Makindo Medical Notes

Related Subjects: |Ventricular Tachycardia |Right Ventricular Outflow Tract Tachycardia |Resuscitation - Adult Tachycardia Algorithm |Automatic Implantable Cardioverter Defibrillator (AICD)

⚡ ARVC is part of the group of arrhythmogenic cardiomyopathies, characterised by fibrofatty replacement of the myocardium, most commonly the right ventricle. It carries a major risk of sudden cardiac death (SCD) due to malignant ventricular arrhythmias, particularly during exertion. 📌 Early recognition and consideration of ICD implantation is essential.

📖 About

• Also known as Arrhythmogenic Right Ventricular Dysplasia (ARVD).
• Initially affects the right ventricle, but studies show progressive left ventricular involvement over time → can become a biventricular disease.
• Prevalence: ~1 in 5,000–10,000 (likely underdiagnosed).
• Important cause of sudden cardiac arrest in young athletes. 🏃‍♂️⚠️

🧬 Genetics

• Usually autosomal dominant inheritance with variable penetrance.
• More than 8 implicated genes, mostly affecting desmosomal proteins (responsible for cell–cell adhesion in myocardium).
• Ask about family history of arrhythmia or sudden unexplained death.
• Accounts for up to 20% of sudden cardiac deaths in young people.

🧪 Key Genes

• Plakophilin-2 (PKP2)
• Desmoplakin (DSP)
• Desmoglein-2 (DSG2)
• Desmocollin-2 (DSC2)
• Plakoglobin (JUP)
• TMEM43
• RYR2 (linked to calcium handling abnormalities)

📸 ECG – Epsilon Waves

🩺 Aetiology / Pathology

• Mutations in desmosomal proteins weaken mechanical junctions → myocyte detachment & death → fibro-fatty replacement of myocardium.
• Predominantly affects RV free wall, outflow tract, and apex (“triangle of dysplasia”).
• Progressive thinning of RV wall → aneurysm formation → arrhythmia substrate.
• Subtypes: RV-dominant, biventricular, and LV-dominant ARVC.

🩺 Clinical Features

• Palpitations/fluttering (ectopics, atrial fibrillation, ventricular tachycardia).
• Exertional syncope or chest pain.
• Dyspnoea from RV failure in advanced disease.
• Dizziness, fatigue, abdominal discomfort from hepatomegaly / venous congestion.
• Exam: Widely split S2, S3 or S4 gallop; later signs of right heart failure.

⚠️ Complications

• Arrhythmias → ventricular ectopics, AF, VT, VF (leading cause of death).
• Progressive biventricular heart failure.
• Bradyarrhythmias, AV block.
• Sudden cardiac death, often during exertion.

🔍 Investigations

• ECG: T-wave inversion in V1–V3, epsilon waves (terminal notching), incomplete RBBB, VT with LBBB morphology.
• Echocardiogram: RV dilation, akinesis/dyskinesis, prominent trabeculations, RVOT dilatation.
• Cardiac MRI: gold standard → RV structural/functional abnormalities + tissue characterization (fibrofatty infiltration).
• Holter/monitoring: detect ventricular arrhythmias of RV or LV origin.
• Endomyocardial biopsy: rarely used, limited sensitivity due to patchy disease.

🔎 Differentials

• Idiopathic RV outflow tract tachycardia (benign, no fibrosis).
• Brugada syndrome (channelopathy with similar arrhythmia risk).
• RV volume overload from congenital lesions (e.g., ASD, Ebstein anomaly).

📸 ECG Showing Epsilon Waves

👨‍👩‍👧 Screening

• All first-degree relatives: 12-lead ECG + cardiac imaging; consider signal-averaged ECG.
• Genetic testing if pathogenic variant identified in proband.
• Family follow-up essential as penetrance increases with age.

💊 Management

• Lifestyle: Avoid competitive or high-intensity sports, caffeine, stimulants. Moderate daily activity only.
• ICD: definitive therapy for high-risk or survivors of cardiac arrest / sustained VT.
• Antiarrhythmics: beta-blockers (mainstay), sotalol, amiodarone for VT suppression.
• Catheter ablation: option for recurrent VT refractory to drugs; often palliative (high recurrence).
• Heart failure therapy: ACEi/ARB, diuretics, MRA as indicated.
• Anticoagulation: if atrial fibrillation present.
• Transplantation: end-stage cases with refractory HF or arrhythmias.
• 🔁 Lifelong cardiology follow-up in specialist inherited cardiac conditions clinic.

📚 References

• 2019 HRS Consensus on Arrhythmogenic Cardiomyopathy
• CSANZ Guidelines – Diagnosis & Management of ARVC

Cases — Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC)

• Case 1 — Sudden Cardiac Symptoms in a Young Athlete: A 22-year-old semi-professional footballer collapses during training with palpitations and presyncope. ECG shows T-wave inversion in V1–V3 and episodes of ventricular tachycardia with left bundle branch block (LBBB) morphology. Echo and MRI demonstrate right ventricular dilation and regional wall motion abnormalities. Family history: cousin died suddenly at age 19. Diagnosis: ARVC presenting with exertional arrhythmia and risk of sudden cardiac death.
• Case 2 — Palpitations and Heart Failure in Middle Age: A 45-year-old man presents with progressive exertional dyspnoea, ankle swelling, and recurrent palpitations. ECG shows frequent ventricular ectopics. Cardiac MRI reveals fibro-fatty replacement of the right ventricular free wall with impaired systolic function. Genetic testing: plakophilin-2 mutation. Diagnosis: ARVC with arrhythmia and right-sided heart failure.

Teaching Commentary ❤️

ARVC is a rare inherited cardiomyopathy (often autosomal dominant, desmosomal gene mutations such as PKP2, DSG2, DSP) where fibro-fatty replacement of the right ventricular myocardium predisposes to ventricular arrhythmias, heart failure, and sudden cardiac death. Typical features: - Young adults, especially athletes. - ECG: T-wave inversion in V1–V3, epsilon waves, ventricular tachycardia with LBBB morphology. - Imaging: RV dilation/dyskinesia, fatty infiltration. Diagnosis uses the Task Force Criteria (structural, histological, ECG, arrhythmic, and family/genetic). Management: exercise restriction, implantable cardioverter-defibrillator (ICD) for sudden death prevention, anti-arrhythmics, and heart failure therapy if needed.