Ventricular arrhythmias in arrhythmogenic right ventricular cardiomyopathy

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited myocardial disease in which ventricular electrical instability may precede obvious structural change. Premature ventricular complexes, nonsustained ventricular tachycardia and sustained monomorphic ventricular tachycardia can emerge in young or middle-aged adults, often during exercise. Although the right ventricle is central to the traditional definition, contemporary concepts recognise a broader arrhythmogenic cardiomyopathy phenotype that may involve the left ventricle or both chambers.

For clinicians in Australia, the condition creates a particularly important balance between early risk recognition and avoidance of unnecessary intervention. A patient from regional Queensland, Western Australia or Tasmania may face long travel for cardiac magnetic resonance imaging, genetic counselling or complex ablation, while family screening can extend across several states. Care is therefore strongest when inherited disease assessment, imaging, electrophysiology and long-term follow-up are coordinated rather than treated as separate episodes.

Recognising the arrhythmogenic phenotype

The clinical presentation ranges from incidental ventricular ectopy to resuscitated sudden cardiac arrest. Palpitations, exertional presyncope and syncope deserve careful assessment, particularly when there is a family history of sudden death, unexplained drowning, cardiomyopathy or premature device implantation. In ARVC, ventricular ectopy with a left bundle branch block morphology and superior axis can suggest a right ventricular origin, although electrocardiographic patterns vary with disease distribution and scar location.

The 2010 Task Force Criteria remain useful for structured diagnosis, but they do not capture every early or left-dominant phenotype. The Padua criteria and contemporary arrhythmogenic cardiomyopathy frameworks place greater emphasis on tissue characterisation, ventricular involvement, late gadolinium enhancement and genotype–phenotype correlation. No single finding should be interpreted in isolation. Athlete’s heart, myocarditis, sarcoidosis and idiopathic right ventricular outflow tract tachycardia can produce overlapping features.

Exercise history is especially relevant. High-intensity endurance and competitive sport may accelerate disease expression in genetically susceptible individuals and increase ventricular arrhythmia burden. Advice should be individualised, with shared decision-making that considers genotype, ventricular function, arrhythmia history and the patient’s occupation. A young person training in a national sporting programme in Melbourne or Brisbane may need a carefully negotiated reduction in intensity rather than an abrupt, poorly supported prohibition.

Imaging and substrate characterisation

Cardiac magnetic resonance is central to defining anatomy, regional akinesia or aneurysm formation, right ventricular volumes and ventricular scar. Late gadolinium enhancement can reveal fibrosis that is not apparent on echocardiography, while mapping techniques may identify diffuse abnormalities before extensive scar develops. Imaging should be interpreted alongside a 12-lead ECG, ambulatory monitoring, exercise testing and family history, since modest abnormalities across several domains may carry more significance than one striking measurement.

The arrhythmogenic substrate is often patchy and predominantly epicardial, particularly in the “triangle of dysplasia” involving the right ventricular outflow tract, inferior wall and diaphragmatic region. Endocardial voltage mapping may therefore underestimate disease extent. Bipolar and unipolar voltage assessment, pace mapping, activation mapping and substrate modification can help define the scar, but the findings are influenced by catheter contact, chamber geometry, signal filtering and the stage of disease.

A multidisciplinary review is valuable when the phenotype is uncertain. In Australia, access may involve a tertiary inherited cardiac disease service in Sydney, Melbourne, Adelaide or Perth, followed by shared care with a local cardiologist. Genetic testing can identify pathogenic variants in desmosomal genes such as PKP2, DSP, DSG2 and DSC2, although a negative result does not exclude disease. Variants of uncertain significance should not be used alone to label relatives or determine invasive treatment.

How ventricular tachycardia develops

Ventricular tachycardia in ARVC is usually re-entrant and related to areas of fibrofatty replacement and fibrosis. The circuit may be stable enough to produce a consistent monomorphic morphology, yet several exits can coexist. As the cardiomyopathy progresses, scar can expand across the right ventricle, involve the left ventricle and generate multiple clinical or inducible tachycardias. This explains why an apparently successful procedure may reduce episodes without eliminating long-term arrhythmic risk.

Antiarrhythmic medication can reduce ventricular tachycardia and implantable cardioverter-defibrillator therapies, but it does not remove the underlying substrate. Sotalol, amiodarone and other agents must be selected with attention to ventricular function, renal and hepatic status, proarrhythmic effects, thyroid disease and the patient’s reproductive plans. Beta-blockade is often important, especially when adrenergic stimulation contributes to arrhythmia, although medication should complement rather than replace risk assessment.

