What are the cardiac diseases in Robbins pathology?

Cardiac Diseases in Robbins Pathology

Robbins Pathology classifies cardiac diseases into several major categories based on morphological and functional phenotypes, including congenital heart disease, cardiomyopathies (hypertrophic, dilated, restrictive, and arrhythmogenic), valvular heart disease, inflammatory/infectious myocardial disease, and ischemic heart disease.

Congenital Heart Disease (CHD)

CHD is organized by anatomic complexity into three tiers 1:

Simple CHD

• Isolated small atrial septal defect (ASD) or ventricular septal defect (VSD) 1
• Mild isolated pulmonic stenosis 1
• Previously repaired secundum ASD, sinus venosus defect, or VSD without residual shunt or chamber enlargement 1
• Previously ligated or occluded patent ductus arteriosus 1

Moderate Complexity CHD

• Atrioventricular septal defects (AVSD), including partial or complete forms and primum ASD 1
• Anomalous pulmonary venous connection (partial or total) 1
• Anomalous coronary artery arising from the pulmonary artery or opposite sinus 1
• Congenital aortic and mitral valve disease 1
• Coarctation of the aorta 1
• Ebstein anomaly (spectrum includes mild to severe variations) 1
• Repaired tetralogy of Fallot 1
• Moderate to large unrepaired secundum ASD or patent ductus arteriosus 1
• Pulmonary valve stenosis or regurgitation (moderate or greater) 1
• Sinus of Valsalva fistula/aneurysm 1
• Subvalvar and supravalvar aortic stenosis 1

Great Complexity (Complex) CHD

• All forms of cyanotic congenital heart defects (unrepaired or palliated) 1
• Single ventricle physiology (including double inlet left ventricle, tricuspid atresia, hypoplastic left heart syndrome) 1
• Fontan procedure 1
• Transposition of the great arteries (d-TGA or congenitally corrected TGA) 1
• Pulmonary atresia (all forms) 1
• Truncus arteriosus 1
• Double-outlet ventricle 1
• Interrupted aortic arch 1
• Mitral atresia 1
• Abnormalities of atrioventricular and ventriculoarterial connection (crisscross heart, isomerism, heterotaxy syndromes) 1

Cardiomyopathies

The classification encompasses five distinct morphological and functional phenotypes 1, 2:

Hypertrophic Cardiomyopathy (HCM)

• Characterized by inappropriate ventricular hypertrophy without evidence of ischemia 1
• Prevalence of approximately 1:250 to 1:500 in adults 1
• Can be familial or nonfamilial 1
• Associated with sudden death risk and heart failure symptoms 1, 3

Dilated Cardiomyopathy (DCM)

• Characterized by ventricular dilation and systolic dysfunction 1, 2
• Prevalence of approximately 1:250 to 1:500 1
• Can be familial (up to 30% of cases) or acquired 2, 4
• Genetic mutations affect cytoskeletal, nuclear, and sarcomeric proteins 4
• Associated with thrombus formation and embolic stroke risk 5

Restrictive Cardiomyopathy/Infiltrative Diseases

• Characterized by impaired ventricular filling with preserved systolic function 1, 2
• Includes amyloidosis (particularly transthyretin cardiac amyloidosis) 2, 3
• Includes endomyocardial fibrosis, hemochromatosis 1
• Can present as both myopathy and neuropathy 2

Arrhythmogenic Cardiomyopathy (Arrhythmogenic Right Ventricular Cardiomyopathy)

• Prevalence of approximately 1:2,000 to 1:5,000 1
• Characterized by ventricular arrhythmias and sudden death risk 1, 2
• Progressive replacement of myocardium with fibrofatty tissue 1

Inflammatory Cardiomyopathy

• Caused by infectious agents (enteroviruses, cytomegalovirus, adenoviruses, parvovirus B19, Epstein-Barr virus, Borrelia burgdorferi, Chlamydia pneumoniae) 2, 4
• Presents with acute chest pain, elevated cardiac enzymes, and abnormal ECG 1
• Can progress to dilated cardiomyopathy 4
• Associated with autoimmune mechanisms and inflammatory infiltrates 4

Valvular Heart Disease

Valvular diseases frequently coexist with cardiomyopathies and share pathophysiological mechanisms 6:

• Mitral valve disease (most common valvular association with atrial fibrillation) 1
• Congenital aortic valve disease (including bicuspid aortic valve) 1
• Congenital mitral valve disease 1
• Mitral regurgitation (commonly complicates dilated and hypertrophic cardiomyopathy) 6
• Tricuspid regurgitation (particularly in congenitally corrected transposition) 1

Arrhythmias and Conduction Disorders

Dysrhythmias affect up to 50% of patients with adult congenital heart disease 1:

• Atrial fibrillation (associated with valvular disease, hypertension, cardiomyopathy) 1
• Ventricular tachycardia and sudden death 1
• Intra-atrial muscle reentry tachycardia/atrial flutter 1
• Bradycardia requiring pacing 1
• Progressive atrioventricular or intraventricular conduction defects (particularly in myotonic dystrophy) 1

Myocardial Dysfunction Associated with Systemic Diseases

Neuromuscular Diseases with Cardiac Involvement

• Myotonic dystrophy type 1 (cardiac manifestations in approximately 80% of patients, including dilated cardiomyopathy and conduction defects) 1, 2
• Myotonic dystrophy type 2 (cardiac problems in 10-20% of patients) 1, 2
• Congenital myopathies (including nemaline myopathies, central core disease, centronuclear myopathy) 1, 2

Connective Tissue Disorders

• Systemic sclerosis (causes smooth muscle atrophy and gut wall fibrosis) 2
• Can present as both myopathy and neuropathy 2

Pulmonary Hypertension

Defined as mean pulmonary artery pressure ≥25 mm Hg by right heart catheterization 1:

• Pulmonary arterial hypertension requires pulmonary capillary wedge pressure ≤15 mm Hg and pulmonary vascular resistance ≥3 Wood units 1
• Associated with nonpulsatile systemic venous-pulmonary connections in single-ventricle palliation 1
• Can complicate congenital heart disease 1

Clinical Pitfalls and Considerations

Lone atrial fibrillation occurs in 30-45% of paroxysmal cases and 20-25% of persistent cases without demonstrable underlying disease 1, though underlying cardiac disease may develop over time.

Ventricular-vascular coupling abnormalities are critical in adult congenital heart disease, including nonpulsatile systemic venous inflow, impaired atrial-ventricular transport, pulmonary endothelial dysfunction, and postoperative diastolic dysfunction 1.

Genetic heterogeneity is substantial—cardiomyopathies do not fit into specific morphological phenotypes, and the MOGE(S) nosology system provides more comprehensive classification describing morphofunctional phenotype, organ stratification, genetic inheritance, etiological annotation, and functional status 1.

Thromboembolic complications are significant—left ventricular dysfunction and mural thrombi increase embolic stroke risk by 3-50%, with atrial fibrillation accounting for up to half of embolic strokes 5.