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Background: Post-myocardial infarction (MI) patients with ventricular tachycardia (VT) are considered at risk for VT recurrence and sudden cardiac death (SCD). Recent guidelines indicate that in selected patients catheter ablation should be considered instead of an implantable cardioverter-defibrillator (ICD)., Objectives: This study aimed to analyze outcomes of patients referred for VT ablation according to left ventricular ejection fraction (LVEF), tolerance of VT, and acute ablation outcome., Methods: Post-MI patients without prior ICD undergoing VT ablation at a single center between 2009 and 2022 were included. Patients who presented with tolerated VT and who had an LVEF >35% were offered catheter ablation as first-line therapy. ICD implantation was offered to all patients but was subject to shared decision according to clinical presentation, LVEF, and ablation outcome., Results: Eighty-six patients (mean age 69 ± 9 years, 84% male, mean LVEF 41 ± 9%) underwent VT ablation. In 66 patients, LVEF was >35%, of whom 51 had tolerated VT. Of these 51 patients, 37 (73%) were rendered noninducible. In 5 of 37 noninducible and in 11 of 14 inducible patients, an ICD was implanted. During a median follow-up of 40 months (Q1-Q3: 24-70 months), 10 of 86 patients had VT recurrence. The overall mortality was 27%, and 1 patient with ICD died suddenly. Among the 37 patients (none on antiarrhythmic drugs) with LVEF >35%, tolerated VT, and noninducibility, no SCD or VT recurrence occurred. Among the 14 patients with LVEF >35%, tolerated VT, and inducibility after ablation, no SCD occurred, but VT recurred in 29%., Conclusions: Post-MI patients with LVEF >35%, tolerated VT, and noninducibility after ablation have an excellent prognosis. Deferring ICD implantation seems to be safe in these patients., Competing Interests: Funding Support and Author Disclosures The authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Patients with dilated cardiomyopathy (DCM) who are undergoing catheter ablation of ventricular arrhythmias (VAs) are at risk of rapidly progressive heart failure (HF). Endocardial voltages decrease with loss of viable myocardium. Global left ventricular (LV) voltage as a surrogate for the amount of remaining viable myocardium may predict prognosis., Objectives: This study evaluated whether the newly proposed parameter volume-weighted (vw) unipolar voltage (UV) can predict HF-related adverse outcomes (HFOs), including death, heart transplantation, or ventricular assist device implantation, in DCM., Methods: In consecutive patients with DCM referred for VA ablation, vwUV was calculated by mathematically integrating UV over the left ventricle, divided by the endocardial LV surface area and wall thickness. Patients were followed for HFOs., Results: A total of 103 patients (57 ± 14 years of age; left ventricular ejection fraction [LVEF], 39% ± 13%) were included. Median vwUV was 9.75 (IQR: 7.27-12.29). During a median follow-up of 24 months (IQR: 8-47 months), 25 patients (24%) died, and 16 had HFOs 7 months (IQR: 1-18 months) after ablation. Patients with HFOs had significantly lower LVEF (29% ± 10% vs 41% ± 12%), vw bipolar voltage (BV) (3.00 [IQR: 2.47-3.53] vs 5.00 [IQR: 4.12-5.73]), and vwUV (5.94 [IQR: 5.28-6.55] vs 10.37 [IQR: 8.82-12.81]; all P < 0.001), than patients without HFOs. In Cox regression analysis and goodness-of-fit tests, vwUV was the strongest and independent predictor for HFOs (HR: 3.68; CI: 2.09-6.45; likelihood ratio chi-square, 33.05; P < 0.001)., Conclusions: The novel parameter vwUV, as a surrogate for the amount of viable myocardium, identifies patients with DCM with VA who are at high risk for HF progression and mortality., Competing Interests: Funding Support and Author Disclosures The Department of Cardiology Leiden receives unrestricted research and fellowship grants from Edward Lifesciences, Boston Scientific, Medtronic, and Biotronik. All authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2023 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Electroanatomical voltage mapping (EAVM) has been compared with late gadolinium enhancement cardiovascular magnetic resonance (LGE-CMR), which cannot delineate diffuse fibrosis. T1-mapping CMR overcomes the limitations of LGE-CMR, but it has not been directly compared against EAVM., Objectives: This study aims to assess the relationship between left ventricular (LV) endocardial voltage obtained by EAVM and extracellular volume (ECV) obtained by T1 mapping., Methods: The study investigated patients who underwent endocardial EAVM for ventricular arrhythmias (CARTO 3, Biosense Webster) together with preprocedural contrast-enhanced T1 mapping (Ingenia 3T, Philips Healthcare). After image integration, EAVM datapoints were projected onto LGE-CMR and ECV-encoded images. Average values of unipolar voltage (UV), bipolar voltage (BV), LGE transmurality, and ECV were merged from corresponding cardiac segments (6 per slice) and pooled for analysis., Results: The analysis included data from 628 segments from 18 patients (57 ± 13 years of age, 17% females, LV ejection fraction 48% ± 14%, nonischemic/ischemic cardiomyopathy/controls: 8/6/4 patients). Based on the 95th and 5th percentile values obtained from the controls, ECV >33%, BV <2.9 mV, and UV <6.7 mV were considered abnormal. There was a significant inverse association between voltage and ECV, but only in segments with abnormal ECV. Increased ECV could predict abnormal BV and UV with acceptable accuracy (area under the curve of 0.78 [95% CI: 0.74-0.83] and 0.84 [95% CI: 0.79-0.88])., Conclusions: This study found a significant inverse relationship between LV endocardial voltage and ECV. Real-time integration of T1 mapping may guide catheter mapping and may allow identification of areas of diffuse fibrosis potentially related to ventricular arrhythmias., Competing Interests: Funding Support and Author Disclosures This work was partially supported by an ESC Research Grant received by Dr Sramko. The authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2023. Published by Elsevier Inc.)

