BACKGROUND AND OBJECTIVES:The electrocardiography (ECG) morphology of lead aVR has been associated with arrhythmic risk in Brugada syndrome, but its role in arrhythmogenic right ventricular cardiomyopathy (ARVC) remains unclear. To evaluate the clinical significance of aVR morphology in ARVC patients. METHODS:A total of 45 subjects diagnosed with ARVC who underwent epicardial-endocardial mapping were enrolled in the study. The patients were divided into two groups based on the presence of an epicardial right ventricular outflow tract (RVOT) scar: the n-RVOT group (scar area <50%, n=10) and the p-RVOT group (scar area ≥50%, n=35). The aVR morphology was classified into QR pattern, R pattern (including R wave, rS or Rs), and QS pattern. The baseline characteristics and procedural parameters were analyzed. RESULTS:A higher incidence of inferior axis ventricular arrhythmia (VA) was observed in the p-RVOT group (64.2% vs. 33.3%, p=0.050). An R wave and QS pattern in aVR were associated with epicardial RVOT scar involvement. Among patients with QR pattern, an R/Q ratio<0.582 discriminated epicardial RVOT scar involvement (area under the receiver operating characteristic curve=0.88), with a sensitivity of 93.3% and specificity 80.0%. An R pattern was associated with reduced right ventricular ejection fraction (p=0.033) and a higher incidence of clinical or inducible ventricular fibrillation (p=0.021). There was no significant difference in post-ablation VA recurrence based on the presence of RVOT scar and aVR morphology. CONCLUSIONS:In patients with ARVC, the ECG morphology of lead aVR was associated with scar distribution and right ventricular dysfunction.

Background Acute myocardial infarction (MI) increases sympathetic tone and increases the risk of life‐threatening ventricular arrhythmias. We tested the hypothesis that spinal cord stimulation (SCS) using pulsed ultrahigh frequency (PUF) from T1 to T3 remodels the sympathetic activity and reduces ventricular arrhythmias. Methods Twenty pigs were used in this study. Six were assigned to the control group, 7 received MI (MI Group), and 7 received MI plus PUF‐SCS (MI+SCS Group). Seven pigs underwent a second surgery to implant the spinal stimulator. Echocardiography, 7‐day Holter monitoring, and blood analyses were performed at baseline, 1 month after MI, and 1 month after PUF‐SCS. All the pigs underwent an electrophysiological study and were euthanized. The left ventricular tissue was extracted for norepinephrine and adrenaline analyses. The sympathetic and stellate ganglia were analyzed. Results Sympathetic tone and ventricular arrhythmia episodes from the Holter monitor increased after MI but were suppressed after PUF‐SCS. The left ventricular ejection fraction decreased in the MI group and improved after PUF‐SCS. The ventricular fibrillation induction rates were 17%, 100%, and 29% in the Control, MI, and MI+SCS groups respectively (P=0.0016). Pathological analysis of the sympathetic and stellate ganglia revealed no significant apoptosis. Conclusions PUF‐SCS effectively suppressed sympathetic tone and reduced ventricular arrhythmia burden without causing permanent damage to the sympathetic ganglia. In the MI model, heart function and ventricular fibrillation vulnerability were reversed 1 month after PUF‐SCS.

J-wave syndromes (JWS)-comprising Brugada syndrome (BrS) and early repolarization syndrome (ERS)-are important causes of malignant ventricular arrhythmias and sudden cardiac death in patients whose hearts appear structurally normal. Since the 2016 consensus, advances in genetics, pathophysiology, and therapy have redefined both understanding and management. BrS, once viewed as a purely electrical disorder, is now recognized along a microstructural-electrical continuum, with sodium-channel dysfunction and subtle epicardial fibrosis of the right ventricular outflow tract as key contributors. Likewise, ERS-historically considered benign-carries significant risk when inferolateral J-waves coexist with arrhythmic events. Genetically, SCN5A remains the sole gene with definitive disease association, while polygenic susceptibility materially modulates risk, underscoring complex inheritance. Risk stratification remains challenging: patients with prior cardiac arrest or arrhythmic syncope are highest risk, whereas asymptomatic individuals warrant multiparametric assessment integrating clinical features, ECG markers, electrophysiologic studies, and genetics. For decades, treatment centered on implantable cardioverter-defibrillators and quinidine, both limited by availability, tolerance, and device complications. More recently, epicardial substrate ablation has emerged as a transformative therapy, with large registries and randomized trials demonstrating durable suppression of ventricular fibrillation and acceptable safety. This APHRS-organized international consensus updates and extends the 2016 Expert Consensus and the 2022 ESC Guidelines, providing contemporary diagnostic frameworks, pragmatic risk-stratification tools, and treatment algorithms for BrS and ERS. It emphasizes JWS as a microstructural-electrical disease spectrum and elevates substrate ablation as a major therapeutic advance, while outlining priorities for genetics, risk-stratification and treatment algorithms.

Background Ventricular arrhythmias (VAs) arising near the left ventricular (LV) summit are often successfully ablated from adjacent anatomic sites. However, the role of bipolar and unipolar electrograms in guiding optimal ablation remains unclear. This study aimed to investigate whether bipolar and unipolar electrogram characteristics can help identify the most effective ablation sites for VAs near the LV summit. Methods We retrospectively analyzed patients with idiopathic VAs originating from the LV summit, excluding those with structural heart disease or reentrant mechanisms. Electrograms were evaluated at the earliest activation sites within the great cardiac vein/anterior interventricular vein, aortic sinus of Valsalva, subvalvular LV regions, and the right ventricular outflow tract. Bipolar local activation time (LATBi) and unipolar local activation time were assessed. Results A total of 78 patients (mean age, 53.9±16.6 years; 59 men) with 80 VAs and 229 mapping points (60 in the great cardiac vein/anterior interventricular vein, 62 in the aortic sinus of Valsalva, 65 in subvalvular LV regions, and 42 in the right ventricular outflow tract) were analyzed. Ablation was successful at 65 sites. The mean LATBi at successful sites was 28.1±21.8 ms. Longer LATBi significantly predicted successful ablation (odds ratio, 1.07 [95% CI, 1.02–1.12]; P=0.004). The optimal LATBi threshold was 14 ms (sensitivity, 85%; specificity, 44%; area under the curve, 0.67). Unipolar local activation time, LATBi−unipolar local activation time differences, unipolar QS morphology, and unipolar waveform characteristics did not predict success. Conclusions Early LATBi was associated with successful ablation of LV summit VAs, whereas unipolar electrogram features were not independently predictive.