Cardiomyopathies: Definition and Types

Cardiomyopathies Defined

• Cardiomyopathies are a heterogeneous group of diseases affecting the myocardium, as defined by the AHA.
• The diseases are associated with mechanical and/or electrical dysfunction, usually involving ventricular hypertrophy or dilatation, and are often genetic.
• Cardiomyopathies can be confined to the heart or be part of systemic disorders, and may lead to cardiovascular death or progressive heart failure.

Primary Cardiomyopathies

• Primary cardiomyopathies are classified based on their etiology: genetic, mixed, or acquired.
• Genetic cardiomyopathies include hypertrophic cardiomyopathy (HCM), arrhythmogenic right ventricular cardiomyopathy (ARVC), left ventricular noncompaction cardiomyopathy, inherited conduction system disorders, and ion channelopathies.
• Acquired cardiomyopathies include conditions originating from inflammatory processes such as myocarditis, stress-induced cardiomyopathy ("tako-tsubo" pericarditis), and peripartum cardiomyopathy (related to pregnancy).

Hypertrophic Cardiomyopathy (HCM)

• HCM involves unexplained left ventricular hypertrophy, with disproportionate thickening of the interventricular septum.
• HCM is also characterized by diastolic filling abnormalities, cardiac arrhythmias, and intermittent left ventricular outflow obstruction.
• Implantable cardioverter defibrillators (ICDs) have proven to be lifesaving for HCM patients.
• Clinical symptoms are often absent; however, dyspnea, chest pain during exertion, exercise intolerance, syncope, and arrhythmias may occur.

Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia (ARVC/D)

• ARVC/D ranks as the second most common cause of sudden cardiac death in young individuals, subsequent to HCM.
• This condition accounts for up to 10% of sudden cardiac deaths in patients younger than 65 years.
• Ventricular ectopic beats or sustained VT (with LBBB morphology) cause symptoms.
• ARVC/D typically presents with palpitations, syncope, or exercise-induced cardiac arrest.
• The initial symptom of ARVC/D may be sudden cardiac death.
• Over time, there is development in the right ventricle resulting in severe biventricular failure and dilated cardiomyopathy.
• A family history of sudden cardiac death is common with ARVC/D.

Epsilon Waves in ARVD

• Epsilon waves are highly specific and characteristic in arrhythmogenic right ventricular dysplasia (ARVD).
• In ARVD, myocytes are replaced by fat, creating islands of viable myocytes amidst fat.
• This process causes a delay in the excitation of some myocytes in the right ventricle.
• The change produces a small "blip" observable during the ST segment on an ECG.

Left Ventricular Noncompaction

• Left Ventricular Noncompaction is characterized by a distinct "spongy" appearance of the myocardium.
• Signs and symptoms are primarily linked to arrhythmias, embolic events, and heart failure.
• Treatment aims to prevent heart failure symptoms, arrhythmias, systemic embolic events, and sudden cardiac death.

Ioon Channelopathies

• Ion channel disorders of the heart include long QT syndrome (LQTS), short QT syndrome (SQTS), Brugada syndrome and catecholaminergic polymorphic ventricular tachycardia.

Brugada Syndrome

• A diagnosis requires two parts: ECG findings and clinical findings.
• You need typical ECG abnormalities and/or one clinical finding.
• Clinical finding include a history of VT/VF, family history of sudden cardiac death, family history of coved-type ECG, agonal respiration during sleep, and/or inducible VT/VF during EP study.

Dilated Cardiomyopathy (DCM)

• DCM accounts for significant instances of heart failure and is a leading of heart transplants.
• DCM is characterized by ventricular enlargement, a reduction in ventricular wall thickness, and impaired systolic function in one or both ventricles.
• Clinical signs of DCM include dyspnea, orthopnea, and reduced exercise capacity.
• Individuals with DCM frequently exhibit ejection fractions below 25%, the normal range being 50% to 60%.
• Reduced blood flow from heart chambers leads to the formation of systemic emboli.

Myocarditis (Inflammatory Cardiomyopathy)

• Myocarditis is defined as inflammation of the myocardium.
• Clinical symptoms are variable, ranging from nonspecific symptoms, such as fever and myalgias, to exertional dyspnea, hemodynamic collapse, and sudden death.
• Acute viral myocarditis involves three phases: acute viral infection, autoimmune activation, and myocardial injury, which can result in dilated cardiomyopathy (DCM).

