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Benefits of Cardiac Resynchronization Therapy in an Asynchronous Heart Failure Model Induced by Left Bundle Branch Ablation and Rapid Pacing
Published on: December 11, 2017
Electrocardiographic Characteristics Associated With Lead Position Variations in Left Bundle Branch Area Pacing
Naoki Matsumoto1, Kenji Shimeno1, Yumi Kashima1
1Department of Cardiology, Osaka City General Hospital, Osaka, Japan.
Background:
Physiology-based electrocardiographic (ECG) criteria are used to assess left bundle branch area pacing (LBBAP), but the impact of lead implantation site on ECG parameters remains unclear.
Methods:
We analyzed 212 patients who underwent successful LBBAP and classified them into high septum (HS, n = 49), mid septum (MS, n = 119), and low septum (LS, n = 44) groups according to the polarity of leads II and III. ECG parameters, including QRS morphology in lead V1, stimulus-to-R-wave peak times in V6 and V1 (sV6RWPT, sV1RWPT), and the V6-V1 interpeak interval, were compared. The proportions meeting proposed physiology-based ECG criteria for left bundle branch (LBB) capture were also evaluated.
Results:
The LS group demonstrated the highest prevalence of dominant R waves in V1 (qR: 38.6%, R: 4.5%, p < 0.01). It had a shorter sV6RWPT than the MS group (59 ± 9 ms, p = 0.011), with no significant difference compared with the HS group. It also demonstrated a longer sV1RWPT (105 ± 11 ms, p = 0.023) and V6-V1 interpeak interval (46 ± 10 ms, p < 0.01). Although no significant differences were observed among the three groups regarding output-dependent QRS transition or LBB potential, the LS group more frequently met the V6-V1 interpeak interval criterion (>44 ms, 86%, p < 0.01).
Conclusions:
In LBBAP, low septal lead placement was associated with prominent R waves in V1, shorter sV6RWPT versus the MS group, and longer V6-V1 interpeak intervals, highlighting the importance of implantation site when interpreting ECG findings.
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