Clinical Electrophysiology -> SCA Risk Assessment: -> Other Noninvasive Techniques D-PO04 - Poster Session IV (ID 15) Poster

D-PO04-225 - Idiopathic Dilated Cardiomyopathy With Arrhythmogenic Phenotype: Prevalence, Cardiac Magnetic Resonance Characteristics And Long-term Outcomes (ID 504)


Background: A subset of patients with nonischemic dilated cardiomyopathy presents with a predominantly arrhythmogenic phenotype (AR-NIDCM).
Objective: We evaluated the prevalence, clinical features, CMR characteristics and long-term outcomes of AR-NIDCM.
Methods: A total of 371 patients (median age 53 years, 69% males) with NIDCM were included in a multicenter registry. Of these, 82 (22%) presented with an arrhythmic phenotype defined by presence of ventricular arrhythmias including frequent PVCs (≥1000 /24-hours) and/or recurrent episodes of non-sustained VT. All patients underwent a CMR study with late gadolinium enhancement (LGE) imaging. Study endpoints were all cause mortality and a composite of major arrhythmic events (MAE) including sudden cardiac death (SCD), resuscitated cardiac arrest and nonfatal episodes of VF or sustained VT requiring appropriate implantable cardioverter defibrillator (ICD) shocks.
Results: Compared to the rest of the NIDCM population, patients with AR-NIDCM were younger (median age 46 vs. 54 years; p<0.01), had more frequently inverted T waves in the anterior and lateral leads (20% vs. 4%; p<0.01), had a higher LV ejection fraction (median 50 [47-50] vs. 41 [31-48]%; p<0.01), a smaller LV end-diastolic volume (median 100 [90-115] vs. 111 [96-135] ml/m2; p=0.01) and a higher prevalence of LV LGE (50% vs. 33%; p<0.01). Patients with AR-NIDCM also had a higher burden of LGE (11 [6-16] vs. 3 [0.5-6]% of LV mass; p<0.01) and a different scar pattern, typically subepicardial/midmyocardial involving the basal lateral wall, with involvement of ≥3 contiguous LV segments in 16% vs. 0% of the cases, respectively (p<0.01). After a median follow-up of 53 (33-72) months, mortality rates were similar in AR-NIDCM and the rest of the NIDCM population (5% vs. 6%; p=0.8), but patients with AR-NIDCM had a significantly higher rate of MAE (33% vs 8%; p<0.01).
Conclusion: Up to 22% of patients with NIDCM present an arrhythmogenic phenotype, which is characterized by specific clinical and CMR characteristics and a particularly high risk of MAE regardless of the LV ejection fraction.