Background: Very high-power, short-duration (90-W/4-second) ablation for pulmonary vein isolation (PVI) may reduce procedural times. However, shorter applications with higher power may impact lesion quality., Objectives: In this multicenter, randomized controlled trial, the authors compared procedural efficiency, efficacy, and safety of PVI using 90-W/4-second ablation to 35/50-W ablation., Methods: Patients with paroxysmal or persistent atrial fibrillation undergoing first-time PVI were randomized to pulmonary vein encirclement with contiguous applications using very high-power, short-duration applications (90 W over 4 seconds) or 35/50-W applications (titrated up to ablation index >550 anteriorly and >400 posteriorly). Prospective endpoints were procedural efficiency (procedure time and first-pass isolation), safety (including esophageal endoscopic evaluation), and 6-month effectiveness using repetitive Holter monitoring., Results: A total of 180 patients were randomized, 90 to the 90-W group (mean age: 64.2 ± 8.9 years) and 90 to the 35/50-W group (mean age: 62.3 ± 10.8 years). Procedural time was shorter in the 90-W group vs the 35/50-W group (70 [IQR: 60-80] minutes vs 75 [IQR: 65-88.3] minutes; P = 0.009). A nonsignificant trend towards lower rates of first-pass isolation was seen in the 90-W group (83.9% vs 90%; P = 0.0852). No major complications were observed in both groups with esophageal injury occurring in 1 patient per group. At 6 months, 17% of patients in the 90-W group vs 15% in the 35/50-W group experienced recurrent arrhythmia (P = 0.681)., Conclusions: Contiguous ablation using very high-power, short-duration applications results in a significant but modest reduction in procedure time with similar safety and 6-month efficacy vs a conventional approach. A hybrid approach combining both ablation modalities might be the most optimal strategy. (POWER PLUS [Very High Power Ablation in Patients With Atrial Fibrillation Schedule for a First Pulmonary Vein Isolation]; NCT04784013)., Competing Interests: Funding Support and Author Disclosures Dr Kobza has served as a consultant for Biosense-Webster, Biotronik, and Medtronic, not related to this work. Drs Duytschaever and Scherr have received speaker fees from Biosense Webster, not related to this work. Dr Manninger has received research grants from Biosense Webster, not related to this work., (Copyright © 2023 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Predicting early reconnection/dormant conduction (ERC) immediately after pulmonary vein isolation (PVI) can avoid a waiting period with adenosine testing., Objective: To identify procedural and biophysical parameters predicting ERC., Methods: Consecutive atrial fibrillation (AF) patients undergoing a first cryoballoon ablation (Arctic Front Advance) between 2014 and 2017 were included. ERC was defined as manifest or dormant pulmonary vein (PV) reconnection with adenosine 30 minutes after PVI. Time to isolation (TTI), balloon temperatures (BT), and thawing times were evaluated as potential predictors for ERC. Based on a multivariable model, cut-off-values were defined and a formula was constructed to be used in clinical practice., Results: A total of 136 patients (60 ± 10 years, 96 male, 95% paroxysmal AF) were included. ERC was found in 40 (29%) patients (ERC group) and in 53 of 575 (9%) veins. Procedural and total ablation time and the number of unsuccessful freezes were significantly longer/higher in the ERC group compared to the non-ERC group (150 ± 40 vs 125 ± 34 minutes; 24 ± 5 vs 17 ± 4 minutes, and 38% vs 24%, respectively ( P = .028). Multivariable analysis showed that a higher nadir balloon temperature (hazard ratio [HR] 1.17 [1.09-1.23, P < .001), a higher number of unsuccessful freezes (HR 1.69 [1.15-2.49], P = .008) and a longer TTI (HR 1.02 [1.01-1.03], P < .001) were independently associated with ERC, leading to the following formula: 0.02 × TTI + 0.5 × number of unsuccessful freezes + 0.2 × nadir BT with a cut-off value of ≤-6.7 to refrain from a waiting period with adenosine testing., Conclusion: Three easily available parameters were associated with ERC. Using these parameters during ablation can help to avoid a 30-minute waiting period and adenosine testing., (© 2021 Heart Rhythm Society. Published by Elsevier Inc.)

