Impact of neuropsychiatric medications on cardiac uptake of I123 mIBG in heart failure subjects

Objectives Medications that interfere with sympathetic neuronal norepinephrine (NE) uptake and storage, such as antidepressants, neuroleptics, and other neuropsychiatrics (NP), are most likely to affect cardiac uptake of 123I-mIBG. The present study examined the effect of such medications on measurements of cardiac 123I-mIBG uptake in heart failure (HF) subjects.

Methods Baseline NP medications taken by the 961 HF subjects (NYHA class II/III, LVEF≤35%) in the ADMIRE-HF study were categorized into 3 groups: high potential (Hi) for 123I-mIBG interference (tricyclic antidepressants, Serotonin-NE Reuptake Inhibitors); low potential (Lo) for 123I-mIBG interference (non-NE-dependent antidepressants, antipsychotics, other neuroleptics); None (No). Myocardial 123I-mIBG heart/mediastinum uptake ratios [H/M] on 4-hr planar and SPECT images were compared among the groups using analysis of variance (ANOVA). Impact of medication group on the prognostic value of the H/M for cardiac (C) and all-cause (AC) death during median 2-year follow-up was also examined using Kaplan Meier survival curves.

Results 149 subjects (15.5%) were taking NP medications, including 71 (7.4%) in the Hi group. H/M results for the 3 groups are summarized in the table. Among subjects taking NP medications, 2-yr C and AC mortality rates were lower for subjects with planar H/M ≥1.60 (compared with H/M<1.60), although differences were not statistically significant due to the small sample sizes (Hi: C: 0% vs 3.9% (p=0.46); AC: 0% vs 9.4% (p=0.24); Lo: C: 6.3% vs 7.5% (p=0.88); AC: 6.3% vs 12.2% (p=0.50)). Differences for both 2-yr C and AC mortality rates were highly significant in the No group (C: 2.0% vs 9.6% (p=0.003); AC: 4.1% vs 14.2% (p=0.0008)).

Conclusions There was a non-significant trend for lower H/M ratios in Hi group subjects. However, planar H/M≥1.60 was indicative of lower 2-year risk for cardiac and all-cause mortality, irrespective of NP medication use.

Research Support GE Healthcare