliary pathway) may serve to solve this problem.

Anemia was shown to be associated with increased risk for adverse events in patients with heart failure (HF). However, there are limited data on the association between anemia and the risk for ventricular arrhythmias (VAs) in patients with an implantable cardioverter defibrillator (ICD). The present study population comprised 2,352 patients who were enrolled and prospectively followed up in the Israeli ICD Registry. The risk for a first appropriate ICD shock for VA was assessed by the presence of anemia, categorized at the lower tertile of hemoglobin distribution (≤12 g/dL [n = 753]). Patients who had anemia displayed higher risk clinical characteristics including older age, more advanced HF symptoms, and atrial fibrillation (p <0.01 for all). Kaplan-Meier survival analysis showed that at 2.5 years of follow-up the rate of appropriate shocks was significantly higher in patients with low (11%) versus high (6%) hemoglobin (log-rank p <0.005). Multivariate analysis showed that anemia was independently associated with a significant 56% increased risk for first appropriate ICD shock (p <0.026). When hemoglobin was assessed as a continuous measure, each 1 g/dL reduction in hemoglobin was independently associated with a significant 8% increased risk for first appropriate shock (p <0.03). Anemia was also associated with increased risk for all-cause mortality (hazard ratio [HR] 1.78, 95% confidence interval [CI] 1.4 to 2.27], p <0.001), HF hospitalizations or death (HR 1.78, 95% CI 1.48 to 1.13, p <0.001), but not with inappropriate ICD shocks (HR 1.24, 95% CI 0.70 to 2.21, p = 0.47). In conclusion, our findings suggest that the presence of anemia in patients with ICD is associated with increased risk for VA during long-term follow-up., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Background: Left posterior fascicular ventricular tachycardia (LPF-VT) is frequently misdiagnosed as supraventricular tachycardia with aberrant right bundle branch block (RBBB) and left anterior hemiblock (LAHB). The purpose of the present study was to define the morphological ECG characteristics of LPF-VT and attempt to differentiate it from RBBB and LAHB aberrancy., Methods and Results: A systematic Medline search was used to identify or locate ECG tracings from patients with LPF-VTs. ECGs with LPF-VT were also collected from patients who underwent ablation of this arrhythmia at the Tel Aviv and Sheba Medical Centers. These ECGs were compared with ECGs of consecutive patients with RBBB and LAHB and no obvious cardiac pathology by echocardiography. Overall, 183 ECGs of LPF-VT were compared with 61 ECGs showing RBBB and LAHB. Univariate analysis demonstrated differences in QRS axis, limb (I, aVr), and precordial (V 1 , V 2 , V 6 ) ECG leads. On multivariate logistic regression analysis, LPF-VT was more often associated with atypical RBBB-like V 1 morphology (odds ratio, 5.1; P =0.004), positive QRS in aVr (odds ratio, 19.2; P <0.001), V 6 R/S ratio ≤1 (odds ratio, 6.7; P =0.01), and QRS ≤140 ms (odds ratio, 7.7; P <0.001). Using these 4 variables, a prediction model was developed that predicted LPF-VT with sensitivity and specificity of 82.1% and 78.3%, respectively. Patients with 3 of 4 positive variables had high probability of having LPF-VT, whereas patients with ≤1 positive variable always had RBBB plus LAHB., Conclusions: The morphological ECG characteristics of LPF-VT were defined, and a high accurate tool for correctly differentiating LPF-VT from RBBB and LAHB aberrancy was developed., (© 2017 American Heart Association, Inc.)

Introduction: A new imaging software (CARTO® Segmentation Module, Biosense Webster) allows preprocedural 3-D reconstruction of all heart chambers based on cardiac CT. We describe our initial experience with the new module during ablation of ventricular arrhythmias., Methods and Results: Eighteen consecutive patients with idiopathic ventricular arrhythmias or ischemic ventricular tachycardia (VT) were studied. In the latter group, a combined endocardial and epicardial ablation was performed. Of the 14 patients with idiopathic arrhythmias, 12 were ablated in the outflow tract (OT), 1 in the midseptal left ventricle, and 1 at the left posterior fascicular area; acute successful ablation was achieved in 11 (78.6%) patients. The procedure was discontinued due to close proximity of the arrhythmia origin to the coronary arteries (CA) in 2 patients. Acute successful uncomplicated ablation was achieved in all 4 patients with ischemic VT. During ablation in the coronary cusps commissures, the CARTO® Segmentation Module accurately defined the cusps anatomy. The precise anatomic location provided by the module assisted in successfully ablating when information from activation mapping was not optimal, by ablating at the opposite side of the cusps. In addition, by demonstrating the precise location of the CA, it allowed safe ablation of arrhythmias that originated in close proximity to the CA both in the OT area and the epicardium, eliminating the need for repeat angiography., Conclusions: The CARTO® Segmentation Module is useful for accurate definition of the exact anatomic location of ventricular arrhythmias and for safely ablating them especially in close proximity to the CA., (© 2016 Wiley Periodicals, Inc.)

