Achieving transmural lesions is critical for durable outcomes in catheter ablation. While electrogram amplitude reduction and pacing threshold changes have been reported as useful parameters, the optimal electrode configuration and cutoff values remain unclear. This preclinical study evaluated the efficacy of conventional and microelectrode configurations in predicting transmurality using the QDOT MICRO catheter. Radiofrequency ablation was performed in 14 swine, creating 131 atrial lesions. Pacing thresholds and electrogram amplitudes were measured before and after ablation using three configurations: conventional bipolar, microelectrode bipolar, and unipolar. Lesion transmurality was determined histologically. Receiver operating characteristic analyses were conducted to assess predictive accuracy. Among all configurations, the conventional bipolar (A1–A2) showed the highest predictive value. Post-ablation bipolar amplitudes were lower in transmural lesions (AUC 0.777, 0.86mV), with greater amplitude reduction (64.4
Real-time monitoring of myocardial tissue response during radiofrequency applications using a mesh-shaped flexible irrigation tip ablation catheter (TactiFlex) remains challenging. This study assessed the dynamics of averaged impedance drop percentage (AID
There is limited evidence regarding the Aveir VR leadless pacemaker in mainland China, and the intraoperative electrical indicators linked to a favorable chronic pacing capture threshold (PCT) are not clearly defined. This retrospective study across multiple centers involved 100 patients from Sichuan Province who received Aveir VR implants between January 2023 and December 2025, with electrical data available for evaluation at least one month after implantation.Chronic PCT was considered excellent if it was ≤ 0.5 V at 0.4 ms during the first device check after at least one month.Intraoperative predictors were identified using multivariable logistic regression.Receiver Operating Characteristic(ROC) analysis with bootstrap validation (500 replicates) was used to assess discrimination, and generalized additive models (GAMs) were employed to evaluate nonlinearity. In 100 patients, the device implantation was successful with no significant complications, and 66 of them (66
To characterize individual-case medical device reports submitted to the U.S. Food and Drug Administration Manufacturer and User Facility Device Experience database for commercially available pulsed-field ablation systems during early postmarket use. We analyzed reports received from February 1, 2024, through April 30, 2026. Master event, device, patient, patient problem code, device problem code, and narrative files were merged by report key. Literature-derived, clinical study-derived, false-positive, indeterminate, and exact duplicate narrative reports were excluded from the primary individual-case cohort. A prespecified hierarchy and targeted narrative review classified reporting phenotypes, reported clinical event categories, and device problem code categories. Duplicate-removal sensitivity analyses were performed. Of 11,563 potential reports, 10,976 individual-case reports formed the primary cohort. Device malfunction without identified patient injury accounted for 7,323 reports (66.7
Pulsed field ablation (PFA) uses high-intensity electric fields to create myocardial lesions and may potentially interact with cardiac implantable electronic devices (CIEDs). This multicenter study evaluated the effects of different PFA technologies on electrical integrity and device-related complications in patients undergoing left- and right-sided atrial ablation. Consecutive patients with CIEDs undergoing catheter ablation with 4 PFA technologies were included. CIED interrogation was performed at baseline, after ablation, and at ≥ 3-month follow-up. Study endpoints were electrical integrity, defined as changes in sensing, pacing threshold, or impedance, and clinically relevant PFA-related CIED malfunction. Real-time device monitoring was performed in a subgroup to assess electromagnetic interference (EMI). A total of 157 patients were included. PFA was performed using a pentaspline catheter in 110 patients, a lattice-tip catheter in 26, a variable-loop circular catheter in 16, and a circular array catheter in 5. No significant changes in lead parameters were observed immediately after ablation or at 3-month follow-up, including in patients undergoing right atrial PFA. PFA was frequently associated with EMI-related oversensing (93
Atrial fibrillation (AF) carries a substantial ischemic stroke risk originating predominantly from the left atrial appendage (LAA). Catheter ablation (CA) is the most effective rhythm-control strategy, while percutaneous LAA closure (LAAC) provides mechanical stroke prophylaxis. Combining both in a single one-stop procedure is increasingly performed, yet data on its rhythmic and periprocedural consequences remain scarce. We performed a systematic review and meta-analysis to compare the efficacy and safety of combined CA + LAAC versus CA-only in patients with AF. PubMed, Scopus and Web of Science were searched through June 12th 2026. The primary efficacy and safety outcomes were arrhythmia recurrence and periprocedural pericardial effusion requiring drainage, respectively. Binary endpoints were pooled as odds ratios (OR), continuous endpoints as mean differences (MD), using a random-effects model with heterogeneity reported as I2. Fourteen studies comprising 3,274 patients (1,505 CA + LAAC; 1,769 CA-only) were included. Arrhythmia recurrence was significantly more frequent after combined CA + LAAC (OR = 1.56, 95
