diease

Cardiomyopathy


OVERVIEW OF Cardiomyopathy :

The  term refers to the disease that is taking part in the heart which makes it harder to supply the blood . It occurs in the myocardium of the heart.


STRUCTURE of Cardiomyopathy :

The heart consists of a four chambers mainly the right atrium, right ventricle, left atrium and left ventricle. The valves present in the heart includes tricuspid valve and bicuspid valve.

The blood from the superior vena cava passes to the right atrium and then to the right ventricle. The right side of the heart carries the deoxygenated blood.

Then the blood enters the right side of the lung. The valves that mediates the blood movement from the right atrium to the right ventricle is Tricuspid valve.

In the lung the deoxygenated blood gets transferred into oxygenated blood and it is carried to the heart through pulmonary veins.

Then the blood is carried to the left atrium and left ventricle. The valve that mediates this blood flow

Bicuspid valve. Then the blood is pumped into the aorta and it is carried throughout the vital organs.


CAUSES :

Ischemic cardiomyopathy caused by heart attacks or coronary artery diseases(CAD).

Non ischemic cardiomyopathy

Autoimmune diseases such as connective tissue diseases

Conditions that damage the heart such as high cholesterol, hemochromatosis or sarcoidosis.

Endocrine conditions such as diabetes or thyroid disease

Previous heart attacks

Pregnancy

Familial history of heart failure, cardiomyopathy or sudden cardiac arrest


PATHOPHYSIOLOGY :

The etiologic factors results in decrease in contractility. This decrease in contractility leads to stretching of ventricular fibers and this result in increase in the wall tension. This results in increased cardiac work and increased oxygen consumption. Decrease in the cardiac output. Decrease in the cardiac output leads to the reduced supply of the blood to the vital organs. Systemic vascular resistance increases and decrease in the stroke volume. And increase in the tension in the heart muscle increases. If it is of genetic origin then structural protein abnormality occurs.

Types:

  • Dilated cardiomyopathy (DCM);
  • Hypertrophic cardiomyopathy (HCM);
  • Restrictive cardiomyopathy (RCM);
  • Arrhythmogenic cardiomyopathy (ACM);
  • Unclassified cardiomyopathies.

 

Dilated cardiomyopathy:

The condition is characterized by the inappropriate ventricular hypertrophy that is the thickening of the ventricular wall or dilatation of one or both ventricles. it might leads to decompensated heart failure. Alcohol overuse, viral infections, genetic diseases play a vital role causing this disease.

Hypertrophic cardiomyopathy:

HCM is a heterogeneous disorder characterised by left ventricular hypertrophy and, in some cases, left ventricular outflow tract obstruction including those affecting proteins important for sarcomere function (a sarcomere is a basic unit of repeating contractile proteins that make up muscle cells). The normal mode of inheritance for gene defects is autosomal dominant, although autosomal and sex-linked recessive patterns have also been described.

Gene defects may include β-myosin heavy chain gene, myosin-binding protein C and troponin T account for 70-80 %  of  all cases of inherited HCM. Some patients inherit more than one gene defect and may experience more severe disease.

  • Family history of sudden cardiac death;
  • Unexplained heart failure or arrhythmias;
  • Signs and symptoms of an underlying systemic cause.

Restrictive Cardiomyopathy:

Ventricular stiffness leading to reduced ventricular filling and diastolic volume during the cardiac cycle. The restrictive cardiomyopathy is suspected when patients have near normal systolic function but diastolic dysfunction on echocardiography. Restrictive cardiomyopathy develops from endomyocardial fibrosis.

Systemic conditions that  cause infiltration of the myocardium for example amyloidosis, sarcoidosis and radiation effects.

Haemochromatosis, glycogen storage disorders or Fabry disease which is caused by accumulation of globotriaosylceramide.

Arrythmogenic Cardiomyopathy:

This occurs due to right ventricle hypertrophy. The hypertrophy results in deposition of fibrous fatty tissue in right ventricle. It might also occur in left ventricle. The condition is a significant cause of sudden cardiac death due to electric instability and subsequent ventricular tachycardia or ventricular fibrillation.


COMMON CLINICAL SIGNS AND SYMPTOMS :

Palpitations or syncope

Life threatening arrhythmias

Signs of ventricular failure such as ascites,

Hepatic congestion

Raised jugular venous pressure

 Marked oedema.


DIAGNOSTIC :

Electrocardiogram:

The heart transmits electrical impulses and electrodes on the skin can capture these recorded impulses generated as the electricity travels throught the heart muscle. The heart which has  decreased blood supply has lower energy and conducts the electricity in a different way.

