Evaluation and Management of Ventricular Tachycardia in Patients with Dilated Cardiomyopathy

Authors, Journal, Affiliations, Type, DOI

• Authors: Micaela Ebert, Sergio Richter, Borislav Dinov, Katja Zeppenfeld, Gerhard Hindricks
• Journal: Heart Rhythm 2019;16(4):624–631 (published online 2018)
• Affiliations: Department of Electrophysiology, HELIOS Heart Center – University of Leipzig, Leipzig, Germany; Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands
• Type: Contemporary review
• DOI: 10.1016/j.hrthm.2018.10.028

Overview

This review addresses ventricular tachycardia (VT) in non-ischaemic dilated cardiomyopathy (DCM), a heterogeneous population in which most treatment evidence has been extrapolated from ischaemic cardiomyopathy. It separates DCM from hypokinetic non-dilated cardiomyopathy, then reviews risk markers (ECG-based parameters, programmed ventricular stimulation, imaging, genetics), the arrhythmogenic substrate (patchy midwall and epicardial fibrosis with two dominant scar patterns), and management (ICD, antiarrhythmic drugs and catheter ablation). The central argument is that LVEF ≤35% alone is an inadequate selection criterion for primary-prevention ICDs in DCM, and that the substrate's intramural and epicardial location makes ablation less successful than in post-infarction disease. The review is a narrative synthesis of evidence available in 2018, not a systematic review.

Keywords

Catheter ablation; Dilated cardiomyopathy; Implantable cardioverter-defibrillator; Non-ischaemic; Risk stratification; Sudden cardiac death; Ventricular tachycardia

Key Takeaways

Definitions and disease heterogeneity

• DCM is defined by left ventricular (LV) or biventricular systolic dysfunction with dilatation; hypokinetic non-DCM is systolic dysfunction (LVEF <45%) without dilatation.
• DCM remains an umbrella term covering infection, inflammation, infiltration, hypertension, valvular disease, drugs, toxins and pregnancy; the aetiology is unclear in about half of cases.
• Familial disease accounts for 25–50% of DCM, a genetic cause is identified in up to 40%, and more than 50 disease-related genes have been described.

Clinical and ECG risk markers

• Syncope carries an event rate similar to sustained VT and identifies a high-risk group.
• Atrial fibrillation has been associated with appropriate ICD therapies; long–short sequences, shortened ventricular refractoriness and QT dispersion are proposed proarrhythmic mechanisms.
• In a meta-analysis of risk tools, T-wave alternans (TWA) and fragmented QRS had the highest odds ratios for arrhythmic events, and TWA was the most sensitive; however, sensitivity (28.8–74.2%) and specificity (36.2–78.4%) are too low for individual decisions.
• LVEF ≤35% remains the only primary-prevention ICD criterion in the guidelines discussed.

Programmed ventricular stimulation

• Inducibility has limited positive predictive value: pooled sensitivity 28.8%, specificity 87.1%, PPV 29.2%, NPV 86.9%.
• QRS prolongation during programmed stimulation, a marker of progressive activation delay, predicts inducible polymorphic VT/VF and correlates with long, thick interstitial fibrosis strands rather than with focal LGE.
• An electrophysiology study may refine risk in early DCM when a discrete scar is not visible on CMR.

Arrhythmogenic substrate and scar patterns

• The substrate is myocardial fibrosis producing conduction slowing, unidirectional block and re-entry; unlike post-infarction scar it is rarely compact, often non-transmural and less often subendocardial.
• Fibrosis is patchy, interstitial or diffuse, affects both ventricles and the epicardium, and is frequently basal/mid-myocardial, unrelated to coronary supply.
• Two dominant patterns account for most substrate: intramural anteroseptal and subepicardial inferolateral.
• Anteroseptal scars are harder to ablate (endocardial/aortic-root access, epicardial anatomical constraints) and have higher ablation failure rates; inferolateral scars are more often approached epicardially.

ECG prediction of substrate location

• Anteroseptal substrate: RBBB VT with left or right inferior axis and positive concordance, or LBBB VT with left/right inferior axis and an early precordial transition at ≤V3.
• Inferolateral substrate: RBBB VT with right inferior or superior axis and a late transition at ≥V5.
• LBBB VT with transition ≥V5 or RBBB VT with transition ≤V3 suggests larger low-voltage areas with apical scar extension.

Imaging and electroanatomical mapping

• LGE-CMR detects myocardial fibrosis in 40–50% of DCM; its presence, extent and location predict monomorphic VT irrespective of LVEF.
• Midwall LGE identifies increased SCD risk in patients with only mildly or moderately reduced LVEF (≥40%), whereas absence of LGE may identify low risk even when LVEF ≤35% — although patients without LGE can still have polymorphic VT/VF, especially after out-of-hospital cardiac arrest.
• Whole-heart histology shows CMR can miss substantial diffuse and patchy fibrosis regardless of the LGE method; T1 mapping may add sensitivity but is unvalidated for substrate delineation.
• PET should be considered in unexplained monomorphic VT to detect inflammatory aetiologies such as cardiac sarcoidosis (lifetime risk 1–2%).
• Bipolar voltage mapping can appear normal because of subendocardial viable myocardium; unipolar mapping has a larger field of view but both are influenced by wall thickness, and no single voltage cutoff performs well in DCM.

