Arrhythmogenic left ventricular cardiomyopathy

Article written and reviewed by Dr Luca Moretti

Arrhythmogenic left ventricular cardiomyopathy is a myocardial disease in which cell loss, nonischemic scar and electrical instability predominantly, or in some cases apparently exclusively, affect the left ventricle. Its most important clinical characteristic is not simply reduced contractility, but the possibility that severe ventricular arrhythmias may emerge when chamber dimensions and ejection fraction are still only mildly abnormal. This dissociation between electrical injury and pump function defines the left-sided arrhythmogenic phenotype.

The international acronym ALVC derives from arrhythmogenic left ventricular cardiomyopathy. In the past, expressions such as left-dominant arrhythmogenic cardiomyopathy or left-sided variant of ARVC were used when the disease was regarded as essentially right ventricular. Contemporary nomenclature instead recognizes a spectrum comprising right-sided, biventricular and left-sided forms, without assuming that every presentation begins in the right ventricle and later extends to the left. Ventricular dominance describes the observed phenotype, not a mandatory sequence.

ALVC is not synonymous with dilated cardiomyopathy. Classic DCM is defined by dilatation and systolic dysfunction not explained by loading conditions or sufficient coronary artery disease, whereas in the left-sided arrhythmogenic form, subepicardial or midmyocardial scar may be extensive in a nondilated, only mildly hypokinetic ventricle. Biologic and genetic overlap exists, but the distinction remains valuable because it changes family diagnosis, rhythm surveillance and the threshold of concern for sudden death.

Nor is nondilated left ventricular cardiomyopathy, designated NDLVC in ESC guidelines, automatically the same as ALVC. NDLVC is a morphofunctional umbrella that includes nonischemic scar or fatty replacement of the left ventricle, with or without wall-motion abnormalities, or global hypokinesia without scar and without dilatation. Assigning a case to the arrhythmogenic spectrum requires multiparametric and etiologic consistency, because healed myocarditis, sarcoidosis and several cardiomyopathies may produce an NDLVC phenotype.

The prevalence of ALVC cannot be defined precisely. Older cohorts selected patients using criteria developed for the right-sided form, echocardiography may not reveal a subepicardial scar, and contrast-enhanced CMR was not systematically available. Even today, frequency depends on the referral setting, the genetic composition of the population and the rigor with which phenocopies are excluded. Any epidemiologic estimate must therefore be interpreted in light of substantial ascertainment bias.

Timely recognition is relevant to the entire family. Ventricular tachycardia with right bundle branch block morphology, low QRS amplitudes, a nonischemic inferolateral scar or recurrent episodes labeled as myocarditis may be parts of the same disease. None of these findings, taken in isolation, is diagnostic; the strength of the assessment comes from convergence among history, electrocardiography, documented arrhythmias, tissue imaging and genetics. Diagnosis is therefore an integrated process.

Pathologic substrate and disease mechanisms

The fundamental pathologic finding is replacement of lost myocardium by fibrous tissue, sometimes associated with an adipose component. In the left ventricle, the process tends to begin in the subepicardial layers and spread toward the midmyocardium, with frequent predilection for the inferolateral wall. This distribution differs from ischemic necrosis, which follows a coronary territory and progresses from the subendocardium toward the epicardium. The topography of injury reflects a specific wall vulnerability.

Fibrofatty replacement is neither uniform nor necessarily visible as macroscopic fat. Fields of viable myocytes remain interspersed with scar, generating slow conduction, unidirectional block and re-entry circuits. The border between healthy and damaged tissue becomes electrically unstable even when residual contractile mass maintains an apparently satisfactory ejection fraction. For this reason, the re-entry substrate may precede heart failure by years.

In desmosomal forms, abnormalities of structures that mechanically connect cardiomyocytes reduce the tissue's ability to tolerate stress. The desmosome also interacts with gap junctions, ion channels and intracellular pathways regulating survival and differentiation; the disease therefore cannot be explained simply as failure of a defective glue. The combination of uncoupling, abnormal signaling and cell death creates electromechanical vulnerability.

Non-desmosomal genes converge on the same outcome through different mechanisms. Truncating FLNC variants impair the linkage of the cytoskeleton to the membrane, PLN alters calcium homeostasis, DES damages the intermediate filament network and LMNA affects the nuclear envelope. The ALVC label therefore describes a common clinical outcome of multiple molecular pathways, not a single biochemical disease. This causal heterogeneity explains part of the prognostic differences.