Stress tests:

During exercise the heart needs more amount of energy and it should work harder and if the heart could be monitored and evaluated during the execise a test might uncover abnormalities in heart function. The patient is asked to walk on a treadmill, to ride a bicycle while simultaneously electrocardiogram is performed. Medications such as persantine, dobutamine and adenosine can be used to stimulate the heart if the heart cannot carry out such difficult tasks.

Echocardiography:

Ultrasound examination of the heart to evaluate the anatomy of the heart valves, muscles and its function are observed. This test might carried solely or it might be combined with other test such as the stress test.

Nuclear Imaging:

A radioactive tracer is injected into the vein and that can be used to indirectly assess blood flow to the heart. Technetium or thallium can be injected while a radioactive counter is used to map out how heart muscle cells absorbs the radioactive chemical and how it is distributed in heart muscle cells may help to determine indirectly whether the blockage exists or not. An area with no uptake of radioactive element suggest that the area is not getting the proper blood supply.

Cardiac Computerized Tomography and Magnetic Resonance Imaging:

Using these test the coronary arteries can be evaluated including hoe much calcium is present in the artery walls and whether blockage or narrowing of artery are present.

Cardiac Catheterization:

A thin tube is inserted through an artery in the groin, elbow, wrist into the coronary arteries. Dye is injected to assess the anatomy and whether blockages are present. This is called as Coronary Angiogram.

If the blockage exist it is called as angioplasty and the treatment to dilate the constricted vessel is known as Angiogram, a balloon is positioned at the site of obstructing the plaque.

A stent can be place din the blood vessels to dilate the narrowed blood vessels.

Holter and Event monitors:

These are portabale monitors and records the electrical activity during normal daily activity. A Holter monitor records the heart’s electrical activity for 24 -48 hours. An event monitor record the electrical activity of the heart only at certain times.

Myocardial Biopsy:

During this procedure your doctor might place a piece of heart in the microscope and he might look for the oppurtunities.

Genetic testing:

The genetic testing might reveals that the cardiomyopathy runs in the family or not.


TREATMENT AND PROGNOSIS :

Nonsurgical procedures used to treat cardiomyopathy or arrhythmia include:

  • Septal ablation. A small portion of the thickened heart muscle is destroyed by injecting alcohol through a long, thin tube (catheter) into the artery supplying blood to that area. This allows blood to flow through the area.
  • Radiofrequency ablation:
  • It uses flexible tubes (catheters) through your blood vessels to your heart. Electrodes at the catheter tips transmit energy to damage a small spot of abnormal heart tissue that is causing the abnormal heart rhythm.

Surgery or other procedures

  • Implantable cardioverter-defibrillator (ICD). This device monitors your heart rhythm and delivers electric shocks when needed to control abnormal heart rhythms.
  • Ventricular assist device (VAD). This helps blood flow through your heart.. It can be used as a long-term treatment or as a short-term treatment while waiting for a heart transplant.
  • Pacemaker. This small device placed under the skin in the chest or abdomen uses electrical impulses to control arrhythmias.

Types of surgery used to treat cardiomyopathy include:

  • Septal myectomy. In this open-heart surgery, your surgeon removes part of the thickened heart muscle wall (septum) that separates the two bottom heart chambers (ventricles). Removing part of the heart muscle improves blood flow through the heart and reduces mitral valve regurgitation. Septal myectomy is used to treat hypertrophic cardiomyopathy.
  • Heart transplant. Your doctor might recommend a heart transplant if you have end-stage heart failure and medications and other treatments no longer work.


PROGNOSIS :

When followed with regular checkup and medications, lifestyle are maintained properly it might give good prognosis. The 15 year survival rate who is diagnosed with heart attack is 48%


PREVENTION :

 

Avoid alcohol consumption

Avoid smoking

Reduce the fat foods

Be physically active

Reduces the stress

Reduce the intake of salt

Maintain good sleep


Medicines used in the Treatment :

Beta blockets:

Atenolol

Metaprolol

Satalol

Propranolol

Calcium channel blocker:

Verapamil

Diltiazem

Nifedipine

Amlodipine

Felodipine

Statins:

Atorvastatin

Lovastartin

Diuretics:

Acetazolamide

Furosemide

Spironolactone

Metalozone

Vasodilators:

Isosorbide dinitrate

Isosorbide mononitrate

Nitriglycerine

Hydralazine

 


REFERENCE :

https://www.heart.org/en/health-topics/cardiomyopathy/symptoms-and-diagnosis-of-cardiomyopathy

https://www.heart.org/en/health-topics/cardiomyopathy/what-is-cardiomyopathy-in-adults

https://my.clevelandclinic.org/health/diseases/16841-cardiomyopathy

https://www.nhlbi.nih.gov/health-topics/cardiomyopathy

https://www.cdc.gov/heartdisease/cardiomyopathy.htm