Myocarditis Signs and Symptoms

• Clinical presentation is highly variable.
• Myocarditis can range from asymptomatic presentation or mild febrile illness to cardiogenic shock and cardiac arrest.
• Symptoms include fever, malaise, fatigue, altered LOC, chest pain, hypotension, palpitations, ventricular arrhythmias, dyspnea, orthopnea, pulmonary rales, peripheral edema, presyncope, and syncope.

Myocarditis - ECG Changes

• Sinus tachycardia and non-specific ST segment/T wave changes are the most common ECG abnormalities.
• Other possible but variable ECG changes include:
• Prolonged QRS, QT prolongation Diffuse T wave inversion, ventricular arrhythmias, AV conduction defects
• When the contiguous pericardium is also inflamed, ECG features of pericarditis may also appear. (=myopericarditis)

Peripartum Cardiomyopathy

• This is a rare disorder of the heart muscle which occurs during the final trimester or the first 5-6 months postpartum.
• A higher rate of incidence in women who are African American, multiparous, older, or women with twin fetuses, preeclampsia, and/or tocolytic therapy usage to prevent premature labor and delivery.
• It presents as LV systolic dysfunction such as shortness of breath (resting or exerting), palpitations, edema, and orthopnea.

Peripartum Cardiomyopathy: Definition

• To diagnose, heart failure is required in the last month of pregnancy or within the first 5 months postpartum with no identifiable co-occuring reason.
• Systolic dysfunction is also required for diagnosis.

Stress or "Tako-Tsubo" Cardiomyopathy

• Pathophysiology involves sympathetic nervous system activation, microvascular spasm, and underlying left ventricular outflow tract (LVOT) obstruction.
• An acute stress response leads to a catecholamine surge.
• Sympathetic activation causes microvascular spasm.
• A degree of underlying left ventricular outflow tract (LVOT) obstruction increases LV workload and worsens sympathetic activation/apical dyskinesis.
• Clinically 90% of cases are in post-menopausal women, often associated with emotional stress.
• Cases in men are likely caused by physical stress.
• There are no ECG criteria to differentiate between STEMI and Tako-Tsubo safely.
• LV function usually returns within 21 days, and treatment is largely supportive.
• Anticoagulation should be initiated in patients with large areas of cardiac hypokinesis due to them being at high risk of thromboembolic events in the brain.

Secondary Cardiomyopathies

• These heart muscle diseases happen along with a system-wide disorder.
• Causes include drugs, diabetes mellitus, muscular dystrophy, autoimmune disorders, and cancer treatments such as radiation or cancer drugs. Alcoholic cardiomyopathy is the most common cause of of DCM in the western world.

Endocarditis

• This is the inflammmation the heart's chambers and valves by infection.

Pathophysiologic Pattern of Endocarditis

• Diseases process occurs in three phases:
• Bacteremia: the presence of microorganisms in the blood
• Adhesion: when microorganisms stick to damaged endothelium
• Colonization: proliferation of organisms with inflammation leading to mature vegetation
• Growths on valves produce toxins which can create holes in surrounding vessels, potentially spreading toxins.

Endocarditis Diagnosis

• Diagnosis is a process of elimination.
• Patient History is required, so are the signs and symptoms.
• Blood cultures are needed, and so is echocardiography/ X-Ray and CT scans.

Signs & Symptoms of Endocarditis

• Symptoms include: Chest Pain, Dyspnea, Cough, Fatigue, Night Sweats, Chills, Edema and presence of a Heart murmur.
• Vitals: Fever, Hypotension, Tachycardia (elevated pulse), Tachypnea (elevated respiration) and Arrythmias.

Treatment of Endocarditis

• Begin treatment with Oxygen Therapy for any case showing it indicated.
• Provide Fluids/Treat any Hypotension.
• Monitor Dysrhythmias with a 12 lead.
• The patient is to be hospitalized, receive surgical treatment and/or antibiotics for 2-6 weeks.

Paramedic Pearls of Wisdom (Endocarditus)

• Endocarditis is possible in patients with IV drug use.
• Look for sepsis, PE, MI, stroke, and abscesses as complications.
• It may manifest after several months, so it is important to advocate for the patient and look for key signs.