title: Clinical profile and significance of delayed enhancement in hypertrophic cardiomyopathy.
abstract: BACKGROUND
  Contrast-enhanced cardiovascular magnetic resonance with delayed enhancement (DE) can provide in vivo assessment of myocardial fibrosis. However, the clinical significance of DE in hypertrophic cardiomyopathy (HCM) remains unresolved.
  
  
  RESULTS
  Cine and cardiovascular magnetic resonance with DE were performed in 202 HCM patients (mean age, 42+/-17 years; 71% male), DE was compared with clinical and demographic variables, and patients were followed up for 681+/-249 days for adverse disease events. DE was identified in 111 (55%) HCM patients, occupying 9%+/-11% of left ventricular myocardial volume, including >25% DE in 10% of patients. The presence of DE was related to occurrence of heart failure symptoms (P=0.05) and left ventricular systolic dysfunction (P=0.001). DE was present in all patients with ejection fraction < or =50% but also in 53% (102/192) of patients with preserved ejection fraction (P<0.001); %DE was both inversely related to (r=-0.3; P<0.001) and an independent predictor of ejection fraction (r=-0.4; P<0.001). DE (7%+/-7% of left ventricle) was present in 54 patients who were asymptomatic (and with normal ejection fraction). Over the follow-up period, the annualized adverse cardiovascular event rate in patients with DE exceeded that in patients without DE but did not achieve statistical significance (5.5% versus 3.3%; P=0.5).
  
  
  CONCLUSIONS
  In a large HCM cohort, DE was an independent predictor of systolic dysfunction but with only a modest relationship to heart failure symptoms. These data suggest an important role for myocardial fibrosis in the clinical course of HCM patients but are not sufficient at this time to consider DE as an independent risk factor for adverse prognosis.
authors.affiliation: Hypertrophic Cardiomyopathy Center, Division of Cardiology, Tufts Medical Center, Boston, Massachusetts 02111, USA. mmaron@tuftsmedicalcenter.org
authors.forename: Martin S
authors.initials: MS
authors.lastname: Maron
authors.forename: Evan
authors.initials: E
authors.lastname: Appelbaum
authors.forename: Caitlin J
authors.initials: CJ
authors.lastname: Harrigan
authors.forename: Jacki
authors.initials: J
authors.lastname: Buros
authors.forename: C Michael
authors.initials: CM
authors.lastname: Gibson
authors.forename: Connie
authors.initials: C
authors.lastname: Hanna
authors.forename: John R
authors.initials: JR
authors.lastname: Lesser
authors.forename: James E
authors.initials: JE
authors.lastname: Udelson
authors.forename: Warren J
authors.initials: WJ
authors.lastname: Manning
authors.forename: Barry J
authors.initials: BJ
authors.lastname: Maron
mesh_terms: D000328:Adult; D002312:Cardiomyopathy, Hypertrophic / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology; D003937:Diagnosis, Differential; D018450:Disease Progression; D004719:Endomyocardial Fibrosis / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D011379:Prognosis; D011446:Prospective Studies; D012307:Risk Factors; D013318:Stroke Volume / Q000502:physiology; D016277:Ventricular Function, Left / Q000502:physiology