CARDIOMYOPATHY

Introduction:

• Cardiomyopathy is a collection of different disease conditions that affects the heart muscle. These diseases have many causes, symptoms, and treatments and can affect people of all ages and races.
• In cardiomyopathy, the normal muscle in the heart becomes thicken, stiffen, thin out, or accumulated with certain substances that do not belong to the heart muscle.
• As a result, the heart muscle’s ability to pump blood is reduced, which can lead to irregular heart contraction or heart beats causing heart failure, which leads to backflow of blood into the lungs or rest of the body

Definition
• Cardiomyopathy is the group of diseases of the heart that affects the structural & functional ability of the myocardium (Heart muscle) that makes it harder for the heart to fill with blood and to pump blood eventually leading to heart failure.

Epidemiology
• Cardiomyopathy can affect people of all ages and races.
• Cardiomyopathy often goes undiagnosed, so the numbers can vary.
• As many as 1 of 500 adults may have this condition.
• Males and females are affected with cardiomyopathy.
• Cardiomyopathy occurs at any ages, in children and young adults with this condition there may be no symptoms, yet they are at high risk of sudden cardiac death.

Types of Cardiomyopathy

• Primary Cardiomyopathy
  • In primary cardiomyopathy, the heart muscles is the only portion that is affected and all other cardiac structures are unaffected.
  • In this cardiomyopathy the Etiology of the heart disease is Idiopathic (Unknown Cause).
• Secondary Cardiomyopathy
  • It is the acquired form of myocardial disease that occurs as a result of another disease process
  • The cause is known which can be due to a medical condition or toxins & medications. The goal of therapy for patients with secondary cardiomyopathy is to identify and correct the medical conditions that are responsible for the disease.

Classification of Cardiomyopathy

• Based on the involvement of Blood supply from the coronary arteries, they are further classified as
Ischemic Cardiomyopathy

It is caused by coronary artery disease and heart attack.
The heart muscle becomes damaged due to block in the coronary arteries that carry blood to the heart, and it leads to cardiomyopathy.

Non- Ischemic Cardiomyopathy

These are cardiomyopathies which are not related to the blood supply involvement or coronary artery disease and are caused due to another disease processes or sometimes Inherited.

Types of Non-Ischemic Cardiomyopathies

Dilated Cardiomyopathy
• It is characterized by a diffuse inflammation and rapid degeneration of myocardial fibres that results in ventricular dilation, where the heart's ability to pump blood is decreased.
• At first, the chambers of the heart respond by stretching to hold more blood to pump through the body. This helps to strengthen the heart's contraction and keep the blood moving for a short while. With time, the heart muscle walls weaken and are not able to pump as strongly leading to impaired systolic function and stasis of blood in the left ventricle.

Hypertrophic Cardiomyopathy
• It is a complex type of heart disease that affects the heart muscle. It causes thickening of the heart muscle, especially the ventricles causing ventricular stiffness, mitral valve changes and cellular changes.
• Thickening of heart muscle can also involve the Septum. The thickened septum may cause a narrowing that can block or reduce the blood flow from the left ventricle to the aorta leading to a condition called “outflow tract obstruction.”

Restrictive Cardiomyopathy
• It the rarest form of cardiomyopathy, is a condition in which the walls of the lower chambers of the heart (the ventricles) are abnormally rigid and lack the flexibility to expand as the ventricles fill with blood.
• Here the systolic function of the ventricle may be normal but the diastolic function (the ability of the heart to fill with blood) is abnormal. Therefore, it is harder for the ventricles to fill with blood, and with time, the heart loses the ability to pump blood properly leading to heart failure.

Arrhythmogenic Cardiomyopathy
• It is a rare form of cardiomyopathy in which the heart muscle of the right ventricle (RV) is replaced by fat and/or fibrous tissue.
• The right ventricle is dilated and contracts poorly. As a result, the ability of the heart to pump blood is usually weakened, increasing the risk of sudden cardiac arrest or death.

DILATED CARDIOMYOPATHY (DCM)
• Dilated cardiomyopathy is a disease of the heart muscle that usually starts in the left ventricle which does the main pumping action of the heart. The ventricle stretches and thins (dilates) as a result the elasticity of the muscles are lost and cannot pump blood, that results in backflow of blood to the previous chambers and over time both ventricles may be affected.

