Until recently, left bundle branch area pacing (LBBAp) has mostly been performed using lumen-less fixed screw leads. There are limited data on LBBAp with conventional style-driven extendable screw-in (SDES) leads, particularly data performed by operators with no previous experience with LBBAp procedures. In total, 42 consecutive patients undergoing LBBAp using SDES leads and newly designed delivery sheaths (LBBAp group) were compared with those treated with conventional right ventricular pacing (RVp) for atrioventricular block (RVp group, n = 84) using propensity score matching (1:2 ratio). The LBBAp was successful in 83% (35/42) of patients, with satisfactory pacing thresholds (0.8 ± 0.2 V at 0.4 ms). In the LBBAp group, the mean paced-QRS duration obtained during RV apical pacing (173 ± 18 ms) was significantly reduced by LBBAp (116 ± 14 ms, p < 0.001). Compared with the RVp group, the LBBAp group showed more physiological pacing, suggested by a much narrower paced-QRS duration (116 ± 14 vs. 151 ± 21 ms, p < 0.001). The pacing threshold was comparable in both groups. The LBBAp group revealed stable pacing thresholds for 6.8 ± 4.8 months post-implant and no serious complications including lead dislodgement or septal perforation. The novel approach of LBBAp using SDES leads and the new dedicated pre-shaped delivery sheaths was effectively and safely performed, even by inexperienced operators with LBBAp procedures.

Background: We hypothesized that analysis of serial ECGs could predict new‐onset atrial fibrillation (AF) more accurately than analysis of a single ECG by detecting the subtle cardiac remodeling that occurs immediately before AF occurrence. Our aim in this study was to compare the performance of 2 types of machine learning (ML) algorithms. Methods and Results: Standard 12‐lead ECGs of patients selected by cardiologists between January 2010 and May 2021 were used for ML model development. Two ML models (single ECG and serial ECG) were developed using a light gradient boosting machine‐learning algorithm. Model performance was evaluated based on the area under the receiver operating characteristic curve, sensitivity, specificity, accuracy, and F1 score. We trained the ML models on 415 964 ECGs from 176 090 patients. When testing the 2 ML models using external validation data sets, the performance of the serial‐ML model was significantly better than that of the single‐ML model for predicting new‐onset AF (single‐ versus serial‐ML model: sensitivity 0.744 versus 0.810; specificity 0.742 versus 0.822; accuracy 0.743 versus 0.816; F1 score 0.743 versus 0.815; area under the receiver operating characteristic curve 0.812 versus 0.880; P <0.001). The Shapley Additive Explanations analysis ranked P‐wave duration and amplitude among the top 10 ECG parameters. Conclusions: An ML model based on serial ECGs from an individual had greater ability to predict new‐onset AF than the ML model based on a single ECG. P‐wave morphologies were associated with future AF prediction.

Background: Electrical cardioversion (ECV) is an effective method for restoring sinus rhythm after atrial fibrillation (AF). However, early recurrence of AF occurs in a significant number of patients after ECV. This study aimed to identify electrocardiographic (ECG) predictors of early AF recurrence after ECV.Methods: A total of 272 patients with persistent AF undergoing successful ECV were consecutively enrolled in this study. We investigated clinical, echocardiographic, and ECG data. The 12‐lead ECG parameters were measured during sinus rhythm right after ECV using a digital caliper. The early AF recurrence was defined as recurrence within 2 months.Results: Of the 272 patients, 165 patients (60.7%) experienced an early AF recurrence. Maximum P‐wave duration (PWD) in limb leads (OR: 1.086; 95% CI: 1.019–1.157; p = .012) and P‐terminal force (PTF) in V₁ (OR: 1.019; 95% CI: 1.004–1.033; p = .011) were independent predictors of early AF recurrence after ECV. The optimal cutoff value of the maximum PWD in limb leads for predicting early AF recurrence was 134 ms, characterized by 90.3% sensitivity and 72.0% specificity. Likewise, the optimal cutoff value of PTF in V₁ was 50 ms × mm, characterized by 80.0% sensitivity and 64.5% specificity.Conclusion: A longer PWD (>134 ms) and a larger PTF (>50 ms × mm) were useful predictors of early recurrence of AF after successful ECV in clinical practice. A more effective rhythm control therapy such as catheter ablation or rate control strategy rather than a repeat ECV should be considered.

Background: In idiopathic outflow tract ventricular arrhythmias (OT‐VAs), identifying the site with the earliest activation time (EAT) using activation mapping is critical to eliminating the arrhythmogenic focus. However, the optimal EAT for predicting successful radiofrequency catheter ablation (RFCA) has not been established.Hypothesis: To evaluate the association between EAT and successful RFCA in idiopathic OT‐VAs and to determine the optimal cut‐off value of EAT for successful ablation.Methods: We retrospectively analyzed patients undergoing RFCA for idiopathic OT‐VAs at a single center from January 2015 to December 2019.Results: Acute procedural success was achieved in 168 patients (87.0%). Among these patients, 158 patients (81.9%) were classified in the clinical success group according to the recurrence of clinical VAs during median (Q1, Q3) follow‐up (330 days [182, 808]). EAT was significantly earlier in the clinical success group compared with the recurrence (p = .006) and initial failure (p < .0001) groups. The optimal EAT cut‐off value predicting clinical success was −30 ms in the right ventricular outflow tract (RVOT) with 77.4% sensitivity and 96.4% specificity. In all cases of successful ablation in the left ventricular outflow tract (LVOT), EAT in the RVOT was not earlier than −29 ms.Conclusions: EAT in patients with successful catheter ablation was significantly earlier than that in patients with recurrence and initial failure. EAT earlier than −30 ms could be used as a key predictor of successful catheter ablation as well as an indicator of the need to shift focus from the RVOT to the LVOT.

The snare technique can be used to overcome unsuitable cardiac venous anatomies for left ventricular (LV) lead implantation in cardiac resynchronization therapy (CRT) procedures. However, limited data exist regarding performance of the snare technique. We classified 262 patients undergoing CRT procedure into the snare (n = 20) or conventional group (n = 242) according to the LV lead implantation method. We compared the safety, efficacy, and composite outcome (all-cause death and heart failure readmission) at 3 years post-implant between the snare and conventional groups. In the snare group, all LV leads were implanted safely using orthodromic (n = 15) or antidromic (n = 5) techniques, and no immediate complications occurred including vessel perforation, tamponade, and lead dislodgement. During follow-up, LV lead threshold and impedance remained stable without requiring lead revision in the snare group. There were no significant between-group differences regarding LV ejection fraction increase (12 ± 13% vs. 12 ± 13%, p = 0.929) and LV end-systolic volume reduction (18 ± 48% vs. 28 ± 31%, p = 0.501). Both groups exhibited comparable CRT-response rates (62.5% vs. 60.6%, p = 1.000). The risk of primary outcome was not significantly different between the two groups (25.9% vs. 30.9%, p = 0.817). In patients who failed conventional LV lead implantation for CRT, the snare technique could be a safe and effective solution to overcome difficult coronary venous anatomy.