title: Relationship of basal-septal fibrosis with LV outflow tract obstruction in hypertrophic cardiomyopathy: insights from cardiac magnetic resonance analysis.
abstract: Myocardial fibrosis is frequently observed and may be associated with the prognosis in patients with hypertrophic cardiomyopathy (HCM); however, the clinical pathophysiological features, particularly in terms of fibrosis, of hypertrophic obstructive cardiomyopathy (HOCM) remain unclear. This study aimed to determine a role of local fibrosis in HOCM using cardiac magnetic resonance (CMR). 108 consecutive HCM patients underwent CMR. HOCM was defined as a left ventricular outflow tract (LVOT) pressure gradient ≥30 mmHg at rest. Myocardial mass and fibrosis mass by late gadolinium-enhancement CMR (LGE-CMR) were calculated and the distribution/pattern was analyzed using the AHA 17-segment model. LV ejection fraction (LVEF) was significantly higher in patients with HOCM (n = 19) than in those with nonobstructive HCM (n = 89) (P < 0.05). Both total myocardial and fibrosis masses in LV were similar in the two groups (P = 0.385 and P = 0.859, respectively). However, fibrosis in the basal septum was significantly less frequent in the HOCM group than in the nonobstructive HCM group (P < 0.01). The LVOT pressure gradient was significantly higher in the basal-septal non-fibrosis group than in the fibrosis group (23.6 ± 37.3 vs. 4.8 ± 11.4 mmHg, P < 0.01). Multivariate analysis revealed that basal-septal fibrosis was an independent negative predictor of LVOT obstruction in addition to the local wall thickness and LVEF as positive predictors in HCM patients. In conclusion, a significant association was observed between LVOT obstruction and basal septal fibrosis by LGE-CMR in HCM patients. In addition to negative impact of basal-septal fibrosis, basal-septal hypertrophy and preserved global LV contractility may be associated with the pathophysiological features of LVOT obstruction.
authors.affiliation: Division of Cardiology, Department of Internal Medicine, Kinki University Faculty of Medicine, 377-2 Ohno-Higashi, Osakasayama, 589-8511, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Nakamura
authors.affiliation: Division of Cardiology, Department of Internal Medicine, Kinki University Faculty of Medicine, 377-2 Ohno-Higashi, Osakasayama, 589-8511, Japan. yiwanaga@med.kindai.ac.jp.
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Iwanaga
authors.affiliation: Division of Cardiology, Department of Internal Medicine, Kinki University Faculty of Medicine, 377-2 Ohno-Higashi, Osakasayama, 589-8511, Japan.
authors.forename: Masakazu
authors.initials: M
authors.lastname: Yasuda
authors.affiliation: Division of Cardiology, Department of Internal Medicine, Kinki University Faculty of Medicine, 377-2 Ohno-Higashi, Osakasayama, 589-8511, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Kawamura
authors.affiliation: Division of Cardiology, Department of Internal Medicine, Kinki University Faculty of Medicine, 377-2 Ohno-Higashi, Osakasayama, 589-8511, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Miyaji
authors.affiliation: Division of Cardiology, Department of Internal Medicine, Kinki University Faculty of Medicine, 377-2 Ohno-Higashi, Osakasayama, 589-8511, Japan.
authors.forename: Hanako
authors.initials: H
authors.lastname: Morooka
authors.affiliation: Division of Cardiology, Department of Internal Medicine, Kinki University Faculty of Medicine, 377-2 Ohno-Higashi, Osakasayama, 589-8511, Japan.
authors.forename: Shunichi
authors.initials: S
authors.lastname: Miyazaki
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002312:Cardiomyopathy, Hypertrophic / Q000150:complications / Q000000981:diagnostic imaging* / Q000473:pathology / Q000503:physiopathology; D003287:Contrast Media; D005260:Female; D005355:Fibrosis; D019786:Gadolinium DTPA; D006346:Heart Septum / Q000000981:diagnostic imaging* / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D007564:Japan; D019028:Magnetic Resonance Imaging, Cine; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009200:Myocardial Contraction; D009206:Myocardium / Q000473:pathology*; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012307:Risk Factors; D013318:Stroke Volume; D016277:Ventricular Function, Left; D014694:Ventricular Outflow Obstruction / Q000000981:diagnostic imaging* / Q000209:etiology / Q000473:pathology / Q000503:physiopathology
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA
keywords: Hypertrophic obstructive cardiomyopathy; Magnetic resonance imaging; Myocardial fibrosis