Ventricular tachycardia burden reduction after substrate ablation: predictors of recurrence.

BACKGROUND Substrate-based ventricular tachycardia (VT) ablation is a first-line treatment in patients with structural cardiac disease and sustained VT refractory to medical therapy. Despite technological improvements and increased knowledge of VT substrate, recurrence still is frequent. Published data are lacking on the possible reduction in VT burden after ablation despite recurrence. OBJECTIVE The purpose of this study was to assess VT burden reduction during long-term follow-up after substrate ablation and identify predictors of VT recurrence. METHODS We analyzed 234 consecutive VT ablation procedures in 207 patients (age 63 6 14.9 years; 92% male; ischemic heart disease in 65%) who underwent substrate ablation in a single center from 2013 to 2018. RESULTS After follow-up of 3.14 6 1.8 years, the VT recurrence rate was 41.4%. Overall, a 99.6% reduction in VT burden (median VT episodes per year: preprocedural 3.546 [1.347-13.951] vs postprocedural 0.001 [0-0.689]; P 5 .001) and a 96.3% decrease in implantable cardioverter-defibrillator (ICD) shocks (preprocedural 1.145 [0.118-4.467] vs postprocedural 0.042 [0-0.111] per year; P 5 .017) were observed. In the subgroup of patients who experienced VT recurrences, VT burden decreased by 69.2% (median VT episodes per year: preprocedural 2.876 [1.105-8.801] vs postprocedural 0.882 [0.505-2.283]; P ,.001). Multivariable analysis showed persistence of late potentials (67% vs 19%; hazard ratio 3.18 [2.18- 6.65]; P ,.001) and lower left ventricular ejection fraction (EF) (30 [25-40] vs 39 [30-50]; P 5 .022) as predictors of VT recurrence. CONCLUSION Despite a high recurrence rate during long-term follow-up, substrate-based VT ablation is related to a large reduction in VT burden and a decrease in ICD therapies. Lower EF and persistence of late potentials are predictors of recurrence. KEYWORDS Arrhythmic burden reduction; Implantable cardioverter-defibrillator shock prevention; Ventricular tachycardia ablation; Ventricular tachycardia recurrence predictors; Ventricular tachycardia storm; Ventricular tachycardia substrate ablatio

Accuracy of standard bipolar amplitude voltage thresholds to identify late potential channels in ventricular tachycardia ablation

Background: Ventricular tachycardia (VT) is caused by the presence of a slow conduction channel (CC) of border zone (BZ) tissue inside the scar-core tissue. Electroanatomic mapping can depict this tissue by voltage mapping. Areas of slow conduction can be detected as late potentials (LPs) and their abolition is the most accepted ablation endpoint. In the current guidelines, bipolar voltage thresholds for BZ and core scar are 1.5 and 0.5 mV respectively. The performance of these values is controversial. The aim of the study is to analyze the diagnostic yield of current amplitude thresholds in voltage map to define VT substrate in terms of CCs of LPs. Predictors of usefulness of current thresholds will be analyzed. Methods: All patients with structural heart disease who underwent VT ablation in Hospital Clinic in 2016-2017 were included. Maps with delineation of CCs based on LPs were created with contact force sensor catheter. Thresholds were adjusted for every patient based on CCs. Diagnostic yield and predictors of performance of conventional thresholds were analyzed. Results: During study period, 57 consecutive patients were included (age: 60.4 ± 8.5; 50.2% ischemic cardiomyopathy, LVEF 39.8 ± 13.5%). Cutoff voltages that better identified the scar and BZ according to the LP channels were 0.32 (0.02-2 mV) and 1.84 (0.3-6 mV) respectively. Current voltage thresholds identified correctly core and BZ in 87.7% and 42.1% of the patients respectively. Accuracy was worse in non-ischemic cardiomyopathy (NICM) especially for BZ (28.6% vs 55.2%, p = 0.042). Conclusions: Accuracy of standard voltage thresholds for scar and BZ is poor in terms of LPs detection. Diagnostic yield is worse in NICM patients specially for border zone

Orthogonal high-density mapping with ventricular tachycardia isthmus analysis vs. pure substrate ventricular tachycardia ablation: A case–control study

Substrate-based ablation has become a successful technique for ventricular tachycardia (VT) ablation. High-density (HD) mapping catheters provide high-resolution electroanatomical maps and better discrimination of local abnormal electrograms. The HD Grid Mapping Catheter is an HD catheter with the ability to map orthogonal signals on top of conventional bipolar signals, which could provide better discrimination of the arrhythmic substrate. On the other hand, conventional mapping techniques, such as activation mapping, when possible, help to identify the isthmus of the tachycardia.The purpose of this study was to compare clinical outcomes after using two different VT ablation strategies: one based on extensive mapping with the HD Grid Mapping Catheter, including VT isthmus analysis, and the other based on pure substrate ablation.Forty consecutive patients undergoing VT ablation with extensive HD mapping method in the hospital clinic (November 2018-November 2019) were included. Clinical outcomes were compared with a historical cohort of 26 consecutive patients who underwent ablation using a scar dechanneling technique before 2018.The density of mapping points was higher in the extensive mapping group (2370.24 ± 920.78 vs. 576.45 ± 294.46; p < 0.001). After 1 year of follow-up, VT recurred in 18.4% of patients in the extensive mapping group vs. 34.6% of patients in the historical control group (p = 0.14), with a significantly greater reduction of VT burden: VT episodes (81.7 ± 7.79 vs. 43.4 ± 19.9%, p < 0.05), antitachycardia pacing (99.45 ± 2.29 vs. 33.9 ± 102.5%, p < 0.001), and implantable cardioverter defibrillator (ICD) shocks (99 ± 4.5 vs. 64.7 ± 59.9%, p = 0.02).The use of a method based on extensive mapping with the HD Grid Mapping Catheter and VT isthmus analysis allows better discrimination of the arrhythmic substrate and could be associated with a greater decrease in VT burden.Copyright © 2022 Vázquez-Calvo, Garre, Sanchez-Somonte, Borras, Quinto, Caixal, Pujol-Lopez, Althoff, Guasch, Arbelo, Tolosana, Brugada, Mont and Roca-Luque

