BACKGROUND:The subcutaneous implantable cardioverter defibrillator (S-ICD) offers protection from sudden cardiac death without transvenous leads. Although contemporary techniques and programming have reduced inappropriate shocks, high rates persist in certain populations. The objective of this study was to evaluate the impact of a novel quantitative vector screening (QVS) protocol on the incidence of sensing-related complications and inappropriate shocks in patients undergoing S-ICD implantation. METHODS:We analyzed 223 consecutive patients who underwent S-ICD implantation at the Hospital of the University of Pennsylvania from December 2018 to July 2025. Traditional vector screening was used before 2023. In 2023, we implemented QVS, which incorporated quantitative sensing scores for each candidate and raised the threshold for S-ICD implantation. The primary end point was time to first inappropriate shock or under-sensed ventricular arrhythmia. Secondary outcomes included SMART Pass deactivation and need for device revision. Outcomes were reported as survival analyses. RESULTS:During preimplant screening, the QVS protocol reduced patient eligibility from 96% to 83%. The median follow-up after implant was 42 months (interquartile range, 48) in the traditional vector screening arm and 18 months (interquartile range, 15) in the QVS arm. The primary end point of time to first inappropriate shock or under-sensed ventricular arrhythmia was longer in the QVS arm (log-rank, P=0.02). There were 23 primary end point events among 145 patients in the traditional vector screening arm (5.2 per 100 patient-years [95% CI, 3.1-7.4]) and 2 primary end point events among 78 patients in the QVS arm (1.8 per 100 patient-years [95% CI, 0.01-4.38]). CONCLUSIONS:Implementation of a novel S-ICD screening protocol with stricter eligibility thresholds reduced sensing-related complications, particularly inappropriate shocks.

Background In patients with interrupted inferior vena cava (IVC) requiring atrial fibrillation (AF) ablation, transhepatic access is an established alternative to femoral venous access. Prior reports have described AF ablation using radiofrequency platforms, but, to our knowledge, transhepatic AF ablation with a dual-energy lattice-tip catheter integrating high-density mapping, pulsed field ablation, and radiofrequency ablation has not been reported. Case Summary We describe 3 patients with symptomatic AF and interrupted IVC who underwent successful transhepatic left atrial access using ultrasound-guided placement of a 12-F hemostatic sheath. Pulmonary vein isolation and posterior wall isolation were performed with pulsed field ablation in all patients. Hepatic tract closure was achieved using absorbable gauze within the hepatic parenchyma. No access-related or procedural complications occurred, and all patients recovered uneventfully. Discussion This series demonstrates the feasibility of transhepatic AF ablation using a dual-energy lattice-tip catheter. Further studies are needed to define procedural safety and long-term outcomes.

Background Cardioneuroablation (CNA) has been increasingly pursued as a treatment for patients with recurrent vasovagal syncope. The optimal procedural approach and acute endpoints are unclear. Objective The goal of this study was to characterize procedural markers linked to durable freedom from syncope. Methods All patients who underwent CNA for vasovagal syncope refractory to lifestyle modification with at least 1 year of follow-up were included in a retrospective cohort. Clinical and procedural characteristics were analyzed for association with recurrence of syncope. Results A total of 57 patients (mean age 39.8 ± 10.7 years; 53% female; 6.7 ± 3.8 episodes of syncope in the prior year) met inclusion criteria. During 2.2 ± 0.8 years of follow-up, 25 patients (44%) had recurrent syncope. Symptomatic inappropriate sinus tachycardia occurred in 14% and was more common after CNA guided by extracardiac vagal stimulation (64% vs 2%). Patients who remained free from recurrent syncope were more likely to exhibit a vagal response during ablation of the left-sided ganglionated plexus (56% vs 12%; P = 0.001), had a greater increase in sinus rate during the ablation (29.9 ± 15.1 beats/min vs 10.0 ± 15.8 beats/min; P = 0.01), and were less likely to exhibit a positive atropine response at the end of the procedure (3% vs 24%; P = 0.04). Patients who exhibited a greater number of these favorable physiological markers had progressively lower rates of recurrent syncope. Patients meeting all 3 criteria had the lowest recurrence rate (14%). Conclusions There is a substantial rate of recurrent syncope after CNA with intermediate-term follow-up. Inadequate acute procedural endpoints may be associated with recurrence.