An implantable cardioverter-defibrillator is considered according to the overall probability of life-threatening ventricular arrhythmia, not simply the presence of a pathogenic variant. Prior cardiac arrest, sustained ventricular tachycardia, significant ventricular dysfunction, unexplained syncope and a high premature ventricular complex burden may all influence the discussion. Device selection must also account for pacing needs, lead complications, inappropriate shocks and the realities of follow-up for patients living far from an electrophysiology centre.

Device therapy is part of a wider arrhythmia strategy. Lessons from broader device populations, including the interaction between rhythm, ventricular function and pacing, can be explored in this discussion of cardiac resynchronisation therapy, although its clinical context differs from ARVC.

Ablation strategy and expected outcomes

Catheter ablation is generally used for recurrent sustained ventricular tachycardia, frequent ICD shocks or drug-refractory arrhythmia. The procedure aims to interrupt critical channels within scar and reduce the burden of clinical VT. In ARVC, an endocardial-only approach may be insufficient because the substrate commonly extends through the epicardium. A combined endocardial and epicardial strategy can improve long-term freedom from recurrent VT in appropriately selected patients, particularly when prior endocardial ablation has failed.

Three-dimensional electroanatomical mapping is used to identify low-voltage regions, abnormal electrograms, late potentials and local conduction delay. Substrate-based ablation during sinus rhythm may be combined with programmed stimulation and entrainment when VT is haemodynamically tolerated. Epicardial access carries specific risks, including coronary injury, phrenic nerve damage, bleeding and pericarditis, so the procedural plan should include coronary imaging, careful anatomical assessment and an experienced team.

Reported outcomes vary because studies differ in diagnostic criteria, disease stage, mapping technology, follow-up duration and the definition of success. Acute elimination of inducible VT does not guarantee freedom from recurrence. Patients with extensive biventricular scar, left ventricular involvement, multiple VT morphologies or advanced heart failure generally have a higher risk of repeat procedures and ongoing ICD therapies. Ablation should therefore be described as a method of arrhythmia control rather than a cure for the cardiomyopathy.

Australian referral patterns can affect timing. A patient in the Northern Territory or remote New South Wales may need coordination of flights, accommodation, device interrogation and post-procedure review, while public hospital waiting lists and private insurance arrangements can shape access. Telehealth can support medication review and family counselling, but it cannot replace high-quality imaging, procedural expertise or urgent assessment after a shock.

Follow-up, family screening and research

Long-term care includes periodic ECGs, Holter monitoring, imaging and review of exercise exposure. The interval should reflect age, genotype, symptoms, ventricular function and prior arrhythmia. A new fall in exercise capacity, increasing ectopy, syncope or an ICD shock warrants prompt reassessment. Patients should receive a clear plan for emergency care and device follow-up, including what to do if they are travelling in the outback or away from their usual hospital.

First-degree relatives may require clinical screening even when they feel well. Depending on age and family history, assessment can include ECG, echocardiography, ambulatory monitoring, exercise testing, cardiac MRI and targeted genetic testing. Children and adolescents need age-appropriate counselling because penetrance is variable and a normal early evaluation does not permanently exclude later disease. Genetic services should also respect family preferences, privacy and the practical burden of testing across dispersed Australian communities.

Research is moving towards more precise substrate phenotyping. Combining electroanatomical voltage maps with MRI fibrosis, electrocardiographic imaging, genetic data and longitudinal rhythm records may help distinguish patients who need early intervention from those best managed with surveillance. Future trials should report clinically meaningful outcomes such as sustained VT, appropriate ICD therapy, hospitalisation, ventricular function and quality of life, rather than relying only on inducibility at the end of a procedure.

Clinicians and researchers can contribute to this evidence base through carefully characterised cohorts and transparent reporting of ablation techniques, epicardial access, complications and recurrence. Manuscripts describing regional practice, inherited disease pathways and outcomes in diverse Australian populations are particularly valuable; authors can review the submission requirements before preparing work for peer review.

The most effective care for ARVC-related ventricular arrhythmia combines early recognition, careful phenotyping, exercise counselling, appropriate ICD consideration and ablation delivered by an experienced multidisciplinary team. Publishing robust outcomes and sharing practical approaches can help electrophysiology services across Australia refine referral pathways and improve care for patients and their families.