title: Effect of Left Ventricular Outflow Tract Obstruction on Left Atrial Mechanics in Hypertrophic Cardiomyopathy.
abstract: Left atrial (LA) volumes are known to be increased in hypertrophic cardiomyopathy (HCM) and are a predictor of adverse outcome. In addition, LA function is impaired and is presumed to be due to left ventricular (LV) diastolic dysfunction as a result of hypertrophy and myocardial fibrosis. In the current study, we assess the incremental effect of outflow tract obstruction (and concomitant mitral regurgitation) on LA function as assessed by LA strain. Patients with HCM (50 obstructive, 50 nonobstructive) were compared to 50 normal controls. A subset of obstructive patients who had undergone septal myectomy was also studied. Utilising feature-tracking software applied to cardiovascular magnetic resonance images, LA volumes and functional parameters were calculated. LA volumes were significantly elevated and LA ejection fraction and strain were significantly reduced in patients with HCM compared with controls and were significantly more affected in patients with obstruction. LA volumes and function were significantly improved after septal myectomy. LVOT obstruction and mitral regurgitation appear to further impair LA mechanics. Septal myectomy results in a significant reduction in LA volumes, paralleled by an improvement in function.
authors.affiliation: Division of Cardiology, Toronto General Hospital, Toronto, ON, Canada M5G 2C4; Department of Cardiology, Papworth Hospital NHS Foundation Trust, Papworth Everard, Cambridge CB23 3RE, UK.
authors.forename: Lynne K
authors.initials: LK
authors.lastname: Williams
authors.affiliation: Division of Cardiology, Toronto General Hospital, Toronto, ON, Canada M5G 2C4.
authors.forename: Raymond H
authors.initials: RH
authors.lastname: Chan
authors.affiliation: Department of Cardiology, Baruch Padeh Medical Center, Poriya and Bar-Ilan University, 15208 Tiberias, Israel.
authors.forename: Shemy
authors.initials: S
authors.lastname: Carasso
authors.affiliation: Department of Medical Imaging, Toronto General Hospital, Toronto, ON, Canada M5G 2C4.
authors.forename: Miranda
authors.initials: M
authors.lastname: Durand
authors.affiliation: Division of Cardiology, Toronto General Hospital, Toronto, ON, Canada M5G 2C4.
authors.forename: Jimmy
authors.initials: J
authors.lastname: Misurka
authors.affiliation: Division of Cardiology, Toronto General Hospital, Toronto, ON, Canada M5G 2C4; Department of Medical Imaging, Toronto General Hospital, Toronto, ON, Canada M5G 2C4.
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Crean
authors.affiliation: Department of Cardiac Surgery, Toronto General Hospital, Toronto, ON, Canada M5G 2C4.
authors.forename: Anthony
authors.initials: A
authors.lastname: Ralph-Edwards
authors.affiliation: Division of Cardiology, University Hospital Zurich, 8091 Zurich, Switzerland.
authors.forename: Christiane
authors.initials: C
authors.lastname: Gruner
authors.affiliation: Division of Cardiology, Toronto General Hospital, Toronto, ON, Canada M5G 2C4.
authors.forename: Anna
authors.initials: A
authors.lastname: Woo
authors.affiliation: Hypertrophic Cardiomyopathy Center, Minneapolis Heart Institute Foundation, Minneapolis, MN 55407, USA.
authors.forename: John R
authors.initials: JR
authors.lastname: Lesser
authors.affiliation: Hypertrophic Cardiomyopathy Center, Minneapolis Heart Institute Foundation, Minneapolis, MN 55407, USA.
authors.forename: Barry J
authors.initials: BJ
authors.lastname: Maron
authors.affiliation: Hypertrophic Cardiomyopathy Center, Tufts Medical Center, Boston, MA 02111, USA.
authors.forename: Martin S
authors.initials: MS
authors.lastname: Maron
authors.affiliation: Division of Cardiology, Toronto General Hospital, Toronto, ON, Canada M5G 2C4.
authors.forename: Harry
authors.initials: H
authors.lastname: Rakowski
mesh_terms: D000368:Aged; D002312:Cardiomyopathy, Hypertrophic / Q000000981:diagnostic imaging / Q000503:physiopathology*; D004452:Echocardiography; D005260:Female; D006325:Heart Atria / Q000000981:diagnostic imaging / Q000503:physiopathology*; D006346:Heart Septum / Q000473:pathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011859:Radiography; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging / Q000503:physiopathology*