Scar channels in cardiac magnetic resonance to predict appropriate therapies in primary prevention.

Background Scar characteristics analyzed by late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) are related with ventricular arrhythmias. Current guidelines are based only on the left ventricular ejection fraction to recommend an implantable cardioverter-defibrillator (ICD) in primary prevention. Objectives Our study aims to analyze the role of imaging to stratify arrhythmogenic risk in patients with ICD for primary prevention. Methods From 2006 to 2017, we included 200 patients with LGE-CMR before ICD implantation for primary prevention. The scar, border zone, core, and conducting channels (CCs) were automatically measured by a dedicated software. Results The mean age was 60.9 ± 10.9 years; 81.5% (163) were men; 52% (104) had ischemic cardiomyopathy. The mean left ventricular ejection fraction was 29% ± 10.1%. After a follow-up of 4.6 ± 2 years, 46 patients (22%) reached the primary end point (appropriate ICD therapy). Scar mass (36.2 ± 19 g vs 21.7 ± 10 g; P 10 g (25.31% vs 5.26%; hazard ratio 4.74; P = .034) and the presence of CCs (34.75% vs 8.93%; hazard ratio 4.07; P = .003) were also strongly associated with the primary end point. However, patients without channels and with scar mass < 10 g had a very low rate of appropriate therapies (2.8%). Conclusion Scar characteristics analyzed by LGE-CMR are strong predictors of appropriate therapies in patients with ICD in primary prevention. The absence of channels and scar mass < 10 g can identify patients at a very low risk of ventricular arrhythmias in this population

Optimized single-point left ventricular pacing leads to improved resynchronization compared with multipoint pacing

[EN] Background Multipoint pacing (MPP) in cardiac resynchronization therapy (CRT) activates the left ventricle from two locations, thereby shortening the QRS duration and enabling better resynchronization; however, compared with conventional CRT, MPP reduces battery longevity. On the other hand, electrocardiogram-based optimization using the fusion-optimized intervals (FOI) method achieves more significant reverse remodeling than nominal CRT programming. Our study aimed to determine whether MPP could attain better resynchronization than single-point pacing (SPP) optimized by FOI. Methods This prospective study included 32 consecutive patients who successfully received CRT devices with MPP capabilities. After implantation, the QRS duration was measured during intrinsic rhythm and with three pacing configurations: MPP, SPP-FOI, and MPP-FOI. In 14 patients, biventricular activation times (by electrocardiographic imaging, ECGI) were obtained during intrinsic rhythm and for each pacing configuration to validate the findings. Device battery longevity was estimated at the 45-day follow-up. Results The SPP-FOI method achieved greater QRS shortening than MPP (-56 +/- 16 vs. -42 +/- 17 ms, p < .001). Adding MPP to the best FOI programming did not result in further shortening (MPP-FOI: -58 +/- 14 ms, p = .69). Although biventricular activation times did not differ significantly among the three pacing configurations, only the two FOI configurations achieved significant shortening compared with intrinsic rhythm. The estimated battery longevity was longer with SPP than with MPP (8.1 +/- 2.3 vs. 6.3 +/- 2.0 years, p = .03). Conclusions SPP optimized by FOI resulted in better resynchronization and longer battery duration than MPP.Centro de Investigacion Biomedica en Red Enfermedades Cardiovasculares, Grant/Award Number: CB16/11/00354; Instituto de Salud Carlos III, Grant/Award Numbers: DTS16/0160, PI16/00435, PI16/00703, PI17/01059, PI17/01106; Sociedad Espanola de Cardiologia, Grant/Award Numbers: 2018, SEC_ESTIM_01; Agencia deGestio d'Ajuts Universitaris i de Recerca, Grant/AwardNumber: 2017_SGR_1548; Fundacio laMarato de TV3, Grant/Award Number: 20152730; Horizon 2020 Framework Programme, Grant/Award Number: 633196 - CATCH MEproject; European Regional Development Fund, Grant/Award Number: EITHealth 19600 AFFINESan Antonio, R.; Guasch, E.; González-Ascaso, A.; Jiménez-Arjona, R.; Climent, AM.; Pujol-López, M.; Doltra, A.... (2021). Optimized single-point left ventricular pacing leads to improved resynchronization compared with multipoint pacing. Pacing and Clinical Electrophysiology. 44(3):519-527. https://doi.org/10.1111/pace.14185S51952744