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Introduction

Ischaemic Heart Disease, otherwise known as Coronary Artery Disease, is a condition that affects the supply of blood to the heart. The blood vessels are narrowed or blocked due to the deposition of cholesterol plaques on their walls. This reduces the supply of oxygen and nutrients to the heart musculature, which is essential for proper functioning of the heart. This may eventually result in a portion of the heart being suddenly deprived of its blood supply leading to the death of that area of heart tissue, resulting in a heart attack.

As the heart is the pump that supplies oxygenated blood to the various vital organs, any defect in the heart immediately affects the supply of oxygen to the vital organs like the brain, kidneys etc. This leads to the death of tissue within these organs and their eventual failure or death. Ischaemic Heart Disease is the most common cause of death in several countries around the world.

Cause and Pathogenesis

A multitude of factors are responsible for the development of Ischaemic Heart Disease. The major risk factors are smoking, diabetes mellitus and cholesterol levels. Those with Hypercholesterolaemia (elevated blood levels of cholesterol) have a much higher tendency to develop the disease. There is also the theory that Hypertension is a risk factor in the development of Ischaemic Heart Disease, Genetic and hereditary factors may also be responsible for the disease. Males are more prone to Ischaemic Heart Disease. However, in post-menopausal women, the risk is almost similar to that of men. Stress is also thought to be a risk factor, though there has been a great deal of debate on this factor of late. The disease process occurs when an atheromatous plaque forms in the coronary vessels, leading to narrowing of the vessel walls and obstructing blood flow to the musculature of the heart. Complete blockage results in deficient oxygenation and nutrient supply to the heart tissues, leading to damage, death and necrosis of the tissue, which is known as Myocardial Infarction (heart attack).

Symptoms and Signs

Quite often, the first sign of Ischaemic Heart Disease may be the severe chest pain of Myocardial Infarction, which may be fatal. However, the warning symptoms occur in a large number of patients in the form of Angina Pectoris. The main symptom of Angina is pain over the central chest that may sometimes radiate down the left arm, to the jaw or to the back. The characteristic feature of the pain is that it is usually aggravated by exercise and relieved by rest, though variant forms may occur. The pain is also relieved by the use of nitrates kept under the tongue. The pain is usually described as a sense of compression or tightness in the middle of the chest, and may last for five to twenty minutes. The pain may be accompanied by sweating. The presence of anginal episodes is virtually diagnostic of Ischaemic Heart Disease.

Other signs that can be observed on clinical examination is the presence of Tendon Xanthomas, thickening of the Achilles Tendon and Arcus Lipidus in young patients, all of which may indicate a hereditary Hyperlipdaemia. The patient should also be examined for anaemia, obesity, diabetes, thyroid and peripheral vascular disease.

Investigations and Diagnosis

Electrocardiography (ECG) may be normal in several patients at rest between attacks of Angina. However, during the episodes of pain there may be depression of the ST segment and a T wave inversion in several leads, indicating Ischaemia. In cases of Infarction (heart attack), there will be ST segment elevation in the ECG, which may gradually evolve. An Echocardiogram may help in showing any functional abnormalities in the various cardiac chambers and in assessing the pumping efficiency of the heart. An exercise testing (Treadmill Test-TMT) is often indicated in patients who have symptoms but have normal ECG patterns. Nowadays, TMT is being indicated in all high-risk categories beyond the age of 35 irrespective of symptoms. Myocardial perfusion scanning with radioactive thallium may also be helpful in the diagnosis. Coronary Angiogram provides accurate information about the actual site and extent of the stenosis (narrowing) and helps in deciding the method of therapy required.

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What is atherosclerosis?

Atherosclerosis (ath”er-o-skleh-RO’sis) comes from the Greek words athero (meaning gruel or paste) and sclerosis (hardness). It’s the name of the process in which deposits of fatty substances, cholesterol, cellular waste products, calcium and other substances build up in the inner lining of an artery. This buildup is called plaque. It usually affects large and medium-sized arteries. Some hardening of arteries often occurs when people grow older.

