Daniel Thuan Tee Chong

Background and Objectives: The role of biventricular pacing (BVP) is less well-established in patients with heart failure with reduced ejection fraction (HFrEF) without left bundle branch block (LBBB). Conduction system pacing (CSP) has gained significant traction and may provide a safe and more physiological alternative to BVP in these patients. A few small studies studying this question have reported conflicting results. This meta-analysis aims to compare procedural and clinical outcomes between CSP and BVP in this group. Materials and Methods: An online literature search was systematically conducted to retrieve studies comparing CSP and BVP in HFrEF patients with non-LBBB. Four studies with 461 patients were included. Results: Implant-derived paced QRS duration was significantly shorter (mean difference [MD] −19.7 ms, 95% confidence interval [CI] −36.2 to −3.3, p = 0.0355) with CSP. Echocardiographic response with significantly greater improvement in left ventricular ejection fraction (MD 5.6%, 95% CI 3.1 to 8.0, p = 0.0106) was also observed with CSP. There were no statistically significant differences in clinical outcomes such as all-cause mortality (relative risk [RR] 0.53, 95% CI 0.18 to 1.60, p = 0.133) and heart failure hospitalization (RR 0.54, 95% CI 0.19 to 1.56, p = 0.129). Conclusions: This meta-analysis suggests that CSP may have better electrical synchrony and echocardiographic response compared to BVP in HFrEF patients with non-LBBB. Further randomized studies with longer follow-up may be required to elucidate potential benefits in clinical outcomes.

Conduction system pacing started with His bundle pacing (HBP) and then rapidly switched gears into left bundle branch pacing (LBBP). We describe our center’s experience with LBBP using either lumenless leads (LLLs) or stylet-driven leads (SDLs). Patients who were admitted to two tertiary centers between 1 April 2021 and 30 June 2024 and met the guidelines for pacing were recruited and prospectively followed up. A total of 124 patients underwent permanent pacemaker (PPM) implantation using the LBBP technique with a mean follow-up of 19.7 ± 13.3 months. In total, 90 patients were implanted with LLLs and 34 with SDLs. There was no significant difference in the procedural time and final paced QRS duration, but fluoroscopy time was significantly longer in the SDLs (26.2 ± 17.7 min vs. 17.5 ± 13.0 min, respectively, p = 0.026). The on-table impedance values were also significantly higher in the LLLs, and this persisted throughout the follow-up. There were no differences in the rates of complications. The success of conduction system pacing implantation with SDLs and LLLs is comparable with reasonable safety and reliable outcomes. Good pre-implant patient selection will contribute to improved outcomes.

Regional differences in pulsed field ablation (PFA) adoption for pulmonary vein isolation (PVI) with additional posterior wall ablation (PWA) in Asia remains unknown. We hereby report our experience on the safety and efficacy of PFA in AF ablation. Consecutive AF patients who underwent PFA from September 2022 to January 2024 were included. The primary efficacy endpoint was freedom from atrial arrhythmia recurrence after a 90-day blanking period at 12 months. Safety endpoints included 30 days of all-cause death, cardiac tamponade, stroke, myocardial infarction, and heart failure hospitalization. One hundred and one (72.3% males, 79.2% pAF) patients underwent PFA for AF. Thirty-one (30.7%) had structural heart disease with mean LVEF of 57.4 ± 8.1% and CHA2DS2-VASc score of 1.4 ± 1.3. Twenty-nine (28.7%) underwent additional PWA (PVI + PWA) using PFA. PWA was acutely successful in all patients. Patients who underwent PWA were more likely to have persistent AF and require general anesthesia and electroanatomic mapping (all p < 0.05). Total PFA applications for PVI, LA dwell time, procedural time, and fluoroscopy time were similar between the PVI-only and PVI + PWA groups (all p > 0.05). The 1-year atrial arrhythmia recurrence rates were 10% for pAF and 21% for the persistent AF group. The primary efficacy endpoint was not significantly different between the PVI-only and PVI+PWA groups (12-month KM estimates 90.3% [95% CI, 83.3–97.3] and 82.8% [95% CI, 68.1–97.4], respectively). There were no complications related to PFA use. PFA can be safely, effectively, and efficiently adopted for AF ablation. Additional PWA, if pursued, had similar procedural metrics to the PVI-only strategy without increased complications.

Background: Routine use of pre‐participation electrocardiograms (ECGs) has been used by the Singapore Armed Forces, targeting early detection of significant cardiac diseases. We aim to describe the impact of demographic and anthropometric factors on ECG variables and establish a set of electrocardiographic reference ranges specific to a young male multiethnic Southeast Asian cohort.Methods and results: Between November 1, 2009, and December 31, 2014, 144,346 young male conscripts underwent pre‐participation screening that included a 12‐lead ECG, demographic and anthropometric measurements. The Chinese population had the longest PR interval (146.7 ± 19.7 vs. 145.21 ± 19.2 in Malays vs. 141.2 ± 18.8 ms in Indians), QRS duration (94.5 ± 9.8 vs. 92.6 ± 9.7 in Malays vs. 92.5 ± 9.4 ms in Indians) and QTcB interval (408.3 ± 21.3 vs. 403.5 ± 21.6 in Malays vs. 401.2 ± 21.4 ms in Indians) (all p < 0.001). Body mass index (BMI) >25 kg/m² and body fat >25% were independently associated with lower prevalence of increased QRS voltage on ECG. Systolic blood pressure of >140 mmHg or diastolic blood pressure of >90 mmHg independently increased the prevalence of increased QRS voltage on ECG.Conclusions: Electrocardiographic parameters vary across different ethnicities and in comparison with international norms. In our population, diagnosis of increased QRS voltage by ECG is less prevalent with obesity and increased body fat. Further analysis of gold standard measurements for the diagnosis of LVH in our population is ongoing, to improve the accuracy of the ECG screening process.