Clinical Research Directory

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.