Electrogram voltage reflects multiple factors, including viable myocardial mass, structural integrity, electrode configuration, catheter orientation, and activation sequence. How local myocardial wall thickness (WT) contributes to voltage amplitude in structurally intact myocardium remains incompletely defined. This study examined the chamber-specific relationships between directly measured WT and unipolar voltage (Uni-V), omnipolar voltage (Omni-V), and peak frequency (PF) in structurally intact swine myocardium. High-resolution electroanatomic maps were created in 25 swine. Radiofrequency (RF) lesions were used as anatomical tags to ensure precise spatial correlation between electrophysiological data and post-mortem WT measurements. A total of 340 atrial and 304 ventricular sites were analyzed. In the atria, WT correlated significantly with Omni-V (R²=0.54, P < 0.0001). This correlation improved after excluding trabeculated regions (R²=0.60, P < 0.0001) and was strongest in non-trabeculated regions with WT < 4 mm (R²=0.65, P < 0.0001). Uni-V also correlated with atrial WT, but less strongly (R²=0.29, P < 0.0001). In contrast, ventricular WT showed only weak associations with Omni-V (R²=0.02, P = 0.07) and Uni-V (R²=0.016, P = 0.06). PF did not correlate with WT in either chamber. In structurally intact swine myocardium, WT was associated with voltage amplitude primarily in the atrium, with a stronger relationship for Omni-V than Uni-V, particularly in thin, non-trabeculated regions. Ventricular WT showed only weak associations with voltage, and PF was independent of WT. These findings indicate that WT is one anatomical contributor to voltage amplitude under healthy conditions, particularly in the atrium, but should not support using voltage as a direct surrogate for physical tissue thickness or for interpreting voltage behavior in diseased substrate. In structurally intact swine myocardium, atrial wall thickness correlated with omnipolar voltage, whereas ventricular wall thickness showed only weak voltage associations, highlighting chamber-specific anatomical contributors to electrogram amplitude.
Catheter ablation for atrial fibrillation (AF) carries a known risk of tachyarrhythmia recurrence, but the recurrence is still difficult to predict before the procedure. This study assessed the value of noninvasive f-wave vector magnitude (FVM) during AF in predicting recurrence following ablation. This observational study included 604 consecutive patients who underwent initial AF ablation between January 2017 and December 2022 at Mitsubishi Kyoto Hospital, and whose baseline 12-lead electrocardiograms during AF were available. The maximal f-wave amplitude (FWA) over a 10-s period was measured manually using computerized calipers, and FVM was defined as the magnitude of atrial depolarization in three‐dimensional space, calculated using the visually transformed Kors’ quasi-orthogonal method. The outcome measure was the recurrence of atrial tachyarrhythmias after a 90-day post-procedural blanking period. The median follow-up was 5.4 (3.9–7.1) years. In multivariable analysis, low FVM (< 0.18 mV) was an independent predictor of recurrence (hazard ratio [HR] = 1.56, 95
Pulsed-field ablation (PFA) is established for pulmonary vein isolation, but data on superior vena cava (SVC) isolation are limited. We assessed the feasibility and acute safety of SVC isolation with the Volt™ balloon-in-basket PFA catheter using two sequentially applied standardised workflows. Retrospective single-centre series of 53 consecutive patients undergoing atrial fibrillation ablation with adjunctive SVC isolation. Workflow 1 (n = 28) used phrenic-nerve pacing and tailored energy; Workflow 2 (n = 25) used low-energy PFA only without phrenic pacing; both shared mapping-guided sinus-node sparing and a 20-second flow-preservation manoeuvre. A pre-specified within-platform sensitivity analysis controlled for a concurrent catheter iteration (20 January 2026). Acute SVC isolation was achieved in all 53 patients (100
Cardiac magnetic resonance (CMR) may provide insights into arrhythmogenic substrate in patients undergoing ventricular tachycardia (VT) ablation, but its prognostic value remains uncertain. We performed a systematic review and meta-analysis, following PRISMA guidelines, of available studies comparing CMR-derived parameters in patients with and without VT recurrence after ablation, from inception to March 2026. Primary outcomes included functional parameters - left ventricular ejection fraction (LVEF) and left ventricular (LV) mass, while secondary outcomes included ventricular volumes and late gadolinium enhancement (LGE) derived structural characteristics. Random-effects models were applied. Seven studies including 415 patients were analyzed, with 36.1
Clinical features associated with sustained ventricular arrhythmias (sVA) during acute myocarditis (AM) are poorly defined. Identify simple clinical characteristics of arrhythmogenic AM patients who develop sVA during acute-phase hospitalization. Case-control study of AM patients hospitalized in two tertiary centers from 2000 to 2020. Patients with documented sVA during AM hospitalization (cases) were compared with AM patients without VA (controls). Patients with history of myocardial infarction, heart failure or VA were excluded. Univariate and multivariable analyses were used to evaluate clinical parameters associated with occurrence of sVA during AM hospitalization. Study included 41 cases with sVA and 137 controls without any VA during AM hospitalization period. VAs included monomorphic VT and polymorphic VT/VF in 24/41 (58.5
