Arrhythmia risk and surveillance in LMNA-related cardiomyopathy

Arrhythmia in dilated cardiomyopathy (DCM) is a major reason for emergency presentations, hospital admission and sudden cardiac death. In patients with a pathogenic LMNA variant, the combination of myocardial dysfunction and conduction disease creates a risk that may emerge before symptoms are obvious. LMNA encodes lamin A/C, structural proteins of the nuclear envelope; its dysfunction can destabilise the cardiomyocyte and make both myocardium and conduction system vulnerable.

Management therefore requires more than a single ejection-fraction measurement. Ventricular tachycardia (VT), ventricular fibrillation, atrioventricular block and atrial fibrillation may follow different trajectories within one family. This article connects variant interpretation and family screening with echocardiography, cardiac magnetic resonance (CMR), ambulatory rhythm monitoring, device-based follow-up, treatment and clinical surveillance while recognising the practical pathways available in Australia.

Genetics behind an unstable rhythm

The genetic clue changes what a clinician is watching for. LMNA-related cardiomyopathy often includes sinoatrial or atrioventricular conduction disease, and ventricular arrhythmias can occur while left ventricular systolic function appears only moderately reduced. The mechanistic chain is still incompletely resolved, but abnormal nuclear architecture, altered mechanotransduction, myocyte injury and fibrotic replacement provide a plausible substrate for both re-entry and slow conduction.

Penetrance is age-dependent and variably expressed, so a variant-positive relative may have normal imaging for years while another develops conduction disease, atrial arrhythmia or DCM in early adulthood. Variant class, family phenotype and age at onset influence prognosis, yet no LMNA genotype should be assigned a fixed risk from its name alone. A pathogenic or likely pathogenic result should therefore be interpreted with phenotype and family history, while a variant of uncertain significance is not a diagnosis.

Genetic counselling should precede testing whenever possible. Once a heterozygous pathogenic variant is identified in a family, each first-degree relative has a 50% chance of inheriting it, and targeted cascade testing can define who needs surveillance. Testing may include blood or saliva, specialist laboratory interpretation and discussion of reproductive, privacy and insurance consequences. Families should be told that a negative test does not exclude another inherited cause of cardiomyopathy, particularly when the LMNA variant remains uncertain.

Phenotype, substrate, and risk markers

The rhythm phenotype is broad. Some people present with palpitations from nonsustained VT, others with syncope from intermittent high-grade block, and some with sudden cardiac arrest. Atrial fibrillation or flutter is also common in LMNA-associated disease and may become persistent as atrial enlargement and fibrosis progress. It does not remove the need to assess ventricular risk. Bradycardia, atrial tachycardia and VT can coexist, so the presenting rhythm may obscure the underlying substrate.

Risk assessment combines electrical and structural information. Marked left ventricular dilatation, reduced ejection fraction, extensive late gadolinium enhancement on CMR, right ventricular involvement and conduction disease are concerning features. In LMNA-associated disease, arrhythmia can precede major systolic impairment, making wall motion, chamber size and fibrosis important alongside the ejection fraction. No imaging marker is sufficiently precise to replace clinical judgement.

Clinical context also matters. Bundle-branch block, first-degree AV block, prolonged QT or repolarisation abnormalities may indicate broader myocardial disease rather than isolated channelopathy. Medication effects, thyroid disease, ischaemia and electrolyte disturbance should be excluded. A family history should be sought across three generations, including unexplained drowning, road deaths, cardiac arrest and pacemaker or ICD implantation at younger ages, because apparent “sporadic” sudden death can conceal a dominant family pattern.

A practical surveillance pathway

A baseline assessment for a suspected LMNA cardiomyopathy case should combine history, examination, 12-lead ECG, echocardiography and a risk-stratified rhythm assessment. CMR with late gadolinium enhancement is valuable for fibrosis, biventricular involvement and tissue characterisation when available. Ambulatory ECG should be selected to match symptom frequency: Holter monitoring captures frequent ectopy, while patch, event or loop recorders extend detection for intermittent symptoms. In Australia, these investigations are usually accessed through general-practitioner referral into public or private cardiology services; Medicare subsidises eligible diagnostic testing, but waiting times and out-of-pocket costs vary.