Inflammation may accompany phases of myocyte loss. In some DSP cardiomyopathies, chest pain, increased troponin, edema and late gadolinium enhancement occur, producing a picture initially indistinguishable from acute myocarditis. Inflammatory infiltrates documented in some specimens do not by themselves demonstrate an infectious origin and may represent a response to genetically determined injury. The so-called hot phase is therefore a mode of expression, not an independent etiologic diagnosis.

Not every episode of myocarditis in a young person is a manifestation of ALVC. Immune-mediated or infectious myocarditis is more common and may leave a similar subepicardial scar. Suspicion increases with recurrence, an extensive or circumferential distribution, a family history of cardiomyopathy or sudden death, and the presence of a coherent causal variant. Correct interpretation requires contextual probability, avoiding both underdiagnosis and indiscriminate genetic attribution.

Intense exertion increases wall stress, adrenergic stimulation and heart rate, conditions that can promote injury and arrhythmias in vulnerable myocardium. The strongest evidence comes from carriers of desmosomal variants and cohorts with predominantly right-sided phenotypes, but the principle is applied across the arrhythmogenic spectrum. The effect is not an identical threshold for everyone: duration, intensity, type of exercise, genotype and already manifest disease all contribute to the mechanical dose.

Anatomic progression is not inevitably continuous. Periods of apparent stability may alternate with increasing scar, new arrhythmias or inflammatory episodes. An unchanged CMR does not eliminate electrical risk, just as increased LGE does not automatically imply imminent pump deterioration. The disease should be considered along two axes, arrhythmic and hemodynamic, which may move at different speeds. This dual trajectory guides follow-up.

Genetics, penetrance and genotype-phenotype correlations

Most familial forms follow autosomal dominant inheritance with age-dependent penetrance and variable expressivity. Each child of a carrier generally has a 50% probability of inheriting the variant, but not a 50% probability of developing the same severity or at the same age. Sex, exercise, modifier variants and still-unknown factors modulate expression. Incomplete penetrance prevents deterministic predictions.

DSP is one of the genes most representative of the left-sided phenotype. Loss-of-function variants may be associated with extensive subepicardial scar, ventricular arrhythmias, left ventricular dysfunction and recurrent episodes of myocardial injury. Cutaneous manifestations such as woolly hair or keratoderma are more evident in some biallelic conditions, but may be absent in dominant cardiac forms. Suspicion of DSP cardiomyopathy therefore does not depend on dermatologic signs.

Truncating FLNC variants produce a spectrum spanning ALVC, DCM and NDLVC, often with fibrosis and arrhythmias disproportionate to dysfunction. Not all FLNC variants have the same mechanism: some missense variants are associated primarily with skeletal myopathy or other phenotypes, whereas loss of function is particularly relevant in arrhythmogenic cardiomyopathies. Interpretation therefore requires consideration of the variant mechanism, not the gene name alone.

The PLN p.Arg14del deletion is an example of a founder variant associated, particularly in certain European populations, with dilated or arrhythmogenic phenotypes featuring low voltages, arrhythmias and scar. DES can also cause left-sided or biventricular involvement, conduction disorders and, in some carriers, myopathy. LMNA enters the genetic differential diagnosis when atrioventricular block and arrhythmias precede dysfunction. The extracardiac and conduction profile helps prioritize hypotheses.

Other genes associated with the arrhythmogenic spectrum, including DSG2, DSC2, PKP2, JUP and TMEM43, should not be treated as equivalent. PKP2 is more closely linked to the classic right-sided phenotype, whereas DSP more often shows left-sided involvement; however, overlap is broad and a family may evolve toward biventricular disease. These associations refer to population probabilities and do not justify reclassifying the affected ventricle on the basis of the gene. The observed phenotype remains essential.

Genetic testing should be performed in an accredited laboratory using panels made up of genes with sufficiently robust disease-gene relationships and methods capable of detecting the main variant classes. Indiscriminately expanding the panel increases variants of uncertain significance without guaranteeing more clinically usable diagnoses. Pre-test counseling explains possible results, limitations, family implications and reproductive options. Panel quality takes precedence over the number of genes.

A pathogenic or likely pathogenic variant may support the etiology and enable cascade testing. A VUS does not confirm ALVC, should not guide implantation of a defibrillator and does not allow relatives who do not carry it to be discharged from follow-up. Segregation, population frequency, functional data and phenotypic compatibility may change its classification over time. A VUS is not causal until the evidence demonstrates otherwise.

