Open AccessRelation between electrical and mechanical dyssynchrony in patients with left bundle branch block: An electro‐ and vectorcardiographic study
Author(s) -
De Pooter Jan,
El Haddad Milad,
Kamoen Victor,
Kallupurackal Thomas Tibin,
Stroobandt Roland,
De Buyzere Marc,
Timmermans Frank
Publication year - 2018
Publication title -
annals of noninvasive electrocardiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.494
H-Index - 48
eISSN - 1542-474X
pISSN - 1082-720X
DOI - 10.1111/anec.12525
Subject(s) - left bundle branch block , medicine , cardiology , cardiac resynchronization therapy , qrs complex , ventricular dyssynchrony , bundle branch block , ejection fraction , vectorcardiography , electrocardiography , heart failure
Background Current guidelines select patients for cardiac resynchronization therapy ( CRT ) mainly on electrocardiographic parameters like QRS duration and left bundle branch block ( LBBB ). However, among those LBBB patients, heterogeneity in mechanical dyssynchrony occurs and might be a reason for nonresponse to CRT . This study assesses the relation between electrocardiographic characteristics and presence of mechanical dyssynchrony among LBBB patients. Methods The study included patients with true LBBB (including mid‐ QRS notching) on standard 12‐lead electrocardiograms. Left bundle branch block‐induced mechanical dyssynchrony was assessed by the presence of septal flash on two‐dimensional echocardiography. Previously reported electro‐ and vectorcardiographic dyssynchrony markers were analyzed: global QRS duration ( QRSD LBBB ), left ventricular activation time ( QRSD LVAT ), time to intrinsicoid deflection ( QRSD ID ), and vectorcardiographic QRS areas in the 3D vector loop ( QRSA 3D ). Results The study enrolled 545 LBBB patients. Septal flash (SF) is present in 52% of patients presenting with true LBBB . Patients with SF are more frequent female, have less ischemic heart disease and smaller left ventricular dimensions. In multivariate analysis longer QRSD LBBB , QRSD LVAT and larger QRSA 3D were independently associated with SF . Of all parameters, QRSA 3D has the best accuracy to predict SF , although overall accuracy remains moderate (59% sensitivity, 58% specificity). The predictive value of QRSA 3D remained constant in both sexes, irrespective of ischemic heart disease, ejection fraction and even when categorizing for QRSD LBBB . Conclusion In LBBB patients, large QRS areas correlate better with mechanical dyssynchrony compared to wide QRSD intervals. However, the overall accuracy to predict mechanical dyssynchrony by electrocardiographic dyssynchrony markers, even when using complex vectorcardiographic parameters, remains low.