Plaques can grow large enough to significantly reduce the blood’s flow through an artery. But most of the damage occurs when they become fragile and rupture. Plaques that rupture cause blood clots to form that can block blood flow or break off and travel to another part of the body. If either happens and blocks a blood vessel that feeds the heart, it causes a heart attack. If it blocks a blood vessel that feeds the brain, it causes a stroke. And if blood supply to the arms or legs is reduced, it can cause difficulty walking and eventually lead to gangrene.

How does atherosclerosis start?

Atherosclerosis is a slow, complex disease that typically starts in childhood and often progresses when people grow older. In some people it progresses rapidly, even in their third decade. Many scientists think it begins with damage to the innermost layer of the artery. This layer is called the endothelium (en”do-THE’le-um). Causes of damage to the arterial wall include:

• elevated levels of cholesterol and triglyceride (tri-GLIS’er-id) in the blood
• high blood pressure
• tobacco smoke
• diabetes

Tobacco smoke greatly worsens atherosclerosis and speeds its growth in the coronary arteries, the aorta and arteries in the legs. (The coronary arteries bring blood to the heart muscle; the aorta is the large vessel that the heart pumps blood through to the body.)

Because of the damage to the endothelium, fats, cholesterol, platelets, cellular waste products, calcium and other substances are deposited in the artery wall. These may stimulate artery wall cells to produce other substances that result in further buildup of cells.

These cells and surrounding material thicken the endothelium significantly. The artery’s diameter shrinks and blood flow decreases, reducing the oxygen supply. Often a blood clot forms near this plaque and blocks the artery, stopping the blood flow.

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Cardiovascular disease

Cardiovascular disease is any of a number of specific diseases that affect the heart itself and/or the blood vessel system, especially the veins and arteries leading to and from the heart. Research on disease dimorphism suggests that women who suffer with cardiovascular disease usually suffer from forms that affect the blood vessels while men usually suffer from forms that affect the heart muscle itself. Known or associated causes of cardiovascular disease include diabetes mellitus, hypertension, hyperhomocysteinemia and hypercholesterolemia.

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What Is Restrictive Cardiomyopathy?

A restrictive cardiomyopathy, the rarest form of cardiomyopathy, is a condition in which the walls of the lower chambers of the heart (the ventricles) are abnormally rigid and lack the flexibility to expand as the ventricles fill with blood.

What Are the Symptoms of Restrictive Cardiomyopathy?

Many people with restrictive cardiomyopathy have no symptoms or only minor symptoms, and live a normal life. Other people develop symptoms, which progress and worsen as heart function worsens.

Symptoms can occur at any age and may include:

* Chest pain or pressure (occurs usually with exercise or physical activity, but can also occur with rest or after meals).
* Heart failure symptoms (shortness of breath and fatigue).
* Swelling of the lower extremities.
* Fatigue (feeling overly tired).
* Weight gain
* Fainting (caused by irregular heart rhythms, abnormal responses of the blood vessels during exercise, or no cause may be found).
* Palpitations (fluttering in the chest due to abnormal heart rhythms).

What Causes Restrictive Cardiomyopathy?

A restrictive cardiomyopathy is not usually inherited and its cause is often unknown. Known causes may include:

• Build-up of fat and proteins (amyloidosis) in the heart muscle.
• Excess of iron (hemochromatosis) in the heart.
• Chest exposure to radiation.
• Connective tissue diseases or various other illnesses.
• Build up of scar tissue after a heart attack.

How is Restrictive Cardiomyopathy Diagnosed?

Restrictive cardiomyopathy is diagnosed based on medical history (your symptoms and family history), physical exam, and tests: such as blood tests, electrocardiogram , chest X-ray , echocardiogram , exercise stress test , cardiac catheterization , CT scan , MRI and radionuclide studies ( Multigated Acquisition Scan ).

Another test often done to determine the cause of a cardiomyopathy is a myocardial biopsy where a tissue sample is taken from the heart to examine the cause of the symptoms.

How is Restrictive Cardiomyopathy Treated?

Treatment of this condition is difficult. Treatment is usually focused on treating the cause of this condition. Doctors recommend lifestyle changes and medications to treat heart failure .

What Lifestyle Changes Are Recommended?

