What Is Arrhythmogenic Right Ventricular Dysplasia?
Arrhythmogenic right ventricular cardiomyopathy (ARVC), also known as arrhythmogenic right ventricular dysplasia, is now represented by ARVD / C, which is characterized by the right ventricular myocardium being replaced by progressive fibrous adipose tissue, often clinically Ventricular enlargement, arrhythmia, and sudden death.
Basic Information
- nickname
- Arrhythmogenic right ventricular dysplasia
- English name
- arrhythmogenc right ventricular cardiomyopathy
- Visiting department
- Internal medicine
- Common locations
- heart
- Common causes
- Etiology unknown, related to heredity, individual developmental abnormality, degeneration or degeneration, inflammation
- Common symptoms
- Labor dyspnea, liver enlargement, lower limb edema, palpitations, fatigue, etc.
Causes of arrhythmogenic right ventricular cardiomyopathy
The cause of ARVC is currently poorly understood and may be related to the following factors:
Genetic factor
The occurrence of this disease is related to genetic factors, and family studies have found that ARVC is an autosomal dominant genetic disease. Nine different chromosomal dominant inheritances have been identified to be associated with the disease.
2. The theory of individual abnormal development
It is thought that the right ventricular disease is caused by congenital dysplasia of the right ventricle, which is morphologically characterized by a very thin wall of the right ventricle, which resembles a Uh1 deformed sheepskin-like appearance. More common in children or young adults. Those who support this view call ARVD / C a right ventricular dysplasia.
3. Degeneration or degeneration theory
Right ventricular myocardial disease is thought to be the result of progressive degeneration and necrosis of myocardial cells due to certain metabolic or ultrastructural defects. The disappearance of myocardial atrophy is similar to skeletal muscle atrophy of Duchenne muscular dystrophy and Becker's chronic progressive muscular dystrophy. The muscular atrophy characterized by progressive degeneration of skeletal muscle can be regarded as the corresponding disease of this disease.
4. Doctrine of inflammation
It is believed that the replacement of the myocardium by adipose tissue is the result of the development of the acquired damage (inflammation, necrosis) and repair process caused by chronic myocarditis. Animal experiments have confirmed that Coxsackie B3 virus and papaya virus can show the same changes when infected.
Clinical manifestations of arrhythmogenic right ventricular cardiomyopathy
Mainly manifested as congestive heart failure and / or arrhythmia. Some patients have insidious onset, manifested as symptoms of pulmonary circulation congestion such as labor dyspnea, and symptoms of systemic circulation congestion such as liver enlargement and lower limb edema. The patient's labor endurance gradually decreases and heart failure progresses progressively. In some patients, only the right heart failure is prominent in the early stage, and the symptoms and signs of systemic congestion appear. In the later stage, the heart disease progresses from right heart failure to bilateral ventricular total heart failure; most patients begin with bilateral ventricular involvement and progress. Aggravated total heart failure. Some patients have recurrent episodes of palpitations, fatigue, etc. ECG manifests as ventricular arrhythmias, such as ventricular premature beats, short-term ventricular tachycardia, supraventricular arrhythmias occasionally seen, and long-term recurrent episodes. Some patients have cardiac arrest and sudden death as their first symptoms. Examination revealed malignant arrhythmias such as persistent ventricular tachycardia, ventricular flutter, and ventricular fibrillation. This is an important cause of sudden death in young people due to right ventricular cardiomyopathy. Early physical examination is often without any abnormalities, and sometimes a variety of arrhythmia symptoms can be seen, may have signs of heart failure.
Arrhythmogenic right ventricular cardiomyopathy
Chest X-ray
The heart is normal or enlarged, the outline is spherical, the pulmonary artery outflow tract is dilated, and the left margin is swollen. Most patients have a cardiothoracic ratio of 0.5.
2. ECG
Common ECG charts available
(1) The timing of QRS complexes in lead V 1 is usually greater than that of lead I and V 6 QRS complexes, reflecting the delay of right ventricular activation. According to statistical analysis, the lead time of the QRS complex of lead V 1 is> 110ms, and the specificity for diagnosis of the disease can reach 100%, and the sensitivity is 55%.
