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Pathology – Cardiomyopathies
Hypertrophic cardiomyopathy
• Rare, having an incidence of 0.5%. • 770% of cases have been associated with mutations in genes that encode sarcomeric proteins, including β-myosin heavy chain, troponin T, myosin binding protein, and α-tropomyosin. • A broad range of manifestations, including dyspnea, angina pectoris, syncope, palpitations, and abrupt mortality.
Macroscopically, the majority of patients exhibit asymmetric left ventricular hypertrophy, primarily affecting the septum. Associated systolic anterior motion of the mitral valve frequently results in a localized area of endocardial fibrosis on the septum, referred to as the sub-aortic mitral impact lesion. In many instances, this condition induces symmetric left ventricular hypertrophy that is indistinguishable from that resulting from hypertension or aortic stenosis. • The histological characteristic of HCM is the presence of myocyte enlargement, myocyte disorganization, and interstitial fibrosis. Myocyte disarray denotes the disruption of the typical parallel alignment of myocytes, which instead assume random oblique configurations.
Idiopathic dilated cardiomyopathy
• Rare, having an incidence of 0.2%. • The modes of inheritance encompass autosomal dominant, X-linked, autosomal recessive, and mitochondrial inheritance. • Numerous gene mutations have been identified, including those in cardiac actin, desmin, sarcoglycan, troponin, and tropomyosin.
• Clinical manifestations include dyspnea, fatigue, and palpitations. Thrombus formation on the akinetic myocardium may lead to systemic emboli. The heart exhibits increased mass with dilatation and thinning of the cardiac chambers, with no identifiable reason such as coronary artery disease, valve disease, hypertension, or alcohol misuse.
Microscopic findings are nonspecific but may exhibit myocyte attenuation and myofibril loss, accompanied by enlarged myocyte nuclei and interstitial fibrosis.
Arrhythmogenic right ventricular cardiomyopathy
The precise incidence and prevalence within the general population are undetermined. • Mutations in genes that encode cell adhesion molecules are delineated. Mutations result in the separation and apoptosis of myocytes under mechanical stress, followed by fat replacement and scarring. • Exhibits palpitations or experiences abrupt death.
Macroscopically, the right ventricle exhibits thinning, particularly in the right ventricular outflow tract, characterized by a yellow hue attributed to fat replacement.
• Microscopically, the normal right ventricular myocardium is replaced by adipose tissue and fibrosis. The illness process typically initiates in the epicardial region and progresses toward the endocardial surface.
Hypertrophic cardiomyopathy
• Rare, having an incidence of 0.5%. • 770% of cases have been associated with mutations in genes that encode sarcomeric proteins, including β-myosin heavy chain, troponin T, myosin binding protein, and α-tropomyosin. • A broad range of manifestations, including dyspnea, angina pectoris, syncope, palpitations, and abrupt mortality.
Macroscopically, the majority of patients exhibit asymmetric left ventricular hypertrophy, primarily affecting the septum. Associated systolic anterior motion of the mitral valve frequently results in a localized area of endocardial fibrosis on the septum, referred to as the sub-aortic mitral impact lesion. In many instances, this condition induces symmetric left ventricular hypertrophy that is indistinguishable from that resulting from hypertension or aortic stenosis. • The histological characteristic of HCM is the presence of myocyte enlargement, myocyte disorganization, and interstitial fibrosis. Myocyte disarray denotes the disruption of the typical parallel alignment of myocytes, which instead assume random oblique configurations.
Idiopathic dilated cardiomyopathy
• Rare, having an incidence of 0.2%. • The modes of inheritance encompass autosomal dominant, X-linked, autosomal recessive, and mitochondrial inheritance. • Numerous gene mutations have been identified, including those in cardiac actin, desmin, sarcoglycan, troponin, and tropomyosin.
• Clinical manifestations include dyspnea, fatigue, and palpitations. Thrombus formation on the akinetic myocardium may lead to systemic emboli. The heart exhibits increased mass with dilatation and thinning of the cardiac chambers, with no identifiable reason such as coronary artery disease, valve disease, hypertension, or alcohol misuse.
Microscopic findings are nonspecific but may exhibit myocyte attenuation and myofibril loss, accompanied by enlarged myocyte nuclei and interstitial fibrosis.
Arrhythmogenic right ventricular cardiomyopathy
The precise incidence and prevalence within the general population are undetermined. • Mutations in genes that encode cell adhesion molecules are delineated. Mutations result in the separation and apoptosis of myocytes under mechanical stress, followed by fat replacement and scarring. • Exhibits palpitations or experiences abrupt death.
Macroscopically, the right ventricle exhibits thinning, particularly in the right ventricular outflow tract, characterized by a yellow hue attributed to fat replacement.
• Microscopically, the normal right ventricular myocardium is replaced by adipose tissue and fibrosis. The illness process typically initiates in the epicardial region and progresses toward the endocardial surface.
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