We congratulate Vijayaraman et al
- Vijayaraman P.
- Herweg B.
- Verma A.
- et al.
Rescue left bundle branch area pacing in coronary venous lead failure or nonresponse
to biventricular pacing: results from International LBBAP Collaborative Study Group.
for their significant work recently published in Heart Rhythm Journal
. The authors draw a conclusion that left bundle branch area pacing (LBBAP) is a viable
alternative to cardiac resynchronization therapy (CRT) in patients who failed conventional
biventricular pacing (BVP) owing to coronary venous lead failure or who were nonresponders.
However, detailed information on the clinical outcomes in patients with left bundle
branch block (LBBB), right bundle branch block (RBBB), or intraventricular conduction
delay (IVCD) was not specifically reported. Recently, Chen et al
- Chen X.
- Ye Y.
- Wang Z.
- et al.
Cardiac resynchronization therapy via left bundle branch pacing vs. optimized biventricular
pacing with adaptive algorithm in heart failure with left bundle branch block: a prospective,
multi-centre, observational study.
has indicated that LBBAP demonstrated better electromechanical resynchronization
and higher super-response than did BVP in heart failure with left ventricular (LV)
ejection fraction ≤ 35% and typical LBBB. Apparently, LBBAP is superior to BVP in
patients with heart failure and typical LBBB. During LBBAP, electromechanical contraction
of the LV is earlier than that of the right ventricle. Therefore, LBBAP may not correct
heart failure with RBBB. In patients with typical LBBB, it was conceivable that LBBAP
provided clinical benefits due to LBBB was corrected by bypassing the block site and
therefore a full recovery of LV synchronization. In the study by Li et al,
- Li Y.
- Yan L.
- Dai Y.
- et al.
Feasibility and efficacy of left bundle branch area pacing in patients indicated for
cardiac resynchronization therapy.
only moderate improvement in LV function was observed in patients with IVCD when
treated with LBBAP alone. Therefore, LBBAP may not significantly improve heart failure
with other etiologies beyond typical LBBB. In the present study, LBBAP-optimized CRT
(LOT-CRT) was performed in 6.5% of nonresponders, which is theoretically more effective
for patients with atypical LBBB or IVCD than LBBAP. Therefore, we wonder whether LBBAP
or LOT-CRT improves the clinical outcomes in patients with RBBB, atypical LBBB, or
IVCD. It would be interesting to reanalyze the data to address this issue. The lack
of detailed information on the patient outcomes in different etiologies in this study
makes it confusing to understand whether LBBAP or LOT-CRT is beneficial in all patients
with coronary venous lead failure or nonresponse to BVP.