Search

Funding Acknowledgements Type of funding sources: None. Introduction Brugada syndrome (BrS) is a channelopathy confining an increased risk of sudden cardiac death (SCD). Asymptomatic patients (pts) management remains challenging enhancing the necessity for additionally stratification tools. Purpose To evaluate the role of the non-invasive assessment of late potentials (LP) based on SA-ECG as stratification tools in a BrS cohort. Methods Prospective, observational single-center study of pts with BrS with the following criteria (1) Type 1 Brugada ECG pattern, either spontaneous or drug induced; (2) SA-ECG performed before anti-arrhythmic treatment; (3) minimum follow up duration of 12 months. LPs were evaluated by SA-ECG with determination of the total filtered QRS duration (fQRS); root mean square voltage of the 40ms terminal portion of the QRS (RMS40) and duration of the low amplitude electric potential component of the terminal portion of the QRS (LAS40) in conventional and modified right precordial leads. Malignant arrhythmic events (MAEs) were defined as a composite event of SCD or appropriate ICD shocks. Association of relevant risk factors and MAE was conducted with Univariate Cox regression analysis, as well as SA-ECG evaluated as a continuous and categorical divided on standard cut-offs (fQRS >114ms, RMS4038ms). A risk score for predicting MAE was computed incorporating the significant LPs variables. Results A total of 106 pts fulfilled the inclusion criteria (mean age: 48 ± 12 years, 67.9% male), 52 (49.1%) with type 1 spontaneous pattern. The majority were asymptomatic at baseline (81.1%) while 13 presented with syncope and 3 with polymorphic VT/cardiac arrest. A total of 10 (7.1%) pts MAEs were documented during a mean 4.7 years - 4 with SCD and 6 with appropriate ICD shocks. Clinical presentation with a polymorphic VT/cardiac arrest (p Conclusion LPs based on noninvasive assessment SAECG represent an useful prognostic stratification tool in BrS. A LP score based on standard cut-offs identified a subset of pts at a higher risk of events and who may deserve individualized preventive strategies.

Funding Acknowledgements Type of funding sources: None. Introduction The decrease in the use of linear ablation for atrial fibrillation treatment has reduced the frequency of iatrogenic feft-sided atypical flutters (AFl). However, AFl are becoming increasingly frequent, associated with population age and risk factors for atrial scar. Revising the mechanisms of non-iatrogenic AFl may lead to a better procedure workflow. Purpose To describe the mechanisms of non-iatrogenic AFl. Methods Retrospective single-center study of AFl patients (pts) submitted high-density mapping from 2018 to 2022. Patients submitted to any prior left atrial linear ablation were excluded. Map collection was performed just visualizing the voltage map and a comprehensive workflow was applied for activation map interpretation, starting by facing the mitral annulus and following the sequence of colors to systematically identify all potential circuits, their common-isthmuses, and eventual slow-conduction sites. Entrainment maneuvers were performed to confirm the circuit interpretation if sinus rhythm was not restored with the completion of the planned ablation set. Results A total of 59 pts were included (male: 56% male; 67 ± 13 years), 28 previously submitted to atrial fibrillation ablation, restricted to pulmonary vein (PV) isolation. About 88% presented a macro-reentrant mechanism, either restricted to the left atrium (N=50) or biatrial (N=2) and involving 2 or 3 loops in 61% - Figure 1. Perimitral loop was the most frequent reentrant circuit, representing 60% of macro-reentrant arrhythmias (N=30) and exhibiting an evident out-of-proportion predominance of counterclockwise rotations (73% versus 27%). Among perimitral flutters with at least one additional loop, a balanced distribution was recognized of rotations around the left and right PVs (10 versus 10). As a result of the existence of additional loops producing common-isthmuses locations in various atrial regions, the classical inferior mitral isthmus line (from the mitral annulus to the left inferior PV) would only terminate as much as 53% of the perimitral AFl. The mechanism-tailored ablation strategy, particularly targeting the AFl common-isthmuses, resulted in restoration of sinus rhythm in 96.6% of pts (N=57). Conclusions In pts not previously submitted to linear ablations, AFl are predominantly caused by macro-reentrant circuits involving a perimitral rotation but not necessarily possible to treat with a conventional mitral isthmus line. With current high-density mapping tools, a comprehensive analysis of the substrate and activation maps and a mechanism-tailored ablation strategy results in an unprecedently high acute success rate.