Cardiomyopathies for PA
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Cardiomyopathies for the Physician Assistant Licensing Exam
- Definition: Cardiomyopathies are a group of heart muscle diseases that impair the heart's ability to pump blood effectively.
- Classification: The main types include dilated, hypertrophic, restrictive cardiomyopathy, and arrhythmogenic right ventricular cardiomyopathy (ARVC).
Dilated Cardiomyopathy (DCM)
- Definition: DCM is characterized by enlargement and weakened contraction of the ventricles, leading to reduced ejection fraction and heart failure.
- Causes:
- Idiopathic: Unknown origin in many cases.
- Genetic: Inherited mutations in muscle proteins.
- Toxins: Alcohol, cocaine, and chemotherapy drugs.
- Infections: Viral myocarditis (e.g., Coxsackievirus).
- Clinical Signs:
- Symptoms of heart failure, including fatigue, dyspnea, and leg swelling.
- Diagnosis:
- Echocardiogram: Enlarged ventricles with low ejection fraction.
- Management:
- Standard heart failure medications (e.g., ACE inhibitors, beta-blockers).
Hypertrophic Cardiomyopathy (HCM)
- Definition: HCM is a genetic disorder causing thickening of the ventricular walls, which can obstruct blood flow.
- Causes: Autosomal dominant mutations in sarcomere proteins.
- Clinical Signs:
- Dyspnea, chest pain, syncope, especially with exertion.
- Systolic murmur that increases with Valsalva maneuver.
- Diagnosis:
- Echocardiogram: Shows ventricular wall thickening, often with left ventricular outflow tract (LVOT) obstruction.
- Management:
- Beta-blockers for symptom relief and risk reduction.
Restrictive Cardiomyopathy (RCM)
- Definition: RCM is marked by stiff ventricular walls, restricting filling.
- Causes: Often due to infiltrative diseases like amyloidosis.
- Clinical Signs:
- Symptoms of right-sided heart failure (e.g., leg edema, hepatomegaly).
- Diagnosis:
- Echocardiogram: Normal-sized ventricles with biatrial enlargement.
- Management:
- Focus on symptom relief with diuretics and treating underlying causes.
Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC)
- Definition: ARVC is a genetic disorder causing fatty replacement of the right ventricular muscle, leading to arrhythmias.
- Clinical Signs:
- Palpitations, syncope, and sudden cardiac death.
- Diagnosis:
- ECG: Epsilon waves in V1-V3 leads.
- Management:
- Avoid strenuous exercise; ICD for high-risk patients.
Key Points
- Dilated Cardiomyopathy (DCM): Common causes include genetics, infections, and toxins. Presents with heart failure and reduced ejection fraction.
- Hypertrophic Cardiomyopathy (HCM): Genetic disorder causing thickened ventricular walls; presents with exertional symptoms and a murmur.
- Restrictive Cardiomyopathy (RCM): Often due to infiltrative diseases, leading to right heart failure symptoms and preserved ejection fraction.
- Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC): Genetic disease causing arrhythmias and risk of sudden cardiac death; managed with lifestyle modification and ICDs.