Arrhythmogenic right ventricular dysplasiaDescription, Causes and Risk Factors:Abbreviation: ARVD.Arrhythmogenic right ventricular dysplasia is a disorder that affects the muscles of the heart. The heart is divided into four chambers: the right ventricle, left ventricle, right atrium, and left atrium. In patients with ARVD, the right ventricle or left ventricle (the chambers responsible for pumping blood to the lungs or other parts of the body) may be affected. Patients with ARVD undergo a progressive deterioration of muscle in the ventricle, and the muscle is replaced by fat and scar tissue. Due to the deterioration of heart muscle, patients with arrhythmogenic right ventricular dysplasia typically experience arrhythmias, which are abnormal heart rhythms. Arrhythmia can lead to a speeding up or slowing down of the heart. If the arrhythmia is more severe, it can affect the ability of the heart to pump blood, which might result in lightheadedness, fainting, or chest pain.In some cases, ARVD may result in sudden death if the heart is not able to pump enough blood to its own muscles, lungs, and the rest of the body. However, sudden death in patients with ARVD is not very common. Patients with ARVD who are under 35 and athletic are at the highest risk for sudden death. It is often recommended that patients with ARVD do not overexert themselves when exercising.Arrhythmogenic right ventricular dysplasia affects about one in 5,000 people. It can affect both men and women, but it is more common in men.Several gene mutations have been associated with ARVD. Individuals who inherit mutant copies of these genes are at greater risk for developing ARVD. In some cases, only one mutated gene copy (from either the mother or the father) needs to be inherited to put an individual at an increased risk for developing the condition. Scientists have found that inheriting one of these defective genes does not always cause Arrhythmogenic right ventricular dysplasia to develop. Therefore, they believe that a combination of genes, as well as other environmental factors (for example, exercise or diet), may influence the development of ARVD. In some cases, two copies (one from the mother and one from the father) need to be inherited in order for the disease to develop.Plakophilin-2 (PKP2), which functions in the development and organization of the heart, is one gene that has been identified in ARVD. Most genes that have been linked to ARVD, such as plakophilin-2, appear to be important for the adhesion of cells in the heart to each other. Other genes linked to arrhythmogenic right ventricular dysplasia include plakoglobin and desmoplakin. However, the specific mechanism by which the mutation of these genes leads to ARVD is not known.Some evidence suggests that viral infection may also lead to arrhythmogenic right ventricular dysplasia. Viral infection of the heart may lead to a heightened immune response against the wall of the heart, which may eventually lead to deterioration and ARVD. Adenovirus and Coxsackievirus have been found in patients with ARVD and may be involved in causing the disease in some cases.There is currently no cure for arrhythmogenic right ventricular dysplasia, but a number of options exist to treat the condition. Some options include medications that can reduce the occurrence of arrhythmias and a device called an implantable cardioverter defibrillator. A cardioverter defibrillator can be implanted in a patient's chest. It uses small electric shocks to reduce the severity of arrhythmias.Symptoms:Symptoms of ARVD are rarely seen in infants or young children. Symptoms of ARVD generally appear in teenagers or adults.Patients with ARVD undergo a progressive deterioration of muscle in the ventricle and the muscle is replaced by fat and scar tissue. This may eventually lead to enlargement of the ventricles in the heart.Due to the deterioration of heart muscle, patients with ARVD typically experience arrhythmias, which are abnormal heart rhythms. Arrhythmia can lead to a slowing down of the heart, or a speeding up of the heart, which may feel like the heart is pounding or racing.If an arrhythmia is more severe, it can affect the ability of the heart to pump blood, which might cause lightheadedness, breathlessness, fainting, nausea, or dizziness.Chest pain (also called angina) may result when the heart's ability to pump blood becomes impaired. Chest pain usually results from a reduced flow of blood (ischemia) to heart muscle. In some cases, the chest pain may be severe and may feel like a heart attack.General Symptoms May Include:Abdominal pain.
Diagnosis:It is difficult to diagnose arrhythmogenic right ventricular dysplasia. There is no single test that can conclusively diagnose the condition. Diagnosis of ARVD is usually based on the results of a variety of different tests, which are described below.Electrocardiogram (ECG): ECG is a test that uses electrodes to measure the electrical activity of the heart. It can detect abnormal rhythms in the heart.
