Kitti Szűcs

Background: The QLV ratio (QLV/baseline QRS width) is an established intraoperative-measurable parameter during cardiac resynchronization therapy (CRT) device implantation, potentially predicting the efficacy of electrical resynchronization. Methods: Left bundle branch area pacing-optimized CRT (LOT-CRT) is a novel approach with the potential to improve both responder rate and responder level in the CRT candidate patient group, even when an optimal electro-anatomical left ventricular lead position is not achievable. In our observational study, 72 CRT-defibrillator candidate patients with a QRS duration of 160 ± 12 ms were consecutively implanted. Using a QLV-ratio-based implant strategy, 40 patients received a biventricular CRT device (Biv-CRT) with an optimal QLV ratio (≥70%). Twenty-eight patients with a suboptimal QLV ratio (p = 0.024). At 12 months, the LOT-CRT group also demonstrated a significantly greater improvement in left ventricular ejection fraction (14.9 ± 8% vs. 10.3 ± 7.4%; p = 0.001), and New York Heart Association functional class (1.2 ± 0.5 vs. 0.8 ± 0.4; p = 0.031), and a significant decrease in NT-pro-BNP levels (1863± 380 pg/mL vs. 1238 ± 412 pg/mL; p = 0.012). Notably, the LOT-CRT patients showed results comparable to Biv-CRT patients with a super-optimal QLV ratio (>80%) in terms of QRS width reduction and LVEF improvement. Conclusions: Our single-center study demonstrated the feasibility of a QLV-ratio-based implantation strategy during CRT implantation. Patients with a LOT-CRT system showed significant improvements, whereas Biv-CRT patients with a super-optimal QLV ratio may not be expected to benefit from an additional LOT-CRT upgrade.

Background: Cardiac resynchronization therapy (CRT) is gold standard treatment option among patients with symptomatic heart failure with reduced left ventricular ejection fraction (LVEF) and intraventricular conduction delay of left bundle branch block (LBBB) morphology. Purpose: Left bundle branch area pacing optimized cardiac resynchronization therapy (LOT CRT) is a novel and promising approach for CRT candidate patients even in advanced intraventricular conduction delay, however convincing follow-up data regarding this patient group is still lacking. Methods: In our observational registry 35 LOT CRT vs. 35 conventional CRT patients were consecutively implanted according to current guidelines. All the patients had LBBB morphology QRS width of >150 ms. The two compared patient group did not show significant difference in age, gender, baseline non-ischemic etiology, LVEF, NYHA functional class, LBBB QRS width. Results: Immediate postoperative results showed significantly increased QRS width reduction (p=.028) and at 6 months of follow-up a significantly greater improvement in LVEF(p=.031), NYHA functional class (p=.04) and Nt-ProBNP levels (p=0.043) were seen in LOT CRT patient group compared to conventional CRT patients. Conclusion: Our single center observational study showed significant improvement in prompt postoperative QRS width and clinical follow-up parameters in LOT CRT implanted patients compared to conventional CRT implanted patients.LOTCRTvs.CRTQRSwidthreductionLOTCRTXray