Diet. Once you have symptoms such as shortness of breath or fatigue, you should restrict your intake of salt (sodium) to 2,000 to 3,000 mg per day. Follow this diet even when your symptoms abate.

Exercise. Your doctor will tell you if you may exercise or not. While exercise is generally good for the heart, people with this cardiomyopathy may experience fatigue and shortness of breath, even with minimal exertion. Therefore, experts recommend that you take frequent breaks, exercise at a time of day where you have the most energy and start slow, gradually building up strength and endurance. Heavy weight lifting is not recommended.

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Arrhythmogenic right ventricular dysplasia (ARVD, also known as arrhythmogenic right ventricular cardiomyopathy or ARVC) is a type of nonischemic cardiomyopathy that involves primarily the right ventricle. It is characterized by hypokinetic areas involving the free wall of the right ventricle, with fibrofatty replacement of the right ventricular myocardium, with associated arrhythmias originating in the right ventricle.

Overview

ARVD is an important cause of ventricular arrhythmias in children and young adults. It is seen predominantly in males, and 30-50% of cases have a familial distribution. It is usually inherited in an autosomal dominant pattern, with variable expression. The penetrance is 20-35% in general, but significantly higher in Italy. Seven gene loci have been implicated in ARVD. However, about 50% of families that express ARVD that undergo genetic screening do not show linkage with any of the known chromosomal loci. It is unclear whether the pathogenesis varies with the different loci involved. A standard genetic screening test is not available.

Naxos Disease

Naxos disease is an autosomal recessive variant of ARVD, described initially on the Greek island of Naxos. There, the penetrance is >90%. It involves the gene that codes for plakoglobin (a protein that is involved in cellular adhesion), on chromosome 17p. Naxos disease is described as a triad of ARVD, palmoplantar keratosis, and wooly hair. The signs of Naxos disease are more severe than with autosomal dominant ARVD.

Incidence

The incidence of ARVD is about 1/10,000 in the general population in the United States, although some studies have suggested that it may be as common as 1/1,000. It accounts for up to 17% of all sudden cardiac deaths in the young. In Italy, the incidence is 40/10,000, making it the most common cause of sudden cardiac death in the young population.

Presentation

Up to 80% of individuals with ARVD present with syncope or sudden cardiac death. The remainder frequently present with palpitations or other symptoms due to right ventricular outflow tract (RVOT) tachycardia (a type of monomorphic ventricular tachycardia).

Symptoms are usually exercise-related. In populations where hypertrophic cardiomyopathy is screened out prior to involvement in competitive athletics, it is a common cause of sudden cardiac death.

The first clinical signs of ARVD are usually during adolescence. However, signs of ARVD have been demonstrated in infants.

Pathogenesis

The pathogenesis of ARVD is largely unknown. Apoptosis (programmed cell death) appears to play a large role. It is unclear why only the right ventricle is involved. The disease process starts in the subepicardial region and works its way towards the endocardial surface, leading to transmural involvement (possibly accounting for the aneurysmal dilatation of the RV). Residual myocardium is confined to the subendocardial region and the trabeculae of the RV. These trabeculae may become hypertrophied.

Aneurysmal dilatation is seen in 50% of cases at autopsy. It usually occurs in the diaphragmatic, apical, and infundibular regions (known as the triangle of dysplasia). The left ventricle is involved in 50-67% of individuals. If the left ventricle is involved, it is usually late in the course of disease, and confers a poor prognosis.

There are two pathological patterns seen in ARVD, Fatty infiltration and fibro-fatty infiltration.

Fatty infiltration

The first, fatty infiltration, is confined to the right ventricle. This involves a partial or near-complete substitution of myocardium with fatty tissue without wall thinning. It involves predominantly the apical and infundibular regions of the RV. The left ventricle and ventricular septum are usually spared. No inflammatory infiltrates are seen in fatty infiltration. There is evidence of myocyte (myocardial cell) degeneration and death seen in 50% of cases of fatty infiltration.

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Hypertrophic cardiomyopathy, or HCM, is a disease of the myocardium (the muscle of the heart) in which a portion of the myocardium is hypertrophied (thickened) without any obvious cause. Though perhaps most famous as a leading cause of sudden cardiac death in young athletes. The occurrence of hypertrophic cardiomyopathy is a significant cause of sudden unexpected cardiac death in any age group and as a cause of disabling cardiac symptoms.