BACKGROUNDClinical recognition of multifocal premature ventricular complexes (PVCs) poses diagnostic and therapeutic challenges. Despite their morphological diversity, these arrhythmias may originate from a confined anatomical region, allowing a systematic mapping and ablation strategy.OBJECTIVETo describe clinical characteristics and propose a stepwise approach to mapping and ablation of multifocal PVCs originating from the basal septal LV ostium.METHODSPatients with multifocal septal PVCs, who underwent coronary venous mapping (CVM), were included. Ablation targeted the basal LV septum from the anterolateral LV ostium to the posterior LV process.RESULTSTwenty-four patients (mean age 64.5±9.2 years; 92% male) were included. Baseline electrocardiogram (ECG) showed PR prolongation >200 ms in 50%, QRS>100 ms in 75%, absent septal r waves in 63% and QRS fractionation in inferior leads in 38%. Left ventricular ejection fraction (LVEF) was preserved or mildly reduced (median 45%). Cardiac magnetic resonance (CMR) showed delayed gadolinium enhancement in 71%, intracardiac echocardiography revealed septal abnormalities in 83%. Intramural CVM was feasible in 75%, revealing fractionated electrograms; intramural activation preceded endocardial activation by 10 ms(p<0.01). Thirteen patients (54%) received implantable cardioverter-defibrillator (ICD). PVC burden decreased from 18.7% to 2.8%(p<0.01), with ≥80% reduction in 83%. During 1.7 years of follow-up, 4 patients (31%) received appropriate therapies.CONCLUSIONSMultifocal septal PVCs are consistently associated with abnormalities on ECG, CMR and/or intramural septal electrograms. A stepwise ablation approach substantially reduces PVC burden, although damage to the conduction system remains clinically relevant. The risk of malignant ventricular arrhythmias remains high despite preserved or mildly reduced LVEF.

Background Intramyocardial mapping of left ventricular outflow tract (LVOT) premature ventricular complexes (PVCs) via septal coronary venous branches is helpful to define the site of origin (SOO) and guide ablation. The limitation of unipolar far-field signals with wire mapping can be obviated through the use of a multipolar mapping catheter. Objectives This study reports our mapping and ablation experience of suspected LVOT PVCs using intraseptal mapping with multipolar catheters. Methods Patients with suspected LVOT PVCs in whom intraseptal mapping was attempted using multipolar catheters were included. The V2 S-wave and R-wave pattern break (PB) ratios were calculated using the S-wave or R-wave amplitudes in lead V2 divided by the sum of the S-wave or R-wave amplitudes in leads V1 and V3, respectively. Endocardial, intramyocardial, or epicardial SOO was based on activation pattern. Results Of 86 patients, multipolar intraseptal mapping was successfully performed in 60 (70%; 30% female, 53% with prior ablation). PVCs were most commonly mapped to an intramyocardial source and least commonly to the epicardium. For left bundle branch block PVCs, a V2 S-wave PB ratio >2.7 ruled in an intramyocardial or epicardial source, whereas a ratio <1.2 ruled out an endocardial source. For right bundle branch block morphology PVCs, a V2 R-wave PB ratio <1.0 ruled out an endocardial source. Acute ablation success was achieved in 98% and freedom from recurrence was 93% at a median follow-up of 12.4 months. Recording of intraseptal late potentials with reversal during PVC was observed in 25 (42%) patients and was associated with long-term success. Conclusions Ablation of LVOT PVCs guided by intraseptal mapping using multipolar catheters is feasible and highly effective. Electrocardiogram predictors of SOO identify patients in whom intraseptal mapping may be useful. Reversal of late potentials with PVCs may represent abnormal substrate in idiopathic PVCs in ostensibly structurally normal hearts.

