Assessment of 123I-mIBG and 99mTc-tetrofosmin Single-photon Emission Computed Tomographic Images for the Prediction of Arrhythmic Events in Patients With Ischemic Heart Failure: Intermediate Severity Innervation Defects Are Associated With Higher Arrhythmic Risk
RATIONALE: 123I-mIBG planar image heart-to-mediastinum ratios effectively risk-stratify heart failure (HF) patients. The value of single-photon emission computed tomographic (SPECT) imaging for identifying increased risk of ventricular arrhythmias is less clear. This study sought to determine if findings from simultaneous interpretation of 123I-mIBG and 99mTc-tetrofosmin SPECT are predictive of arrhythmic events (ArEs). METHODS: 123I-mIBG SPECT images from 622 patients with ischemic HF were presented in standard displays alongside 99mTc-tetrofosmin images. Consensus interpretations using a 17-segment model produced summed scores. Cox proportional hazards analyses related findings to adjudicated ArEs over 2 years. RESULTS: 471 patients had images adequate for total 17-segment scoring. There were 48 ArEs (10.2%). Neither 123I-mIBG nor 99mTc-tetrofosmin SPECT summed scores were univariate predictors. On multivariate proportional hazards analysis, the 123I-mIBG SPECT score was independently predictive of ArEs (HR: 0.975, 95% CI 0.951-0.999, P = 0.042), but HR<1 indicated that risk decreased with increasing score. This occurred because patients with intermediately abnormal SPECT studies had a higher likelihood of ArEs compared to patients with extensive abnormalities. CONCLUSIONS: The presumption of a monotonic increase in ArE risk with increasing summed 123I-mIBG SPECT score may not be correct as ischemic HF patients with abnormalities of intermediate extent appear at highest risk.
Travin, M., Henzlova, M., van Eck-Smit, B., Jain, D., Carrio, I., Folks, R., Garcia, E., Jacobson, A., & Verberne, H. (2017). Assessment of 123I-mIBG and 99mTc-tetrofosmin Single-photon Emission Computed Tomographic Images for the Prediction of Arrhythmic Events in Patients With Ischemic Heart Failure: Intermediate Severity Innervation Defects Are Associated With Higher Arrhythmic Risk. Journal of Nuclear Cardiology, 24 (2), 377-391. https://doi.org/10.1007/s12350-015-0336-8