A cardiomyopathy is a disease that primarily affects the muscle of the heart. With hypertrophic cardiomyopathy (HCM), the normal alignment of muscle cells is disrupted, a phenomenon known as myocardial disarray. HCM also causes disruptions of the electrical functions of the heart. HCM is believed to be due to a mutation in one of many genes that results in a mutated myosin heavy chain, one of the components of the myocyte (the muscle cell of the heart). Depending on whether the distortion of normal heart anatomy causes an obstruction of the outflow of blood from the left ventricle of the heart, HCM can be defined as obstructive or non-obstructive. The obstructive variant of HCM, Hypertrophic obstructive cardiomyopathy (HOCM) has also historically been known as idiopathic hypertrophic subaortic stenosis (IHSS) and asymmetric septal hypertrophy (ASH). Another, non-obstructive variant of HCM is apical hypertrophic cardiomyopathy, first described in individuals of Japanese descent.

While most literature so far focuses on European, American, and Japanese populations, HCM appears in all racial groups. The incidence of HCM is about 0.2% to 0.5% of the general population.

Genetics

Hypertrophic cardiomyopathy is inherited as an autosomal dominant trait and is attributed to mutations in one of a number of genes that encode for one of the sarcomere proteins including beta-cardiac myosin heavy chain (the first gene identified), cardiac actin, cardiac troponin T, alpha-tropomyosin, cardiac troponin I, cardiac myosin-binding protein C, and the myosin light chains. Currently there are more than 400 mutations in these genes. Approximately 45% of these mutations occur in the β myosin heavy chain gene on chromosome 14 q11.2-3, while approximately 35% involve the cardiac myosin binding protein C gene. The prognosis is variable, based on the gene mutation. In individuals without a family history of HCM, the most common cause of the disease is a de novo mutation of the gene that produces the β-myosin heavy chain.

An insertion/deletion polymorphism in the gene encoding for angiotensin converting enzyme (ACE) alters the clinical phenotype of the disease. The D/D (deletion/deletion) genotype of ACE is associated with more marked hypertrophy of the left ventricle and may be associated with higher risk of adverse outcomes.

Anatomic characteristics

Individuals with HCM have some degree of left ventricular hypertrophy. Usually this is an asymmetric hypertrophy, involving the inter-ventricular septum, and is known as asymmetric septal hypertrophy (ASH). This is in contrast to the concentric hypertrophy seen in aortic stenosis or hypertension. About two-thirds of individuals with HCM have asymmetric septal hypertrophy.

About 25% of individuals with HCM demonstrate an obstruction to the outflow of blood from the left ventricle during rest. In other individuals obstruction only occurs under certain conditions. This is known as dynamic outflow obstruction, because the degree of obstruction is variable and is dependent on the amount of blood in the ventricle immediately before ventricle systole (contraction).

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Dilated cardiomyopathy or DCM, also known as congestive cardiomyopathy, is a condition in which the heart becomes weakened and enlarged, and cannot pump blood efficiently. The decreased heart function can affect the lungs, liver, and other body systems.

DCM is one of the cardiomyopathies, a group of diseases that primarily affect the myocardium (the muscle of the heart). Different cardiomyopathies have different causes, and affect the heart in different ways. In DCM a portion of the myocardium is dilated, often without any obvious cause. Left and/or right ventricular systolic pump function of the heart is impaired, leading to progressive cardiac enlargement and hypertrophy, a process called remodeling.

Dilated cardiomyopathy is the most common form of cardiomyopathy. It occurs more frequently in men than in women, and is most common between the ages of 20 and 60 years. About one in three cases of congestive heart failure (CHF) is due to dilated cardiomyopathy. Dilated cardiomyopathy also occurs in children.

Causes

Although no cause (etiology) is apparent in many cases, dilated cardiomyopathy is probably the end result of damage to the myocardium produced by a variety of toxic, metabolic, or infectious agents. It may be the late sequel of acute viral myocarditis, possibly mediated through an immunologic mechanism. Autoimmune mechanisms are also suggested as a cause for dilated cardiomyopathy. A reversible form of dilated cardiomyopathy may be found with alcohol abuse, pregnancy (peripartum cardiomyopathy), thyroid disease, stimulant use, and chronic uncontrolled tachycardia. Many cases of dilated cardiomyopathy are described as idiopathic - meaning that the cause is unknown.

