Cardiac Pathology

Cardiac Pathology


dilation = loss of overlap of actin and myosin = weaker contraction
            = distorted gap junctions

Heart Failure = defined as decreased cardiac output

• pressure overload -  concentric hypertrophy = sarcomeres added in parallel
• volume overload - dilated ventricle = sarcomeres added in series - eccentric hypertrophy

Cardiomegaly

• bigger is not better
• increased size does not come with increased capillaries
• Exception - physiological hypertrophy

Heart Failure

dead myocytes are replaced by scar tissue

Chronic ischemic heart disease

at autopsy:

• Enlarged, heavy hearts 
• Left ventricular hypertrophy and dilation 
• Discrete scars = healed infarcts 
• Increased fibrosis 
• Subendocardial vacuolization

Acute MI

at autopsy:

• normal

Hypertensive Heart Disease

Cardiomyopathies - mechanical & electrical (gap junction) problems

Dilated = systolic dysfunction (decreased overlap of actin-myosin); 

• Genetic - 20-50%
• Infections – VIRAL 
• Toxins - ALCOHOL 
• Metabolic – thyroid disorders 
• Neuromuscular disease – muscular dystrophy 
• Storage disorders – glycogen storage disease 
• Infiltrates – leukemia 
• Immunological; e.g, lupus
• Peripartum
• Restrictive 

Hypertrophic

• myocyte disarray
• outflow obstruction due to hypertrophy
• genetic - mutations in genes that encode sarcomeres

Restrictive

• decrease in ventricle compliance (deltaV/deltaP
• Causes 
• Radiation fibrosis 
• Amyloidosis -amyloid deposited between myofibrils
• Sarcoidosis - granulomas
• Metastatic tumors - multiple transfusions - iron overload
• Inborn errors of metabolism 

Myocarditis - inflammation of myocardium

Viral myocarditis 

• Causes MOST cases in the US 
• Coxsackie viruses A and B most common 
• Also see other enteroviruses, CMV, HIV, etc 
• Presentation ranges from sudden death to heart failure 
• Other 
• Rickettsiae, bacteria (diphtheria, Lyme disease), fungal 
  

  (candidal), protozoal (Chagas disease and 

  toxoplasmosis) 
• Hypersensitivity myocarditis - eosinophils present
• Giant-cell myocarditis - giant cells = collection of macrophages

Miscellaneous Myocardial Disease

• Cardiotoxic drugs 
• Catecholamines 
• Amyloid 
• Iron overload 
• Hyper and hypothyroidism

Cardiac Tumors

• myxoma - most common - usually in left atrium
• etc.

Pericardial Disease

• fluid volume in pericardium normally < 50 ml
• pericarditis = inflammation of pericardium = increased fluid (effusion)
• serous = non infectious inflammation
• fibrinous = most common; acute MI, radiation, autoimmune, trauma
• purulent = infections