Abstract 2431: Left Ventricular Scar Burden Predicts Life-Threatening Arrhythmia in Recipients of Implantable Cardioverter Defibrillilators
Objective. Implantable cardioverter defibrillators (ICD) reduce arrhythmic deaths and are implanted based on LV ejection fraction (LVEF) and symptoms. Myocardial scar is a substrate for ventricular tachyarrhythmia (VT). We aimed to assess if number of LV scar segments [#SS, by cardiac magnetic resonance (CMR)] would predict life-threatening VT in recipient of ICD.
Methods. Among 722 recipients of ICD (2002–2006), 54 [age 32– 84 (mean 63±12) years, 89% men, 76% ischemic, LVEF ≤35%] had CMR with delayed gadolinium enhancement prior to ICD. Using a 17-segment LV model, presence of scar was determined. End point was defined as confirmed VT requiring termination by anti-tachycardia pacing or shock.
Results. At a mean follow-up of 15 (median 11.5) months, 12 (22%) patients reached end point. Univariate analysis identified LVEF and #SS as predictors whereas age, coronary artery disease, diabetes, hypertension, medications (anti-arrhythmic, beta-blocker, angiotensin-converting enzyme inhibitor, statin), creatinine, LV end-diastolic volume or LV mass were not predictive. #SS was higher in those who reached endpoint (8.5±1.2 vs 5.2±0.7, p=0.03). By receiver operator curve, a cut-off of ≥7 scarred segments identified those at high risk for VT (Graph - open circles are those with <7 scarred segments). By logistic regression, after control for EF, #SS remained significant (P 0.03) with 1.3 times higher incidence of VT per added scarred segment. LVEF and #SS did not correlate (p=0.07).
Conclusion. Presence of large scar burden predicts VT in patients with advanced LV dysfunction. Assessment of myocardial scar burden by CMR may improve risk stratification prior to ICD implantation.