Left ventricular septal pacing combined with left ventricular pacing improves acute electric resynchronization, hemodynamic responses and clinical outcomes: results of SPORT study

Left bundle branch pacing is effective for cardiac resynchronization therapy (CRT), but the role of left ventricular septal pacing (LVSP) for CRT remains controversial due to lack of LBB capture. We hypothesized that combining LVSP with LV pacing (LVP) may provide additional benefits.

This prospective observational study enrolled consecutive patients undergoing LVSP for CRT. LVSP was acceptable if paced QRS duration (QRSd)＜130 ms or QRSd reduction ≥ 20%. If neither criterion were met, a CS-LV lead was implanted. Acute hemodynamic response (AHR) represented by LV maximum first derivative (dP/dt_max) was accessed. All patients were followed up for echocardiographic parameters, NT-proBNP levels, NYHA classes, and clinical events. The clinical outcomes included all-cause mortality, heart failure hospitalization, and ventricular tachyarrhythmias. A total of 45 patients achieved left bundle branch area pacing (LBBAP) without confirmed LBB capture were enrolled, including 25 with LVSP alone and 20 with LVSP + LVP. QRSd reduction was significantly greater in LVSP + LVP than LVSP (46.2 ± 19.2 ms vs. 32.6 ± 23.0 ms, P = 0.049). LVSP + LVP resulted in greater improvement in AHR than LVSP (20.0 ± 9.2% vs. 10.4 ± 8.2%, P＜0.001) in 10 patients. After a median follow-up of 26-month, LVEF improvement was significantly higher in LVSP + LVP than LVSP (mean difference: 3.05%; 95% CI: 0.05–6.05; P = 0.047). LVSP + LVP was also independently associated with 87% lower risk of clinical outcomes compared with LVSP [aHR: 0.13 (0.03, 0.62), P = 0.011].

LVSP combined with LVP might offer greater AHR, electrical resynchronization and as well as improved clinical outcomes than LVSP alone in patients undergoing LBBAP-CRT without LBB capture.