Cardiomyopathy

Cardiomyopathy: diseases affecting the Heart Muscles

Cardiomyopathy is a group of diseases affecting the heart muscle. It is characterized by minimal to no symptoms in the initial stages. The heart muscle becomes enlarged, thick, or rigid, and weaker as the disease progresses.

Types:

  • Hypertrophic cardiomyopathy – Ventricles, septum, and heart muscle thicken without any apparent cause.
  • Dilated cardiomyopathy – Ventricles enlarge and weakens, and over time, become unable to pump blood effectively.
  • Restrictive cardiomyopathy – Ventricles become stiff, rigid, and become unable to pump blood. Still, the walls of the heart do not thicken.
  • Arrhythmogenic Right Ventricular Dysplasia – muscle tissue of the right ventricle is replaced with fatty or fibrous tissue and causes arrhythmias.
    • Unclassified cardiomyopathy –Left ventricular non – compaction – Rare congenital cardiomyopathy characterized by the projections of muscle inside the ventricles.
    • Takotsubo cardiomyopathy (broken heart syndrome) – Sudden temporary weakening of the muscular portion of the heart due to extreme stress.

What Causes Cardiomyopathy?

  • It can be acquired or inherited, but the etiology is often unknown.
  • The common etiological reasons are:
    • Inherited genetic mutation
    • High blood pressure
    • Thyroid disease
    • Aging-related changes 
    • Excessive alcohol consumption
    • Drug abuse
    • Viral infections affecting the heart
    • Amyloidosis, connective tissue disorders
    • Cardiac diseases
    • Chemotherapy and radiation therapy.

Risk factors:

  • Age – Teenagers and young adults are at a higher risk of developing arrhythmogenic right ventricular dysplasia than older adults.
  • Gender – The incidence of dilated cardiomyopathy is higher in men as compared to women.
  • Genetics – Patients with a family history of cardiomyopathy, heart failure, or sudden cardiac arrest show a higher rate of cardiomyopathy.
  • Medical conditions – Ischemic heart disease, heart attack, or a viral infection causing inflammation of the heart muscle elevates the risk.
  • Cardiac diseases – Diseases that damage the heart muscle like hemochromatosis, sarcoidosis, or amyloidosis also increase cardiomyopathy risk.
  • Unhealthy lifestyle habits – Long–term alcoholism, severe obesity, and other metabolic diseases are other risk factors.
  • Ethnicity – African Americans are more susceptible to developing dilated cardiomyopathy as compared to Whites.

Signs and symptoms:

  • Fatigue
  • Swelling of the lower extremities
  • Shortness of breath after exertion
  • Palpitations
  • Fainting or briefly passing out
  • Chest pain after physical exertion or heavy meals
  • Arrhythmias
  • Heart murmurs

Complications:

Cardiomyopathy can lead to additional complications like:

  • Heart failure
  • Heart valve regurgitation
  • Heart rhythm problems
  • Sudden cardiac arrest
  • Blood clots (emboli)
  • Heart block

Diagnosis: How is Cardiomyopathy diagnosed?

  • Medical history – Family history of cardiac disease and signs and symptoms experienced by the patient is assessed by the physician.
  • Physical examination – Heart sounds, the timing of heart murmurs, swelling of the ankles and legs, and other physical signs are examined.
  • Diagnostic tests – 
    • Blood tests – The levels of B – type natriuretic peptide (BNP) in the blood are evaluated to rule out the other conditions.
    • Chest x-ray
    • Electrocardiogram (ECG)
    • Holter and event monitors – Records the heart’s electrical activity for 24 to 48 hours while performing normal daily activities.
    • Echocardiography (echo)
    • Stress test – Tests like nuclear heart scanning, echo, and positron emission tomography (PET) scan of the heart are done. At the same time, the patient is asked to exercise to assess the heart’s efficiency.
  • Additional tests –
    • Cardiac catheterization – Blood pressure, blood flow in the heart’s chambers, and the insides of the arteries are evaluated for blockages.
    • Coronary angiography 
    • Myocardial biopsy – Changes in the cardiac cells are viewed under a microscope and used for diagnosing different types of cardiomyopathy.
    • Cardiac magnetic resonance imaging (MRI)
    • Radionuclide ventriculography – Radioactive tracer is injected into the patient’s blood. The radioactivity is measured to determine the blood flow in the large vessels and heart chambers.
  • Genetic testing – Genetic mutations that can cause cardiomyopathy are detected using patients’ blood with a family history of the disease.

Treatment: How is Cardiomyopathy treated?

  • The primary rationale behind cardiomyopathy treatment involves controlling the signs and symptoms and reducing the risk factors. 
  • It is also aimed at managing the conditions that trigger or exacerbate the disease and reducing the complications caused by it. The other major goal is to prevent the aggravation of the disease.
  • Surgery – 
    • Septal Myectomy – An open–heart surgery for removing a part of the thickened septum that bulges into the ventricle.
    • Heart transplant – Replacement of the diseased heart with a healthy heart in people with end-stage heart failure.
  • Surgically implanted devices –
    • Pacemaker 
    • Left ventricular assist device (LVAD) – helps the heart to pump blood before heart transplantation or for long–term therapy.
    • Cardiac resynchronization therapy (CRT) device – Coordinates the contractions between the heart’s left and right ventricles.
    • Implantable cardioverter-defibrillator (ICD) – Controls life-threatening arrhythmias.
  • Non – surgical procedures – Alcohol septal ablation is done to shrink the hypertrophic cells to normal size by using ethanol.
  • Medications – Drugs prescribed for different purposes are given below:
    • To lower blood pressure – Angiotensin-converting enzyme (ACE) inhibitors (captopril, enalapril, etc.), angiotensin II receptor blockers (losartan, telmisartan, etc.), beta-blockers ( bisoprolol, carvedilol, etc.), and calcium channel blockers (amlodipine, bepridil, etc.).
    • To lower heart rate – Beta-blockers, calcium channel blockers, and digoxin.
    • To prevent arrhythmia – Anti-arrhythmic drugs (adenosine, verapamil, etc.)
    • Balance electrolyte levels – Aldosterone blockers (spironolactone, eplerenone, etc.)
    • Remove excess fluid and sodium – Diuretics (furosemide, bumetanide, etc.)
    • Prevent blood clots – Anticoagulants (rivaroxaban, dabigatran, etc.) and blood thinners (aspirin, clopidogrel, etc.)
    • Reduce inflammation – Corticosteroids

Prevention:

  • Living with cardiomyopathy –
    • Heart-healthy eating
    • Managing a healthy weight
    • Physical activity
    • Quitting smoking
    • Not skipping any dose of medicine.
  • Preventing cardiomyopathy –
    • Regular checkups
    • Avoiding alcohol
    • Getting adequate sleep
    • Managing stress

When to see a doctor? :

Consult immediately with a cardiologist if there is trouble breathing when lying flat, shortness of breath unrelated to exercise, or sudden weight gain of 5 or more pounds in a week. The cost of open-heart surgery lies around Rs. 3 lakhs while that of pacemaker implantation ranges between Rs. 2.5 to 3.5 lakhs.

References:

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