Dilated cardiomyopathy: causes, family screening, recovery — practice case: DCM with conduction disease

Presentation

Practice case (not a real patient). A 34-year-old woman in New Zealand presents with 3 months of breathlessness on exertion (NYHA class II). Echo shows a dilated left ventricle with LVEF 30%; her coronary arteries are normal, her blood pressure is normal and she has no valve disease.^[1] Her ECG shows a PR interval of 260 ms with left bundle branch block. Her mother had a pacemaker at 48 and her maternal uncle, who had DCM, died suddenly at 45.^[1][8]

Step 1 — Work-up

Discussion:

• She meets the ESC 2023 definition of DCM: LV dilatation and systolic dysfunction unexplained solely by abnormal loading conditions or CAD.^[1]
• Systematic multiparametric evaluation (Class I, Level C) and a three- to four-generation family tree (Class I, Level C) are recommended (ESC 2023); AHA/ACC/HFSA 2022 also recommends a 3-generation family history (COR 1, LOE B-NR).^[1][4]
• In patients with established HF, ESC 2026 recommends contrast-enhanced CMR in suspected cardiomyopathy, or where the underlying aetiology of HF is uncertain, if further characterization is likely to add value to patient care (Class I, Level C); ESC 2023 notes that the LGE distribution may point towards specific aetiologies, for example septal mid-wall LGE in LMNA carriers.^[2][1]
• Conduction disease may be an early presentation of certain genetic DCM subtypes, and ESC 2023 gives LMNA, EMD and DES as examples of such gene variants.^[1]

Step 2 — Genetics

Discussion:

• In patients with established HF, ESC 2026 recommends genetic testing in patients fulfilling diagnostic criteria for cardiomyopathy where it enables diagnosis, prognostication, therapeutic stratification or reproductive management, or cascade genetic evaluation of relatives who would otherwise be enrolled into long-term surveillance (Class I, Level C), with pre- and post-test counselling (ESC 2023, Class I, Level B).^[2][1]
• In Australia and New Zealand, NHFA/CSANZ 2018 says genetic testing may be considered in DCM with conduction disease, for prognostic stratification and to guide ICD decisions (weak recommendation for; low quality of evidence).^[5]
• The panel shows a pathogenic LMNA variant. ESC 2022 notes that LMNA variants are associated with early arrhythmias, premature conduction disease, a high risk of SCD and progression to end-stage heart failure.^[3]

Step 3 — Treatment and devices

Discussion:

• ESC 2026 foundational therapy for symptomatic HFrEF includes these recommended drugs (each Class I, Level A): a beta-blocker (in stable patients) and an ACE-I or ARNI to reduce the risk of HF hospitalization and death, and an MRA (sMRA for HFrEF) and an SGLT2 inhibitor (dapagliflozin or empagliflozin) to reduce the risk of HF hospitalization or CV death.^[2]
• With an LMNA variant, prolonged PR interval and LBBB, ESC 2021 pacing says an ICD with pacing capability should be considered if at least 1-year survival is expected (Class IIa, Level C); ACC/AHA/HRS 2018 calls permanent pacing with defibrillator capability if needed reasonable when the PR interval exceeds 240 ms with LBBB and meaningful survival >1 year is expected (COR IIa, LOE B-NR).^[7][8]
• ESC 2023 Table 21 gives LMNA an annual SCD rate of 5–10%, with the LMNA risk score as the predictor; ESC 2023 says validated SCD algorithms or scores, where available, should be considered as aids to shared decision-making when offering ICD implantation in DCM (Class IIa, Level B), and its narrative adds that gene-specific scores should be used to guide primary prevention ICD implantation.^[1]
• The ICD decision is shared and evidence-based (ESC 2023, Class I, Level C), with counselling about inappropriate shocks, complications and driving (Class I, Level C).^[1]
• High-intensity exercise, including competitive sport, is not recommended with a pathogenic LMNA variant (ESC 2023, Class III, Level C); regular low- to moderate-intensity exercise is recommended in all able individuals with cardiomyopathy (Class I, Level C).^[1]
• For her chronic HFrEF, ESC 2026 cardiac rehabilitation recommends CR to reduce all-cause hospital admissions and improve physical functioning (VO₂ peak) and HRQoL (Class I, Level B1).^[11]

Step 4 — Family and pregnancy

Discussion:

• Now that a P/LP variant is known, cascade genetic testing with pre- and post-test counselling is recommended for her adult at-risk relatives, starting with first-degree relatives if available (ESC 2023, Class I, Level B); after cascade testing, first-degree relatives who carry the same variant need clinical evaluation including ECG and cardiac imaging and long-term follow-up (Class I, Level B).^[1]
• Psychological support should be offered to individuals who have experienced the premature sudden cardiac death of a family member with cardiomyopathy (ESC 2023, Class I, Level B).^[1]
• She asks about pregnancy: ESC 2025 recommends pre-conception genetic counselling in couples with heritable CVD (Class I, Level C), and lists severe LV systolic dysfunction and NYHA class III/IV among high-risk criteria for major adverse cardiovascular events during pregnancy in DCM.^[6]
• ESC 2025 says ACE-Is, ARBs, ARNIs, MRAs, ivabradine and SGLT2 inhibitors are not recommended during pregnancy due to adverse foetal effects (Class III, Level C).^[6]

Examiner criteria

• Pass: confirms DCM against the ESC 2023 definition; takes a three-generation family history; recognises conduction disease as an LMNA clue and offers genetic testing with counselling; starts foundational therapy; applies the LMNA pacing and ICD rows with shared decision-making; arranges cascade testing of adult relatives for the P/LP variant and psychological support; counsels on pregnancy and drug contraindications.^[1][2][7][6]
• Fail: implants a pacemaker without considering defibrillator capability in an LMNA carrier, skips genetic testing, or advises high-intensity sport with an LMNA variant.^[7][8][2][1]