Cardiovascular magnetic resonance features of mechanical dyssynchrony in patients with left bundle branch block.
Patients with left bundle branch block (LBBB) can exhibit mechanical dyssynchrony which may contribute to heart failure; such patients may benefit from cardiac resynchronization treatment (CRT). While cardiac magnetic resonance imaging (CMR) has become a common part of heart failure work-up, CMR features of mechanical dyssynchrony in patients with LBBB have not been well characterized. This study aims to investigate the potential of CMR to characterize mechanical features of LBBB. CMR examinations from 43 patients with LBBB on their electrocardiogram, but without significant focal structural abnormalities, and from 43 age- and gender-matched normal controls were retrospectively reviewed. The following mechanical features of LBBB were evaluated: septal flash (SF), apical rocking (AR), delayed aortic valve opening measured relative to both end-diastole (AVOED) and pulmonic valve opening (AVOPVO), delayed left-ventricular (LV) free-wall contraction, and curvatures of the septum and LV free-wall. Septal displacement curves were also generated, using feature-tracking techniques. The echocardiographic findings of LBBB were also reviewed in those subjects for whom they were available. LBBB was significantly associated with the presence of SF and AR; within the LBBB group, 79 % had SF and 65 % had AR. Delayed AVOED, AVOPVO, and delayed LV free-wall contraction were significantly associated with LBBB. AVOEDand AVOPVOpositively correlated with QRS duration and negatively correlated with ejection fraction. Hearts with electrocardiographic evidence of LBBB showed lower septal-to-LV free-wall curvature ratios at end-diastole compared to normal controls. CMR can be used to identify and evaluate mechanical dyssynchrony in patients with LBBB. None of the normal controls showed the mechanical features associated with LBBB. Moreover, not all patients with LBBB showed the same degree of mechanical dyssynchrony, which could have implications for CRT.
Department of Medical Imaging, University of Ottawa, The Ottawa Hospital, General Campus, 501 Smyth Road, Ottawa, ON, K1H 8L6, Canada.
Giselle
G
Revah
Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, 660 First Avenue, Room 411, New York, NY, USA.
Vincent
V
Wu
CARIM School of Cardiovascular Diseases, Maastricht University Medical Center, Universiteitssingel 50, 6229 ER, Maastricht, Netherlands.|L'Institut de Rythmologie et Modélisation Cardiaque (IHU-LIRYC), Université de Bordeaux, Pessac-Bordeaux, France.
Peter R
PR
Huntjens
Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, 660 First Avenue, New York, NY, USA.
Eve
E
Piekarski
Division of Cardiology, Department of Medicine, Columbia University Medical Center, 171 Fort Washington Avenue, Irving Pavilion, 6-648, New York, NY, 10032, USA.
Janice Y
JY
Chyou
Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, 660 First Avenue, Room 411, New York, NY, USA. leon.axel@nyumc.org.
Leon
L
Axel
D002037:Bundle-Branch Block / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology; D003287:Contrast Media / Q000008:administration & dosage; D004452:Echocardiography; D004562:Electrocardiography; D005260:Female; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction; D015588:Observer Variation; D009864:Ontario / Q000453:epidemiology; D011237:Predictive Value of Tests; D015995:Prevalence; D015203:Reproducibility of Results; D012189:Retrospective Studies; D013318:Stroke Volume; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000453:epidemiology / Q000503:physiopathology; D016277:Ventricular Function, Left
D003287:Contrast Media
Apical rocking; Cardiovascular magnetic resonance; Left bundle branch block; Mechanical dyssynchrony; Septal flash