Abstract 14170: Incremental Value of Magnetic Resonance-Based Ventricular and Atrial Strain in Predicting Ventricular Arrhythmia

Introduction: Only a small subset of patients with primary prevention ICDs, for whom left ventricular ejection fraction (LVEF) is emphasized in current guidelines, receive appropriate ICD therapy. Objectives: To study the incremental value of cardiovascular MR (CMR)-derived right and left ventricular and left atrial strain measured using feature tracking in predicting ventricular arrhythmia in patients eligible for implantable cardioverter-defibrillator (ICD) primary prevention of ventricular arrhythmia. Methods: The study included patients who met the current clinical guideline to receive an ICD for primary prevention of SCD. CMR imaging was performed on either a 1.5 or a 3T scanner, including standard evaluation of LV function and structure, LV/RV/LA strains, LGE. Outcomes were comprised of 1) unstable VT/VF >30sesonds, 2) appropriate ICD therapy; shock or anti-tachycardia pacing for VT/VF, or 3) SCD. The primary outcome was a composite endpoint of any of the above three outcomes. Results: A total of 239 patients were included and the average age was 57±14 years old. Patients with outcomes had slightly lower RV global longitudinal strain (GLS). Univariate Cox proportional hazards regression showed that every standard deviation increase in RV GLS was associated with a 73% increase in risk (p< 0.01). The baseline multivariable Cox’s proportional hazards regression model with a standardized clinical risk score, standardized LVEF, LGE had an AUC of 0.64. The best performing model, which included standardized LV and RV GLS, significantly improved prognosis compared with the baseline model, with an AUC of 0.72 and a categorical free NRI of 0.88 (p=0.04). Model 1 indicated an increased risk of 77% for every standard deviation increase in RV GLS (p< 0.01) and a decreased risk of 49% for every standard deviation increase in LV GLS (p= 0.02). Kaplan-Meier curves could be stratified using the selected thresholds; LV GCS ≥ 5.3 and RV GLS ≥ -10.8, respectively (p=0.02, p<0.01).