Author + information
- Received January 28, 2019
- Revision received September 30, 2019
- Accepted October 3, 2019
- Published online February 17, 2020.
- Antonius M.W. van Stipdonk, MDa,∗ (, )
- Renske Hoogland, MDa,
- Iris ter Horst, MD, PhDb,
- Marielle Kloosterman, MDc,
- Sophie Vanbelle, PhDd,
- Harry J.G.M. Crijns, MD, PhDa,
- Frits W. Prinzen, PhDe,
- Mathias Meine, MD, PhDb,
- Alexander H. Maass, MD, PhDc,∗ and
- Kevin Vernooy, MD, PhDa,e,f,∗
- aDepartment of Cardiology, Maastricht University Medical Center, Maastricht, the Netherlands
- bDepartment of Cardiology, University Medical Centre Utrecht, Utrecht, the Netherlands
- cDepartment of Cardiology, University Medical Centre Groningen, University of Groningen, Groningen, the Netherlands
- dMethodology and Statistics, Care and Public Health Research Institute, Maastricht University, Maastricht, the Netherlands
- eDepartment of Physiology, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, the Netherlands
- fDepartment of Cardiology, Radboud University Medical Centre, Nijmegen, the Netherlands
- ↵∗Address for correspondence:
Dr. Antonius M.W. van Stipdonk, Department of Cardiology, Maastricht University Medical Center, P.O. Box 5800, 6202AZ Maastricht, the Netherlands.
Objectives This study aimed to evaluate the association of 4 left bundle branch block (LBBB) definitions and their individual ECG characteristics with clinical outcome. Furthermore, it aimed to combine relevant outcome-associated electrocardiographic (ECG) characteristics into a novel outcome-based definition.
Background LBBB morphology is associated with positive response to cardiac resynchronization therapy. However, there are multiple LBBB definitions. Associations with outcomes may differ between definitions and depend on varying contributions of the individual ECG characteristics that these LBBB definitions are composed of.
Methods A retrospective multicenter study was conducted in 1,492 cardiac resynchronization therapy patients. Patients were classified as LBBB or non-LBBB according to definitions provided by the European Society of Cardiology, American Heart Association, MADIT-CRT (Multicenter Automatic Defibrillator Implantation with Cardiac Resynchronization Therapy) trial, and according to Strauss et al., the primary endpoint was left ventricular assist device implantation, cardiac transplantation, and all-cause mortality.
Results LBBB classification differed significantly between the 4 definitions (kappa coefficients ranging from 0.09 to 0.92). The American Heart Association definition correlated the least (0.09 to 0.12) with the other definitions. Only 13.8% of patients were classified as LBBB by all definitions. During a follow-up period of 3.4 ± 2.4 years, 472 (32%) patients experienced the primary endpoint. For each LBBB definition survival analysis showed a significant association of LBBB with outcome, with relative risk reduction ranging from 39% to 43%. Each LBBB definition included characteristics that were not associated with outcome. Combining outcome-associated ECG characteristics into a novel prediction model did not significantly improve diagnostic performance (relative risk reduction 43%).
Conclusions The classification of LBBB is highly dependent on the LBBB definition used. However, each LBBB definition provides a comparable difference in risk of adverse clinical events between LBBB and non-LBBB patients. Combining individual outcome-associated ECG-characteristics into a novel prediction model does not improve association with outcome.
↵∗ Drs. Maass and Vernooy contributed equally to this work and are joint senior authors.
Dr. ter Horst is an employee of Philips Healthcare. Dr. Prinzen has received research grant support from Medtronic, Abbott, Microport, and Biotronik. Dr. Vernooy has received research grant support from Medtronic and Abbott. Dr. Vernooy has received research grant support from Medtronic and Abbott. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
The authors attest they are in compliance with human studies committees and animal welfare regulations of the authors’ institutions and Food and Drug Administration guidelines, including patient consent where appropriate. For more information, visit the JACC: Clinical Electrophysiology author instructions page.
- Received January 28, 2019.
- Revision received September 30, 2019.
- Accepted October 3, 2019.
- 2020 American College of Cardiology Foundation
This article requires a subscription or purchase to view the full text. If you are a subscriber or member, click Login or the Subscribe link (top menu above) to access this article.