Dilated Cardiomyopathy (DCM)

Details

Dilated cardiomyopathy is defined as left ventricular dilatation with global or regional systolic dysfunction not explained solely by abnormal loading conditions (hypertension, valve disease, congenital heart disease) or coronary artery disease; right ventricular involvement may be present but is not required. (sources/esc-cmp-2023, rating: very high) Prevalence in adults is 0.036–0.400%, and DCM is the leading indication for cardiac transplantation. About 30% of patients carry a monogenic cause; the remainder reflect non-genetic insults — viral myocarditis, autoimmune disease, alcohol, anthracyclines or trastuzumab, metabolic disease, peripartum cardiomyopathy and tachycardia-induced cardiomyopathy — frequently acting on an inherited predisposition (the "second hit" model). Pharmacological management follows heart failure guidelines; device and ICD decisions are increasingly genotype-informed. (sources/esc-cmp-2023)

Key Facts

Diagnosis

• Core criteria: LV dilatation plus global or regional systolic dysfunction, not explained by abnormal loading or coronary disease; RV involvement is optional. (sources/esc-cmp-2023, rating: very high)
• "Isolated LV dilatation" with normal ejection fraction does not fulfil DCM criteria but may represent early DCM. (sources/esc-cmp-2023)
• CMR is recommended at baseline. The LGE pattern narrows the differential: (sources/esc-cmp-2023)

• Biomarkers: NT-proBNP/BNP and high-sensitivity troponin T carry diagnostic, prognostic and therapeutic-monitoring value. (sources/esc-cmp-2023)
• Hypokinetic non-dilated cardiomyopathy (HNDCM) is an ESC 2022 phenotype — wall motion abnormality without the dilatation required for classic DCM; it is managed identically to DCM for VA and SCD purposes. (sources/VA-SCD-ESC-2022, rating: very high)
• Pinto 2016 criteria for at-risk relatives — first-degree relatives need ECG and echocardiography from childhood, annually through adolescence, then every 2–3 years in adults: (sources/dcm-precision-hfreview-2022, rating: high)

Causes and Mimics

• Non-genetic causes include viral myocarditis, autoimmune disease, toxins (alcohol, anthracyclines, trastuzumab), metabolic disease, peripartum cardiomyopathy and tachycardia-induced cardiomyopathy. (sources/esc-cmp-2023, rating: very high)
• Mitochondrial DCM is caused by nuclear- and mtDNA-encoded genes — TAFAZZIN (Barth syndrome), DNAJC19 (DCMA syndrome), TWNK/C10orf2, MGME1 and OXPHOS complex I/III/IV deficiencies. These genes are not included in standard DCM panels, so a negative panel does not exclude a mitochondrial cause; WGS is first-line when maternal inheritance, multisystem disease, elevated lactate, hearing loss or diabetes are present. DCM may also follow mitochondrial HCM as systolic function declines. See concepts/Mitochondrial-Cardiomyopathy and concepts/Heteroplasmy. (sources/mitochondrial-cv-aha-2025, rating: very high)
• Peripartum cardiomyopathy (PPCM) presents in the last month of pregnancy or within 5 months of delivery without another cause; risk factors are African ancestry, multiparity, hypertensive disorders of pregnancy and advanced maternal age. About 15% of patients carry loss-of-function variants in DCM genes at nearly identical frequencies to DCM cohorts, supporting a shared genetic spectrum in which pregnancy is the environmental second hit; FLNC and DSP variants may carry the same VA risk as in DCM, and LAMP2 (Danon) or DMD variants can present first as PPCM. See entities/Peripartum-Cardiomyopathy. (sources/DCM-Lancet-2023, rating: very high; sources/peripartum-cmp-nejm-2024, rating: high)
• Second-hit model: genetic predisposition plus an environmental trigger — alcohol, pregnancy, chemotherapy — drives phenotypic expression. TTNtv are enriched in alcoholic (13.5%) and cancer-therapy-induced cardiomyopathy. (sources/esc-cmp-2023)

Genetics

• Genetic yield: ~30% of DCM patients carry a monogenic cause. (sources/esc-cmp-2023, rating: very high)
• ClinGen gene–disease validity for DCM (curation dated 2026-05-09): (sources/clingen-summary-2026-05-09, rating: high)