Epicardial and endocardial left atrial appendage occlusion (LAAO) is commonly performed for stroke prevention for atrial fibrillation (AF) patients at increased risk for stroke who cannot tolerate long-term oral anticoagulation. However, there is limited data on the outcomes of unsuccessful LAAO procedures. This study aims to assess the incidence and outcomes of unsuccessful LAAO procedures. A retrospective analysis was performed on patients undergoing LAAO at our institution from 2020 to 2023. The primary endpoint was a failure to deploy the LAAO device, which was defined as unsuccessful device implantation (UDI). A total of 411 patients underwent LAAO (Lariat = 6.8
Pulse field ablation (PFA) is an ablation modality based on irreversible electroporation and is typically used to isolate the pulmonary veins in the treatment of atrial fibrillation (AF). The safety and efficacy of PulseSelect PFA for other linear lesions is less well substantiated in the literature. We describe a novel use of this circular, over-the-wire PFA catheter for the ablation of the cavotricuspid isthmus (CTI), mitral isthmus (MI), and posterior wall isolation (PWI) as part of ablation for AF. Data was collected prospectively on consecutive patients undergoing AF ablation using the PulseSelect catheter. CTI, MI, and PWI ablation was performed as based on patient factors and if there was documented atrial flutter. Acute bidirectional block was tested for both the CTI and MI, and isolation of the posterior wall was demonstrated during remapping. Continuous periprocedural ECG monitoring was performed. Patients underwent clinical follow-up at 3, 6, and 12 months. 62 patients were included in this dataset. 61 patients had PVI, 52 patients had CTI ablation, 36 had MI ablation, and 38 had PWI. Successful PVI was observed in all patients where the veins were targeted. Acute CTI block was observed in 98
Helix retraction during septal lead deployment can complicate left bundle branch pacing (LBBP) procedures performed with extendable–retractable helix leads. A helix locking tool (HLT) has been developed to stabilize the helix of a stylet-driven lead during implantation, but clinical performance data remain limited. This study aimed to evaluate the acute safety and procedural performance of this tool in a multicenter setting. In this prospective multicenter registry, 87 consecutive patients who underwent LBBP were enrolled in eight centers in Spain. Implantation was performed using a stylet-driven Tendril STS lead and CPS Direct 3D sheath, with the HLT used during septal deployment. The primary endpoint was freedom from acute adverse events related to the HLT. Secondary endpoints included procedural success, lead repositioning, and acute electrical parameters. LBBP was successfully achieved in 79 of 87 patients (90.8
Cardiac implantable electronic devices (CIED) have been associated with an increased incidence of tricuspid regurgitation (TR) due to several factors. We examined the outcomes of patients who underwent left bundle brunch area pacing (LBBAP) with stylet-driven leads and compared them with a 1:1 matched historical cohort of patients treated with conventional cardiac resynchronization therapy (CRT). This retrospective analysis included a total of 396 patients, of whom 132 underwent LBBAP and 264 underwent CRT. After propensity score matching, 95 patients were included in each group. Baseline tricuspid regurgitation severity and left ventricular ejection fraction were also similar. However, diabetes mellitus was more prevalent in the CRT group (47.4
Epicardial cryoablation is increasingly utilized in open surgical procedures for treatment of ventricular arrhythmias in patients with structural heart disease when percutaneous epicardial access cannot be obtained. There are limited data regarding the effects of cryoablation within ventricular scar tissue, particularly in comparison to the performance of radiofrequency (RF) catheter ablation. This study aimed to investigate the comparative performance of ablation delivered epicardially in an open chest animal model with a linear cryoprobe versus a radiofrequency catheter. An infarct model was created in five Yorkshire swine using microsphere injection into the left anterior descending artery. After 6–8 weeks, animals underwent median sternotomy with targeted epicardial RF ablation lesions, and linear cryoablation lesions were delivered to myocardial infarct scar regions. Specimens were pressure perfused with 10
Epicardial access is often required for catheter ablation of ventricular tachycardia (VT) when arrhythmogenic substrates are located on the epicardial surface, but it is associated with potentially serious complications, including cardiac tamponade and coronary artery injury. The use of a needle-in-needle (NiN) micropuncture technique for percutaneous epicardial access may reduce myocardial trauma and improve procedural safety. We aimed to describe a standardized workflow and assess the feasibility and acute safety of epicardial access for VT ablation using a NiN micropuncture technique. This retrospective, single-center observational study without a comparator group included 40 consecutive patients who underwent epicardial access for VT ablation using the NiN micropuncture technique between January 2020 and July 2025. Baseline clinical characteristics, procedural details, success of epicardial access, and acute access-related complications were evaluated. Nurse-administered propofol sedation was used in 37 patients (93
