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[Hypertrophic cardiomyopathy: mode of death and pathological findings]
H Fujiwara1, M Tanaka, T Onodera
1Department of Internal Medicine, Kyoto University Hospital.
Insights
Sudden death in hypertrophic cardiomyopathy (HCM) is linked to greater myocyte fibrosis and disarray, not hypertrophy. Heart failure deaths show extensive fibrosis and myocyte disarray in dilated ventricles.
Area of Science:
- Cardiovascular Pathology
- Cardiac Hypertrophy Research
- Sudden Cardiac Death Etiology
Background:
- Hypertrophic cardiomyopathy (HCM) is a primary cause of sudden cardiac death.
- Understanding pathological differences across HCM death modes is crucial for risk stratification.
Purpose of the Study:
- To investigate the relationship between modes of death and pathological parameters in hypertrophic cardiomyopathy.
- To quantitatively analyze myocyte disarray, fibrosis, and size in relation to death cause.
Main Methods:
- Quantitative histological analysis of myocyte disarray and fibrosis in 22 autopsied HCM subjects.
- Categorization of subjects into sudden death, heart failure, and control groups.
- Image analysis of interventricular septum and left ventricular free wall.
Main Results:
- Sudden death group exhibited significantly greater fibrosis and myocyte disarray compared to controls.
- No significant differences in hypertrophy parameters (heart weight, wall thickness, myocyte size) between sudden death and control groups.
- Heart failure group showed extensive replacement fibrosis and myocyte disarray, particularly with dilated left ventricular cavities.
Conclusions:
- Myocyte disarray and fibrosis, rather than hypertrophy, are key pathological features associated with sudden death in HCM.
- Distinct pathological patterns exist between sudden death and heart failure in HCM patients.
Abstract:
To ascertain relationships between modes of death and various pathological parameters in hypertrophic cardiomyopathy (HCM), quantitative analysis of the disarray, fibrosis, and size of myocytes was performed in 22 autopsied subjects with HCM. According to mode of death, the subjects were categorized as three groups; (1) a sudden death group (10 patients), (2) a heart failure group (7 patients) and (3) a control group (5 patients). The group consisted of patients with HCM who were over 55 years old and who died of other diseases (e.g., cancer 3) or from accidents. The hearts were fixed in 10% formalin and sectioned from the base to the apex at 1 cm intervals. A section with maximal septal hypertrophy was histologically examined. The histologic findings in the interventricular septum (VS) and the left ventricular free wall (FW) were quantitatively analyzed using an image analyzer (Olympus VIP-21). The extents of fibrosis and disarray were greater in the sudden death group (fibrosis: VS/FW = 16 + 3/11 + 5%, disarray: VS/FW = 58 + 18/32 + 17%) than in the control group (fibrosis: VS/FW = 7 + 2/6 + 4%; disarray: VS/FW = 24 + 7/8 + 6%), but there were no significant differences in the various parameters of hypertrophy (heart weight, wall thickness, degree of asymmetric septal hypertrophy and size of myocytes) between these two groups. The heart failure group consisted of four hearts with dilated LV cavities and two hearts with small LV cavities. The former showed extensive replacement fibrosis (VS/FW = 37 + 7/25 + 5%) and disarray of residual myocytes (VS/FW = 20 + 16/14 + 6%).(ABSTRACT TRUNCATED AT 250 WORDS)