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

Combined Area of Left and Right Atria May Outperform Atrial Volumes as a Predictor of Recurrences after Ablation in Patients with Persistent Atrial Fibrillation—A Pilot Study

Background and Objectives: Left atrial (LA) remodelling and dilatation predicts atrial fibrillation (AF) recurrences after catheter ablation. However, whether right atrial (RA) remodelling and dilatation predicts AF recurrences after ablation has not been fully evaluated. Materials and Methods: This is an observational study of 85 consecutive patients (aged 57 ± 9 years; 70 [82%] men) who underwent cardiac magnetic resonance before first catheter ablation for AF (40 [47.1%] persistent AF). Four-chamber cine-sequence was selected to measure LA and RA area, and ventricular end-systolic image phase to obtain atrial 3D volumes. The effect of different variables on event-free survival was investigated using the Cox proportional hazards model. Results: In patients with persistent AF, combined LA and RA area indexed to body surface area (AILA + RA) predicted AF recurrences (HR = 1.08, 95% CI 1.00-1.17, p = 0.048). An AILA + RA cut-off value of 26.7 cm2/m2 had 72% sensitivity and 73% specificity for predicting recurrences in patients with persistent AF. In this group, 65% of patients with AILA + RA > 26.7 cm2/m2 experienced AF recurrence within 2 years of follow-up (median follow-up 11 months), compared to 25% of patients with AILA + RA ≤ 26.7 cm2/m2 (HR 4.28, 95% CI 1.50-12.22; p = 0.007). Indices of LA and RA dilatation did not predict AF recurrences in patients with paroxysmal AF. Atrial 3D volumes did not predict AF recurrences after ablation. Conclusions: In this pilot study, the simple measurement of AILA + RA may predict recurrences after ablation of persistent AF, and may outperform measurements of atrial volumes. In paroxysmal AF, atrial dilatation did not predict recurrences. Further studies on the role of RA and LA remodelling are needed

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