Abstract 19194: Cardiac MRI and Electrophysiology Study Can Risk Stratify Patients with Ventricular Tachycardia and Structurally Normal Heart

Abstract

Introduction The role of MR imaging in risk stratification of patients with ventricular tachycardia (VT) and structurally normal heart is not well defined. Methods From 2005-2010, patients who presented with sustained VT or frequent nonsustained VT without echocardiographic evidence of structural heart disease were reviewed. All patients had a normal ejection fraction and no angiographic evidence of coronary artery disease. Patients received cardiac MRI and electrophysiology study (EPS) as part of their evaluation and long term outcomes were assessed. Results Thirty-two pts were evaluated for VT or nonsustained VT despite structurally normal hearts and underwent cardiac MRI with delayed gadolinium hyperenhancement (DHE) protocol to assess for scar prior to EPS. Fifteen had outflow tract VT (OTVT) morphology and eighteen presented with “non idiopathic” VT (not compatible with OTVT or fascicular VT). All 15 patients with OTVT morphology had a normal MRI and only the clinical VT was induced during EPS. Of the 18 patients with “non idiopathic” VT morphology, four patients had evidence of delayed enhancement on MRI (3 basal inferior/inferolateral LV, 1 basal to mid anterior LV). 3/4 with DHE had multiple VT (mean 2.25) induced during EPS. One patient had normal MRI yet multiple VT induced during EPS. All other patients had a negative MRI and EPS. During mean followup of 32+/-29 months, 2/4 patients (50%) with DHE on MRI, had recurrent VT requiring either ICD therapy or cardioversion. Additionally, the patient with multiple VT induced during EPS and normal MRI, also had recurrent VT at 7 months requiring cardioversion. The remaining 13 patients with non idiopathic VT morphology but normal MRI and EPS have not had recurrence. No deaths have occurred in any patient. All patients with outflow tract VT had normal MRI and have been managed medically or with ablation without reccurrence. Conclusions Cardiac MRI and EPS can help risk stratify patients with “non idiopathic” VT and structurally normal heart. Abnormal findings on MRI and EPS may identify a subgroup of patients who may be at higher risk for recurrent arrhythmic events.