Causes of Dilated Cardiomyopathy

• Idiopathic/ Infective DCM
  • When the exact cause of the cardiomyopathy is unknown. It may be due to illness caused by viral organisms in the present or past may lead to development of inflammatory response to infection which causes irreversible myocardial Injury that leads to progressive ventricular dysfunction.
• Familial DCM
  • Familial DCM is a genetic condition, a rare autosomal dominant inheritance patterns (at least two family member have idiopathic DCM), first degree relatives (parents, siblings, children) have a chance of inheriting the condition
• Valvular DCM

• It is any cardiovascular disease process that involves one or more valves of the heart, in which the heart can’t effectively pump blood, due to backward movement of the blood leading to dilation & heart has to pump harder causing DCM

• Alcoholic DCM
  • Due to direct toxic effects of alcohol on heart muscle the heart is unable to pump effectively leading to ventricular dilation & heart failure
• Drug Induced DCM
  • Certain drugs like Anti-neoplastic Drugs & psychiatric agents can lead to cardiac muscle Dysfunction inducing Dilated Cardiomyopathy
• Peri-partum DCM
  • It is the weakness of the heart muscles that can occur anytime through the final months of pregnancy through about 5 months after delivery due to extra pumping action of the heart to transfer oxygen & nutrients to the growing baby can cause the hear to become enlarged
• Diabetic DCM
  • This occurs due to the structural, functional & metabolic changes that takes place in the heart muscles which can lead to inability of the heart to pump effectively and circulate the blood leading to enlargement of the heart chambers
• Thyrotoxic DCM
  • The combination of direct toxic effects of excess thyroid hormone along with prolonged tachycardia, arrhythmia, and a hyper dynamic state contribute to impaired cardiac contractility & decreased cardiac output causing enlargement of heart chambers.

Pathophysiology of Dilated Cardiomyopathy

Any pre-disposing factors that causes increased stasis of blood in the left ventricle
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Ventricles stretch initially to accommodate the increased blood flow & work harder to pump & eject the blood

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Further stasis of the blood in the left ventricle

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Rapid Degenerative changes that alters the structural & functional ability of the Myocardium
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Impaired Systolic Function that results in ventricular Dilation & enlarged Chamber size (Cardiomegaly)

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Inability of the heart to contract & maintain Cardiac Output (Heart Failure)

Clinical Manifestations of Dilated Cardiomyopathy

• Shortness of breath.
• Swelling of the legs and feet.
• Fatigue (extreme tiredness), inability to exercise, or carry out daily activities.
• Weight gain
• Cough and congestion related to fluid retention.
• Palpitations or fluttering in the chest due to abnormal heart rhythms
  (arrhythmia).
• Dizziness or light-headedness.
• Fainting
• Blood clots due to blood flowing more slowly through the body

HYPERTHROPHIC CARDIOMYOPATHY (HCM)
• Hypertrophic cardiomyopathy (HCM) is a disease in which the heart muscle becomes
abnormally thick (hypertrophied). The thickened heart muscle has to pump harder to
eject the blood into the aorta.

Types of Hypertrophic Cardiomyopathy

• Hypertrophic obstructive Cardiomyopathy/Asymmetric Septal Hypertrophy:
  • The septum between the two ventricles become enlarged & obstructs the blood flow from the left ventricle.
  Hypertrophic Non-Obstructive Cardiomyopathy
  • The ventricles enlarge in shape, size and become stiff that limits the blood flow to the ventricles as a result the heart is not able to pump out the blood.

Causes of Hypertrophic Cardiomyopathy

• Genetic Disorders
  • It is usually caused by abnormal genes (gene mutations) that cause the heart muscle to grow abnormally thick.
  • It is familial, a parent with hypertrophic cardiomyopathy have a 50% chance of having the genetic mutation for the disease.
• Muscular disarray
  • The cells appear disorganized and irregular (called “disarray”) instead of being organized and parallel. This disorganized pattern of muscles lead to hypertrophy of the heart muscles that cause changes in the electrical signals traveling through the lower chambers of the heart and impair ventricular filling.
• Hypertension or Ageing
  • Hypertension & Ageing causes increased systemic vascular resistance which increases the pumping action of the heart that can result in cellular changes of the myocardial muscle leading to formation of hypertrophied tissue.
• Aortic Stenosis
  • In Aortic Stenosis, there is a need for rapid forceful contraction of the left ventricle that progressively results in hypertrophied ventricles that become resistant to ventricular filling and they become Non-compliant.