Echocardiogram: An echocardiogram uses sound waves to produce a moving picture of the heart. It is a noninvasive test that can be used to look at the chambers of the heart to see if there are any structural abnormalities (such as a thinning of the muscle or an enlargement of the ventricle) and to see if the heart is pumping normally.
Cardiac MRI: A cardiac MRI is a noninvasive imaging procedure that uses a magnetic field and radio waves to produce a detailed image of the heart. This test can be used to assess the structure of the heart in detail and check for any structural abnormalities in the ventricle.
Holter monitor: A Holter monitor is a device that has small electrodes attached to a recording monitor. The electrodes are kept attached to a patient's chest for a 24-hour period to record the electrical heart activity, and the recording monitor can be kept in the patient's pocket for ease. This can be used to detect any abnormalities in a patient's heart rhythm over a longer period of time. Patients wearing a Holter monitor usually keep a log of their activities, so that comparisons can be made between the level of physical activity and heart activity.
Exercise stress test: This is a test in which a patient walks on a treadmill. It can be used to determine what effect exercise has on a patient's heart and what level of exercise is appropriate for a patient. Because a patient's need for oxygen increases as more time is spent on the treadmill, the test can measure the reaction of the heart to this increased need. During the test, ECG is used to measure the electrical activity of the heart and blood pressure is also monitored. Abnormal results during the test may indicate that a patient is experiencing arrhythmias or increased stress on the heart.
Biopsy: If arrhythmogenic right ventricular dysplasia is suspected, a biopsy may be performed. In a biopsy, a small amount of the heart tissue is surgically removed and checked for physical signs of deterioration. Because heart deterioration can be patchy in ARVD, a biopsy may not always be able to detect the disease.
Genetic testing: Genetic testing exists to check for defects in some genes that have been linked to ARVD, such as plakophilin-2. Genetic testing is usually recommended for patients who have a family history of ARVD.
Key findings in diagnosis may include:T-wave inversions beyond lead V1.
Epsilon waves in leads V1-V3.
Abnormal electrical potentials in high-resolution (signal-averaged) ECG.
Ventricular premature beats with left bundle branch configuration.
Treatment:Currently, there is no known cure for arrhythmogenic right ventricular dysplasia. Treatment generally focuses on trying to reduce the symptoms, especially arrhythmia.Medications called antiarrhythmic agents have been developed that can reduce the severity and intensity of heart arrhythmias. A commonly used antiarrhythmic agent is called a beta-blocker, which blocks proteins located on the heart called beta receptors. Blocking beta receptors reduces the action of the hormone epinephrine, which results in a relaxed beating of the heart. Some common beta-blockers are atenolol (Tenormin®), bisoprolol (Zebeta®), metoprolol (Lopressor®), and carvedilol (Coreg®). Side effects of beta-blockers may include fatigue, cold hands and feet, and sleep disturbances. Another class of drugs, called ACE-inhibitors, may be used by some patients. ACE-inhibitors make it easier for the heart to pump blood by enlarging blood vessels and reducing blood pressure.Surgical Options:Surgical ablation: The specific area of the heart that has undergone deterioration may be surgically removed from a patient with arrhythmogenic right ventricular dysplasia. This procedure may be successful in treating arrhythmias caused by deterioration in a specific area. Because ARVD is a progressive disease, however, this is not considered a permanent cure.
Heart transplant: In very severe cases, a heart transplant may be used to treat ARVD. A heart transplant is often only performed after other treatments have been tried and found to be ineffective.
Preventive Measures:Patients with ARVD should avoid stimulants such as nicotine or caffeine, as these substances may increase the risk of arrhythmia.
It is often recommended that patients with ARVD do not overexert themselves when exercising. Too much exercise can increase the strain on the heart and may lead to sudden cardiac death. Patients should engage only in mild forms of exercise, all of which should be discussed with a doctor.
NOTE: The above information is for processing purpose. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition.DISCLAIMER: This information should not substitute for seeking responsible, professional medical care.
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