Abstract 516: Imaging of Myocardial Sympathetic Innervation for Prediction of Arrhythmic Events in Heart Failure Patients: Insights From the ADMIRE-HF Trial
Objectives The significance of reduced cardiac uptake of 123I-mIBG for prediction of non-fatal and fatal arrhythmic events in heart failure (HF) patients was examined in an analysis of the international ADMIRE-HF trial.
Methods 961 subjects with NYHA class II (83%) and III (17%) HF (66% ischemic, 34% non-ischemic), LVEF≤35% (mean 27%; median 29%), and no prior treated ventricular arrhythmic events, had determination of heart/mediastinum ratio (H/M) on 4 hour planar myocardial 123I-mIBG imaging and then a maximum of 2 years follow-up. Occurrence of arrhythmic events (sustained (>30 sec) VT, resuscitated cardiac arrest; or appropriate ICD discharge (ATP or DC shock)) or sudden cardiac death (SCD) was determined by an adjudication panel. Relationships of H/M and arrhythmic events were examined using Kaplan-Meier survival methods.
Results During median 17 months follow-up, 86 subjects (9%) experienced arrhythmic events: 45 ICD activations; 22 SCD; 12 self-limited sustained VT; 6 resuscitated arrests; 1 resuscitated arrest with later SCD. Arrhythmic events were significantly more common for H/M<1.60 (79/760 (10.4%) vs 7/201 (3.5%) (p<0.01)). Among subjects with H/M<1.60, those with H/M 1.30 –1.59 were at highest risk, with 2-year arrhythmic event rate of 16.8% (vs 3.7% for H/M≥1.60 (p<0.001) and 10.1% for H/M<1.30 (p<0.05 vs H/M≥1.60; p=0.17 vs 1.30 –1.59)). Of 578 subjects (60%) without ICDs, 20 (3.5%) experienced SCD; of 383 subjects with ICDs, 3 (0.8%) experienced SCD (p<0.01). All SCDs occurred in the 770 subjects (80.2%) with H/M≤1.60. Only 5 of 191 subjects (2.6%) with H/M>1.60 had arrhythmic events; 2 of 137 subjects without ICDs experienced self-limited episodes of VT, while 3 of 54 subjects with ICDs had device activations (2 ATP, 1 DC shock). Of the 22 arrhythmic events that occurred in subjects with LVEF above the median (≥30%), 19 (86%) occurred in subjects with H/M 1.30 –1.59.
Conclusion 123I-mIBG cardiac imaging identifies subpopulations of NYHA Class II/III HF patients with extremely low 2-year risk of fatal arrhythmic events (NPV 1.0 for H/M>1.60) and with a higher than average likelihood of fatal and non-fatal ventricular arrhythmias (H/M 1.30 –1.59), suggesting a potential role for this procedure in decisions regarding ICD therapy.