Arrhythmic Risk in Biventricular Pacing Compared With Left Bundle Branch Area Pacing: Results From the I-CLAS Study

Abstract

Background: Left bundle branch area pacing (LBBAP) may be associated with greater improvement in left ventricular ejection fraction and reduction in death or heart failure hospitalization when compared with biventricular pacing (BVP) in patients requiring cardiac resynchronization therapy (CRT). We sought to compare the occurrence of sustained ventricular tachycardia or ventricular fibrillation (VT/VF) and new onset atrial fibrillation (AF) in patients undergoing BVP and LBBAP. Methods: This International Collaborative LBBAP Study (I-CLAS) included patients with LVEF≤35% who underwent BVP or LBBAP for CRT between Jan 2018 to June 2022 at 15 centers. We performed propensity score matched (PS) analysis of LBBAP and BVP in a 1:1 ratio. We assessed the incidence of VT/VF and new-onset AF among patients with no prior history of AF. Time to sustained VT/VF and time to new-onset AF was analyzed using Cox proportional hazards survival model. Results: Among 1778 patients undergoing CRT (981-BVP, 797-LBBAP), PS matched 1414 patients (PS-BVP:707, PS-LBBAP:707). The occurrence of VT/VF was significantly lower with LBBAP compared with BVP (4.2% vs 9.3%;HR 0.46;95%CI 0.29-0.74;p<0.001). The incidence of VT storm (>3 episodes in 24 hours) was also significantly lower with LBBAP compared with BVP (0.8% vs 2.5%;p=0.013). Among 299 patients with CRT-pacemakers (BVP-111, LBBAP-188), VT/VF occurred in 8 patients in the BVP group vs. none in the LBBAP group (7.2% vs 0%;p<0.001). In 1194 patients with no prior history of VT/VF or antiarrhythmic therapy (BVP-591, LBBAP-603), the occurrence of VT/VF was significantly lower with LBBAP compared with BVP (3.2% vs 7.3%;HR 0.46;95%CI 0.26-0.81;p=0.007). Among patients with no prior history of AF (n=890), the occurrence of new-onset AF >30 seconds was significantly lower with LBBAP compared with BVP (2.8% vs 6.6%;HR 0.34;95%CI 0.16-0.73;p=0.008). The incidence of AF lasting >24 hours was also significantly lower with LBBAP compared with BVP (0.7% vs 2.9%;p=0.015). Conclusions: LBBAP was associated with lower incidence of sustained VT/VF and new-onset AF compared with BVP. This difference remained significant after adjustment for differences in baseline characteristics between patients with BVP and LBBAP. Physiologic resynchronization by LBBAP may be associated with lower risk of arrhythmias compared with BVP.

Ultra-High-Frequency ECG in Cardiac Pacing and Cardiac Resynchronization Therapy: From Technical Concept to Clinical Application

“…CSP-CRT was associated with a lower incidence of VT/VF, (4.2% vs. 9.3%, p < 0.001) and lower occurrence of VT storm (0.8% vs. 2.5%, p = 0.013) compared to conventional BiV-CRT. This observation was also present in a subanalysis involving patients who received CRT for primary prevention (CSP-CRT vs. BiV-CRT: 3.2% vs. 7.3%, p = 0.007) [ 81 ]. One might hypothesize that more physiological activation (rather than the non-physiological epicardial to endocardial activation during BiV-CRT) could induce a more physiological repolarization, subsequently inducing more antiarrhythmic effects.…”

“…With the widespread adoption of CSP, studying repolarization in relation to ventricular arrhythmias becomes particularly intriguing. The occurrence of sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) in patients undergoing either CSP-CRT or BiV-CRT was recently investigated in a multicenter observational study involving 1778 patients [ 81 ]. CSP-CRT was associated with a lower incidence of VT/VF, (4.2% vs. 9.3%, p < 0.001) and lower occurrence of VT storm (0.8% vs. 2.5%, p = 0.013) compared to conventional BiV-CRT.…”

Novel Medical Treatments and Devices for the Management of Heart Failure with Reduced Ejection Fraction

“…Studies show that LBBAP, compared to a conventional biventricular resynchronization strategy, seems to reduce QRS duration and pacing thresholds, while improving the left ventricular end-diastolic diameter, hospitalizations for HF and LVEF [68]. Other positive effects have been shown in a recent study that showed a reduced incidence in ventricular arrhythmic events and atrial fibrillation [71]. Despite the early positive effects, there are some cases where a diffuse conduction system failure may impair the efficacy of LBBAP.…”

Implantable Cardioverter Defibrillator Tachycardia Therapies: Past, Present and Future Directions

“…Conventional CRT was shown to reduce appropriate ventricular arrhythmias and ICD shocks, particularly in responders [ 148 , 149 , 150 ]. In addition, left bundle branch area pacing CRT was associated with significantly fewer ventricular arrhythmias than conventional CRT in a recently published propensity score-matched analysis of 1778 patients [ 151 ], which may be due to the normalization of repolarisation with conduction system pacing [ 152 ].…”