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may contribute to the indications for device implantation, informs genetic counselling, and allows familial screening for relatives. Moreover, genetic testing in DCM has long-term implications in terms of costeffectiveness by identifying at-risk family members with positive genotypes, and thus reducing the number of family members requiring serial clinical follow-up.229 Genetic testing can therefore be beneficial in all patients with DCM, including children856,857 and those with alcohol-/ chemotherapy-induced and peripartum DCM. Where resources are limited, scores designed to identify DCM patients with a high probability of a positive genotype (e.g. the Madrid DCM Genotype Score [https://madridDCMscore.com]) may be considered to prioritize genetic testing.858 Of note, age should not be a limiting factor when deciding which DCM patients should undergo genetic testing.185,858,859 Recommendations for clinical screening, genetic counselling, and testing are described in Sections 6.8.3 and 6.11. More detailed evaluation of conduction defects or arrhythmia, which may be an early presentation of certain genetic DCM subtypes, should be considered in the context of certain gene variants (e.g. LMNA, EMD, DES). Cardiac MRI should also be considered in relatives with normal cardiac function who carry causative genetic variants associated with increased risk of SCD (e.g. FLNC, DES, DSP, PLN, LMNA, TMEM43, RMB20). If there are no additional family members with DCM, other than the proband, periodic evaluation of first-degree relatives should follow the same intervals according to age (see Section 6.11), but termination of periodic surveillance in families in whom a genetic variant has not been identified could be considered in first-degree relatives ≥50 years of age with normal ECG and normal cardiac imaging tests.

7.2.3 Assessment of symptoms

Patients with DCM often develop symptoms of heart failure, although this can occur many years after the appearance of ECG or echocardiographic abnormalities. Assessment of symptoms in patients with cardiomyopathies is described in Section 6.10.1.

7.2.4 Management

The clinical management of heart failure and other manifestations of DCM has been described in the 2021 ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure, the 2020 ESC Guidelines for the diagnosis and management of atrial fibrillation, and the 2021 ESC Guidelines on cardiac pacing and cardiac resynchronization therapy.69,336,724 In these guidelines, recommendations are generally independent of the aetiology of heart failure, AF, and other clinical presentations. As such, although they summarize large and robust datasets and trials, the treatment recommendations must be regarded as generic and not specific to the different forms of genetic DCM. However, as large cohorts of genetic DCMs with uniform genetic features are relatively rare, adequately powered RCTs in cardiomyopathies are scarce. The Task Force therefore recommends applying the 2021 ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure, which contain treatment guidelines for patients with signs and symptoms of heart failure, for symptom management of patients with DCM.69 Treatment recommendations for asymptomatic LV dysfunction or dilatation are scarce, which presents a challenge for genetic DCM, where a sizeable proportion of the patients are young with no or mild symptoms, and where asymptomatic patients are frequently discovered through cascade screening. Recommendations for the pharmacological management of heart failure symptoms in patients with cardiomyopathies are described in Section 6.10.2. 7.2.5 Sudden cardiac death prevention in dilated

cardiomyopathy Predicting SCD is a challenging aspect of the clinical care of patients with DCM. Implantable cardioverter defibrillators are effective at treating potentially lethal ventricular arrhythmias and preventing SCD, but are also associated with complications, particularly in young patients, who will require several replacements during their lifetimes (see Section 6.10.5).

7.2.5.1 Secondary prevention of sudden cardiac death

Implantable cardioverter defibrillators reduce mortality in survivors of cardiac arrest and in patients who have experienced sustained symptomatic ventricular arrhythmias with haemodynamic compromise.531 An ICD is recommended in such patients when the intent is to increase survival; the decision to implant should consider the patient’s view and their QoL, as well as the absence of other diseases likely to cause death within the following year.

7.2.5.2 Primary prevention of sudden cardiac death

Available RCTs examining the usefulness of ICDs to prevent SCD and improve survival have included only patients with LVEF ≤35%, with conflicting results. While a trial including both ischaemic and nonischaemic symptomatic heart failure patients showed reduction in mortality,860 trials including only patients without CAD did not significantly improve the overall risk of mortality despite the fact that there was an absolute reduction in SCD with ICDs, and subgroup analysis suggested that there was a survival benefit in patients ≤70 years.861,862 Nevertheless, in a recent meta-analysis of studies that examined the effect of ICDs in DCM, a survival benefit was observed, although the effect was modest compared with LVEF ≤35% patients with CAD.863 Although LVEF ≤35% has been reported as an independent risk marker of all-cause and cardiac death in DCM, it has also shown only modest ability in identifying DCM patients with higher risk of SCD, suggesting that additional factors should be taken into consideration when deciding on ICD implantation in a disease with significant aetiological heterogeneity. Recent natural history studies suggest that phenotype plays a role a role in SCD risk, with patients harbouring disease-causing variants in PLN, DSP, LMNA, FLNC, TMEM43, and RBM20 having a substantially higher rate of major arrhythmic events than other causes of DCM regardless of LVEF.440,542,864–870 A recent retrospective study of 1161 individuals with DCM has shown that DCM patients with P/ LP DCM-causing genetic variants have a worse clinical evolution and higher rate of major arrhythmic events than genotype-negative DCM patients and particularly in DCM patients with LVEF ≤35%.185 The study also observed a higher risk of major arrhythmic events in DCM patients affected by DCM-causing variants in certain genotypes regardless of LVEF. Genes associated with higher arrhythmic risk included genes coding for nuclear envelope (LMNA, EMD, TMEM43), desmosomal (DSP, DSG2, DSC2, PKP2), and certain cytoskeletal proteins.185 Together, these data suggest that DCM patients harbouring DCM-causing variants in high-risk genes (LMNA, EMD, TMEM43, DSP, RBM20, PLN, FLNC-truncating variants) should be considered as patients with a high-risk genetic background for SCD and primary prevention ICD implantation should be considered with LVEF thresholds higher than 35%, particularly in the presence of additional risk factors (e.g. NSVT, increased ventricular ectopic beats, male sex, significant LGE, specific gene variant). For some high-risk genotypes (e.g. LMNA [https://lmna-risk-vta.fr]541), gene-specific (or, in the case of the PLN Downloaded from academic.oup.com/eurheartj/article/44/37/3503/7246608 by guest on 07 October 2026