(2) There may be complete or incomplete right bundle branch block.
(3) In some patients, an erect sharp wave (epsilon wave) can be seen in the terminal part of the QRS complex (commonly in lead V1), which is caused by the delayed activation of a part of the right ventricle. It is easy to find this wave by increasing the sensitivity of ECG recording by 2 to 3 times.
(4) In half of the patients, the T wave inversion of the right chest lead was inversely proportional to the extent of right ventricular enlargement.
(5) Ventricular late potentials are often positive in patients with ventricular tachycardia.
(6) Ventricular tachycardia or ventricular fibrillation with a pattern of left bundle branch block can be found during palpitations or syncope.
3. Echocardiography and Radionuclide Ventricular Angiography
The two most important non-invasive testing methods for the diagnosis of this disease. The former shows that the right ventricular end-diastolic diameter is enlarged, the right or left ventricular generalized or limited activities are reduced, and the right ventricular wall is segmentally bulging; the right ventricle and left ventricle end-diastolic diameter ratio is> 0.5 (specificity 93%, sensitivity 86 %, With a positive predictive value of 86% and a negative predictive value of 93%); the latter has a specific and positive predictive value of 100% for the diagnosis of right ventricular systolic anomalies, but the sensitivity is only 80%. If the results of the above two tests show that the right ventricle and left ventricular end-systolic volume ratio is> 1.8, or the right ventricular ejection fraction is <0.50 during exercise, or the right ventricular wall exercise score is> 1 during exercise, the diagnosis of this disease is almost certainly confirmed .
4. Cardiovascular angiography
It can be seen that the right ventricle is enlarged and the right ventricle wall movement is abnormal. Coronary angiography was normal.
5. Magnetic resonance imaging (MRI)
It is of great value to find the local fat increase in ventricular muscle. If the magnetic resonance imaging technology that can accurately measure the right ventricular volume is applied, it can show that the right ventricular volume is increased.
6. Endocardial myocardial biopsy
If you can find a typical lesion of cardiomyocytes replaced by fibrous fat, the disease can be diagnosed. However, since endocardial myocardial biopsies are mostly taken from the ventricular septum, and most patients have limited right ventricular disease, and the ventricular septum is generally not involved, a negative biopsy result cannot rule out the disease. At the same time, as normal small ventricular myocardial cells often have small island-like adipose tissue, the clinical evaluation of this pathological change should be cautious.
7. Electrophysiological examination
Through endocardial mapping technology, it is found that the conduction through the right ventricle is particularly slow, especially in the lesion. This test can also determine the origin of ventricular tachycardia and help localize ablation.
Arrhythmogenic right ventricular cardiomyopathy diagnosis
The clinical manifestations of this disease are diverse, especially early diagnosis is difficult. In 1994, the European Heart Association developed diagnostic criteria for this disease (see Table 1).
According to the clinical performance, according to the above criteria, ARVD / C can be diagnosed if there are 2 main indicators, or 1 main indicator plus 2 secondary indicators, or 4 secondary indicators.
Differential diagnosis of arrhythmogenic right ventricular cardiomyopathy
1.Uh1 deformity
Identification points are shown in Table 2.
Uh1 malformation ARVD / C identification points
| Uh1 deformity | ARVD / C |
Family history Gender: Male Female) Age of onset Clinical findings Exercise-induced death pathology | no 1.3: 1 Baby, child Congestive heart failure rare Right ventricular free wall myocardium is completely absent, and the endocardium and epicardial layer are directly opposite | Some patients have 2.7: 1 Young and middle-aged Arrhythmia, syncope, sudden death may The right ventricular free wall is scattered and replaced by fibrous adipose tissue |
2. Dilated cardiomyopathy
Although ARVD / C patients may occasionally have left ventricular involvement, they are milder and do not show progressive left heart failure. Dilated cardiomyopathy often has left ventricular systolic dysfunction, and often progresses progressively.