Objectives: This study aimed to assess the frequency of (likely) pathogenic variants (LP/Pv) among dilated cardiomyopathy (DCM) ventricular tachycardia (VT) patients referred for CA and their impact on procedural outcome and long-term prognosis., Background: The prevalence of genetic variants associated with monomorphic VT among DCM is unknown., Methods: Ninety-eight consecutive patients (age 56 ± 15 years; 84% men, left ventricular ejection fraction [LVEF] 39 ± 12%) referred for DCM-VT ablation were included. Patients underwent electroanatomical mapping and testing of ≥55 cardiomyopathy-related genes. Mapping data were analyzed for low-voltage areas and abnormal potentials. LP/Pv-positive (LP/Pv+) patients were compared with LP/Pv-negative (LP/Pv-) patients and followed for VT recurrence and mortality., Results: In 37 (38%) patients, LP/Pv were identified, most frequently LMNA (n = 11 of 37, [30%]), TTN (n = 6 of 37, [16%]), PLN (n = 6 of 37, [16%]), SCN5A (n = 3 of 37, [8%]), RBM20 (n = 2 of 37, [5%]) and DSP (n = 2 of 37, [5%]). LP/Pv+ carriers had lower LVEF (35 ± 13% vs. LP/Pv-: 42 ± 11%; p = 0.005) and were less often men (n = 27 [73%] vs. n = 55 [90%]; p = 0.03). After a median follow-up of 2.4 years (interquartile range: 0.9 to 4.4 years), 63 (64%) patients had VT recurrence (LP/Pv+: 30 of 37 [81%] vs. LP/Pv-: 33 of 61 [54%]; p = 0.007). Twenty-eight patients (29%) died (LP/Pv+: 19 of 37 [51%] vs. LP/Pv-: 9 of 61 [15%]; p < 0.001). The cumulative 2-year VT-free survival was 41% in the total cohort (LP/Pv+: 16% vs. LP/Pv-: 54%; p = 0.001). The presence of LP/Pv (hazard ratio: 1.9; 95% confidence interval: 1.1 to 3.4; p = 0.02) and unipolar low-voltage area size/cm 2 increase (hazard ratio: 2.5; 95% confidence interval: 1.6 to 4.0; p < 0.001) were associated with a decreased 2-year VT-free survival., Conclusions: In patients with DCM-VT, a genetic cause is frequently identified. LP/Pv+ patients have a lower LVEF and more extensive VT substrates, which, in combination with disease progression, may contribute to the poor prognosis. Genetic testing in patients with DCM-VT should therefore be recommended., (Copyright © 2020 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: This study proposed entropy as a new late gadolinium enhanced cardiac magnetic resonance-derived parameter to evaluate tissue inhomogeneity, independent of signal intensity thresholds. This study hypothesized that entropy within the scar is associated with ventricular arrhythmias (VAs), whereas entropy of the entire left ventricular (LV) myocardium is associated with mortality., Background: In patients after myocardial infarction, the heterogeneity of fibrosis determines the substrate for VA. Fibrosis in remote areas has been associated with heart failure and mortality. Late gadolinium-enhanced cardiac magnetic resonance has been used to delineate fibrosis, but available methods depend on signal intensity thresholds and results have been inconsistent., Methods: Consecutive post-myocardial infarction patients undergoing late gadolinium enhanced cardiac magnetic resonance prior to implantable cardioverter-defibrillator implantation were included. From cardiac magnetic resonance imaging, total scar size, scar gray zone, scar transmurality, and tissue entropy were derived. Patients were followed for appropriate implantable cardioverter-defibrillator therapy and mortality., Results: A total of 154 patients (age 64 ± 10 years, 84% male, LV ejection fraction 29 ± 10%, 47% acute revascularization) were included. During a median follow-up of 56 (interquartile range: 40 to 73) months, appropriate implantable cardioverter-defibrillator therapy occurred in 46 patients (30%), and 41 patients (27%) died. From multivariable analysis, higher entropy of the scar (hazard ratio [HR]: 1.9; 95% confidence interval [CI]: 1.0 to 3.5; p = 0.042) was independently associated with VA, after adjusting for multivessel disease, acute revascularization, LV ejection fraction, scar gray zone, and transmurality. Entropy of the entire LV was independently associated with mortality (HR: 3.2; 95% CI: 1.1 to 9.9; p = 0.038)., Conclusions: High entropy within the scar was associated with VA and may indicate an arrhythmogenic scar. High entropy of the entire LV was associated with mortality and may reflect a