Conduction time from left bundle branch pacing to the left ventricular lateral wall in two patients in whom cardiac
Takefumi Fujito1, Ken Masuda1, Hirohito Takahashi2
1Department of Cardiovascular, Renal and Metabolic Medicine, Sapporo Medical University School of Medicine, Sapporo, Japan.
Insights
Left bundle branch pacing (LBBP) may not always improve left ventricular (LV) conduction. Long conduction times during LBBP indicate potential CRT inefficacy. Left bundle branch-optimized CRT (LOT-CRT) may be more effective in these cases.
Area of Science:
- Cardiology
- Electrophysiology
- Medical Devices
Background:
- Left bundle branch pacing (LBBP) is an emerging technique for cardiac resynchronization therapy (CRT).
- However, its effectiveness depends on improving left ventricular (LV) electrical conduction.
- LBBP may not always resolve LV conduction disturbances.
Abstract:
The efficacy of left bundle branch pacing (LBBP) as cardiac resynchronization therapy (CRT) has been reported, but LBBP may not always improve conduction disturbance in the left ventricle (LV). To evaluate LV electrical conduction delay during LBBP, we measured conduction time from the pacing at left bundle branch to LV lead sensing (LBBP-LV) in two patients in whom left bundle branch-optimized cardiac resynchronization therapy (LOT-CRT) was attempted. Case 1 was a 77-year-old female with dilated cardiomyopathy (DCM) and left bundle branch block. The QRS duration during LBBP was 160 ms and the interval between the stimulus artifact and peak of the R wave in lead V6 (Stim-V6RWPT) was 74 ms. LBBP-LV at the LV mid-lateral wall and LV mid-posterolateral wall were 112 ms and 102 ms, respectively. Case 2 was a 75-year-old female with DCM and nonspecific intraventricular conduction delay. The QRS duration during LBBP was 156 ms and Stim-V6RWPT was 66 ms. LBBP-LV at the LV mid-anterolateral wall, LV mid-lateral wall, and LV mid-posterolateral wall were 96 ms, 107 ms, and 121 ms, respectively. In conclusion, LBBP-LV at the LV mid-lateral area was relatively long. If LBBP does not improve LV conduction disturbances, LOT-CRT may be more effective.
Learning Objective:
The efficacy of left bundle branch pacing (LBBP) for cardiac resynchronization therapy (CRT) has been reported. However, if the conduction time from pacing to the left ventricular (LV) lateral area during LBBP is long, LBBP may not improve LV conduction disturbance, resulting in ineffective CRT. In such cases, more effective CRT would be expected with LV lead implantation at the area of the LV conduction delay during LBBP.
Related Concept Videos
01:20Conduction System of the Heart
This system relies on the unique properties of nodal and Purkinje cells:...
01:25Correlation between ECG and Cardiac Cycle
A cardiac action potential originates in the SA node and spreads throughout the atria and the AV node in approximately 0.03 seconds. This results in the P wave in an ECG and triggers atrial contraction. The action potential is then briefly slowed at the AV node, allowing the atria to contract and fill the ventricles with blood before...
01:19Electrophysiology of Normal Cardiac Rhythm
01:30Cardiac Action Potential
The cardiac action potential process involves a series of phases characterized by the movement of ions across the cardiac cell membranes, leading to the depolarization and repolarization of the cardiac myocytes.
Ionic Basis of Cardiac Action Potentials
01:13The Cardiac Cycle
The Process
Electrical signals—sent from the sinoatrial (SA) node in the right atrial wall to the atrioventricular (AV) node between the right atrium and right ventricle—cause both atria to simultaneously contract. When the signal reaches the AV node, it pauses for approximately a tenth of a second, allowing the atria to contract and...