71. Cardiomyopathies. Tumors and tumor-like conditions of the heart

Cardiomyopathies definition?

Defined as a primary heart muscle disease.

- Ischemia, hypertension & valvular disease must be excluded to establish the presence of a cardiomyopathy.

What is the difference between cardiomyopathies and most other heart muscle diseases?

Most heart diseases are secondary to some other conditions, like CAD, hypertension etc...

Cardiomyopathies are NOT secondary. They are defined as a primary heart muscle disease.

3 major types of cardiomyopathies?

1. Dilatative/congestive cardiomyopathy

2. Hypertrophic cardiomyopathy

3. Restrictive cardiomyopathy

Dilatative/congestive cardiomyopathy?

Lead to severe dilation of the heart. All four chambers dilate, but especially the left ventricle.

Causes:

- Idiopathic

- Genetic mutations

- Alcohol consumption

- Peripartum (around labour)

Consequences of dilatative cardiomyopathy?

- Systolic heart failure (problems emptying)

- Turbulent flow in ventricles (thrombus formation)

- Functional insufficiency of AV valves

Functional insufficiency of mitral valve?

When left ventricle dilates significantly in dilatative cardiomyopathy -> mitral valve will be unable to close properly

- Blood will regurgitate into left atrium during systole

(Nothing wrong with the valve itself, therefore called functional insufficiency)

Histology of dilatative cardiomyopathy?

Does not show anything specific, only hypertrophy and fibrosis

Mortality of dilatative cardiomyopathy?

Will progressively dilate, leading to a progressive congestive heart failure.

- 50% of patients die within 2 years.

Hypertrophic cardiomyopathy?

The whole heart is thick-walled, heavy & hyperconntractile

- Septum is 3x times more hypertrophied than the rest of the myocardium - bulges into the left ventricle

Causes of hypertrophic cardiomyopathy?

Missense mutation in ß-myosin heavy chain gene

OR:

mutation in myosin-bindnig protein C or troponin T

Most common consequences of hypertrophic cardiomyopathy?

- Diastolic heart failure (impaired filling, stiff wall decreases compliance)

- Obstruction of outflow-part of LV (sudden cardiac death)

- Hypertrophy causes increased risk for ischemia -> AMI, angina

- Arrhythmias

How is SV and EF in hypertrophic cardiomyopathy?

- SV is decreased

- EF is normal/increased, as filling is generally low, the fraction will not be changed

What are the consequences of a thick ventricular wall (hypertrophic cardiomyopathy)?

It becomes very stiff, which decreases the ventricles compliance (the ability to be filled up)

-> Diastolic heart failure

What other diseases causes same symptoms as hypertrophic cardiomyopathy?

• Amyloidosis (Also leads to decreased compliance of ventricles)

• Hypertensive heart disease (leads to hypertrophy)

• Valvular aortic stenosis (leads to hypertrophy)

Restrictive cardiomyopathy?

Rarest form.

- Proliferation of C.T. in myocardium

- Restricts & decrease compliance of ventricular wall

- EDp increase a lot to be able to fill the ventricles

Common causes of restrictive cardiomyopathy?

- Idiopathic (no known cause)

- Amyloidosis

- Sarcoidosis

- Metastatic tumor invasion

Consequences of restrictive cardiomyopathy?

Decreased filling due to decreased compliance - cause backwards venous congestion.

- Increased hydrostatic pressure of pulmonary capillaries - wet lungs

Secondary restrictive heart conditions?

These are not cardiomyopathies, but secondary to some other conditions

1. Endomyocardial fibrosis

2. Löffler´s endomyocarditis

3. Endocardial fibroelastosis

Endomyocardial fibrosis?

Restrictive condition in children in Africa and the tropics

- Fibrosis of endocardium & tricuspid & mitral valve

Löffler´s endomyocarditis?

Is the late-stage of Löffler´s endocarditis, which is characterized by fibrosis of endocardium + a large thrombi, that takes up a large portion of the ventricular lumen.

Late stage: myocardium will also be inflamed. Thrombi is organized into scar tissue.

- Myocardial fibrosis causes heart to be restrictive.

Endocardial fibroelastosis?

Diffuse fibroelastic thickening of the left ventricular endocardium.

- Congenital heart disease

Cardiac tumors?

Very uncommon, due to low turnover of cells in the heart.

- Only 5% of cancer-related deaths present with metastatic invasion of heart.

What cancers have higher tendency to metastasize into the heart?

1. Lung cancer

2. Lymphoma

3. Breast cancer

4. Leukaemia

5. Melanoma

Are cardiac tumors usually benign or malignant?

80-90% of primary heart tumors are benign.

Cardiac myxoma?

Most common benign primary cardiac tumor.

- Mostly in left atrium.

- 1-10cm, soft & translucent masses

Can loosen & cause emboli, or swing into the AV-valve and cause damage

Cardiac fibroma?

Most common in childhood.

- Associated with arrhythmias, HF & sudden cardiac death

- Compresses the conducting system

- Usually seen in Gorlin syndrome

Gorlin syndrome?

Naevoid Basal Cell Carcinoma (Basal Cell Nevous Syndrome)

Cardiac rhabdomyoma?

most common pediatric cardiac neoplasms.

- Often seen in a condition called tuberous sclerosis

- Obstructs the outflow tract (-> HF)

- Regresses spontaneously w/ no obvious reason

Other types of benign cardiac tumors?

- Cardiac haemangioma

- Cardiac lipoma

Malignant cardiac tumors?

(Remember; very rare)

• Angiosarcoma (most common)

• Leiomyosarcoma

• Lymphoma