The characteristics of the electrocardiogram and the intracardiac electrogram in left bundle branch pacing

Abstract

Introduction: Left bundle branch pacing (LBBP) has recently been reported to maintain left ventricular electrical synchrony with a low and stable threshold. However, the electrocardiogram (ECG) definitions of LBBP have not been well established. We report four cases to show the characteristics of the ECG and the intracardiac electrogram (EGM) in LBBP. Methods and Results: Four patients, two with an atrioventricular block (AVB) and two with left bundle branch block (LBBB), were included in the study. LBBP was performed and the ECGs and EGMs were collected and compared at different pacing outputs. Selective LBBP (S-LBBP) was defined as only capturing the LBB with a typical RBBB morphology and a discrete component between the pacing stimulus and ventricular activation in the EGMs. While nonselective LBBP (NS-LBBP) captured both the LBB and the local myocardium, resulting in a narrow right bundle branch block (RBBB) morphology without the discrete component. The left bundle branch (LBB) potential was recorded in two cases during narrow QRS complex or LBBB correction by selective His bundle pacing and SLBBP (n = 3) was achieved. A constant and shortest stimulus to left ventricular activation time (LVAT) in LBBP was obtained at different pacing outputs. Conclusion: The ECG and EGM characteristics of LBBP can be summarized as: 1) RBBB pattern; 2) usually with the LBB potential; 3) SLBBP with specific ECG changes and a discrete component in EGM; and 4) with a constant and shortest stimulus to LVAT at different pacing outputs. Further studies are necessary to confirm these observations. K E Y W O R D S His bundle pacing, left bundle branch pacing, left bundle branch potential, selective left bundle branch pacing, stimulus to peak left ventricular activation time Xueying Chen and Shengjie Wu contributed as co-first authors. The characteristics of the electrocardiogram and the intracardiac electrogram in left bundle branch pacing.

Electrophysiological characteristics and clinical values of left bundle branch current of injury in left bundle branch pacing

“…In 2017, Huang et al 7 first reported left bundle branch pacing (LBBP), which is a transvenous, trans‐septal implantation technique resulting in left bundle branch (LBB) capture with low capture thresholds. Recent studies demonstrated the feasibility and effectiveness of LBBP in patients indicated for ventricular pacing and cardiac resynchronization therapy 8–10 . We previously found the LBB COI in a patient with atrial fibrillation, 11 however, there have been no systematic studies on the COI with leads implanted at the LBB.…”

“…Recent studies demonstrated the feasibility and effectiveness of LBBP in patients indicated for ventricular pacing and cardiac resynchronization therapy. [8][9][10] We previously found the LBB COI in a patient with atrial fibrillation, 11 however, there have been no systematic studies on the COI with leads implanted at the LBB. Unlike HBP where the target zone is small, the LBB fibers are widely distributed as a subendocardial network, 12,13 and it may be easier to reach the LBB area.…”

Electrocardiographic morphology during left bundle branch area pacing: Characteristics, underlying mechanisms, and clinical implications

“…Since it was initially described by Huang in 2017, 1 left bundle branch area pacing (LBBAP), a novel form of physiological pacing, has been increasingly adopted in clinical practice, with growing evidence demonstrating its feasibility and potential clinical benefits. [2][3][4][5][6][7][8] It is widely recognized that the surface electrocardiogram (ECG) during LBBAP generally presents a right bundle branch block (RBBB) pat-tern, as a result of early penetration of the electrical impulse into the left bundle branch (LBB) conduction system and a delay in right ventricular (RV) activation. However, differences in ECG characteristics between LBBAP and native RBBB have not been systematically compared.…”

Short‐term and intermediate‐term performance and safety of left bundle branch pacing

“…Among the various physiological pacing strategies that are available, LBBP has been applauded as a feasible strategy for patients with heart failure, especially for those who failed in traditional BiV or His bundle pacing (HBP) 12 . Initial investigation also confirmed the safety and feasibility of LBBP during short‐term and medium‐term follow‐ups 7,8,13‐16 . Although a previous study demonstrated that the electric parameters remained stable within a mean follow‐up duration of 3 months, 17 only few studies have investigated the intermediate‐term outcomes of this new technique named LBBP.…”