title: Relation of strain by feature tracking and clinical outcome in children, adolescents, and young adults with hypertrophic cardiomyopathy.
abstract: Evaluation of hypertrophic cardiomyopathy (HC) in young patients is limited by lack of age-specific norms for wall thickness on cardiovascular magnetic resonance (CMR) images. Left ventricular strain may have a role in identifying and risk stratifying patients with HC, but few data exist for strain measurement on CMR images. In 30 patients (14.1 ± 3.2 years) with clinically diagnosed HC and 24 controls (15.6 ± 2.8 years), strain (radial, longitudinal, and circumferential) was evaluated by 2 experienced readers using CMR feature tracking. In patients with HC, hypertrophied segments had decreased radial (28.0 ± 5.2% vs 58.6 ± 3.9%, p = 0.0002), circumferential (-23.7 ± 1.1% vs -28.3 ± 0.8%, p = 0.004), and longitudinal (-11.2 ± 1.2% vs -21.7 ± 0.8%, p <0.0001) strains versus control segments. Hypertrophied segments had decreased longitudinal (basal segments -12.2 ± 1.9% vs -22.6 ± 1.2%, p = 0.0002), radial (basal segments 22.7 ± 10.8% vs 78.8 ± 7.2%, p = 0.0001), and circumferential (basal segments -22.4 ± 1.7% vs -30.6 ± 1%, p = 0.0004) strains versus nonhypertrophied segments in patients with HC. Longitudinal strain had the lowest intraobserver and interobserver variabilities (coefficient of variability -15.7% and -18.5%). After a median follow-up of 28.1 months (interquartile range [IQR] 4.2 to 33.1), 7 patients with HC with an adverse event outcome (5 ventricular tachycardia, 1 appropriate implantable cardioverter-defibrillator discharge, and 1 death) had reduced global radial (median 39.7%, IQR 39.6% to 46.6% vs 65.4%, IQR 46.1% to 83.4%, p = 0.01) and longitudinal strains (median -16.5%, IQR -18.7% to -15.5% vs -19.7%, IQR -23.8% to -17.5%, p = 0.046) compared with patients with HC without an event. In conclusion, CMR feature tracking detects differences in global and segmental strains and may represent a novel method to predict clinical outcome in patients with HC. Further study is necessary to evaluate longitudinal changes in this population.
authors.affiliation: Division of Pediatric Cardiology, Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, Michigan. Electronic address: bsmi@med.umich.edu.
authors.forename: Brandon M
authors.initials: BM
authors.lastname: Smith
authors.affiliation: Division of Pediatric Cardiology, Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, Michigan; Section of Pediatric Radiology, Department of Radiology, University of Michigan, Ann Arbor, Michigan.
authors.forename: Adam L
authors.initials: AL
authors.lastname: Dorfman
authors.affiliation: Division of Pediatric Cardiology, Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, Michigan.
authors.forename: Sunkyung
authors.initials: S
authors.lastname: Yu
authors.affiliation: Division of Pediatric Cardiology, Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, Michigan.
authors.forename: Mark W
authors.initials: MW
authors.lastname: Russell
authors.affiliation: Division of Cardiothoracic Radiology, Department of Radiology, University of Michigan, Ann Arbor, Michigan.
authors.forename: Prachi P
authors.initials: PP
authors.lastname: Agarwal
authors.affiliation: Section of Pediatric Radiology, Department of Radiology, University of Michigan, Ann Arbor, Michigan.
authors.forename: Maryam
authors.initials: M
authors.lastname: Ghadimi Mahani
authors.affiliation: Division of Pediatric Cardiology, Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, Michigan; Section of Pediatric Radiology, Department of Radiology, University of Michigan, Ann Arbor, Michigan.
authors.forename: Jimmy C
authors.initials: JC
authors.lastname: Lu
mesh_terms: D000293:Adolescent; D002312:Cardiomyopathy, Hypertrophic / Q000175:diagnosis* / Q000235:genetics / Q000503:physiopathology; D002648:Child; D018450:Disease Progression; D004452:Echocardiography; D005260:Female; D005500:Follow-Up Studies; D005820:Genetic Testing / Q000379:methods; D005838:Genotype; D006352:Heart Ventricles / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology*; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D009206:Myocardium / Q000473:pathology*; D010641:Phenotype; D011379:Prognosis; D012372:ROC Curve; D012189:Retrospective Studies; D013318:Stroke Volume; D016277:Ventricular Function, Left / Q000502:physiology*; D055815:Young Adult