Exercise-induced ventricular tachycardia (VT) rarely occurs in the absence of organic heart disease. Idiopathic monomorphic VT has an excellent prognosis. The main aspect of the risk stratification process is recognizing subtle forms of organic heart disease, particularly arrhythmogenic right ventricular cardiomyopathy. Exercise-induced polymorphic VT is potentially malignant. Exercise-induced polymorphic VT has also been seen in mitral valve prolapse. Some patients with stable coronary disease, and even healthy athletes, sometimes have short bursts of polymorphic VT during exercise tests but these arrhythmias are usually not reproducible during repeated testing and have unknown long-term clinical significance., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Background: Left ventricular outflow tract (LVOT) arrhythmias are increasingly recognized. Data regarding the distribution of the sites of origin (SOO) of the arrhythmias are sparse., Objectives: To describe the clinical characteristics of patients with LVOT arrhythmias and the distribution of their SOO., Methods: All 42 consecutive patients with LVOT arrhythmias who underwent radiofrequency (RF) ablation during the period 2000-2014 were included. SOO identification was based on mapping activation, pace mapping and a 3D mapping system in eight patients., Results: The study group comprised 28 males (66.7%) and 14 females, the mean age was 55 ± 15.4 years. Most patients (76%) were symptomatic. All suffered from high grade ventricular arrhythmias. Left ventricular (LV) dysfunction (ejection fraction ≤ 50%) was observed in 15 patients (35.7%), of whom 14 (93.3%) were males. The left coronary cusp (LCC) was the most common arrhythmia SOO (64.3%). Other locations were the right coronary cusp (RCC), the junction of the RCC-LCC commissure, aortic-mitral continuity, endocardial-LVOT, and a coronary sinus branch. Acute successful ablation was achieved in 29 patients (69%) and transient arrhythmia abolition in 40 (95.2%). There was a trend for a higher success rate using cooled tip ablation catheters as compared to standard catheters. The ablation procedure significantly improved LV function in all patients with tachycardiomyopathy., Conclusions: LVOT arrhythmias mostly originate from the LCC and are associated with LV dysfunction in 36% of patients. Knowledge regarding the prevalence of the anatomic origin of the LVOT arrhythmias may help achieve successful ablation. The use of cooled tip ablation catheters might have beneficial effects on the success rate of the procedure.

Background: There is a paucity of data on biophysical parameters during radiofrequency ablation of scar-mediated ventricular tachycardia (VT)., Methods and Results: Data were collected from consecutive patients undergoing VT ablation with open-irrigation. Complete data were available for 372 lesions in 21 patients. The frequency of biophysical parameter changes were: >10Ω reduction (80%), bipolar EGM reduction (69%), while loss of capture was uncommon (32%). Unipolar injury current was seen in 72% of radiofrequency applications. Both EGM reduction and impedance drop were seen in 57% and a change in all 3 parameters was seen in only 20% of lesions. Late potentials were eliminated in 33%, reduced/modified in 56%, and remained after ablation in 11%. Epicardial lesions exhibited an impedance drop (90% vs. 76%, P = 0.002) and loss of capture (46% vs. 27%, P < 0.001) more frequently than endocardial lesions. Lesions delivered manually exhibited a >10Ω impedance drop (83% vs. 71%, P = 0.02) and an EGM reduction (71% vs. 40%, P < 0.001) more frequently than lesions applied using magnetic navigation, although loss of capture, elimination of LPs, and a change in all 3 parameters were similarly observed., Conclusions: VT ablation is inefficient as the majority of radiofrequency lesions do not achieve more than one targeted biophysical parameter. Only one-third of RF applications targeted at LPs result in complete elimination. Epicardial ablation within scar may be more effective than endocardial lesions, and lesions applied manually may be more effective than lesions applied using magnetic navigation. New technologies directed at identifying and optimizing ablation effectiveness in scar are clinically warranted., (© 2014 Wiley Periodicals, Inc.)