A negative test does not exclude a hereditary basis. The variant may lie in a gene not yet recognized, in an unanalyzed region or belong to a technically difficult-to-detect class; in other families the architecture may be oligogenic or complex. If the pedigree and phenotype remain convincing, clinical screening of relatives continues. An uninformative negative result is not equivalent to absence of familial risk.

Genotype-prognosis correlation is useful but imperfect. DSP and FLNC are associated in many cohorts with arrhythmic risk that may precede a severe reduction in ejection fraction, whereas LMNA and PLN require additional gene-specific algorithms or considerations. Tertiary-center case series overrepresent severe forms, and founder variants cannot be generalized to every population. Gene-specific risk must be combined with the individual's history.

Clinical presentation and natural history

Palpitations are a common mode of presentation, but range from isolated premature beats to sustained ventricular tachycardia. Right bundle branch block morphology during the arrhythmia suggests a left ventricular origin because depolarization proceeds from left to right; axis and precordial configuration help localize the circuit. Morphology does not, however, prove the etiology and must be interpreted in the structural context.

Syncope and presyncope require careful reconstruction. A sudden episode during exertion, without vagal prodromes and with rapid recovery, is more suspicious for arrhythmia than loss of consciousness associated with pain, heat or orthostasis, but no feature is absolute. Monitoring, family history and the CMR substrate determine probability. Unexplained syncope carries particular weight in the ICD decision.

Cardiac arrest may be the first manifestation in a person previously considered healthy. This does not mean that all asymptomatic carriers face imminent risk, but it illustrates the limitation of surveillance based only on symptoms or ejection fraction. In relatives, electrical abnormalities and scar may precede dysfunction. The early electrical phase must be actively sought.

The myocarditis-like presentation includes chest pain, increased troponin, ST-T changes and myocardial edema, often in adolescents or young adults. It may be isolated or recurrent and, in DSP families, may precede stable scar and arrhythmias. During the episode, coronary syndrome, infection, toxic causes and immune-mediated myocarditis must still be excluded according to the clinical picture. Recurrent troponin elevation is a clue, not proof.

Dyspnea and exercise intolerance develop when reduced systolic reserve, diastolic dysfunction, functional mitral regurgitation or arrhythmias limit output. The ventricle may remain nondilated despite elevated filling pressures, whereas in advanced phases it may assume a dilated phenotype. Clinical severity is not captured by a single measurement. Heart-failure physiology requires volumes, function, congestion and functional capacity.

Atrial arrhythmias are less specific, but atrial fibrillation and supraventricular tachycardias may worsen symptoms or promote heart failure. Anticoagulation follows validated indications for thromboembolic risk and is not prescribed solely because of the ALVC diagnosis. A ventricular aneurysm or thrombus introduces specific considerations. Embolic prevention remains distinct from prevention of arrhythmic death.

The trajectory does not necessarily progress from silence to heart failure through orderly stages. Some patients remain for years with stable scar and controlled arrhythmias; others progress mainly on the hemodynamic side, whereas a third group has inflammatory phases interspersed with apparent well-being. Comparing ECG, Holter monitoring and imaging over time is more informative than a snapshot. The longitudinal phenotype may also shift from left-dominant to biventricular.

Age and mode of onset vary markedly. Biallelic forms or some severe variants may manifest in childhood, whereas dominant carriers remain phenotype-negative until adulthood. An older person with new scar and arrhythmias should not be excluded a priori, but requires even greater attention to coronary artery disease, sarcoidosis and acquired causes. Age-based diagnosis cannot replace etiologic assessment.

Multiparametric diagnosis, CMR and international criteria

Assessment begins with a three-generation clinical history focused on sudden death, cardiomyopathy, transplantation, arrhythmias, recurrent myocarditis and implanted devices. Age, documentation of events and autopsy findings are also essential, because a generic cardiac death at advanced age has little discriminatory power. The sports history quantifies years, hours, intensity and discipline. A documented pedigree guides testing and interpretation.

The electrocardiogram may show QRS amplitudes below 0.5 mV in peripheral leads, inferolateral T-wave inversion, fragmentation or conduction delays. Low voltages become meaningful only after marked obesity, pericardial effusion, emphysema, amyloidosis and technical problems have been excluded. The absence of abnormalities does not eliminate early disease. The electrocardiographic signal reflects the amount and distribution of electrically active myocardium.