fibrosis pattern associated with adverse remodeling., (Copyright © 2019 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: The purpose of this study was to randomly compare the incidence of asymptomatic cerebral embolism (ACE) between the second-generation pulmonary vein ablation catheter (PVAC Gold) and the irrigated Thermocool catheter., Background: Pulmonary vein isolation (PVI) with the PVAC is associated with ACE. The PVAC Gold was designed to avoid this complication., Methods: Patients with paroxysmal atrial fibrillation were randomized 1:1 to PVI with the PVAC Gold or Thermocool catheter. Cerebral magnetic resonance imaging was performed in the days before and after ablation and repeated after 3 months in case of a new lesion. Monitoring for microembolic signals (MES) was performed by using transcranial Doppler ultrasonography. Parameters of coagulation were determined before, during, and after ablation. Neuropsychological tests and questionnaires were applied 10 days before and 3 months after ablation., Results: Seventy patients were included in the study (mean age 61 ± 9 years; 43 male subjects; CHA 2 DS 2 -VASc [congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, stroke/transient ischemic attack, vascular disease, age 65 to 74 years, sex category] score 1.6 ± 1.2; international normalized ratio 2.7 ± 0.5; activated clotting time 374 ± 24 s; p > 0.05 for all parameters). Procedural duration was shorter in the PVAC Gold group (140 ± 34 vs. 207 ± 44 min; p < 0.001). Eight (23%; 7 infarcts) patients in the PVAC Gold group exhibited a new ACE, compared with 2 (6%; no infarcts) patients in the Thermocool group (p = 0.042). Median number of MES was higher in the PVAC Gold group (1,111 [interquartile range, 715-2,234] vs. 787 [interquartile range, 532-1,053]; p < 0.001). There were no differences between groups regarding coagulation and neuropsychological outcomes., Conclusions: PVI with the new PVAC Gold was associated with a higher incidence of ACE/cerebral infarcts and number of MES. Both catheters induced a comparable procoagulant state. Because there were no measurable differences in neuropsychological status, the clinical significance of ACE remains unclear. (Cerebral Embolism [CE] in Catheter Ablation of Atrial Fibrillation [AF] [CE-AF]; NCT01361295)., (Copyright © 2019 The Authors. Published by Elsevier Inc. All rights reserved.)

Objectives: This study sought to determine whether ablation of hidden substrate unmasked by right ventricular extrastimulation (RVE) improves ablation outcome of post-myocardial infarction (MI) ventricular tachycardia (VT)., Background: In patients with small or nontransmural scars after MI, part of the VT substrate may be functional and, in addition, masked by high-voltage far-field signals arising from adjacent normal myocardium., Methods: In 60 consecutive patients, systematic analysis of electrograms recorded from the presumed infarct area was performed during sinus rhythm, RV pacing at 500 ms, and during a short-coupled RV extrastimulus. Sites showing low-voltage, near-field potentials with evoked conduction delay in response to RVE were targeted., Results: In 37 (62%) patients, ablation target sites located in areas with normal voltage during sinus rhythm were unmasked by RVE (hidden substrate group). These patients had better left ventricular function (36 ± 11% vs. 26 ± 12%; p = 0.003), smaller electroanatomical scars (<1.5 mV), and smaller dense scars (<0.5 mV) (median 59 and 14 cm 2 vs. 82 and 44 cm 2 ; p = 0.044 and p = 0.003) than did those in whom no hidden substrate was identified (overt substrate group). During a median follow-up of 16 months, 13 (22%) patients had VT recurrence. Patients with hidden substrate had a lower incidence of VT recurrence (12-month VT-free survival 89% vs. 50% in patients with overt substrate; p = 0.005). Compared with a historical cohort of 90 post-MI patients matched for left ventricular function and electroanatomical scar area, in whom no RVE was performed, patients in the hidden substrate group had a higher 1-year VT-free survival (89% vs. 73%; p = 0.039)., Conclusions: Hidden substrate ablation unmasked by RVE improves ablation outcome in post-MI patients with small or nontransmural scars., (Copyright © 2018 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)