Background: Epicardial ablation has been shown to be a useful adjunct for treatment of ventricular tachycardia (VT)., Objective: To report the trends, safety, and efficacy of epicardial mapping and ablation at a single center over an 8-year period., Methods: Patients referred for VT ablation (June 2004 to July 2011) were divided into 3 groups: ischemic cardiomyopathy (ICM), nonischemic cardiomyopathy (NICM), and idiopathic ventricular arrhythmias (VA). Patients with scar-mediated VT who underwent combined epicardial and endocardial (epi-endo) mapping and ablation were compared with those who underwent endocardial-only (endo-only) ablation with regard to patient characteristics, acute procedural success, 6- and 12-month clinical outcomes., Results: Among 144 patients referred for VT ablation, 95 patients underwent 109 epicardial procedures (94% access rate). Major complications were seen in 8 patients (8.8%) with pericardial bleeding (>80 cm(3)) in 6 cases (6.7%), although no tamponade, surgical intervention, or procedural mortality was seen. Patients with ICM who underwent a combined epi-endo ablation had improved freedom from VT compared with those who underwent endo-only ablation at 12 months (85% vs 56%; P = .03). In patients with NICM, no differences were seen between those who underwent epi-endo ablation and those who underwent endo-only ablation at 12 months (36% vs 33%; P = 1.0). In idiopathic VA, only 2 of 17 patients were successfully ablated from the epicardium., Conclusions: In this large tertiary single-center experience, complication rates are acceptably low and improved clinical outcomes were associated with epi-endo ablation in patients with ICM. Patients with NICM represent a growing referred population, although clinical recurrence remains high despite epicardial ablation. Epicardial ablation has a low yield in idiopathic VA., (Copyright © 2013 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Ventricular tachycardia as a late complication of blunt chest trauma has never been reported. We present a case of combined endocardial and epicardial delineation of the right ventricular arrhythmogenic substrate, where other causes of cardiomyopathy were excluded. The epicardial scar was more extensive than endocardial scar, and the central isthmus was likely intramural. A history of blunt chest trauma should be considered in patients with right ventricular cardiomyopathy., (©2012, The Authors. Journal compilation ©2012 Wiley Periodicals, Inc.)

Background: Myocardial scars harbor areas of slow conduction and display abnormal electrograms. Pace-mapping at these sites can generate a 12-lead ECG morphological match to a targeted ventricular tachycardia (VT), and in some instances, multiple exit morphologies can result. At times, this can also result in the initiation of VT, termed pace-mapped induction (PMI). We hypothesized that in patients undergoing catheter ablation of VT, scar substrates with multiple exit sites (MES) identified during pace-mapping have improved freedom from recurrent VT, and PMI of VT predicts successful sites of termination during ablation., Methods and Results: High-density mapping was performed in all subjects to delineate scar (0.5-1.5 mV). Sites with abnormal electrograms were tagged, stimulated (bipolar 10 mA at 2 ms), and targeted for ablation. MES was defined as >1 QRS morphology from a single pacing site. PMI was defined as initiation of VT during pace-mapping (400-600 ms). In a 2-year period, 44 consecutive patients with scar-mediated VT underwent mapping and ablation. MES were observed during pace-mapping in 25 patients (57%). At 9 months, 74% of patients who exhibited MES during pace-mapping had no recurrence of VT compared with 42% of those without MES observed (P=0.024), with an overall freedom from VT of 61%. Thirteen patients (30%) demonstrated PMI, and termination of VT was seen in 95% (18/19) of sites where ablation was performed., Conclusions: During pace-mapping, electrograms that exhibit MES and PMI may be specific for sites critical to reentry. These functional responses hold promise for identifying important sites for catheter ablation of VT.

Background: Prior chest surgery limits the ability to obtain epicardial access in patients referred for catheter ablation of ventricular tachycardia (VT)., Objective: The purpose of this study was to describe the utility of different surgical approaches to access the epicardium for VT ablation., Methods: Clinical data of 14 patients with drug-refractory VT who underwent hybrid surgical epicardial access for catheter mapping and ablation in the electrophysiology lab were reviewed. Baseline patient and procedural characteristics including access, exposure, mapping techniques, and ablation were analyzed., Results: Of a total of 14 patients (age 63.2 ± 10.3 years), 11 had a subxiphoid window performed, and three patients underwent limited anterior thoracotomy to access the epicardium. The indication for surgical access was prior cardiac surgery (n = 12), previous failed epicardial access (n = 1), and ablation in close proximity to the coronary arteries and phrenic nerve (n = 1). Mapping in patients with subxiphoid surgical access was limited to the inferior and diaphragmatic surface of the heart extending posteriorly to the basal lateral wall. With limited anterior thoracotomy, access to the apex, anterior, and mid to apical anterolateral walls was obtained. In these regions, adhesions were more severe and repeat entry into the epicardial region at a different intercostal level was needed in two of three patients., Conclusion: Surgical access with subxiphoid window and limited anterior thoracotomy in the electrophysiology lab is feasible and safe. The surgical approach can be tailored to the region of interest in the ventricle to be mapped and ablated., (Copyright © 2010. Published by Elsevier Inc.)