• PKP2 is disputed for DCM despite being the primary ARVC gene — a "PKP2-positive, DCM" report should prompt reconsideration of an ARVC/ALVC phenotype. MYBPC3, the leading HCM gene, has only limited DCM evidence. See concepts/ClinGen-Gene-Disease-Validity. (sources/clingen-summary-2026-05-09)
• Genotype–phenotype associations:

• GWAS and polygenic risk:
  • Loci at MYBPC3, ALPK3 and FHOD3 show opposing effect directions for HCM and DCM — the allele raising HCM susceptibility lowers DCM susceptibility. This places HCM (sarcomere stiffness) and DCM (sarcomere insufficiency) at opposite poles of one contractility axis, mirrored therapeutically by mavacamten (HCM) and omecamtiv mecarbil (DCM). See concepts/GWAS-Cardiac-Genetics. (sources/gwas-arrhythmias-cmp-genes-2025, rating: high)
  • Jurgens 2024 DCM PRS validated multi-ancestry: OR 1.73 (European), 1.61 (African) and 1.34 (Admixed-American) per SD — the most ancestry-diverse cardiac PRS validation for any cardiomyopathy. A common low-frequency BAG3 p.C151R variant acts as an independent modifier, sitting between the common- and rare-variant spectra. See concepts/Polygenic-Risk-Score. (sources/gwas-arrhythmias-cmp-genes-2025)
• TTNtv pathomechanism: truncating TTN variants account for 15–25% of DCM and are also the commonest predisposition in peripartum, alcoholic and anthracycline cardiomyopathy. The mechanism is triple — lifelong titin haploinsufficiency, late truncated-protein toxicity (truncated titin reaches up to 50% of the titin pool and correlates with younger age at transplantation) and progressive protein-quality-control failure. UPS inhibition and CRISPR correction each restore wild-type titin and contractility in hiPSC-CMs. See entities/TTN. (sources/TTN-CVResearch-2022, rating: high)

Genetic Testing

• Who to test and with what:

• Expected yield: 10–40% in familial DCM and 10–25% in isolated DCM; ESC 2023 reports ~30%, while a pooled mean is ~19% and some familial cohorts reach ~50%. (sources/genetic-cmp-jcf-2018, rating: very high; sources/esc-cmp-2023)
• Gene frequencies: TTN 10–20%, LMNA 5.5%, BAG3 and RBM20 ~2% each; adding TTN and BAG3 to a panel raises yield by >10%. Multigene panel testing is standard of care, and all HCM and ARVC genes should be included because of phenotype overlap. (sources/genetic-cmp-jcf-2018)
• TTNtv interpretation caveat: population frequency, non-segregation and population-level LV function decrements mean some TTNtv behave as risk alleles rather than fully penetrant pathogenic variants. (sources/genetic-cmp-jcf-2018)
• Early-onset AF: a cardiomyopathy/arrhythmia panel yields ~10% P/LP — comparable to non-familial DCM; in the largest cohort (n=1293) DCM genes explained 7.2% of EOAF patients, HCM genes 3.3% and ARVC genes 2.9%. (sources/genetic-eoaf-ehj-2024, rating: high)
• Special populations: genetic evaluation should be considered in peripartum cardiomyopathy (TTNtv rates similar to DCM); carrier mothers of Duchenne/Becker patients may develop DCM in the 3rd–5th decade. (sources/genetic-cmp-jcf-2018)
• See concepts/Genetic-Testing-in-Cardiomyopathy and concepts/Cascade-Family-Screening.

