meritmedscript.blogspot.com · Clinical exam notes · September 2026

ARRHYTHMOGENIC RIGHT VENTRICULAR CARDIOMYOPATHY

ARVC / ACM · 2026 Clinical Practice Guidelines and Exam Protocol

Dr. Sidhartha Mullapudi · MD (General Medicine), PGDHSc Diabetology, DrNB Cardiology

Dr. Sree Vani Gayathri · MD (General Medicine), Associate Professor

meritmedscript.blogspot.com

ESC Guidelines · Braunwald 13th Ed · Padua 2020 Criteria · 2019 ARVC Risk Calculator

One-line viva summary: Desmosomal disease (PKP2 most common). Triangle of dysplasia plus LV inferolateral involvement. 2010 TFC and Padua 2020. Complete restriction from high-intensity endurance sports (Class I). ICD for secondary prevention or 5-year risk ≥10–15%. Combined endocardial–epicardial ablation for refractory VT.

Part 1. Pathophysiology and Genetics

The desmosomal disease

Over 50% of probands carry pathogenic variants in cardiac desmosomal genes.

Gene	Clinical note
PKP2 (plakophilin-2)	Most common desmosomal mutation.
DSP (desmoplakin)	Often LV-dominant ACM.
DSG2 / DSC2	Desmoglein-2 and desmocollin-2.
TMEM43, PLN, FLNC, DES	Non-desmosomal genes that still produce an ACM phenotype.

Mechanical and signaling stress

Wall tension during intense endurance exercise disrupts cell-to-cell adhesion, activates Wnt/β-catenin signaling, and drives progenitor cells toward adipocytes and fibroblasts.

Triangle of dysplasia — and the LV

Classic RV triad: inflow (subtricuspid), apex, and RVOT. Modern CMR frequently adds posterolateral basal LV involvement in biventricular and LV-dominant ACM.

Part 2. Diagnostic Framework: 2010 TFC and Padua 2020

Six categories. Major = 2 points, Minor = 1 point.

Definite diagnosis: 2 Major, or 1 Major + 2 Minor, or 4 Minor from distinct categories.

Category	Major	Minor / update
1. Structure / function	Echo: regional RV akinesia/dyskinesia/aneurysm PLUS RVOT PLAX ≥32 mm (≥19 mm/m²), PSAX ≥36 mm (≥21 mm/m²), FAC ≤33%. CMR: WMA PLUS RVEDVi ≥110 (M) / ≥100 (F) mL/m² and RVEF ≤40%.	Padua 2020 adds LV LGE in subepicardial / mid-myocardial inferolateral wall.
2. Tissue	EMB: fibrous/fatty replacement with residual myocytes <60% by morphometry.	Biopsy is supportive, not first-line in most pathways.
3. Repolarization	TWI in V1–V3 or beyond, age >14, no complete RBBB.	TWI in V1–V2 without CRBBB; or TWI V1–V4 with complete RBBB.
4. Depolarization	Epsilon wave in V1–V3 (low-amplitude signal after QRS, before T).	SAECG late potentials in ≥2 of 3 parameters; or TAD ≥55 ms (S-nadir to QRS end in V1–V3).
5. Arrhythmias	Sustained or NSVT, LBBB morphology, superior axis (neg/indet II, III, aVF; pos aVL).	LBBB inferior-axis VT (RVOT-like); or >500 PVCs / 24 h.
6. Family / genetics	First-degree relative meeting TFC, or P/LP mutation in a validated ARVC gene.	—

Part 3. Risk Stratification for SCD

2019 ARVC Risk Calculator (ARVCrisk.com)

Predicts 5-year sustained VA using: male sex, age, recent syncope (<6 months), NSVT, 24-hour PVC burden, number of leads with TWI, and RVEF.

High-risk features

Secondary prevention (Class I ICD): aborted SCA or hemodynamically unstable VT.
Severe RV dysfunction: RVEF ≤35% or FAC ≤24%.
Severe LV dysfunction: LVEF ≤35%.
Unexplained syncope, especially exertion-related.

Part 4. Management Algorithm

Step	Action
1. Lifestyle (Class I)	Complete avoidance of competitive and high-intensity endurance sport. Exercise uncouples desmosomes and accelerates phenotype and heart failure. Low-to-moderate recreation only after shared decision-making.
2. Drugs	Beta-blockers first-line (Class I/IIa) to max tolerated dose. Sotalol or amiodarone for symptomatic PVC/VT or ICD shocks. Full HF GDMT (ACEi/ARNI, BB, MRA, SGLT2i) if RV or LV systolic dysfunction.
3. ICD	Class I: documented sustained VT or resuscitated arrest. Class IIa: severe RV/LV dysfunction; unexplained syncope with high-risk features; or calculated 5-year risk ≥10–15%.
4. Ablation	Substrate VT ablation for recurrent VT or shocks despite drugs. Combined endocardial and epicardial mapping is often required because fibrofatty disease spreads epicardium → endocardium.

Part 5. High-Yield Pitfalls

ARVC vs idiopathic RVOT VT. Benign RVOT VT is inferior-axis and structurally normal. ARVC is superior-axis VT, extensive TWI V1–V4, and CMR abnormalities.
Ignoring the LV. Think ACM. RV-only imaging misses inferolateral LGE and biventricular disease.
Sport in gene-positive relatives. Pathogenic desmosomal carriers avoid high-intensity endurance sport even before overt phenotype.
Endocardial-only ablation fails. Plan combined endo–epi mapping.

Part 6. Quick Viva Cards

Question	Model answer
Most common gene?	PKP2 (plakophilin-2).
Classic ECG sign?	TWI in V1–V3 or beyond, age >14, no complete RBBB.
Triangle of dysplasia?	RV inflow, RV apex, RVOT. Add LV inferolateral wall on CMR.
Exercise restriction?	Class I: no competitive / high-intensity endurance sport.
ICD — primary vs secondary?	Secondary Class I: SCA or sustained VT. Primary Class IIa: 5-year risk ≥10–15%, severe RV/LV dysfunction, or high-risk unexplained syncope.
Why endo + epi ablation?	Substrate spreads from epicardium inward.
What does Padua 2020 add?	LV inferolateral LGE — captures biventricular and LV-dominant ACM.

Part 7. Sources

ESC Guidelines on cardiomyopathies and ventricular arrhythmias;

Braunwald 13th Edition;

2010 Task Force Criteria and Padua 2020 update;

2019 ARVC Risk Calculator consensus.