Pathophysiology of Hypertrophic Cardiomyopathy

Any condition that causes obstruction to the outflow of blood from the left ventricles
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Rapid forceful contraction of the left ventricle to eject the blood through the Aorta
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Failure of the Myocardial stretch fibres to relax results In Inappropriate increase in the number & size of Myocardial cells (Hypertrophy)

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Impaired Ventricular Filling as the Ventricles become Non-compliant & unable to relax
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Ventricles become Stiff Causing Diastolic Dysfunction

Clinical Manifestations of hypertrophic cardiomyopathy

• Chest pain or pressure that usually occurs with exercise or physical activity
• Shortness of breath and fatigue, especially with exertion
• Syncope
• Palpitations due to abnormal heart rhythms

RESTRICTIVE CARDIOMYOPATHY (RCM)

• Restrictive cardiomyopathy is the disease of the heart muscle characterized by noncompliant ventricular walls that resist diastolic filling & stretch; in which one or both ventricles may be affected.

Types of Restrictive Cardiomyopathy

• Non-Obliterative RCM
  • It is the Infiltration of abnormal substance in the myocardium like inflammatory mediators & amyloid protein etc.
• Obliterative RCM
  • It is the fibrosis of the endocardium & sub endocardium due to thrombosis.

Etiology of Restrictive Cardiomyopathy

• Genetic Disease
  • Hemochromatosis: A genetic disorder characterized by excessive iron (Fe) accumulation that results in damage to heart tissues called cardiomyopathy.
  • Fabry Disease: It is an X-linked deficiency of the lysosomal enzyme alpha- galactosidase A, that results in accumulation of Glycolipid in many tissues such as heart.
  • Gaucher Disease: An inherited disorder of metabolism, resulting from glucocerebrosidase deficiency, causing deposition of glucocerebroside and related compounds.
• Connective Tissue Disorders
  • Amyloidosis: It is a group of disparate conditions characterized by extracellular deposition of insoluble fibrils composed of disaggregated proteins. These proteins may accumulate locally, or widely, involving multiple organs and causing severe multi-organ failure.
  • Systemic Sclerosis: It is a rare chronic disease of unknown cause characterized by diffuse fibrosis and vascular abnormalities in the heart.
• Other conditions
  • Hyper Eosinophilic Syndrome: Diseases that occur in the pulmonary & vascular structures of the heart.
• Sarcoidosis: It is an inflammatory disorder of unknown etiology resulting in granulomas in one or more organs and tissues leading to multiple organ failure
• Endomyocardial Fibrosis: Thrombus formation in the endomyocardial layer leading to fibrous tissue deposition.
• Radiation therapy: Chronic exposure to radiation effects causes fibrosis of the heart tissue.

Pathophysiology of Restrictive Cardiomyopathy

Any Infiltrative disorder of the heart that leads to Endocardial thickening

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Formation of fibrous deposits leading to Myocardial Fibrosis & death of Myocytes in the Ventricles

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Ventricles become rigid & non- Compliant

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Ventricles become resistant to filling

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Diastolic Dysfunction
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Further Infiltration & fibrous deposition leads to restriction of heart to Systolic

Function
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Inability of the heart to contract & maintain Cardiac Output (Heart Failure)

Clinical Manifestations of Restrictive Cardiomyopathy

• Shortness of breath (at first with exercise; but over time it occurs at rest)
• Fatigue (Extreme tiredness)
• Inability to exercise
• Swelling of the legs and feet (Edema)
• Weight gain
• Nausea, bloating, and poor appetite (related to fluid retention)
• Palpitations (fluttering in the chest due to abnormal heart rhythms)
• Fainting
• Chest Pain or pressure especially with Exercise

ARRHYTHMOGENIC CARDIOMYOPATHY (ACM)
• Arrhythmogenic cardiomyopathy is an inherited heart muscle disorder, common in young patients and athletes that is characterized by loss of Myocytes and fibro fatty replacement of right ventricular myocardium or biventricular involvement.

Causes of Arrhythmogenic Cardiomyopathy

• Genetic Disorders
  • ACM is an inherited autosomal dominant pattern, with variable expression and it is associated with gene Mutation.
• Fatty Infiltration
  • This involves a partial or near-complete substitution of myocardium with fatty tissue without wall thinning. It involves predominantly the apical and infundibular regions of the Right ventricle.
• Fibro-fatty Infiltration
  • It is the replacement of Myocytes with fibro fatty tissue that leads to Myocardial Atrophy.
• Exercise
  • Strenuous Exercise has an risk for accelerated progression of the disease.