Management

• Pharmacological therapy follows the four-pillar HFrEF model — ACEi/ARNI + beta-blocker + MRA + SGLT2 inhibitor (dapagliflozin or empagliflozin), reducing cardiovascular death and worsening HF. Under ESC 2026, SGLT2 inhibitors and MRAs are Class I, Level A in all symptomatic HF regardless of ejection fraction, and HFrEF absorbs the former HFmrEF band. See entities/HFrEF. (sources/HF-ESC-2026, rating: very high; sources/esc-cmp-2023)
• Do not withdraw therapy after recovery (HFimpEF): in TRED-HF, withdrawal after partial or complete LVEF recovery (>40%) caused relapse in 44% within 6 months, with early remodelling even in non-relapsers. AHA 2022 gives continuation Class 1 (LOE B-R); only ~50% of attempted withdrawals succeed long term. See entities/HFrEF. (sources/HF-ESC-2021; sources/HF-AHA-2022, rating: very high)
• Genotype-specific reverse remodelling: ~40% achieve significant LVRR with optimal medical and device therapy over 6 months–2 years. TTN pathogenic variants predict a higher likelihood (Verdonshot; dal Ferro); LMNA, FLNC, DES and DMD predict lower rates (dal Ferro). (sources/dcm-precision-hfreview-2022, rating: high)
• "Apparent healing": ~15% normalise LV size and function on therapy and remain normal at 10 years, but 5% deteriorate again by 15 years (HF, transplantation or ICD requirement) — lifelong therapy and follow-up are required. (sources/dcm-precision-hfreview-2022)
• Iron deficiency (ESC 2026 update): defined by transferrin saturation <20% alone — the 2021 ferritin-based definition is considered unreliable. IV iron is Class I, Level B1 for symptoms and quality of life and Class IIa, Level B1 to reduce HF hospitalisation, in HFrEF. This supersedes the ESC 2023 framing (ferritin <100 μg/L or TSAT <20%; Class I, Level A for symptoms and IIa, Level A for hospitalisation). (sources/HF-ESC-2026, rating: very high; sources/HF-update-ESC-2023, very high)
• Post-discharge strategy (STRONG-HF): intensive oral therapy up-titration before discharge plus close follow-up (congestion, BP, HR, NT-proBNP, K⁺, eGFR) during the first 6 weeks — Class I, Level B to reduce rehospitalisation or death. (sources/HF-update-ESC-2023)
• Atrial fibrillation: anticoagulation and rate or rhythm control follow standard AF guidance. See entities/Atrial-Fibrillation.
• Advanced therapy: cardiac transplantation and LVAD for end-stage HF refractory to medical therapy. (sources/esc-cmp-2023)
• Single-pathway therapy has failed in LMNA-DCM: the phase 3 REALM-DCM trial of the p38α-MAPK inhibitor PF-07265803/ARRY-371797 showed no benefit, consistent with LMNA acting simultaneously in cardiomyocytes, fibroblasts, endothelial and inflammatory cells. (sources/DCM-Lancet-2023, rating: very high)
• Gene therapy pipeline: AAV9-LAMP2B for Danon disease (NCT03882437) showed preliminary efficacy without prohibitive toxicity — the first proof-of-concept for AAV gene therapy in a monogenic cardiomyopathy; PLN-ASO prevented PLN aggregation and improved survival in PLN-R14del mice; CRISPR-Cas9 is in phase 3 ex vivo for sickle cell disease, with in vivo cardiac use awaiting cardiac-specific delivery. See concepts/AAV-Gene-Delivery, concepts/Gene-Silencing-Therapy and entities/CRISPR-Therapeutics. (sources/DCM-Lancet-2023)

Arrhythmia, SCD and Devices

• SCD risk varies by genotype; LMNA, FLNC and RBM20 carry the highest risk. Gene-specific calculators exist for LMNA and PLN p.Arg14del. (sources/esc-cmp-2023, rating: very high)
• VA risk predictors (Sammani 2020 meta-analysis, 55 studies, 11,451 patients): (sources/VA-DCM-Sammani-2020, rating: high)

• Non-pooled signals include nsVT (significant in 9/14 studies), TWA (HR 6.5) and PLN/LMNA/FLNC mutations. Categorical LVEF cutoffs (<30%, <35%) were non-significant — LVEF alone is insufficient for risk stratification. See concepts/VA-Risk-Stratification-DCM. (sources/VA-DCM-Sammani-2020)
• ICD indications:

• VT substrate: patchy, interstitial or diffuse midwall/epicardial fibrosis unrelated to coronary supply, with two dominant patterns — intramural anteroseptal and subepicardial inferolateral. Anteroseptal scars have higher ablation failure; inferolateral scars are more often approached epicardially. RBBB VT with inferior axis and positive concordance, or LBBB VT with transition ≤V3, suggests anteroseptal substrate; RBBB VT with transition ≥V5 suggests inferolateral scar. (sources/vt-dcm-hrs-2018, rating: high)
• Ablation outcomes: acute success 38–73%, recurrence 46–60% at 1 year, and complications up to 9%; one series reported 69% VT-free survival at 60 months with multiple procedures in 36%. Non-inducibility is the key endpoint; low LVEF, prior VT storm, high VT burden and failed antiarrhythmic drug trials predict recurrence. (sources/vt-dcm-hrs-2018)
• Endo-epicardial scar homogenisation (93 patients, non-randomised) improved acute non-inducibility (69.4% vs 42.1%) and VA-free survival (64% vs 39% at 14 months; adjusted HR 0.48), with fewer rehospitalisations but longer RF and fluoroscopy times; recurrences clustered in septal/midmyocardial and perivalvular scar. (sources/vt-ablation-nicm-jacc-2016, rating: medium)
• Versus ischaemic cardiomyopathy: in HELP-VT, 1-year VT-free survival was 40.5% in NICM versus 57.0% in ischaemic cardiomyopathy (p=0.039), with more repeat procedures in NICM. (sources/vt-ablation-jaccep-2019, rating: high)
• Epicardial substrate mandates epicardial ablation in 32–63% of NICM patients because of midmyocardial and basal perivalvular scar. See concepts/VT-Ablation-Nonischemic-Cardiomyopathy and concepts/Epicardial-VT-Ablation. (sources/epicardial-vt-ablation-jaccep-2024, rating: high)
• Drugs: amiodarone is first-line for recurrent ICD shocks despite optimal programming; disopyramide, flecainide and sotalol should generally be avoided in HFrEF because of proarrhythmia and worsening LV function. The evidence predates contemporary GDMT. See concepts/VT-Management. (sources/vt-dcm-hrs-2018)
• ICD programming: high-rate cutoffs, long detection, empirical ATP and high-output first shocks reduced appropriate and inappropriate shocks and were associated with 30% lower mortality in a meta-analysis — not validated in a DCM-only randomised trial. (sources/vt-dcm-hrs-2018)

Sports and Exercise

• Low-to-moderate intensity recreational exercise is integral to DCM management. (sources/DCM-Lancet-2023, rating: very high)
• Competitive and high-intensity sport:

• Exercise echocardiography distinguishes DCM from athlete's heart: inability to increase LVEF >11% or a peak LVEF >63% has >80% sensitivity and >90% specificity for DCM, outperforming ECG + BNP + 24-h Holter + CMR, which misses >30% of mild DCM in endurance athletes. (sources/dcm-precision-hfreview-2022)
• Contraindications to high-intensity exercise (shared decision-making required): LVEF <45%; unexplained syncope; extensive fibrosis on CMR or biopsy; high-risk genotype (LMNA, FLNC); frequent VT on Holter or exercise testing. See concepts/Sports-Cardiology-SDM. (sources/DCM-Lancet-2023)

Hypertrabeculation — a Trait, Not a Prognosis

• Left ventricular hypertrabeculation is present in ~30% of DCM by either fractal-dimension or Petersen criteria, and predicts nothing after adjustment for genotype, LGE, NYHA class and LVEF (embolism HR 1.50, 0.75–3.00; MVA HR 0.93, 0.59–1.48; advanced HF HR 0.82, 0.43–1.57). (sources/trabeculation-dcm-circ-2026, rating: high)
• Hypertrabeculation is commonest in the genotypes with the best prognosis — motor sarcomeric 57%, TTN 38%, genotype-negative 33% — and rarest in the worst: nuclear envelope 5% (LMNA 1 of 20), cytoskeleton/Z-disk 7%. The genotypes that cause arrhythmic death do not produce the trait.
• Do not anticoagulate for hypertrabeculation. Embolic events were 3.2% over 5.1 years with no excess in hypertrabeculated patients, including in sinus rhythm with LVEF ≤40% (HR 1.89, 0.66–5.46). AF (HR 3.26) and low LVEF (HR 1.04 per 1% decrease) carried the risk. See concepts/LV-Hypertrabeculation.

