Abstract 14398: Predictors of Major Adverse Cardiac Events in Individuals With Left Bundle Branch Block and Cardiac Resynchronization Therapy: Analysis From the Derivate Registry
Authors: Mueller Joshua , Jensen Hanna , Robinson Samantha , Abete Raffaele , Aquaro Giovanni , Baggiano Andrea , Barison Andrea , Bogaert Jan , Camastra Giovanni , Carigi Samuela , Carrabba Nazario , Casavecchia Grazia , Censi Stefano , Cicala Gloria , De Cecco Carlo , De Lazzari Manuel , Di Giovine Gabriella , Calo Leonardo , Dobrovie Monica , Focardi Marta , Fusini Laura , Gaibazzi Nicola , Gismondi Annalaura , Gravina Matteo , Guglielmo Marco , Lanzillo chiara , lombardi massimo , Lorenzoni Valentina , Lozano Torres Jordi , Margonato Davide , Martini Chiara , Marzo Francesca , Masci Pier-Giorgio , Masi Ambra , Moro Claudio , Muscogiuri Giuseppe , Mushtaq Saima , Nese Alberto , Palumbo Alessandro , Pavon Anna Giulia , Pedrotti Patrizia , Perazzolo Marra Martina , Pradella Silvia , Presicci Cristina , Rabbat Mark , Raineri Claudi , Rodriguez-Palomares Jose , Pontone Gianluca , Al'Aref Subhi J ,   on behalf of DERIVATE Local PI and Co-investigators
Published: December 2023

Background:
Cardiac resynchronization therapy (CRT) plays an important role in managing patients with advanced heart failure (HF) with reduced ejection fraction and interventricular conduction block, as it reestablishes synchrony and cardiac function while reducing the risks of HF-related hospitalizations and mortality. Despite the well-described advantages of CRT, approximately 30% to 40% of patients fail to respond to therapy. Therefore, our study aimed to define patient characteristics associated with major adverse cardiac events (MACE) in individuals with left bundle branch block (LBBB) who received CRT.

Methods:
The study cohort included patients enrolled in the CarDiac MagnEtic Resonance for Primary Prevention Implantable CardioVerter DefibrillAtor ThErapy (DERIVATE) registry who had LBBB and had previously undergone CRT. We defined MACE as a composite outcome including cardiac death, hospitalization for heart failure, or major adverse arhythmic events. Cox regression analysis was used to examine the relationship between MACE and CRT therapy. Kaplan-Meier curves were utilized to explore the association between CRT and cardiac death.

Results:
Out of 300 individuals, 144 (48%) experienced MACE. The cohort had a mean age of 63.9 ± 10.9, with 29% being male. The median follow-up period was 1285 days. Ischemic cardiomyopathy was identified as an independent predictor of MACE (HR = 3.54; 95% CI [2.31-5.41]; P<0.01) and cardiac death (HR = 24.10; 95% CI [10.71-54.21]; P<0.01) in patients with LBBB and CRT. Amiodarone therapy was associated with a 1.91-fold (95% CI [1.20-3.05]; P=0.01) increased risk of MACE. Notably, multivariate analysis did not reveal a significant association between gender, hypertension, renal function, diabetes mellitus, or NYHA class III/IV and the occurrence of MACE.

Conclusion:
Our findings suggest that ischemic cardiomyopathy and the use of amiodarone therapy are independent predictors of MACE in patients with LBBB who previously underwent CRT. These findings suggest that patient-level characteristics are important predictors of MACE; however, further research is needed to better understand the interplay between ejection fraction, conduction disease, and patient characteristics post-CRT therapy.