title: Creatine kinase adenosine triphosphate and phosphocreatine energy supply in a single kindred of patients with hypertrophic cardiomyopathy.
abstract: A lethal and extensively characterized familial form of hypertrophic cardiomyopathy (HC) is due to a point mutation (Arg403Gln) in the cardiac β-myosin heavy chain gene. Although this is associated with abnormal energy metabolism and progression to heart failure in an animal model, in vivo cardiac energetics have not been characterized in patients with this mutation. Noninvasive phosphorus saturation transfer magnetic resonance spectroscopy was used to measure the adenosine triphosphate supplied by the creatine kinase (CK) reaction and phosphocreatine, the heart's primary energy reserve, in 9 of 10 patients from a single kindred with HC caused by the Arg403GIn mutation and 17 age-matched healthy controls. Systolic and diastolic function was assessed by echocardiography in all 10 patients with HC. The patients with HC had impairment of diastolic function and mild systolic dysfunction, when assessed using global systolic longitudinal strain. Myocardial phosphocreatine was significantly decreased by 24% in patients (7.1 ± 2.3 μmol/g) compared with the controls (9.4 ± 1.2 μmol/g; p = 0.003). The pseudo-first-order CK rate-constant was 26% lower (0.28 ± 0.15 vs 0.38 ± 0.07 s⁻¹, p = 0.035) and the forward CK flux was 44% lower (2.0 ± 1.4 vs 3.6 ± 0.9 μmol/g/s, p = 0.001) than in the controls. The contractile abnormalities did not correlate with the metabolic indexes. In conclusion, myocardial phosphocreatine and CK-ATP delivery are significantly reduced in patients with HC caused by the Arg403Gln mutation, akin to previous results from mice with the same mutation. A lack of a relation between energetic and contractile abnormalities suggests the former result from the sarcomeric mutation and not a late consequence of mechanical dysfunction.
authors.affiliation: Cardiology Division, Department of Medicine, Johns Hopkins Hospital and Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: M Roselle
authors.initials: MR
authors.lastname: Abraham
authors.forename: Paul A
authors.initials: PA
authors.lastname: Bottomley
authors.forename: Veronica Lea
authors.initials: VL
authors.lastname: Dimaano
authors.forename: Aurelio
authors.initials: A
authors.lastname: Pinheiro
authors.forename: Angela
authors.initials: A
authors.lastname: Steinberg
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Traill
authors.forename: Theodore P
authors.initials: TP
authors.lastname: Abraham
authors.forename: Robert G
authors.initials: RG
authors.lastname: Weiss
mesh_terms: D000255:Adenosine Triphosphate / Q000097:blood*; D000328:Adult; D002312:Cardiomyopathy, Hypertrophic / Q000097:blood* / Q000235:genetics / Q000503:physiopathology; D003402:Creatine Kinase / Q000097:blood*; D004247:DNA / Q000235:genetics; D004252:DNA Mutational Analysis; D018450:Disease Progression; D004452:Echocardiography; D004734:Energy Metabolism; D005260:Female; D006352:Heart Ventricles / Q000000981:diagnostic imaging / Q000503:physiopathology; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D009154:Mutation; D018995:Myosin Heavy Chains / Q000235:genetics; D010725:Phosphocreatine / Q000097:blood*; D011379:Prognosis
chemical_list: D010725:Phosphocreatine; D000255:Adenosine Triphosphate; D004247:DNA; D003402:Creatine Kinase; D018995:Myosin Heavy Chains