### Date : 2024-11-03 13:55 ### Topic : Restrictive Cardiomyopathy (RCM) #cardiology ---- **Restrictive Cardiomyopathy (RCM)** is a type of cardiomyopathy in which the **walls of the heart, particularly the ventricles, become stiff** and lose their ability to relax and fill properly during diastole. This leads to **diastolic dysfunction** while often preserving normal or near-normal systolic function (ejection fraction). As a result, blood flow through the heart is impaired, and blood backs up into the atria, causing symptoms related to **elevated pressures in the heart and lungs**. ### Key Characteristics of Restrictive Cardiomyopathy 1. **Stiffened Myocardium**: - The heart muscle becomes rigid and less compliant, restricting its ability to expand and fill during diastole. - The stiffening typically occurs due to infiltration of abnormal substances or fibrotic changes in the myocardium. 2. **Diastolic Dysfunction**: - Diastolic filling is impaired, leading to increased pressures within the heart, especially in the left and right atria, which often become dilated. - Despite impaired filling, systolic function (ejection fraction) usually remains within the normal range initially. 3. **Normal or Near-Normal Wall Thickness**: - In contrast to hypertrophic or dilated cardiomyopathies, the wall thickness and overall size of the ventricles may remain normal, though they are less compliant. ### Causes of Restrictive Cardiomyopathy RCM can be **idiopathic** (no known cause) or secondary to various systemic diseases. Common causes include: - **Infiltrative Diseases**: - **Amyloidosis**: The most common cause of RCM, where abnormal protein deposits (amyloid) infiltrate the heart muscle, making it stiff. - **Sarcoidosis**: Involves granuloma formation in the myocardium. - **Hemochromatosis**: Iron overload that can deposit in the heart and impair its flexibility. - **Non-Infiltrative Causes**: - **Idiopathic Fibrosis**: Can occur with aging, where fibrotic changes reduce myocardial compliance. - **Scleroderma** and other systemic conditions that affect connective tissue. - **Storage Diseases**: - **Glycogen storage diseases** and **Anderson-Fabry disease**: Can lead to myocardial deposition of storage materials, leading to stiffness. ### Symptoms of Restrictive Cardiomyopathy RCM symptoms are primarily due to **congestive heart failure** and include: - **Dyspnea (shortness of breath)**: Commonly worsens with exertion or lying flat. - **Fatigue and Weakness**: Due to reduced cardiac output and poor blood flow. - **Peripheral Edema and Ascites**: Caused by right-sided heart failure. - **Jugular Venous Distention (JVD)**: Reflects elevated right atrial pressures. - **Hepatomegaly and Abdominal Discomfort**: Due to congestion of the liver. ### Physical Examination Findings Examination findings are similar to those of heart failure and may include: - **Elevated Jugular Venous Pressure** with a prominent "y" descent. - **Hepatojugular Reflux**: Increased jugular venous pressure with abdominal pressure. - **Peripheral Edema**: In advanced cases. - **S3 and S4 Heart Sounds**: These are often heard due to abnormal ventricular filling. ### Diagnosis Diagnosis of RCM relies on imaging and specific tests to distinguish it from other types of cardiomyopathy: 1. **Echocardiography**: - Shows **normal ventricular size** with **diastolic dysfunction** and typically **biatrial enlargement** due to increased filling pressures. - Doppler imaging can show impaired relaxation and elevated filling pressures. 2. **Cardiac MRI**: - Useful for identifying **infiltrative diseases** (e.g., amyloidosis) and differentiating RCM from other cardiomyopathies. - Can show fibrosis or specific patterns of infiltrates. 3. **Endomyocardial Biopsy**: - May be performed if an infiltrative disease (e.g., amyloidosis) is suspected, allowing for a definitive diagnosis. 4. **Electrocardiogram (ECG)**: - Shows **low voltage** QRS complexes (particularly in amyloidosis) and sometimes conduction abnormalities, but it is generally non-specific. 5. **Other Tests**: - **Blood tests** for specific markers of infiltrative diseases (e.g., serum protein electrophoresis for amyloidosis, iron studies for hemochromatosis). ### Treatment of Restrictive Cardiomyopathy Treatment focuses on managing symptoms and treating the underlying cause: 1. **Diuretics**: - Used to relieve congestion and reduce symptoms of heart failure, though caution is needed to avoid reducing preload excessively, as this can worsen diastolic filling. 2. **Rate Control**: - **Beta blockers** or **calcium channel blockers** can help manage heart rate and allow more time for ventricular filling in diastole. 3. **Treatment of Underlying Cause**: - **Amyloidosis**: Specific treatments may include chemotherapy or monoclonal antibodies (e.g., tafamidis). - **Hemochromatosis**: Iron chelation therapy or phlebotomy. - **Sarcoidosis**: Corticosteroids or other immunosuppressive treatments if granulomas are present. 4. **Heart Transplant**: - In advanced cases where medical management fails and the underlying cause is not reversible, a heart transplant may be considered. ### Prognosis - **Variable**: Prognosis depends on the underlying cause and response to treatment. - **Poor Prognosis in Infiltrative Causes**: Conditions like amyloidosis and sarcoidosis can progress despite treatment, leading to worsening heart failure. ### Summary of Restrictive Cardiomyopathy | Feature | Restrictive Cardiomyopathy (RCM) | |-------------------------|-------------------------------------------------------| | **Primary Issue** | Stiff, non-compliant ventricles, impaired diastolic filling | | **Common Causes** | Amyloidosis, sarcoidosis, idiopathic fibrosis, hemochromatosis | | **Symptoms** | Dyspnea, fatigue, peripheral edema, JVD, hepatomegaly | | **EKG Findings** | Low voltage QRS complexes, possible conduction abnormalities | | **Echocardiogram** | Normal LV size, biatrial enlargement, diastolic dysfunction | | **Treatment** | Diuretics, rate control, treat underlying cause, possible transplant in advanced cases | Restrictive cardiomyopathy is a challenging condition to manage and diagnose, with a focus on symptom relief and underlying disease treatment. It requires careful differentiation from other cardiomyopathies due to its distinct pathophysiology and management strategies. ### Reference: - ### Connected Documents: -