3. Idiopathic right ventricular ventricular tachycardia
Unexplained benign ventricular tachycardia. The characteristic is that the ventricular tachycardia is not easy to induce, and the late potential is negative, and the right ventricle is normal in various cardiac examinations. The disease is sometimes difficult to distinguish from atypical ARVD / C. The differential diagnosis of the two is shown in Table 3.
Idiopathic right ventricular tachycardia and identification points with ARCD / C
| Idiopathic right ventricular tachycardia | ARCD / C |
Clinical manifestation | Labor palpitations, dizziness, syncope, and sudden death are rare | Palpitation, syncope, and sudden death |
Age of onset | <35 years | <35 years |
Cause | unknown | Heritable |
Checkup | normal | Occasionally right ventricular enlargement or right heart failure |
VT-induced | Atrial or ventricular stimulation | Ventricular stimulation |
VT pattern | LBBB graphics | Available in many different forms |
Late potential | Often negative | Often positive |
Right ventricular electrogram | normal | Shatter |
Echocardiogram | normal | Right ventricle enlargement or local bulging |
Origin | RVOT or high bit interval | RVOT, spacer or lower wall |
Adenosine sensitivity | sensitive | Not sensitive |
treatment | Verapamil, beta-blockers, radiofrequency ablation | Antiarrhythmic drugs Sotalol, Amiodarone, Surgery, ICD |
Arrhythmogenic right ventricular cardiomyopathy complications
Common complications of this disease include arrhythmia, syncope, and sudden death.
Arrhythmia
Ventricular arrhythmias are the most common and are characterized by recurrent and non-sustained ventricular tachycardia. When VT occurs, dizziness, palpitations, syncope, or even ventricular fibrillation can cause sudden death. Emotional excitement or fatigue can induce ventricular tachycardia.
Syncope
This disease is often caused by severe ventricular arrhythmias (ventricular tachycardia or ventricular fibrillation) affecting hemodynamics.
3. Sudden death
More common in young people 35 years of age, can induce sudden death when emotional or strenuous exercise. A few have a family history of sudden death.
Arrhythmogenic right ventricular cardiomyopathy treatment
Medical treatment
Various antiarrhythmic drugs can be used for arrhythmic patients. It has been reported that the electrical stimulation method, dynamic electrocardiogram and exercise test are combined to determine the effective rate of drug treatment of the disease in order: sotalol (83%), verapamil (50%), and amiodarone (25%). ), -blockers (29%). Some people also believe that amiodarone or amiodarone combined with other antiarrhythmic drugs is the most effective drug to prevent recurrence of ventricular tachycardia in patients with ARVD / C.
2. Catheter ablation
It has been reported that patients with ventricular tachycardia find the origin of ventricular tachycardia under endocardial mapping and perform radiofrequency ablation to control ventricular tachycardia. However, during the follow-up period, another type of tachycardia occurred in some cases. Ventricular tachycardia, suggesting that ARVD / C is a cardiomyopathy with progressive progression of the disease, and is prone to multiple types of ventricular tachycardia.
3.Buried Automatic Cardioversion Defibrillator
For patients with high-risk patients with a history of syncope or persistent ventricular tachycardia who are not responding to antiarrhythmic drugs, ICD implantation has proven to effectively terminate all ventricular tachycardia and is an effective treatment that can improve the long-term prognosis of the disease means.
4. Surgical treatment
For end-stage patients whose medication is difficult to control, consider heart transplantation.
Prognosis of arrhythmogenic right ventricular cardiomyopathy
ARVD / C is a chronic progressive disease. In some patients, the condition is stable for a long time. This is because patients with this disease generally maintain good left ventricular function, and less ventricular tachycardia develops into ventricular fibrillation. However, with a history of syncope, especially those with recurrent syncope, the prognosis is poor. In addition, the risk of sudden death is higher in patients with left ventricular involvement; those with obvious right ventricular wall motion abnormalities or difficult to control ventricular tachycardia on echocardiography or ventricular angiography also have a worse prognosis.
