Prediction of appropriate ICD therapy in patients with ischemic heart failure.

BACKGROUND

Previous studies show inconsistent results on the role of innervation imaging (with I-123-mIBG) and perfusion imaging in predicting appropriate ICD therapy (aICDth). These studies included patients with both dilated and ischemic cardiomyopathy. This study compared the ability of I-mIBG imaging along with perfusion imaging (using thallium-199) to predict aICDth in patients with ischemic heart failure (IHF) in relation to indication for ICD implantation (primary vs. secondary prevention of sudden cardiac death (SCD)).

METHODS

mIBG/thallium SPECT imaging were performed before ICD implantation in 80 patients with IHF: 49 candidates for primary and 31 for secondary SCD prevention.

RESULTS

During a mean follow-up of 18 months, the imaging results could not predict patients with appropriate ICD therapy among patients with ICD implants for primary SCD prevention. While in the secondary SCD prevention group, those who received a ICDth had significantly larger summed scores of regional perfusion and innervation impairment, but not higher heart-to-mediastinal mIBG ratio. The best results to predict aICDth were using mIBG summed score (cut-off point > 34%, sensitivity 72%, specificity 100%, AUC 0.909, P < 0.0001).

CONCLUSION

The prognostic value of innervation and perfusion imaging in patients with IHF differ based on indication for ICD implantation (primary vs. secondary prevention of SCD).