Primary cardiomyopathies are specifically related to issues with the myocardium alone. 

Secondary cardiomyopathies are a result of systemic disease i.e. amyloidosis, hemochromatosis, etc. 

Cardiomyopathies can be broken up even further into whether they impact diastolic vs systolic function. Dilated cardiomyopathy is a form of both systolic and diastolic dysfunction. 

Primary diastolic cardiomyopathies include hypertrophic cardiomyopathy and restrictive cardiomyopathy. 

In dilated cardiomyopathy the ventricle becomes enlarged with the walls of the ventricles become very thin leading to poor contractility. 

In hypertrophic cardiomyopathy there is isolated thickening of the wall of the septum, which leads to smaller filling volumes during diastole. 

In restrictive cardiomyopathy the size of the ventricle appears to be the same size as a normal heart, but it is unable to stretch during diastole leading to lower filling volumes. The wall becomes universally thickened. 

Causes of Restrictive Cardiomyopathy: 

• Storage Diseases: Hemochromatosis, Fabry Disease, Gaucher Disease, Glycogen Storage Diseases, Hurler Syndrome, Hunter Syndrome, Neimann-Pick Disease
• Infiltrative: Amyloidosis, Sarcoidosis, Primary Hyperoxaluria
• Non-Infiltrative: Idiopathic, Diabetic Cardiomyopathy, Scleroderma, Myofibrillar Myopathies, Sarcomere Disease, Werner’s Syndrome 
• Endomyocardial: Carcinoid Heart Disease, Endomyocardial Fibrosis, Idiopathic, Hypereosinophilic Syndrome, Drugs, Cancer, Radiation, Chemotherapy 

Presentation:

Most patients will present with typical heart failure symptoms including lower extremity edema and shortness of breath. They may have an S3 and S4 on exam with rales heard in bilateral lung fields. These patients may also have ascites depending on the extent of their disease. These patients typically do not have chest pain, unlike other forms of cardiomyopathy. 

Studies:

Labs may show elevated BNP or Troponin. These patients may have a completely normal appearing chest x-ray depending on the extent of their disease. The heart will appear normal in size. They may have pulmonary edema if they are presenting with heart failure symptoms. EKG will show diffuse low voltage. They often develop arrhythmias as the disease progresses and the electrical conduction system is interrupted. The most common arrhythmia is atrial fibrillation. Ultrasound will show thickened ventricular walls in a “starry sky” appearance. Typically, there will be bilateral dilated atrium as well from increased filling pressures in the ventricles. 

Differential Diagnosis:

• Diastolic Left Ventricular Dysfunction
• Hypertrophic Cardiomyopathy
• Ischemia
• Chronic HTN
• Age-Related Changes
• Constrictive Pericarditis 
• Infectious
• Post-Cardiac Surgery
• Post- Radiation Therapy
• Connective Tissue Disorder
• Idiopathic 

*** It is crucial to rule out constrictive pericarditis as this is a surgical emergency. 

Treatment:

• Symptomatic
• Loop Diuretics primarily 
• Ace Inhibitors- offer renal protection 
• Important- avoid CCBs in these cases because it’s important to not decrease cardiac contractility since it is used to compensate for decreased diastolic volumes
• Treat the Underlying Cause:
• Amyloidosis: stem cell transplant, chemotherapy, heart transplant
• Sarcoidosis: steroids
• Hemochromatosis: chelation therapy