Background Inherited cardiomyopathies cause ventricular tachycardia (VT) and heart failure, yet genotype‐based substrate characterization is limited. Methods Patients with inherited cardiomyopathy undergoing VT (n=80) or premature ventricular complex (n=25) ablation between 2010 and 2024 were evaluated for arrhythmia substrate, ablation, and heart failure outcomes. Results Among 105 patients, the median age was 51 years, 72% were men, and the cohort comprised desmosomal (desmoplakin [DSP], 11%; non‐DSP, 24%), titin (22%), lamin A/C (LMNA; 20%), sarcomeric (14%), ion‐channel (5%), and cytoskeletal/Z‐disk (4%) genotype groups. In the VT cohort, low‐voltage substrate was predominantly septal in the LMNA (55%), titin (67%), and sarcomeric (75%) groups; both septal (75%) and lateral left ventricle (75%) in the cytoskeletal/Z‐disk group; perimitral (71%) and lateral left ventricle (57%) in the DSP desmosomal group; and right ventricular free wall (91%) in the non‐DSP desmosomal group. Ablation eliminated clinical VT in 90%, with noninducibility of any VT in 52 of 80 (65%) cases. VT‐free survival was 51% during 3 years (1.8–6.3 years). Among recurrences, 11 of 39 (28%) patients had a single VT episode. VT‐free survival was highest in the non‐DSP desmosomal group and lowest in the LMNA group (66% versus 20%, P=0.03). Residual VT inducibility (hazard ratio [HR], 2 [95% CI, 1.05–3.77]) and LMNA variant (HR, 2.25 [95% CI, 1.1–4.57]) predicted recurrence. In the premature ventricular complex cohort, the burden decreased from 12% (interquartile range [IQR]=Q3–Q1, 21–8) to 3.75% (IQR 3–1, 6–1), and 17 of 25 (68%) had ≤5% burden. End‐stage heart failure outcome (left ventricular assist device, transplant, or death) occurred in 29% overall and 52% in the LMNA group. Conclusions Genotype correlates with VT substrate. Ablation successfully reduced VT and premature ventricular complex burden; however, long‐term VT recurrence was common except in non‐DSP desmosomal variants. LMNA variants portend worse outcomes.

Background Pulmonary veins (PVs) are major sources of atrial fibrillation (AF) triggers, but patients may also have non-PV (NPV) triggers. Data on the impact of targeting NPV triggers on AF ablation outcomes are limited. Objectives This study aimed to assess the outcome of patients undergoing AF ablation based on their NPV trigger status. Methods Patients undergoing first-time AF ablation using radiofrequency energy between 2018 and 2023 who received trigger provocative maneuvers were included. The provocative maneuvers consisted of cardioversion of AF, incremental isoproterenol infusion (3, 6, 12, and 20-30 μg/min) and/or an atrial burst pacing protocol. NPV triggers were defined as ectopic foci initiating AF, sustained focal atrial tachycardia (AT), or atrioventricular nodal reentrant tachycardia. Recurrence was defined as AF/AT >30 seconds after a 90-day blanking period. Results Of 2,315 patients included, 2,046 (88.4%) did not have NPV triggers, 233 (10.1%) had NPV triggers that were ablated, and 36 (1.6%) had NPV triggers that were not targeted or failed localization/ablation attempts. One-year recurrence rate was 29.5% in patients without NPV triggers, 38.2% in those with ablated NPV triggers (adjusted HR: 1.35; 95% CI: 1.08-1.69), and 72.2% in those with untreated NPV triggers (adjusted HR: 3.71; 95% CI: 2.48-5.54). This response pattern remained consistent regardless of NPV trigger subtype (AF vs focal AT) or provocation method (spontaneous vs induced triggers). Conclusions Failure to ablate induced NPV triggers is associated with a high risk of recurrence. Although the ablation of NPV triggers reduces recurrence rates to levels approaching those without such triggers, their presence indicates a modestly worse prognosis.