Genetics

• About one-third of "idiopathic" DCM is hereditary; arrhythmic DCM genes highlighted are LMNA, PLN, SCN5A, DES and FLNC.
• LMNA carriers have progressive heart failure, conduction disease and atrial/ventricular arrhythmias; LVEF <45%, non-sustained VT, male sex and non-missense variants are independent risk factors for ventricular arrhythmias. VT or SCD can be the first manifestation despite normal or near-normal LV function.
• DES mutations are associated with adverse cardiac events and phenotypic overlap with arrhythmogenic right ventricular cardiomyopathy; FLNC truncating variants with progressive DCM, fibrosis and VT. Both evidence bases are small.
• Genetic testing is recommended in suspected familial DCM or when conduction disease or VT/VF suggests a genetic cause.

Management — ICD

• Secondary-prevention ICD is recommended after cardiac arrest or symptomatic VT/VF.
• Primary prevention is debated: DANISH showed no all-cause mortality reduction (HR 0.87) but a significant reduction in SCD (HR 0.50), with benefit concentrated in patients younger than 70; 58% of both arms received CRT, which may have attenuated the ICD effect.
• ICD therapy-reduction programming — high-rate cutoffs, long detection windows, empirical ATP for slow and fast VT, and high-output first shocks — reduced appropriate and inappropriate shocks and was associated with a 30% lower risk of death versus conventional programming in a meta-analysis, but has not been validated in a DCM-only randomised trial.

Management — antiarrhythmic drugs

• Amiodarone is the drug of choice for recurrent ICD shocks despite optimal programming; toxicity may outweigh benefit in some patients.
• Disopyramide, flecainide and sotalol should generally be avoided in heart failure with reduced LVEF because of proarrhythmia and worsening LV function.
• All AAD evidence in DCM predates contemporary heart failure therapy and comes from mixed ischaemic/non-ischaemic populations.

Management — catheter ablation

• RFCA is the criterion-standard substrate-based treatment, but evidence comes from experienced single-centre registries with mixed DCM aetiologies.
• Acute success 38–73%; recurrence 46–60% at 1 year; one series reported 69% VT-free survival at 60 months, with multiple procedures in 36%. Complication rates reach 9% even in experienced centres.
• Deep intramural or epicardial scars may not be reached by endocardial lesions; epicardial fat can mimic scar and blunt ablation; coronary proximity limits epicardial delivery.
• Non-inducibility is the key procedural endpoint, predicting freedom from recurrence and mortality. Low LVEF, prior VT storm, high VT burden, failed AAD trials and short induced VT cycle length predict recurrence.
• Guidelines recommend RFCA for recurrent monomorphic VT when AADs fail or are contraindicated, for incessant VT or storm, and for bundle-branch re-entrant/interfascicular VT.
• Last-resort options include ECMO-supported ablation, transcoronary ethanol ablation, cardiac sympathectomy and surgical cryoablation; early transplant assessment is appropriate for intractable recurrent VT.

Limitations of the document

• Narrative review, not a systematic review. There is no search protocol, risk-of-bias assessment or formal evidence grading; recommendations reflect the authors' interpretation.
• Evidence is dated to 2018. It predates the 2022 ESC ventricular arrhythmia guideline, the 2023 cardiomyopathy guideline and trials such as VANISH2 (2025), so some management statements are now superseded.
• Most primary data come from ischaemic or mixed cohorts, and ablation outcomes are drawn from single-centre registries with heterogeneous DCM aetiologies and variable diagnostic work-up.
• Risk-marker performance is weak. The ECG and programmed-stimulation markers reviewed have low sensitivity and positive predictive value, and the review does not propose a validated DCM-specific risk score.
• Genotype evidence is limited for DES and FLNC, and recommendations for ICD irrespective of LVEF rest on small, poorly phenotyped cohorts.
• Imaging underestimates fibrosis. CMR may fail to delineate diffuse and patchy fibrosis, so a "negative" LGE scan does not exclude substrate.
• No cost, quality-of-life or shared-decision analysis is included.

Key Concepts Mentioned

• concepts/VA-Risk-Stratification-DCM — the risk-stratification framework this review informs
• entities/DCM — the disease population
• concepts/Late-Gadolinium-Enhancement — CMR fibrosis detection and its limits
• concepts/VT-Ablation-Ischemic-Cardiomyopathy — the ischaemic comparator whose evidence has been extrapolated to DCM
• entities/ICD — primary and secondary prevention
• entities/Amiodarone — first-line antiarrhythmic for recurrent VT
• concepts/Sudden-Cardiac-Death — the outcome being prevented
• concepts/Genetic-Testing-in-Cardiomyopathy — testing indications in DCM
• entities/LMNA, entities/PLN, entities/FLNC, entities/DES — arrhythmic DCM genes

Key Entities Mentioned

• HELIOS Heart Center – University of Leipzig — first author's institution
• Leiden University Medical Center — co-author's institution
• Heart Rhythm Society — journal publisher

Wiki Pages Updated

• Created: wiki/sources/vt-dcm-hrs-2018.md
• Updated: wiki/concepts/VA-Risk-Stratification-DCM.md
• Updated: wiki/entities/DCM.md
• Updated: wiki/concepts/Late-Gadolinium-Enhancement.md
• Updated: wiki/sourceindex.md
• Updated: log.md