Introduction: Antitachycardia pacing (ATP) may be less effective in ICD patients with transmural scar and areas of ischemia than in those with none-transmural MI.
Methods: We reviewed data from 1316 cases with ICD-delivered therapies for sustained monomorphic VT during 2008-2012, and selected VT episodes treated with ATP. We identified patients who had undergone nuclear imaging and the extent of scar and ischemia were assessed using the summed stress score (SSS), summed rest score (SRS) and summed difference score (SDS).
Results: 123 patients with VT who received ATP therapy and underwent nuclear imaging were identified. When we compared degree of ischemia, expressed by SDS score, between ATP responders and non-responders we showed that non-ischemic myocardium was more commonly found in ATP-responders: 62 (72.9%) vs 20 (52.6%) in patients with ATP failure, p<0.05. There was no significant difference in ATP success in SDS categories 1, 2 and 3, which represented mild, moderate and severe ischemia.
Conclusions: ATP success rate was found to be associated with degree of ischemia and scar extent, as more patients with successful ATP had normal perfusion.