Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC)

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 Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC)  

1. Epidemiology

  • ARVC is most commonly diagnosed in young adults, with a mean age of about 30 years.

  • Estimated prevalence: 1 in 1,000–2,000 individuals.

  • Many patients remain asymptomatic initially, making early diagnosis challenging.

2. Etiology (Causes)

  • ARVC is caused by genetic mutations affecting cardiac desmosomal proteins, which help heart muscle cells stick together.

  • Common genes involved include:

    • JUP (plakoglobin)

    • DSP (desmoplakin)

    • PKP2 (plakophilin-2)

    • DSG2 (desmoglein-2)

    • DSC2 (desmocollin-2)

  • Inheritance may be autosomal dominant or recessive, depending on the mutation.

  • Mutations disrupt cell connections → structural weakness of the right ventricular (RV) myocardium.

3. Pathophysiology

  • Mutated genes → death of RV myocardial cells via apoptosis and inflammation.

  • Dead heart muscle is replaced by fatty and fibrous tissue → thinning of the RV wall.

  • Consequences:

    • Right ventricular dilation → decreased pumping efficiency

    • Arrhythmias → ventricular tachycardia, sudden cardiac death

  • The left ventricle may also be affected, but usually less severely.

4. Clinical Features

  • ARVC symptoms vary widely; some patients are asymptomatic.

  • Common symptoms include:

    • Palpitations (due to arrhythmias)

    • Syncope or fainting, particularly with exercise

    • Angina (chest discomfort)

    • Dyspnea (shortness of breath)

    • Signs of right heart failure: peripheral edema, ascites, liver and spleen congestion

    • Sudden cardiac death, especially in young athletes

5. Diagnostics

Diagnosis of ARVC is based on a combination of clinical, imaging, ECG, histological, and genetic criteria (AHA guidelines).

A. ECG Findings

  • Right precordial repolarization abnormalities (V1–V3)

  • Epsilon wave: small deflection at the end of the QRS complex (seen in ~1/3 of patients)

  • Prolonged QRS duration

  • Ventricular arrhythmias: monomorphic or polymorphic VT

B. Imaging

  • Echocardiography / Cardiac MRI:

    • Right ventricular enlargement

    • Wall motion abnormalities

    • Decreased RV ejection fraction

    • Localized RV aneurysms

C. Endomyocardial Biopsy

  • Reveals fibrofatty replacement of RV myocardium.

D. Genetic Testing

  • Identifies mutations in desmosomal proteins (JUP, DSP, PKP2, DSG2, DSC2).

  • Important for family screening and counseling.

6. Clinical Complications

  • Ventricular arrhythmias (VT, ventricular fibrillation) → sudden cardiac death

  • Heart failure (primarily right-sided, sometimes left-sided)

  • Stroke is rare but can occur if arrhythmias lead to thrombus formation

7. Management

A. Lifestyle

  • Avoid intense physical exertion, which can trigger arrhythmias

B. Pharmacologic

  • Antiarrhythmic drugs:

    • Beta blockers (e.g., sotalol)

    • Amiodarone

    • Calcium channel blockers (as adjuncts)

C. Invasive / Device Therapy

  • AICD (Automatic Implantable Cardioverter-Defibrillator): for high-risk patients, especially with left ventricular involvement

  • Radiofrequency ablation: used to treat specific arrhythmia foci (ancillary therapy)

  • Heart transplantation: in severe, refractory cases

D. Family Screening

  • Genetic counseling and screening of first-degree relatives is essential due to hereditary nature

Summary

ARVC is a genetic heart muscle disease affecting primarily the right ventricle, characterized by fibrofatty replacement of myocardium, ventricular arrhythmias, and risk of sudden cardiac death. Diagnosis involves a combination of ECG, imaging, biopsy, and genetic testing, while management focuses on arrhythmia prevention, device therapy, and family screening. Early detection, especially in athletes and young adults, is crucial to prevent life-threatening complications.

 

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