Pathophysiology of Arrhythmogenic Cardiomyopathy

Due to development disorders that cause dysplasia of the Myocardial tissue

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Replacement of the Myocardium with a fibrous fatty tissue

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Impaired Myocardial Function

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Inability of the heart to contract & maintain Systemic Circulation

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Life threatening Arrhythmias

DIAGNOSTIC FINDINGS OF CARDIOMYOPATHY

• Medical History
  • Collect regarding family history of cardiomyopathy, childhood congenital disorders of the heart & Genetic History like marriage within first degree relatives & presence of siblings with cardiomyopathy.
• Physical Examination
  • Inspect for signs of Edema, shortness of breath
  • Palpation of the chest reveals presence of forced apical impulse that may be displaced laterally
  • Auscultation reveals abnormal heart sounds & systolic ejection murmur between the apex & sternal border.
• Laboratory tests
  • Routine Complete blood Count (CBC) to monitor anemia, Infection & platelet dysfunction
  • Cardiac Markers like CPK, CPK-MB, Trop-I & Trop-T to monitor cardiac Function
  • Renal Function tests like urea, creatinine & Serum Electrolytes to monitor kidney Function
  • B-Type Natriuretic Peptide- Elevated denotes the presence of Heart Failure.
• Electrocardiogram (ECG)
  • Reveals the presence of Ventricular tachycardia, ventricular hypertrophy, atrial Fibrillation, Atrio-Ventricular Block and other dysrhythmias.
• IMAGING STUDIES
  Chest X-ray
  • It shows cardiomegaly with right & left heart enlargement and signs of pulmonary hypertension.
  Doppler Echocardiography
  • Demonstrates regional wall motion abnormality, dilated atria & ventricles, systolic & diastolic dysfunction.
  CT/ MRI Scan of chest
  • To identify structural & vascular changes in the heart & pulmonary vessels.
  Multi gated Acquisition (MUGA) Scans
  • It is a radionuclide Angiography scan done to determine Ejection Fraction.
  Cardiac Catheterization
  • It is a confirmatory test to identify the type of cardiomyopathy & to monitor the pressure in the chambers & vessels of the heart and to rule out coronary Artery Disease.
  Endomyocardial Biopsy
  • It is done to detect the Atrophy & hypertrophied heart muscle and presence of viral Antigens in the myocardial Tissue.

EMERGENCY MANAGEMENT OF CARDIOMYOPATHY

• CARDIO-PULMONARY RESUSCITATION (CPR)
  • CPR is an emergency procedure that combines chest compressions often with artificial ventilation in an effort to manually preserve intact brain function until further measures are taken to restore spontaneous blood circulation and breathing in a person who is in cardiac arrest.
  • It is recommended in those who are unresponsive with no breathing or abnormal breathing.
• OXYGEN THERAPY
  • Oxygen is given to treat hypoxemia
  • Oxygen is usually given by face mask, nasal prongs or cannulas & high flow, air entrainment mask
  •  If the patient remains hypoxemic on high flow oxygen masks, continuous positive airways pressure (CPAP) may be used to improve oxygenation to the under ventilated alveoli.
  • Endotracheal intubation and ventilation is the next step in the management of Hypoxemia. Arterial blood gas analysis or measurements of peak expiratory flow rate and vital capacity in deciding the need for intubation. Continuous monitoring, particularly the heart rate and blood pressure, is essential and resuscitation drugs must be kept at Bedside.
• DEFIBRILLATION
  • Defibrillation is an emergency treatment for ventricular fibrillation and other life- threatening arrhythmias (abnormal heartbeats). Defibrillation restores a normal heartbeat by providing electrical shocks on the chest wall which signals the natural pacemaker of the heart to produce the Normal rhythm.
  • A heart in ventricular fibrillation stops pumping blood to the brain and body & will lead to cardiac arrest and death within a few minutes if not treated immediately.

MANAGEMENT OF CARDIOMYOPATHY

• Pharmacologic Therapy
  • Diuretics- Lasix to decrease preload
  • Nitrates- Nitroglycerine to decrease Systemic Vascular resistance
  • ACE Inhibitors- Captopril to reduce Afterload
  • Β-Adrenergic Blockers- Metoprolol to prevent Heart Failure
  • Aldosterone Agonists- Spironolactone to control Neuro-hormonal Stimulation
  • Digoxin- to treat Atrial Fibrillation
  • Dobutamine or Milrinone Infusion is used to treat Irregular heart rhythms
  • Anti-Dysrhythmics- Amiodarone to treat dysrhythmias
  • Anti-Coagulation therapy- low molecular weight heparin to reduce the risk of clot & systemic Emboli Formation.
• Nutritional Therapy
  • Restrict salt intake (sodium) to 2,000 to 3,000 mg per day
  • Avoid oily foods
  • Initially Liquid diet is advised later progressing to soft solid & semi-solid foods.
• Exercise
  • Adequate rest will relieve chest pain & pressure
  • Advice to do non-competitive daily activities
  • Elevation of legs & Feet during sleep to improve venous return to the heart
  • Avoid strenuous Exercises, lifting Heavy Objects & activities that leads to dehydration
  • Consult with the physician about walking & other Aerobic Exercises.