Ambulatory monitoring quantifies premature beats, couplets, nonsustained tachycardia and their relationship to symptoms or activity. A 24-hour recording may underestimate an intermittent burden, so duration and technology are adapted to the probability and frequency of symptoms. In device carriers, electrograms provide longitudinal information. The ventricular arrhythmic burden is dynamic and should not be reduced to a single threshold.

Exercise testing may reproduce adrenergic arrhythmias and assess functional capacity and blood pressure response, but is not used to demonstrate the safety of intense sport. A negative test does not exclude arrhythmias during longer training sessions or under different conditions. In high-risk patients, the procedure is scheduled with adequate surveillance. Controlled provocation answers specific clinical questions.

Echocardiography evaluates global and regional function, volumes, strain, valves, pressures and the right ventricle. In early ALVC it may be normal because scar affects the outer layers without clearly altering the endocardial border. Reduced strain or regional hypokinesia increases suspicion but does not have the specificity of tissue characterization. A normal echocardiogram does not end the assessment when the context is convincing.

Cardiac magnetic resonance is central because it combines measurement of volumes with identification of edema and scar. Typical late gadolinium enhancement appears as a subepicardial or midmyocardial stria, often inferolateral, that may extend to multiple segments and become circumferential. Confirmation in orthogonal planes reduces artifacts and partial-volume effects. The nonischemic pattern should be described by location, layer, extent and continuity.

The term ring-like denotes subepicardial or midmyocardial involvement of at least three contiguous segments in the same short-axis section. The European Task Force criteria published in 2024 assign greater weight to subepicardial or midmyocardial stria-pattern LGE extending to at least three segments of the bull's-eye model, whether contiguous with a ring-like arrangement or noncontiguous, provided the finding is confirmed in two orthogonal views. Involvement of one or two segments carries lesser weight after focal, patchy or junctional nondiagnostic distributions have been excluded. Circumferential LGE is highly suggestive, but not pathognomonic.

T1 mapping, extracellular volume and T2 may show diffuse fibrosis or inflammatory activity not fully represented by LGE. Values depend on scanner, sequence and local reference ranges and do not constitute universally validated stand-alone criteria for ALVC. Edema during a hot phase may regress, whereas residual scar persists. Tissue quantification complements CMR without replacing morphologic interpretation.

The 2020 Padua criteria addressed the limitation of the 2010 Task Force Criteria, which had been developed for the right ventricle, by introducing left-sided morphofunctional, structural, electrocardiographic, arrhythmic and genetic-family categories. In that system, a diagnosis of ALVC required the absence of right-sided structural or morphofunctional criteria, one major left-sided structural criterion and a pathogenic or likely pathogenic disease-associated variant. The genetic requirement protected against the low specificity of left ventricular scar.

The 2024 European Task Force consensus refined this framework. It graded the extent of LGE, promoted the ring-like pattern, better defined low voltages, repolarization abnormalities and arrhythmias of left ventricular origin, and distinguished the weight of genetic evidence: a pathogenic variant constitutes a major criterion, whereas a likely pathogenic variant constitutes a minor criterion, without either being an absolute requirement. The new scheme allows possible, borderline or definite classification even in acquired or idiopathic forms, but requires their etiology to be specified. The phenotype-etiology diagnosis avoids conflating genetics with scar.

Under the updated system, ALVC classification presupposes the absence of right-sided morphofunctional or structural criteria and at least one left-sided structural criterion. The diagnosis is definite with two major criteria, or one major and two minor criteria, or four minor criteria; borderline with one major and one minor or with three minor criteria; and possible with one major criterion or with two minor criteria, always combining different categories and retaining the left-sided structural requirement. The mandatory structural criterion prevents premature beats alone or a gene from defining the phenotype.

Endomyocardial biopsy is not routine. Right ventricular sampling may fail to capture a left-sided subepicardial disease, whereas left ventricular biopsy carries risks and is affected by sampling error. It may be indicated when active myocarditis, sarcoidosis, infiltrative disease or rapidly progressive forms need to be distinguished, preferably guided by imaging or mapping. A negative result does not exclude a focal lesion.

Differential diagnosis and major pitfalls

Myocarditis is the most frequent alternative. A single episode with edema and inferolateral LGE may heal without progression, whereas ALVC is supported by recurrence, persistent arrhythmias, scar progression, family history or a coherent genotype. Even the presence of histologic inflammation does not always resolve the issue because it may accompany cardiomyopathy. Reassessment over time is often more informative than a label assigned during the acute phase.

