Abstract 12013: Electrical Remodeling in Patients With Iatrogenic Left Bundle Branch Block
Purpose: Left bundle branch block (LBBB) is induced in approximately one third of all transcatheter aortic valve implantation (TAVI) procedures. TAVI-induced LBBB is associated with an increased risk of death. We investigated the remodeling of electrophysiological properties in patients with TAVI-induced LBBB and the impact on survival.
Methods: This retrospective study comprises of 46 patients with initially narrow QRS complex, in whom 12-lead electrocardiograms (ECGs) were available before TAVI, acutely after (acute LBBB) and 1-12 months after TAVI (chronic LBBB). All patients had persistent LBBB. A vectorcardiogram (VCG) was reconstructed from the recorded 12-lead ECG using a modified Kors method. Survival of the patients was studied during a 30 months follow-up time.
Results: The entire cohort was divided into two groups using an optimal cut-off value for the T-wave area change between acute and chronic LBBB. One group showed a percent reduction in T-wave area larger than 13.5% (n = 27, “Remodeling”) and the other group an increase or reduction smaller than 13.5% (n = 15, “No-remodeling”). In the Remodeling group QRS and T-wave area decreased by 16% and 32%, respectively, whereas in the No-remodeling group these indices increased by 14% and 6%, respectively (Table). Heart rate and QRS duration were comparable between groups and did not change significantly over time, but the QTc interval decreased in both groups. A higher mortality rate was observed in the Remodeling vs. No-remodeling group (67% vs. 37%, p = 0.046). Before TAVI the Remodeling group had a trend towards lower frontal QRS axis than the No-remodeling group (9° ± 29° vs. 19° ± 36°, p = 0.18).
Conclusion: This unique study in patients with TAVI-induced LBBB shows that a decrease in QRS and T-wave area over time is associated with an increased risk of death. The decreases in QRS- and T-wave area may be explained by increasing electrical uncoupling in the myocardium.
Author Disclosures: E. Engels: None. T.T. Poels: None. P. Houthuizen: Speakers Bureau; Significant; Edwards LifeSciences. P. de Jaegere: None. K. Vernooy: Research Grant; Significant; Medtronic. Consultant/Advisory Board; Significant; Medtronic. F.W. Prinzen: Research Grant; Significant; Biological Delivery Systems (Johnson&Johnson), EBR Systems, Medtronic, Proteus Biomedical, MSD. Consultant/Advisory Board; Significant; St. Jude Medical.
- © 2014 by American Heart Association, Inc.