The restrictive cardiomyopathy usually presents with exertional dyspnea and orthopnea as main symptoms and often is already at an advanced stage of the disease when diagnosed. Shortness of breath shows gradually worsening course and causes exercise intolerance. Patients also complain about nocturnal dyspnea. Generalized fatigue may be experienced as a result of progressive heart failure. Peripheral edema may also be present if the right ventricle is involved in the pathological process. Some possible manifestations depend on the extent of the lesion. Atrial and ventricular arrhythmias as well as AV block are common with involvement of conduction and pacemaker tissues. Angina and syncopal episodes are possible, however, uncommon. RCM manifestation is very alike to that of constrictive pericarditis. The presentation of RCM is often heterogeneous and the diagnosis should not be suspected based on patient's complaints only.

There is a variety of findings characteristically for RCM on physical exam. Auscultation may reveal a quiet pericardium, pulmonary crackles due to pulmonary hypertension and rapid carotid pulse with low volume. The distention of neck veins will be prominent and have a rapid "y" descent. An additional 4th heart sound is found in most of the cases, while 3rd heart sound may or may not be heard and should be distinguished from constrictive pericarditis precordial knock. Murmur may be present from the mitral or tricuspid regurgitation caused by extensive fibrosis or infiltration of endocardium, hordae and ventricular walls. The absence of pulsus paradoxus helps to differentiate RCM from constrictive pericarditis.

Patients may complain about chest pain due to compression of small vessels. The pain may mimic angina pectoris or myocardial ischemia. This is particularly common in patients with amyloidosis. Palpitations caused by atrial fibrillation is another common complaint of patients with RCM.

An abdominal exam may reveal distention and ascites as well as tenderness of the liver or generalized abdominal discomfort.

In adults and adolescents the most common complaint is exertional dyspnea (71% of cases). In children the most common reason for consulting a cardiologist is pulmonary causes with cardiomegaly (47% of cases), followed by abnormal findings on a physical exam (either a murmur, gallop rhythm, edema, ascites or hepatomegaly). Other symptoms such as palpitations, fatigue, chest pain and syncope comprise only up to 9% of cases in the pediatric practice.

The initial work-up for patients with restrictive cardiomyopathy should include electrocardiogram (ECG), chest X-ray and echocardiography.

The ECG will most likely show nonspecific findings in the ST segment and T-waves. Sometimes pathological Q-waves not related to previous myocardial infarction may be observed. Left ventricular hypertrophy will be prominent on the ECG if the compensatory hypertrophy events took place in the myocardium.

The chest x-ray usually shows normal or slightly decreased size of the heart, however, may reveal an enlarged shadow in late-stage cases of amyloidosis and hemochromatosis.

Echocardiography may demonstrate normal systolic function of the heart. However, the dilatation of the atria and hypertrophy of the myocardium are quite common. In amyloidosis there may be an increase in image brightness pattern on echocardiography. Echocardiography is crucial for differential diagnosis with constrictive pericarditis which may show a specific finding of thickened pericardium. Paradoxical septal motion is also a common finding, however, may be present in both RCM and constrictive pericarditis.

More complex imaging studies such as computed tomography (CT) and magnetic resonance imaging (MRI) may be used if the precise diagnosis is challenging. CT may detect pericardial abnormalities, whereas MRI has proven to reveal specific textures in myocardium in the infiltrating conditions such as amyloidosis and hemochromatosis. 

Other procedures such as cardiac catheterization, myocardial biopsy and coronary angiography are rarely done.

On cardiac catheterization a RCM would manifest as atrial hypertension with elevated plateau in the ventricular pressure curve. Unlike constrictive pericarditis, RCM will often show an increase in few mm Hg of pressure in left ventricle compared to right.

Angiography will show normal size of ventricles and normal or lowered systolic shortening. AV valve involvement may result in prominent regurgitation. Coronary arteries are usually normal and may be rarely affected in cases of amyloidosis with epicardial arteries involvement.

Myocardial biopsy may reveal pathological processes within the tissues: endocardial fibrosis and thickening and infiltration by amyloid or iron.

All patients with suspected RCM should undergo tests for the possible causes, such as rectal biopsy, liver biopsy and iron studies.

So far no effective treatment strategy has been developed [8]. Treatment is mostly supportive and usually consists of medical regimen of diuretics and other antihypertensive drugs as well as anticoagulation therapy [9]. Several surgical procedures may be considered as options for various groups of patients. 

Diuretics are helpful to reduce the peripheral edema and congestion of pulmonary circulation. A decreased preload may be one of the possible side effects to consider with diuretics use. Preload is a huge factor in maintaining cardiac output in patients with impaired ventricle compliance.

β-blockers or Ca-channel blockers are used in low doses to control the heart rate and arrhythmias. Digoxin use is strongly discouraged, as it may cause fatal arrhythmias and hemodynamic instability in patients with cardiomyopathy, who are prone to increased digitalis sensitivity. Nitrates and other afterload reducers should also be excluded because of possible severe hypotension.

Of surgical procedures, septal myectomy or ablation are recommended. Implantation of the pacemaker may be the other choice for patients who do not wish to proceed with invasive surgery. Implantation of defibrillators may be effective in preventing younger patients from having a sudden cardiac death.

Cardiac transplantation is rarely performed as the RCM often recurs in the donor's heart as well. It may only be considered in patients with highly refractory symptoms and idiopathic causes of RCM.

The causing conditions should be treated as their management may positively affect the course of RCM. This has been proven to be especially effective in cases of early diagnosis and appropriate intervention. Loeffler endocarditis is treated with corticosteroids. Hemochromatosis therapy includes phlebotomy and chelation agents. Amyloidosis is managed with chemotherapy.

