Predictors of ventricular ablation's success: Viability, innervation, or mismatch?

Aims Sympathetic dys-innervation may play an important role in the development of post-ischemic ventricular arrhythmias (VA). Aim of this study was to prove that perfusion/innervation mismatch (PIM) evaluated by SPECT can identify areas of local abnormal ventricular activities (LAVA) on electroanatomic mapping (EAM). Methods Sixteen patients referred to post-ischemic VA catheter ablation underwent pre-procedural and 1-month post-ablation I-123-MIBG/Tc-99m-tetrofosmin rest SPECT myocardial imaging. PIM was defined according to the segmental distributions of 99mTc-tetrofosmin and 123I-MIBG. A 17-segment LV analysis was used for either SPECT or LV EAM voltage map. All patients were followed up clinically for at least 1 year. Results Before ablation, the mean voltage in the PIM segments was higher than in the scarred ones but lower than in the normal regions. The presence of PIM in a specific LV zone was an independent predictor of LAVA. After ablation, PIM value was significantly reduced, mainly due to an increase in perfusion summed rest score, in particular in patients that were responders to ablation. Conclusions PIM may associate with VA substrate expressed by LAVA and might provide a novel guide for substrate ablation. A significant reduction of PIM could predict a positive clinical response to ablation.