Malalignment of the sarcomeric filaments in hypertrophic cardiomyopathy with cardiac myosin heavy chain gene mutation. Issue 5 (1st November 1999)

• Record Type: Journal Article
• Authors: Muraishi, A; Kai, H; Adachi, K; Nishi, H; Imaizumi, T
• Is Part Of: Heart. Volume 82:Issue 5(1999)
• Page Start: 625
• Page End: 629
• Publication Date: 1999-11-01
• Subjects: hypertrophic cardiomyopathy -- β myosin heavy chain -- myosin filament -- sarcomere; Heart -- Diseases -- Treatment -- Periodicals; Cardiology -- Periodicals; 616.12
• DOI: 10.1136/hrt.82.5.625
• Languages: English
• ISSNs: 1355-6037

Abstract

Abstract : OBJECTIVE: To investigate changes in the alignment of the sarcomeric filaments in hypertrophic cardiomyopathy and the effects of cardiac β myosin heavy chain (β-MHC) mutation on the sarcomeric ultrastructure. DESIGN: A retrospective analysis. PATIENTS: Endomyocardial biopsy samples were examined by transmission electron microscopy in seven patients with hypertrophic cardiomyopathy and β-MHC mutation, six with hypertrophic cardiomyopathy but without the mutation, and five controls (with chest pain syndromes). MAIN OUTCOME MEASURE: Alignment of the sarcomeric filaments and the distance between neighbouring thick myosin filaments. RESULTS: In controls, cross sections of the sarcomere at the A band showed a highly organised orthohexagonal array with 6 thin actin filaments surrounding one thick myosin filament, whereas in hypertrophic cardiomyopathy the alignment of the sarcomeric filaments was sparse and disrupted. In hypertrophic cardiomyopathy with a mutation, the distance between neighbouring thick myosin filaments was greater than in controls (mean (SD) 45.3 (4.7) v 38.5 (3.5) nm, p < 0.05), and the variance of the distance was greater than in controls (8.0 (0.7) v 4.8 (1.0) nm, p < 0.001) or in patients with hypertrophic cardiomyopathy without a mutation (6.7 (0.6) nm, p < 0.05). In the latter, the variance of the distance was also greater than in the controls (p < 0.01). A significant correlation was found between the grade of the myocyte hypertrophy and the variance of the distance ( r = 0.654; p < 0.01). CONCLUSIONS: The alignment of the sarcomeric filaments is disrupted in hypertrophic cardiomyopathy, particularly when there is β-MHC mutation.