For relatives without an overt phenotype but with a documented familial variant, the family’s pattern should determine review frequency. Many inherited-cardiomyopathy services use annual or two-yearly clinical review, ECG and echocardiography for selected carriers, shortening intervals when conduction disease or ventricular dysfunction appears. Patients under active surveillance may need six- to twelve-monthly review, longer-duration rhythm monitoring or CMR according to symptoms and findings. These intervals are pragmatic and require individual specialist assessment.

Red-flag symptoms need same-day attention: syncope, sustained palpitations, chest pain, sudden dyspnoea or exercise intolerance. In a remote Australian area, telehealth can connect a patient with a cardiologist, but acute instability still requires emergency care through Triple Zero (000) and use of the nearest available automated external defibrillator. Exercise advice should be individualised, particularly for carriers with ventricular arrhythmia, conduction disease or prior cardiac arrest.

Treatment, devices, and escalation

Reducing the arrhythmic substrate remains central. Guideline-directed therapy for reduced-EF DCM—an ACE inhibitor or ARB/ARNI, evidence-based beta blocker, mineralocorticoid antagonist and, when appropriate, an SGLT2 inhibitor—should be optimised alongside genotype-specific risk assessment. This treatment addresses ventricular remodelling and heart-failure outcomes, although it does not eliminate inherited susceptibility. Electrolytes, thyroid function and other reversible contributors should be checked when the rhythm changes.

Devices must match the problem. Symptomatic bradycardia or high-grade AV block may require pacing; an implantable cardioverter-defibrillator (ICD) can terminate VT or VF, but primary-prevention decisions in LMNA-related disease are complex and may be considered even before severe LV dysfunction when other risk features are present. Cardiac resynchronisation is used when indicated for systolic dysfunction and dyssynchrony. Remote device interrogation is important because it can identify arrhythmia burden, lead problems and device therapies between clinic visits.

Recurrent VT may require antiarrhythmic drugs, usually with attention to amiodarone toxicity, and catheter ablation at an experienced electrophysiology centre. Diffuse scar and disease progression can make ablation less durable, so treatment goals should be discussed openly. Advanced disease may progress to transplantation; after transplantation, atrial tachyarrhythmias become a distinct rhythm complication, and the Journal of Arrhythmia’s practical post-transplant arrhythmia guidance sets out monitoring and management considerations. ICD programming, shocks and driving restrictions also require explicit counselling and coordination with state road authorities.

Building an Australian evidence pathway

Specialist access is concentrated in major metropolitan centres. Families in Melbourne can access inherited-cardiomyopathy and advanced-heart-failure expertise through tertiary networks including Royal Melbourne Hospital, while Sydney networks such as Westmead Hospital and Royal Prince Alfred Hospital provide multidisciplinary care, genetics and device follow-up. These services commonly coordinate electrophysiology, imaging, psychology and social work, an important advantage when the diagnosis affects several generations. Access should not depend on living near a tertiary centre.

Countrywide distances shape surveillance. Shared-care models can use local echo services, nurse-led device clinics and telehealth reviews, with records and family histories transferred securely to the specialist team. Medicare pathways, private electrophysiology and consumer support from Cardiomyopathy Australia and the Heart Foundation all contribute, but access can remain uneven for rural, remote and lower-income households. Regional services should be designed so that surveillance does not end when distance makes attendance difficult.

Driving is a practical arrhythmia issue. In Victoria, VicRoads applies restrictions following relevant cardiac events or ICD implantation, and NSW Road and Motor Services has its own assessment and licence categories; clinicians should check current state guidance and document advice in the care plan. For research, the priorities are larger LMNA cohorts, genotype-specific risk models, validated screening intervals, sex-informed outcomes and equitable access to cascade testing. The Journal of Arrhythmia’s open-access, peer-reviewed platform offers a route to share these data, and investigators can submit original research aligned with its arrhythmia and device focus.

Families and clinicians should treat LMNA-related cardiomyopathy as a rhythm disease as well as a structural one. A secure family history, expert genetic interpretation, serial ECG and imaging, symptom-sensitive ambulatory monitoring and coordinated device review can expose risk before collapse. The aim is targeted surveillance that matches each person’s genotype, phenotype and life circumstances.

Action starts with a GP referral to an inherited-cardiomyopathy or heart-failure service, followed by genetic counselling and a written surveillance plan. Anyone experiencing syncope, sustained palpitations or sudden breathlessness should seek urgent assessment rather than waiting for the next review. Regional services can support this pathway through tele-cardiomyopathy links and funded family testing. The immediate next step for each family is to agree on named clinicians, review dates and clear escalation instructions with specialist input.