LBBP as Initial Therapy in Patients With Non-ischemic Heart Failure and LBBB

"Quadruple anti-heart failure drug therapy: BB, ACEI/ARB/ARNI, MRA, and SGLT2i. If the initial dose according to guidelines is tolerated, the protocol would then direct the uptitration of medication dose over time to a specified target dose, unless not well tolerated.~\*Criteria for \<3 months of optimized (complete) GDMT: 1) according to the latest management of HF, any of the new quadruple therapy is not used if the condition allowed; Or 2) the dose of any drug dose not reach the maximum tolerated target; Or 3) under the maximum tolerated dose of BB, ivabradine is not added with a heart rate still ≥70 bpm at rest."

"GDMT is the same as Drug intervention. LBBP is confirmed when: 1) the LBBB morphology disappeared and the paced RBBB pattern (typical or atypical) is observed in V1; and 2) LVAT is ≤100 ms at low output(≤3 V/0.5 ms); and at least 1 of the following is achieved: a) abrupt shortening of LVAT by \>10 ms during mid/deep septal lead placement with a RBBB pattern in V1 at high output, which then remains short and constant at high and low output with further advancement of the lead to the final position; b) transition from nonselective to selective LBBP (QRS morphology transition from atypical RBBB to typical rsR' pattern in V1 and wide/large S-wave in V6 , with the appearance of an isoelectric segment and no LVAT change at high and low outputs); and c) transition from nonselective LBBP to LV septal pacing (lengthening of LVAT by at least 10 ms with or without obvious QRS morphology transition during threshold testing).~HBP or BiVP is attempted using the standard-of-care technique."