Cardiac sarcoidosis can cause conduction block, tachycardias, dysfunction and multifocal subepicardial or midmyocardial LGE. Basal septal involvement, focal PET uptake, lymphadenopathy, extracardiac disease and biopsy of an accessible site support the diagnosis, without any single element being sufficient. Appropriate immunosuppression for sarcoidosis makes the distinction therapeutically decisive. The inflammatory phenocopy should be excluded before concluding that disease is inherited.

Dilated cardiomyopathy more often shows marked dilatation and hypokinesia with limited midmyocardial septal scar, whereas ALVC tends to show a minimally dilated ventricle with more extensive inferolateral subepicardial fibrosis. These are tendencies, not rules; DSP and FLNC may present as DCM and advanced DCM may develop arrhythmias. Genotype, LGE pattern and the relationship between scar and dysfunction define the overlap zone.

Ischemic heart disease must be excluded according to age and clinical probability. An ischemic scar involves the subendocardium and follows a coronary territory, whereas a subepicardial stria does not; however, ischemia and cardiomyopathy may coexist. Coronary CT angiography or invasive angiography is used when indicated, without automatically attributing every abnormality to an incidental stenosis. Transmural distribution is more informative than the mere presence of LGE.

Muscular dystrophies and myofibrillar myopathies may produce lateral scar, arrhythmias and dysfunction. Weakness, contractures, CK, neurologic history and genetics provide direction, but cardiac disease may precede muscle signs. Fabry disease, amyloidosis and other infiltrative conditions also have specific tissue patterns and systemic manifestations. Extracardiac assessment reduces overly narrow cardiologic diagnoses.

The athlete's heart may show increased volumes and bradycardia, but does not explain extensive subepicardial scar, complex arrhythmias or regional dysfunction. Small foci at right ventricular insertion points have a different significance from an inferolateral stria; detraining may help clarify volumes but does not erase scar. Physiologic adaptation must be interpreted in relation to sport, sex and body surface area.

Isolated intramyocardial fat is not pathognomonic and its assessment by CMR is technically complex. Obesity, age and artifacts may simulate infiltration, whereas many ALVC cases are predominantly fibrotic and show no obvious fat. Likewise, an incidental LGE finding alone is not equivalent to arrhythmogenic cardiomyopathy. Diagnostic specificity arises from the combination of findings and reasoned exclusion of alternatives.

Risk stratification and treatment

The first prognostic decision concerns the risk of lethal arrhythmias. Resuscitated cardiac arrest, ventricular fibrillation or hemodynamically poorly tolerated sustained tachycardia are established indications for secondary prevention with a defibrillator, unless reversible conditions or contraindications are present. Even tolerated sustained ventricular tachycardia, when arising on an arrhythmogenic scar, requires individualized specialist assessment for an ICD rather than an automatic rule. A life-saving ICD terminates the arrhythmia but does not treat scar or prevent heart failure.

For primary prevention, ejection fraction is insufficient. Likely arrhythmic syncope, nonsustained tachycardia, premature ventricular beat burden, LGE extent and pattern, function of both ventricles, genotype, family history, age, sex and exercise exposure are integrated. Evidence specific to ALVC is less robust than that for ARVC. Shared decision-making compares estimated risk, device complications and patient preferences.

The risk calculator developed for arrhythmogenic right ventricular cardiomyopathy was derived mainly from patients diagnosed with ARVC and should not be transferred automatically to the left-sided form. In DSP or FLNC genotypes, left ventricular function and scar may carry weight not captured by the model. Using it outside its population can create false precision. External validity comes before numerical convenience.

Genotype changes the threshold for concern but does not by itself create a universal indication for an ICD. ESC guidelines allow prevention to be considered in some cardiomyopathies with high-risk variants and additional factors even when ejection fraction is above 35%. For DSP and FLNC, arrhythmic history and LGE are particularly important; for LMNA and PLN, additional gene-specific data exist. Integrated risk avoids genetic automaticity.

Beta-blockers reduce adrenergic stimulation and are used in the presence of arrhythmias, dysfunction or an implanted device, despite the absence of specific trials demonstrating absolute prevention of sudden death in ALVC. Sotalol or amiodarone may reduce recurrences and shocks in selected patients, taking QT interval, renal function, thyroid, lung and interactions into account. Antiarrhythmic therapy does not replace an ICD when it is indicated.