INTERVENTIONAL THERAPIES OF CARDIOMYOPATHY

Percutaneous trans-luminal Septal Myocardial Ablation

• This procedure consists of administering alcohol into the first septal artery branching off the left Anterior descending artery, which causes Ischemia & septal wall Myocardial Infarction.
• Ablation of the septal wall will decrease the outflow obstruction & improves symptoms of Heart Failure.

Ventriculomyotomy: 

• It involves incising the hypertrophied  Septal Muscles to relieve obstruction of the aortic outflow.

Septal Myectomy:

• It is a surgical procedure, where a small amount of the thickened septal wall  is removed to widen the outflow tract (the path the blood takes) from the left ventricle to the aorta.

Cardiac Resynchronization Therapy (CRT):

•  In some patients progressing to heart failure, biventricular pacing (a pacemaker that senses and initiates heartbeats in the right and left ventricle) is applied to improve survival, reduce symptoms and increases exercise  tolerance.

Implantable Cardioverter Defibrillator (ICD):

• ICDs are suggested for people at risk for life-threatening arrhythmias or sudden cardiac death.
• The ICD is a small device placed just under the skin and is connected to wire leads that are threaded through the vein to the heart. 
• It constantly monitors the heart rhythm, when it detects a very fast, abnormal heart rhythm, it delivers energy (a small but powerful shock) to the heart muscles & reverts into normal heart rhythm

Surgical Management

Ventricular Assist Devices (VAD):

• A left ventricular assist device (VAD -- also called ventricular assist system or VAS) is a type of mechanical circulatory support device (MCSD), where a mechanical pump is implanted in patients who have progressed to heart failure. This device assists the weakened left ventricle to pump & maintain Systemic Circulation.

Heart Transplantation: 

• In heart transplant, the donor heart will be placed in proper position and attached to your major blood vessels
• Orthotopic Transplant: The patient's own heart is removed and replaced with the donor heart 
• Heterotopic Transplant: The recipient's (patient) diseased heart is left in place to support the donor heart

Nursing Management:

• Administer oxygen therapy as prescribed
• Monitor the client continuously for vital signs, saturation, I/O chart, level of consciousness dysrhythmias etc.
• Administer IV fluids as Prescribed
• Monitor the Nutritional Needs of the client by Inserting NG feeding tube if oral feeds are not tolerated
• Keep all emergency articles like suctioning, Endo-tracheal Intubation tray, Defibrillators & Mechanical Ventilator at the bed side to meet emergencies 
• Alleviate the symptoms & prevent complications
• Administer all medications & set the Infusion rate of emergency drugs as Prescribed
• Provide Psychological & Emotional Support to patient & family members
• Prepare the client for Invasive therapies & Surgical Intervention, when necessary
• Administer Prophylactic Antibiotics for peri-operative Client to prevent Infection
• Follow Anti- coagulant prophylaxis as prescribed or use Anti- Embolic Stockings & Sequential Compressive Devices as prescribed
• Advice the client to keep the legs & feet elevated with a pillow in bed to prevent & treat Edema
• Teach & perform Hygienic Practices & meet the activities of Daily living for the client
• Monitor the Skin regularly & prevent Bedsores by using Alpha bed or air mattresses

Patient & Family Education:

• Instruct patient to take all medicines as prescribed and to follow with health care provider.
• Advice the client to take low sodium & low Cholesterol diet.
• Encouraged to drink 6 to 8 glasses of water per day unless restricted in case of Edema
• Advise the patient to avoid alcohol, smoking, caffeine and over the counter drugs
• Advice the client to Schedule adequate periods of rest & Activity
• Instruct the patient to avoid lifting of heavy weights and vigorous activities but perform mild to moderate Exercises & activities of Daily living
• Encourage the use of stress reduction activities like relaxation, meditation, distraction & prayers to relieve tension.
• Instruct the patient to report the hospital any signs of heart failure like increased weight gain, edema, shortness of breath and increased fatigue.
• Demonstrate CPR procedure to the family members & care givers & advice them to perform CPR in case of sudden cardiac arrest at home.
• Instruct the patient to notify the physician before any dental and medical procedures to be done as there is a high risk for Infective endocarditis.