Prognosis is usually poor. Most of the cases are diagnosed at late stages and there is no treatment available. The course may vary in severity and relies on adequacy of supportive and symptomatic treatment. Progressive worsening is usually inevitable. In children RCM has worse prognosis when there is prominent heart failure, with a mortality of 50% in the first 2 years of the diagnosis [7]. Adults usually have a more prolonged course. 

The exact etiology of restrictive cardiomyopathy is unknown. RCM is further divided into primary and secondary, relying on the presumed underlying cause.

Primary RCM comprises the cardiomyopathy resulting from idiopathic causes, genetic predisposition or sporadic causes. Primary RCM only affects the myocardium layer and does not involve other tissues.

Secondary RCM is most commonly a result of systemic infiltrative disorders such as amyloidosis and sarcoidosis, metabolic storage diseases such as hemochromatosis, glycogen storage diseases and Fabry disease. Secondary RCM may also rise from severe inflammatory conditions such as Loeffler cardiomyopathy, endomyocardial fibrosis (EMF), and eosinophilic endomyocardial disease [4].

Particular association has been found for secondary RCM and diseases affecting various organs and tissues such as amyloidosis and hemochromatosis. Myocardial infiltration in these may also extend into other layers of cardiac tissues and even coronary arteries. Sarcoidosis and Fabry disease can infiltrate the nodal conduction region. Loeffler syndrome is a hypereosinophillic syndrome with major cardiac involvement and characterized by thrombosis of endocardium, acute arteritis and progressive fibrosis. Endocardial fibroelastosis has been linked only with left ventricular lesion.

Idiopathic cases of RCM are mostly reported from United States. There is some data stating that the majority of cases of Loeffler endocarditis develop in the temperate climate zone, whereas chronic EMF is more common in tropical and subtropical zones such as Uganda and Nigeria [5]. It is more common in children and young adults. RCM may accounts for as much as one fourth of mortality cases from cardiac conditions in these countries.

The pathophysiology of RCM comprises the gradual thickening and infiltration of myocardium with subsequent myocyte apoptosis, infiltration of papillary muscles, compensatory hyperthrophy and eventually fibrosis. It can be idiopathic or due to systemic diseases [4] [6]. The process may occur uni- or bilaterally in right, left or both ventricles and may affect the tricuspid and mitral valves causing regurgitant malfunction. The regurgitation may be due to infiltration of myocardium or thickening of endocardium. The lesion may extend into nodal and conduction systems within the heart leading to sinoatrial damage and subsequent AV blockage of different severity.

The anatomical changes lead to hemodynamic dysfunction. The main systemic manifestation is diastolic heart failure because of rigidity and noncompliance of ventricle(s). The disruption of diastolic filling (increased in early diastole and ends early at the end of the filling phase) and high filling pressure result in pulmonary hypertension. Compensatory mechanisms involve the hypertrophy of the myocardium, however, they may pose inadequate and lead to systolic dysfunction. Later, there can be a predisposition to systemic emboli due to formation of thrombi on the ventricle walls.

Preventive measures should be focused on lifestyle modification. Salt intake should be limited to decrease the hemodynamic load on lungs and peripheral circulation. Exercise should be moderated and frequently interrupted for time of rest. The intensity should be gradually increased over time to develop endurance and stamina.

Restrictive cardiomyopathy (RCM) is a cardiac condition characterized by increased stiffness of the heart ventricles, resulting in impaired filling of the ventricular chamber during diastole. Most cases of RCM lead to severe heart failure [1].

The etiology of RCM is unknown. The disease can be idiopathic and secondary to systemic diseases such as amyloidosis, hemochromatosis, Fabry disease, Loffler syndrome and other conditions.

From pathophysiological point of view, RCM is a progressive thickening and infiltration of myocardium of the ventricles. The process can occur in one or both ventricles simultaneously and may even involve valves leading to regurgitant lesions as well conductive system of the heart and cause arrhythmias. Hemodynamic changes comprise diastolic heart failure due to rigidity and noncompliance of ventricles. Later in the disease course, compensatory hypertrophy and systolic dysfunction may arise.

RCM usually presents with shortness of breath, progressive exercise intolerance, fatigue, peripheral edema and other signs of heart failure. Other possible symptoms include arrhythmias, syncopal episodes, chest pain and ascites with liver tenderness.

Treatment is focused on managing of symptoms and supportive care. Symptoms of pulmonary congestion and edema are managed with antihypertensive drugs such as diuretics. Heart rate is controlled with β-blockers or Ca-channel blockers. A few surgical procedures are available.

Prognosis is usually poor [2] [3].

Restrictive cardiomyopathy (RCM) is a disease of the heart in which the walls of the heart ventricles become stiff and unable to dilate when the blood comes from the body vessels. This results in impaired filling of the heart and leads to heart failure. The disease may appear on its own or may be caused by other serious conditions, such as amyloidosis or hemochromatosis, in which abnormal compounds deposit in the body tissues.

Patients with RCM may feel short of breath, especially when exercising. The shortness of breath will gradually worsen with the disease progressing. Patients also frequently feel general fatigue and malaise due to inability of the heart to pump the blood normally through the body. Due to congestion of blood in the vessels patients may experience a distended belly and swelling of the legs. Other less common symptoms include chest pain, fainting and sensation of abnormal heartbeats.

Doctors use several tests to diagnose this condition. Electrocardiography detects electric activity of the heart and reveals any abnormalities in it. Echocardiography examines the heart structure and may detect stiff walls of the ventricles. Chest x-ray may also be performed.

Treatment is focused on reversing the heart failure by unloading the body of excessive fluids with the help of diuretics and other antihypertensive medications. Several surgical procedures are available such as a mechanical pacemaker, or a  heart transplantation, however, this disease is very difficult to treat.

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