Abstract 12155: Fragmented and Delayed Electrograms within Fibro-Fatty Scar Predict Arrhythmic Events in Arrhythmogenic Right Ventricular Cardiomyopathy: Results from a Prospective Multicenter Study
Introduction. Islets of myocytes within fibro-fatty scars may provide the substrate for slow conduction, non-uniform anisotropy, and reentrant ventricular arrhythmias in arrhythmogenic right ventricular cardiomyopathy (ARVC). Electroanatomic mapping (EAM) can reliably identify such areas. We prospectively tested the association between late and fragmented electrograms within scar and arrhythmic events in patients with ARVC.
Methods. High-density EAM of the RV endocardium was performed in 32 consecutive ARVC patients (age 47 ± 13 years, 20 males) without history of cardiac arrest or sustained ventricular arrhythmias. Standard definitions of electroanatomic scars and fractionated, isolated, and very late potentials were used. All patients received an ICD for the primary prevention of sudden cardiac death.
Results. After a mean follow-up of 25 ± 7 months, 12 (38%) patients received appropriate ICD shock for VT/VF. With the exception of a higher rate of previous syncope (58% vs. 20%, p = 0.053), patients with arrhythmic events at follow-up did not differ from those who remained free from arrhythmic events in terms of other baseline clinical variables, including presence and burden of non-sustained ventricular arrhythmias, and cardiac magnetic resonance findings (RV enlargement, ejection fraction, presence and distribution of late gadolinium enhancement and of intramyocardial fatty infiltration). Electroanatomic scars were present in all patients. The distribution and extent of electroanatomic scars were similar in the two groups (38 ± 25 cm² vs. 33 ± 20 cm², p = 0.51). However, patients with ICD shock had higher prevalence of fractionated potentials (92% vs. 20%, p < 0.001), of isolated late potentials (75% vs. 20%, p = 0.004), and of very late potentials (67% vs. 25%, p = 0.030). Fragmented potentials were the only variable independently associated with arrhythmic events at follow-up (hazard ratio = 19, p = 0.018).
Conclusions. Presence of late and fragmented electrograms within scar predicts arrhythmic events in ARVC. These findings provide a novel tool for arrhythmic risk stratification in these patients and define promising targets for prophylactic substrate modification by catheter ablation.
- © 2011 by American Heart Association, Inc.