Pregnancy

• DCM carries the highest maternal risk of the inherited cardiomyopathies: major adverse cardiovascular events in 39% of pregnancies and maternal mortality up to 7% in high-risk groups. (sources/cmp-pregnancy-jaccadv-2026, rating: medium)
• Pre-pregnancy LVEF <50% is the strongest predictor of poor outcome — of heart failure, further LVEF deterioration and death. It outranks every genetic variable: genotype predicts how likely the LVEF is to fall, the echocardiogram says where it is now.
• mWHO classification by ejection fraction: LVEF 30–45% is mWHO III — pregnancy discouraged and not fully recommended, requiring intensive specialist monitoring; LVEF <30% or NYHA III–IV is mWHO IV — pregnancy contraindicated, and if continued, Pregnancy Heart Team assessment at a tertiary centre with at least monthly follow-up.
• Pregnancy forces withdrawal of the therapy that was controlling the disease. ACE inhibitors, ARBs, MRAs, SGLT2 inhibitors, ivabradine and vericiguat all must be stopped and replaced with beta-blockers, hydralazine and nitrates — and the conversion itself can precipitate reflex hypertension or decompensation. Severe or symptomatic patients may need admission to make the switch safely.
• Surveillance: every 3 months in low-risk patients (2025 European guideline) with NT-proBNP, ECG, echocardiogram and 24-hour Holter; bimonthly at mWHO II; monthly at mWHO III.
• Delivery at ≥39 weeks unless function is worsening, arrhythmia burden is increasing, or preeclampsia develops; vaginal delivery preferred, with neuraxial anaesthesia and telemetry intrapartum and through the immediate postpartum period.
• ESC 2023's nondilated LV cardiomyopathy has no pregnancy outcome data; management is extrapolated from DCM. See concepts/Pregnancy-in-Genetic-Cardiomyopathy.

Contradictions / Open Questions

• Dual Class IIa ICD thresholds within ESC 2022 itself: the standard threshold (LVEF ≤35%, NYHA II–III, ≥3 months OMT) and the multi-risk-factor threshold (LVEF <50% plus ≥2 risk factors) are both Class IIa despite meaningfully different LVEF cutoffs. A patient with LVEF 40% and an LMNA mutation could qualify under either with no guidance on which applies. (sources/VA-SCD-ESC-2022)
• ESC 2022 versus ESC CMP 2023 on genotype-guided ICD: ESC CMP 2023 recommends ICD for LMNA, FLNC, RBM20, DES and TMEM43 carriers with LVEF >35% and additional risk factors, citing genotype-specific calculators; ESC VA 2022 uses the LVEF <50% + ≥2 factors framework for the same population. The criteria overlap but are not identical. (sources/VA-SCD-ESC-2022, sources/esc-cmp-2023)
• The standard DCM ICD threshold was downgraded from Class I to Class IIa between the 2015 and 2022 ESC guidelines, reflecting DANISH's failure to show an all-cause mortality benefit in DCM — yet the Class I indication for CAD with identical LVEF/NYHA criteria was maintained. The distinction remains controversial. (sources/VA-SCD-ESC-2022)
• Is TTNtv a pathogenic variant or a risk allele? Population frequency, non-segregation in some families and population-level LV function decrements suggest that some TTNtv behave as risk alleles rather than fully penetrant causes; the penetrance threshold and surveillance implications are unresolved. (sources/genetic-cmp-jcf-2018)
• PKP2 is disputed for DCM (ClinGen, 2025-05-30) despite being the definitive ARVC gene, and MYBPC3 has only limited DCM evidence (2026-03-04) despite being the most common HCM gene. Reports linking either gene to "DCM" should prompt phenotype re-review. (sources/clingen-summary-2026-05-09, rating: high)
• The actionable DCM gene list is expanding: DES, FLNC, TNNC1, TNNT2 and CAMK2D have moved to definitive or strong evidence in 2025–2026, and TNNI3 now has strong evidence for both AD and AR DCM — beyond the traditional TTN/LMNA/RBM20/MYH7/SCN5A core. (sources/clingen-summary-2026-05-09)
• Exercise guidance conflicts across guidelines: AHA/ACC 2025 considers competitive sport reasonable to consider in clinical DCM after shared decision-making, whereas ESC 2020/2022 permit high-intensity sport only when five criteria are met and prohibit it outright in LMNA/FLNC carriers. The same athlete can be eligible under one framework and ineligible under the other. (sources/competitive-sports-aha-2025, sources/dcm-precision-hfreview-2022, sources/VA-SCD-ESC-2022)
• ICD programming evidence is extrapolated: the therapy-reduction bundle associated with 30% lower mortality comes from mixed-cohort meta-analysis, not a DCM-only randomised trial. (sources/vt-dcm-hrs-2018)
• Gene therapy timing is unresolved: when to initiate cardiac gene therapy — and how to balance benefit against the risk of the adjunctive immunosuppression or delivery procedure — has no evidence base. (sources/DCM-Lancet-2023, rating: very high)
• Hypertrabeculation is classified as a cardiomyopathy by one society and a trait by another, and the DCM data support the trait. The AHA calls it a primary cardiomyopathy; ESC 2023 calls it a phenotypic trait. In 1,160 genotyped DCM patients it was neither prognostic overall nor within any genotype — but the genotypes with the worst prognosis contained almost no hypertrabeculated patients, so the negative interaction is underpowered exactly where it matters. (sources/trabeculation-dcm-circ-2026, rating: high)
• Prophylactic anticoagulation in hypertrabeculated DCM is still recommended in several reviews and guidelines despite a contemporary embolic rate of ~0.5 per 100 patient-years. The recommendation rests on 1990s case series that rarely reported whether AF was present — and in this cohort 57% of embolic events were AF events. The residual uncertainty is real (adjusted HR 1.89 in sinus rhythm with LVEF ≤40%, CI to 5.46) but the absolute risk does not support treating the group. (sources/trabeculation-dcm-circ-2026)

