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

D-PO04-223 - Prevalence And Prognostic Value Of Incidental Isolated Myocardial Late Gadolinium Enhancement In Patients With Idiopathic Outflow Tract Ventricular Arrhythmias (ID 1489)

Abstract

Background: Patients with idiopathic outflow tract ventricular arrhythmias (OTVAs) and structurally normal heart by ECG and echocardiogram often undergo cardiac magnetic resonance (CMR) study to evaluate for presence of concealed myocardial abnormalities with late gadolinium enhancement (LGE). However, the clinical impact of incidental LGE finding in patients with idiopathic OT-VAs is unclear.
Objective: We investigated the prevalence, characteristics and prognostic significance of isolated LGE in a large population of patients with OTVA undergoing CMR.
Methods: A total of 364 consecutive patients (43±16 years, 53% male) with OTVA and negative routine diagnostic work-up were included. All patients underwent a CMR study with LGE imaging for detection of fibrosis. Presence of LGE was correlated with long term major adverse cardiovascular events including sudden cardiac death (SCD), resuscitated cardiac arrest and nonfatal documented sustained ventricular tachycardia.
Results: Isolated LGE was identified in 15 patients (4%), located exclusively in the left ventricle (LV) and typically involving the inferolateral wall (11 cases, 73%) with a median extension of 3 (2-5)% of the LV mass. All cases showed a midmyocardial/subepicardial distribution consistent with a possible prior myocarditis. Patients with incidental finding of LV-LGE were older (55±13 years vs. 42±16 years; p<0.01) and were more frequently males (80% vs. 51%; p=0.03). After a median follow-up of 69 (47-98) months, none of the patients in the LV-LGE group and 1 patient (0.3%) in the non-LGE group (p=1.0) experienced the composite end-point which consisted in an episode of sustained VT with hypotension and dizziness. The patient subsequently underwent effective radiofrequency ablation of the VT from the right ventricular outflow tract.
Conclusion: In this large CMR study, isolated LV scar was found in 4% of patients with idiopathic OT-Vas, was small in size with distribution consistent with prior myocarditis. The LGE abnormality did not portend a negative prognosis.
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