Po-03-016 electrical and non-electrical predictors of shorter postprocedural paced qrs duration in patients receiving left bundle area pacing.

Left bundle area pacing (LBAP) has been demonstrated as a physiological pacing modality better than conventional right ventricular pacing. Postprocedural paced QRS duration (QRSd) is an important indicator of ventricular synchrony. Current procedure methods are majorly guided by anatomy with fluoroscopy, 3D mapping, or echocardiography. Repeated trials are sometimes inevitable to achieve ideal left bundle selection and better postprocedural electrical properties. We hypothesize some demographic factors and prescrew electrical signals can be useful markers to guide LBAP and achieve posprocedural narrow paced QRS. We retrospectively analyzed patients who received LBAP and deep septal pacing in a tertiary medical center in 2021. Patient characteristics, pre-screw and post-screw ECG during procedure were recorded. QRS patterns were categorized into 5 common subtypes, including R, Rs, rs, rS, S, which were further score as 1-5. Precordial transition zones were also identified. We compared the electrical features in patients with post-screw QRSd <120ms and ≥120ms. Total 59 patients (age 70.7 ± 11.4 years, male 57.6%) were enrolled. The baseline intrinsic QRSd was 108.3 ± 27.6ms and right ventricular endocardial paced QRSd was 144.6 ± 23.0ms. After Screwing the lead, LBAP QRSd became 129.5 ± 23.0ms. The target area showed score in lead II 1.9 ± 1.0, lead III 3.8 ± 1.2, and aVF 2.9 ± 1.3, indicating inferior discordant pattern. The precordial transition zone was after 3.4 ± 1.2. Comparing electrical parameters in post-screw QRSd <120ms and ≥120ms group, significantly less pre-screw QRSd (p=0.001) and pLVAT (p<0.001) and higher V1r ’(p=0.016) were observed in QRSd <120ms group. Male (odds ratio [OR], 0.2; P<0.007), LV size (OR, 0.87; P<0.004), pre-screw QRSd (OR, 0.95; P<0.003), and pre-screw pLVAT (OR, 0.94; P<0.001) were independent predictors of QRSd<120ms, while history of atrial arrhythmia (OR, 3.27; P=0.037) prediscts QRSd > 120ms. The predictive validity of the score reached an AUC of 0.95 with a global specificity of 84% and a sensitivity of 95%. Male, LV size, pre-screw QRSd, pLVAT, and history of no atrial arrhythmia were independent predictors of postprocedural narrow paced QRS. Post screw right inferior axis and presence of V1 r’ were associated efficient left ventricular activation.