Background: Management of ventricular tachycardia (VT) in patients with hypertrophic cardiomyopathy (HCM) is challenging., Objective: The purpose of this study is to assess the value of radiofrequency catheter ablation (RFCA) for the treatment of the VTs in the setting of HCM., Methods: Twenty-two patients (18 with ICD) with HCM and multiple episodes of VTs resistant to medical therapy underwent RFCA with an open irrigation catheter. Epicardial access was obtained if required. All patients were followed for at least 1 year after RFCA., Results: Mean age was 50.4 +/- 15.3, and mean ejection fraction was 34.3% +/- 9.8%. RFCA was performed endocardially in all patients, while epicardial radiofrequency applications were needed in 13 patients. A previous endocardial ablation was unsuccessful in six patients. At 20 +/- 9 months of follow-up, elimination of VTs reached 73%. No major complication was observed during and after the procedures in all patients., Conclusion: Catheter ablation of VTs in patients with hypertrophic cardiomyopathy refractory to medical therapy is safe, feasible, and successful in eliminating VT. Epicardial VT mapping and ablation should be considered as an important access option for the treatment of these patients to increase the success rate., (Copyright 2010 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: Reducing sympathetic output to the heart from the neuraxis can protect against ventricular arrhythmias. The purpose of this study was to assess the value of thoracic epidural anesthesia (TEA) and left cardiac sympathetic denervation (LCSD) in the management of ventricular arrhythmias in patients with structural heart disease., Methods and Results: Clinical data of 14 patients (25 to 75 years old, mean+/-SD of 54.2+/-16.6 years; 13 men) who underwent TEA, LCSD, or both to control ventricular tachycardia (VT) refractory to medical therapy and catheter ablation were reviewed. Twelve patients were in VT storm, and 2 experienced recurrent VT despite maximal medical therapy and catheter ablation procedures. The total number of therapies per patient before either procedure ranged from 5 to 202 (median of 24; 25th and 75th percentile, 5 and 56). Eight patients underwent TEA, and 9 underwent LCSD (3 patients had both procedures). No major procedural complications occurred. After initiation of TEA, 6 patients had a large (> or =80%) decrease in VT burden. After LCSD, 3 patients had no further VT, 2 had recurrent VT that either resolved within 24 hours or responded to catheter ablation, and 4 continued to have recurrent VT. Nine of 14 patients survived to hospital discharge (2 TEA alone, 3 TEA/LCSD combined, and 4 LCSD alone), 1 of the TEA alone patients underwent an urgent cardiac transplantation., Conclusions: Initiation of TEA and LCSD in patients with refractory VT was associated with a subsequent decrease in arrhythmia burden in 6 (75%) of 8 patients (68% confidence interval 51% to 91%) and 5 (56%) of 9 patients (68% confidence interval 34% to 75%), respectively. These data suggest that TEA and LCSD may be effective additions to the management of refractory ventricular arrhythmias in structural heart disease when other treatment modalities have failed or may serve as a bridge to more definitive therapy.

Objectives: The purpose of this study was to compare the characteristics and prevalence of late potentials (LP) in patients with nonischemic cardiomyopathy (NICM) and ischemic cardiomyopathy (ICM) etiologies and evaluate their value as targets for catheter ablation., Background: LP are frequently found in post-myocardial infarction scars and are useful ablation targets. The relative prevalence and characteristics of LP in patients with NICM is not well understood., Methods: Thirty-three patients with structural heart disease (NICM, n = 16; ICM, n = 17) referred for catheter ablation of ventricular tachycardia were studied. Electroanatomic mapping was performed endocardially (n = 33) and epicardially (n = 19). The LP were defined as low voltage electrograms (<1.5 mV) with onset after the QRS interval. Very late potentials (vLP) were defined as electrograms with onset >100 ms after the QRS., Results: We sampled an average of 564 +/- 449 points and 726 +/- 483 points in the left ventricle endocardium and epicardium, respectively. Mean total low voltage area in patients with ICM was 101 +/- 55 cm(2) and 56 +/- 33 cm(2), endocardial and epicardial, respectively, compared with NICM of 55 +/- 41 cm(2) and 53 +/- 28 cm(2), respectively. Within the total low voltage area, vLP were observed more frequently in ICM than in NICM in endocardium (4.1% vs. 1.3%; p = 0.0003) and epicardium (4.3% vs. 2.1%, p = 0.035). An LP-targeted ablation strategy was effective in ICM patients (82% nonrecurrence at 12 +/- 10 months of follow-up), whereas NICM patients had less favorable outcomes (50% at 15 +/- 13 months of follow-up)., Conclusions: The contribution of scar to the electrophysiological abnormalities targeted for ablation of unstable ventricular tachycardia differs between ICM and NICM. An approach incorporating LP ablation and pace-mapping had limited success in patients with NICM compared with ICM, and alternative ablation strategies should be considered., (Copyright (c) 2010 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)