Genetics

About 20-40% of patients have familial forms of the disease, with mutations of genes encoding cytoskeletal, contractile, or other proteins present in myocardial cells. The disease is genetically heterogeneous, but the most common form of its transmission is an autosomal dominant pattern. Autosomal recessive, as found, for example, in Alström syndrome, X-linked, and mitochondrial inheritance of the disease is also found.Relatives of dilated cardiomyopathy patients have been found to show preclinical, asymptomatic heart-muscle changes.

Although the disease is more common in African-Americans than in whites, it may occur in any patient population.

Associated symptoms

For many affected individuals, dilated cardiomyopathy is a condition which will not limit the quality or duration of life. A minority, however, experience significant symptoms and there is sometimes a risk of sudden death. Evaluation by a cardiologist is recommended to confirm the diagnosis and to assess the outlook and particularly the risk of complications. In some patients symptoms of left- and right-sided congestive heart failure develop gradually. Left ventricular dilatation may be present for months or even years before the patient becomes symptomatic.

Vague chest pain may be present, but typical angina pectoris is unusual and suggests the presence of concomitant ischemic heart disease. Syncope due to arrhythmias, and systemic embolism may occur.

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Cardiomyopathy,which literally means “heart muscle disease,” is the deterioration of the function of the myocardium (i.e., the actual heart muscle) for any reason. People with cardiomyopathy are often at risk of arrhythmia or sudden cardiac death or both.

Cardiomyopathies can generally be categorized into two groups, based on World Health Organization guidelines: extrinsic cardiomyopathies and intrinsic cardiomyopathies.

Extrinsic cardiomyopathies

These are cardiomyopathies where the primary pathology is outside the myocardium itself. Most cardiomyopathies are extrinsic, because by far the most common cause of a cardiomyopathy is ischemia. The World Health Organization calls these specific cardiomyopathies:

* Coronary artery disease
* Congenital heart disease
* Nutritional diseases
* Ischemic (or ischaemic) cardiomyopathy
* Hypertensive cardiomyopathy
* Valvular cardiomyopathy
* Inflammatory cardiomyopathy
* Cardiomyopathy secondary to a systemic metabolic disease
* Alcoholic cardiomyopathy
* Diabetic cardiomyopathy

Ischemic cardiomyopathy

Ischemic cardiomyopathy is a weakness in the muscle of the heart due to inadequate oxygen delivery to the myocardium with coronary artery disease being the most common cause. Anemia and sleep apnea are relatively common conditions that can contribute to ischemic myocardium and hyperthyroidism can cause a ‘relative’ ischemia secondary to high output heart failure. Individuals with ischemic cardiomyopathy typically have a history of myocardial infarction (heart attack), although longstanding ischemia can cause enough damage to the myocardium to precipitate a clinically significant cardiomyopathy even in the absence of myocardial infarction. In a typical presentation, the area of the heart affected by a myocardial infarction will initially become necrotic as it dies, and will then be replaced by scar tissue (fibrosis). This fibrotic tissue is akinetic; it is no longer muscle and cannot contribute to the heart’s function as a pump. If the akinetic region of the heart is substantial enough, the affected side of the heart (i.e. the left or right side) will go into failure, and this failure is the functional result of an ischemic cardiomyopathy.

Cardiomyopathy due to systemic diseases

Many diseases can result in cardiomyopathy. These include diseases like hemochromatosis, (an abnormal accumulation of iron in the liver and other organs), amyloidosis (an abnormal accumulation of the amyloid protein), diabetes, hyperthyroidism, lysosomal storage diseases and the muscular dystrophies.

Intrinsic cardiomyopathies

An intrinsic cardiomyopathy is weakness in the muscle of the heart that is not due to an identifiable external cause. To make a diagnosis of an intrinsic cardiomyopathy, significant coronary artery disease should be ruled out (amongst other things). The term intrinsic cardiomyopathy does not describe the specific etiology of weakened heart muscle. The intrinsic cardiomyopathies are a mixed-bag of disease states, each with their own causes.

