title: Comparison of Outcomes in Patients With Nonobstructive, Labile-Obstructive, and Chronically Obstructive Hypertrophic Cardiomyopathy.
abstract: Patients with nonobstructive hypertrophic cardiomyopathy (HC) are considered low risk, generally not requiring aggressive intervention. However, nonobstructive and labile-obstructive HC have been traditionally classified together, and it is unknown if these 2 subgroups have distinct risk profiles. We compared cardiovascular outcomes in 293 patients HC (96 nonobstructive, 114 labile-obstructive, and 83 obstructive) referred for exercise echocardiography and magnetic resonance imaging and followed for 3.3 ± 3.6 years. A subgroup (34 nonobstructive, 28 labile-obstructive, 21 obstructive) underwent positron emission tomography. The mean number of sudden cardiac death risk factors was similar among groups (nonobstructive: 1.4 vs labile-obstructive: 1.2 vs obstructive: 1.4 risk factors, p = 0.2). Prevalence of late gadolinium enhancement (LGE) was similar across groups but more non-obstructive patients had late gadolinium enhancement ≥20% of myocardial mass (23 [30%] vs 19 [18%] labile-obstructive and 8 [11%] obstructive, p = 0.01]. Fewer labile-obstructive patients had regional positron emission tomography perfusion abnormalities (12 [46%] vs nonobstructive 30 [81%] and obstructive 17 [85%], p = 0.003]. During follow-up, 60 events were recorded (36 ventricular tachycardia/ventricular fibrillation, including 30 defibrillator discharges, 12 heart failure worsening, and 2 deaths). Nonobstructive patients were at greater risk of VT/VF at follow-up, compared to labile obstructive (hazed ratio 0.18, 95% confidence interval 0.04 to 0.84, p = 0.03) and the risk persisted after adjusting for age, gender, syncope, family history of sudden cardiac death, abnormal blood pressure response, and septum ≥3 cm (p = 0.04). Appropriate defibrillator discharges were more frequent in nonobstructive (8 [18%]) compared to labile-obstructive (0 [0%], p = 0.02) patients. In conclusion, nonobstructive hemodynamics is associated with more pronounced fibrosis and ischemia than labile-obstructive and is an independent predictor of VT/VF in HC.
authors.affiliation: Johns Hopkins HCM Center of Excellence, Baltimore, Maryland.
authors.forename: Iraklis
authors.initials: I
authors.lastname: Pozios
authors.affiliation: Department of Radiology, Johns Hopkins University, Baltimore, Maryland.
authors.forename: Celia
authors.initials: C
authors.lastname: Corona-Villalobos
authors.affiliation: Johns Hopkins HCM Center of Excellence, Baltimore, Maryland.
authors.forename: Lars L
authors.initials: LL
authors.lastname: Sorensen
authors.affiliation: Department of Radiology, Johns Hopkins University, Baltimore, Maryland.
authors.forename: Paco E
authors.initials: PE
authors.lastname: Bravo
authors.affiliation: Johns Hopkins HCM Center of Excellence, Baltimore, Maryland.
authors.forename: Marco
authors.initials: M
authors.lastname: Canepa
authors.affiliation: Johns Hopkins HCM Center of Excellence, Baltimore, Maryland.
authors.forename: Chiara
authors.initials: C
authors.lastname: Pisanello
authors.affiliation: Johns Hopkins HCM Center of Excellence, Baltimore, Maryland.
authors.forename: Aurelio
authors.initials: A
authors.lastname: Pinheiro
authors.affiliation: Johns Hopkins HCM Center of Excellence, Baltimore, Maryland.
authors.forename: Veronica L
authors.initials: VL
authors.lastname: Dimaano
authors.affiliation: Johns Hopkins HCM Center of Excellence, Baltimore, Maryland.
authors.forename: Hongchang
authors.initials: H
authors.lastname: Luo
authors.affiliation: Johns Hopkins HCM Center of Excellence, Baltimore, Maryland.
authors.forename: Zeina
authors.initials: Z
authors.lastname: Dardari
authors.affiliation: Johns Hopkins HCM Center of Excellence, Baltimore, Maryland.
authors.forename: Xun
authors.initials: X
authors.lastname: Zhou
authors.affiliation: Department of Radiology, Johns Hopkins University, Baltimore, Maryland.
authors.forename: Ihab
authors.initials: I
authors.lastname: Kamel
authors.affiliation: Department of Radiology, Johns Hopkins University, Baltimore, Maryland.
authors.forename: Stefan L
authors.initials: SL
authors.lastname: Zimmerman
authors.affiliation: Radiology and Imaging Sciences, National Institutes of Health Clinical Center, Bethesda, Maryland.
authors.forename: David A
authors.initials: DA
authors.lastname: Bluemke
authors.affiliation: Johns Hopkins HCM Center of Excellence, Baltimore, Maryland.
authors.forename: M Roselle
authors.initials: MR
authors.lastname: Abraham
authors.affiliation: Johns Hopkins HCM Center of Excellence, Baltimore, Maryland. Electronic address: tabraha3@jhmi.edu.
authors.forename: Theodore P
authors.initials: TP
authors.lastname: Abraham
mesh_terms: D000328:Adult; D000368:Aged; D002312:Cardiomyopathy, Hypertrophic / Q000145:classification / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology*; D015331:Cohort Studies; D018450:Disease Progression; D025401:Echocardiography, Stress; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging; D006333:Heart Failure / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology*; D006801:Humans; D053208:Kaplan-Meier Estimate; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D055414:Myocardial Perfusion Imaging; D009206:Myocardium / Q000473:pathology; D016016:Proportional Hazards Models; D017180:Tachycardia, Ventricular / Q000209:etiology*; D014693:Ventricular Fibrillation / Q000209:etiology*; D014694:Ventricular Outflow Obstruction / Q000145:classification / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology*