Cardiomyopathies Quiz

Cardiomyopathies: Definitions and Types

• Cardiomyopathy is a structurally or functionally abnormal cardiac muscle disease that can lead to heart failure and dysrhythmias.
• Major types of cardiomyopathy include dilated, restrictive, hypertrophic, arrhythmogenic right ventricular dysplasia (ARVD), and unclassified cardiomyopathy.

Epidemiology and Etiology

• Cardiomyopathy affects 5-10% of the 5-6 million heart failure patients in the US and can occur in people of all ages and races.
• Risk factors for cardiomyopathy include family history, ischemic heart disease, viral myocarditis, diabetes, obesity, and long-term alcohol or drug use.

Presentation and Treatment

• Cardiomyopathy can be asymptomatic or present with symptoms such as shortness of breath, fatigue, peripheral edema, arrhythmias, and syncope.
• Treatment goals for cardiomyopathy generally aim to slow the disease progression, control symptoms, and prevent sudden death through lifestyle changes, heart failure and arrhythmia therapies.

Dilated Cardiomyopathy: Characteristics and Epidemiology

• Dilated cardiomyopathy (DCM) is characterized by dilation and impaired contraction of one or both ventricles, often leading to heart failure and arrhythmias.
• DCM has an epidemiology of 5-8 cases per 100,000 with a prevalence of 36 cases per 100,000, and it is a primary indication for cardiac transplantation.

Etiology, Presentation, and Diagnosis of DCM

• The cause of DCM is often unknown, with around one-third of cases being inherited, and it can present with symptoms of heart failure and arrhythmias.
• Diagnosis of DCM involves echocardiogram, B-type natriuretic peptide (BNP), chest X-ray, ECG, and cardiac catheterization to assess chamber dimensions, wall motion, and hemodynamics.

Treatment of DCM

• Treatment of DCM includes addressing underlying causes, lifestyle modifications, medications such as ACEIs/ARBs and beta-blockers, and interventions like implantable cardioverter-defibrillator (ICD), left ventricular assist device (LVAD), and heart transplant.

Hypertrophic Cardiomyopathy: Characteristics and Etiology

• Hypertrophic cardiomyopathy is a heterogeneous disorder associated with hypertrophy of the left ventricle, caused by a variety of mutations, with around 50% showing an autosomal dominant pattern.
• It is characterized by hypertrophy of the myocardium, which can lead to obstruction of blood flow.

Cardiomyopathies: Restrictive, Arrhythmogenic Right Ventricular Dysplasia, and Stress Cardiomyopathy

• Restrictive cardiomyopathy is characterized by non-dilated ventricles, impaired ventricular filling, and absence of hypertrophy, with some common etiologies including amyloidosis, connective tissue disorders, and hemochromatosis
• The epidemiology of restrictive cardiomyopathy varies among different etiologies, such as amyloidosis being more prevalent in both genders, while sarcoidosis is more common in women of African American descent
• Patients with restrictive cardiomyopathy typically present with progressive shortness of breath, exercise intolerance, orthopnea, fatigue, and signs of heart failure
• Diagnostics for restrictive cardiomyopathy include echocardiogram demonstrating non-dilated, nonhypertrophied ventricles with bi-atrial enlargement, abnormal diastolic function, and elevated BNP
• Treatment for restrictive cardiomyopathy is mainly directed at the underlying etiology, with mainstays such as diuretics, vasodilators, and ACEIs, and implantables like pacemakers and heart transplantation
• Arrhythmogenic right ventricular dysplasia (ARVD) is a rare cardiomyopathy characterized by muscle tissue in the right ventricle being replaced by fatty or fibrous tissue, often leading to conduction abnormalities and arrhythmias
• Symptoms of ARVD include dizziness, palpitations, syncope, and atypical chest pain, with the most common arrhythmia being monomorphic ventricular tachycardia
• Diagnostic workup for ARVD involves EKG and echocardiogram, showing abnormal right ventricular function and wall movement, with severe cases demonstrating global right ventricular dilation
• Management of ARVD focuses on heart failure and arrhythmia treatment using beta blockers, antiarrhythmics, radiofrequency ablation, surgery, and lifestyle changes, with ICD placement being the only proven mortality benefit
• Stress cardiomyopathy, also known as takotsubo cardiomyopathy, is a transient regional systolic dysfunction predominantly affecting the left ventricle, often mimicking myocardial infarction without obstructive coronary artery disease
• Stress cardiomyopathy predominantly affects women, with presentations similar to acute coronary syndrome, often triggered by intense emotional or physical stress, and may lead to signs of heart failure, tachyarrhythmias, or cardiogenic shock
• Diagnostics for stress cardiomyopathy involve ECG changes, elevated troponin and BNP, left ventricular movement abnormalities on echocardiogram, and cardiac catheterization to rule out obstructive coronary disease