Catheter ablation treats recurrent monomorphic tachycardias or shocks not controlled by drugs. Because the left-sided substrate is often subepicardial, an exclusively endocardial procedure may not reach it; epicardial mapping and specialist access improve control in selected cases. Recurrences remain possible because of progression or multiple circuits. Substrate ablation reduces arrhythmic burden but does not eliminate the disease.

When systolic dysfunction develops, contemporary heart-failure therapy is applied with renin-angiotensin system inhibition or an ARNI, an evidence-based beta-blocker, a mineralocorticoid receptor antagonist and an SGLT2 inhibitor, adapted to blood pressure, renal function and potassium. Diuretics correct congestion. ALVC is not a reason to delay the four pillars, while acknowledging the scarcity of trials dedicated to this subtype.

Cardiac resynchronization follows criteria based on dyssynchrony, QRS duration and morphology, function and symptoms, and is not indicated for scar alone. In candidates who require pacing, system choice considers arrhythmic risk and future progression. An inferolateral scar may limit response or influence lead position. The device strategy requires imaging and long-term planning.

Competitive sports and high-intensity endurance exercise are generally discouraged in manifest disease. The aim is not to impose sedentary behavior, which is also harmful, but to prescribe low- or moderate-intensity activity after assessment of arrhythmias, function, symptoms and therapy. An ICD does not make an otherwise contraindicated level of exertion safe. The exercise prescription is reassessed if the phenotype changes.

Refractory heart failure, uncontrollable electrical storms or low output may require transplant evaluation. Ventricular assist support is technically possible in some advanced left-sided phenotypes, but right ventricular function, arrhythmias and scar distribution affect its outcome. Referral should precede irreversible kidney, liver or pulmonary vascular injury. The timing of referral is not synonymous with the last available option.

Family screening, follow-up and special situations

First-degree relatives receive clinical assessment even if the proband does not yet have a genetic result. ECG, ambulatory monitoring and imaging seek a phenotype that may be electrical, scar-related or functional; echocardiography alone is insufficient in families with left-sided involvement. Starting age and intervals depend on genotype, age at familial onset and activity. Multiparametric screening is repeated because penetrance evolves over time.

If a pathogenic or likely pathogenic variant is identified, targeted testing distinguishes carriers from non-carriers. A relative who tests negative for the causal variant can generally be discharged from specific surveillance, provided the variant confidently explains the family and there is no second affected branch. Phenotype-negative carriers do not automatically receive drugs or an ICD. Cascade testing focuses resources without unnecessary medicalization.

In genotype-positive, phenotype-negative carriers, follow-up seeks the first appearance of low voltages, ectopy, LGE or dysfunction. CMR should not be repeated at rigid intervals regardless of age, findings and contrast availability; it is scheduled when it can change classification or management. New symptoms bring the visit forward. Prephenotypic surveillance is preventive, not predictive of an inevitable fate.

Reproductive counseling separates transmission risk from the probability and severity of the phenotype. Natural conception, prenatal diagnosis and preimplantation genetic testing may be discussed in accordance with the couple's values and the law, without presenting any choice as mandatory. In variants with incomplete penetrance, communicating uncertainty is essential. Reproductive autonomy requires understandable, noncoercive information.

Pregnancy causes plasma volume expansion and increased cardiac demand. Many stable women tolerate it favorably with monitoring, but substantial dysfunction, uncontrolled arrhythmias or previous heart failure increase risk and require multidisciplinary planning. Potentially fetotoxic drugs should be reviewed before conception. Maternal risk is distinct from the genetic probability for the offspring.

Follow-up of patients with an ICD includes device interrogation, review of appropriate or inappropriate shocks, lead integrity and psychological impact. In young people, cumulative complications and generator replacements make a sound initial indication particularly important. Antitachycardia programming and detection zones are individualized. Device care continues long after implantation.

Anxiety, fear of exertion and occupational restrictions can become a substantial part of the disease. Accurate information, adapted rehabilitation and psychological support help maintain safe activity and quality of life without minimizing risk. Recommendations should be justified and updated, especially in younger patients. Comprehensive care therefore includes the person, family and clinical trajectory, not only the scar.

Arrhythmogenic left ventricular cardiomyopathy remains a diagnosis requiring expertise and longitudinal review. Ring-like LGE, a compatible gene or tachycardia of left ventricular origin are powerful but not self-sufficient pieces of information; phenocopies and classification errors may expose patients to unnecessary devices or, conversely, leave a vulnerable patient unprotected. The final principle is concordance of evidence, applied to proportionate decisions that are periodically reassessed.