Abstract 11411: Left Ventricular Mechanical Dyssynchrony by Phase Analysis of Gated Myocardial Perfusion SPECT and Sudden Cardiac Death Events in Systolic Heart Failure: A Propensity-Matched Case-Control Study

Abstract

Introduction: The ADMIRE-HF (AdreView Myocardial Imaging for Risk Evaluation in Heart Failure) study demonstrated the prognostic value of iodine-123 meta-iodobenzylguanidine (MIBG) imaging in patients with symptomatic heart failure (HF) and left ventricular ejection fraction (LVEF) ≤35%. Because LV dyssynchrony is associated with sudden cardiac death (SCD), a major cause of mortality in HF, we hypothesized that LV mechanical dyssynchrony assessed by phase analysis of gated myocardial perfusion SPECT with technetium-99m tetrofosmin is associated with SCD events in symptomatic HF.

Methods and Results: Of the 964 subjects studied in ADMIRE-HF, 92 (9.5%) experienced adjudicated SCD events (SCD [n=23], fatal myocardial infarction [n=5], resuscitated cardiac arrest [n=7], appropriate ICD therapy [n=46] or sustained ventricular tachycardia [n=11]) during a median follow-up of 17 months. Propensity scores for SCD events were estimated for each of the 964 patients and used to assemble a matched cohort of 65 pairs of subjects with and without SCD who were balanced on 21 baseline characteristics (Table). Baseline SPECT images were reprocessed using phase analysis software to derive the phase standard deviation (SD) or SD of phase distribution for the onset of mechanical contraction. Subjects who experienced SCD events had significantly wider phase SD than those who did not, but had no significant difference in SPECT myocardial perfusion defect size or MIBG heart/mediastinum (H/M) uptake ratio. The findings were unchanged when the analysis was limited to subjects who had SCD, resuscitated cardiac arrest or appropriate ICD therapy.

Conclusions: Among symptomatic subjects with systolic HF, LV mechanical dyssynchrony assessed by phase analysis of gated SPECT is independently associated with SCD events. Phase analysis may provide incremental prognostic information on top of current indicators of SCD risk in systolic HF.