Connections

• Phenotype and overlap: entities/Heart-Failure · entities/HFrEF · entities/NDLVC · entities/Peripartum-Cardiomyopathy · entities/HCM (inverse contractility axis) · entities/ARVC (PKP2 dispute) · concepts/Mitochondrial-Cardiomyopathy · concepts/Heteroplasmy
• Genetics and testing: entities/TTN · entities/LMNA · entities/FLNC · entities/PLN · entities/MYBPC3 · entities/SCN5A · concepts/ClinGen-Gene-Disease-Validity · concepts/Genetic-Testing-in-Cardiomyopathy · concepts/Cascade-Family-Screening · concepts/GWAS-Cardiac-Genetics · concepts/Polygenic-Risk-Score · concepts/Titin-Isoform-Switch · concepts/Titin-PTMs · concepts/MEPPC
• Arrhythmia and devices: concepts/VA-Risk-Stratification-DCM · concepts/VT-Ablation-Nonischemic-Cardiomyopathy · concepts/Epicardial-VT-Ablation · concepts/VT-Management · entities/ICD · concepts/Sudden-Cardiac-Death · concepts/Late-Gadolinium-Enhancement
• Pregnancy: concepts/Pregnancy-in-Genetic-Cardiomyopathy · concepts/mWHO-Classification · concepts/Cardio-Obstetrics
• Therapy and clinical approach: concepts/Sports-Cardiology-SDM · concepts/LV-Hypertrabeculation · concepts/AAV-Gene-Delivery · concepts/Gene-Silencing-Therapy · entities/CRISPR-Therapeutics · concepts/Phenotypic-Approach-to-Cardiomyopathy

Sources

• sources/DCM-Lancet-2023
• sources/trabeculation-dcm-circ-2026
• sources/cmp-pregnancy-jaccadv-2026
• sources/HF-AHA-2022
• sources/HF-ESC-2021
• sources/HF-ESC-2026
• sources/HF-update-ESC-2023
• sources/TTN-CVResearch-2022
• sources/VA-DCM-Sammani-2020
• sources/VA-SCD-ESC-2022
• sources/clingen-summary-2026-05-09
• sources/competitive-sports-aha-2025
• sources/dcm-precision-hfreview-2022
• sources/epicardial-vt-ablation-jaccep-2024
• sources/esc-cmp-2023
• sources/genetic-cmp-jcf-2018
• sources/genetic-eoaf-ehj-2024
• sources/gwas-arrhythmias-cmp-genes-2025
• sources/mitochondrial-cv-aha-2025
• sources/mybpc3-gene-2015
• sources/peripartum-cmp-nejm-2024
• sources/scn5a-jaccep-2018
• sources/vt-ablation-jaccep-2019
• sources/vt-ablation-nicm-jacc-2016
• sources/vt-dcm-hrs-2018