Intrinsic cardiomyopathy has a number of causes including drug and alcohol toxicity, certain infections (including Hepatitis C), and various genetic and idiopathic (i.e., unknown) causes.

Intrinsic cardiomyopathies are generally classified into four types,[2][3] but additional types are also recognized:

* Dilated cardiomyopathy (DCM), the most common form, and one of the leading indications for heart transplantation. In DCM the heart (especially the left ventricle) is enlarged and the pumping function is diminished. Approximately 40% of cases are familial, but the genetics are poorly understood compared with HCM. In some cases it manifests as peripartum cardiomyopathy, and in other cases it may be associated with alcoholism.
* Hypertrophic cardiomyopathy (HCM or HOCM), a genetic disorder caused by various mutations in genes encoding sarcomeric proteins. In HCM the heart muscle is thickened, which can obstruct blood flow and prevent the heart from functioning properly.
* Arrhythmogenic right ventricular cardiomyopathy (ARVC) arises from an electrical disturbance of the heart in which heart muscle is replaced by fibrous scar tissue. The right ventricle is generally most affected.
* Restrictive cardiomyopathy (RCM) is an uncommon cardiomyopathy. The walls of the ventricles are stiff, but may not be thickened, and resist the normal filling of the heart with blood. A rare form of restrictive cardiomyopathy is the obliterative cardiomyopathy, seen in the hypereosinophilic syndrome. In this type of cardiomyopathy, the myocardium in the apices of the left and right ventricles becomes thickened and fibrotic, causing a decrease in the volumes of the ventricles and a type of restrictive cardiomyopathy.
* Noncompaction cardiomyopathy has been recognized as a separate type since the 1980s. The term refers to a cardiomyopathy where the left ventricle wall has failed to grow properly from birth and has a spongy appearance when viewed during an echocardiogram.

Signs and symptoms Cardiomyopathy is usually found incidentally - “case finding” - by healthcare professionals during a routine checkup. The only test for hypertension is a blood pressure measurement. Hypertension in isolation usually produces no symptoms although some people report headaches, fatigue, wanting to sleep more than usual, dizziness, blurred vision, facial flushing or tinnitus.

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Diagnosis and treatment of patients with virus induced inflammatory cardiomyopathy

U.Kühl,M.Pauschinger,M. Noutsias,J.-F.Kapp and H.-P.Schultheiss

* Department of Cardiology and Pneumonology, Medical Clinic II, Department of Cardiology, University Hospital Benjamin Franklin, Free University of Berlin, Berlin, Germany
b Schering AG, Spezial Therapeutika, Berlin, Germany

* Correspondence: Uwe Kühl, PhD, University Hospital Benjamin Franklin, Department of Cardiology and Pneumonology, Free University of Berlin, Hindenburgdamm 30, D-12200 Berlin, Germany.

Abstract

Chronic viral induced inflammatory cardiomyopathy causes progression of left ventricular dysfunction and is an important cause of dilated cardiomyopathy. Despite of the progress made in heart failure therapy, mortality of dilated cardiomyopathy is still 10% per year. Current heart failure therapy is symptomatic and does not impact on the specific underlying pathogenic mechanisms. Thus, specific treatment strategies that are directed against the underlying pathogenetic causes are required if myocarditis and its sequela, namely inflammatory cardiomyopathy, are to be successfully treated. Because histological and, especially, clinical diagnosis is fraught with numerous problems, an aetiological classification based on histology, immunohistochemistry and molecular biology is favourable, particularly in view of the improvements in methods made in recent years. The combination of these diagnostic techni-ques allows a new classification of dilated cardiomyo-pathy by differentiating the disease entity in subgroups of virus positive and virus negative patients with or without cardiac inflammation. This may not only contribute toward improving our understanding of underlying pathological mechanisms, but ultimately may also assist in developing specific immunomodulatory treatments. Preliminary results from ongoing treatment trials suggest that specific antiviral or anti-inflammatory treatment strategies are successful in patients who have been carefully selected and characterized according to biopsy-based diagnostic criteria.

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