Abstract 3263: The Effect of Ischemia/Reperfusion on The Pacing Threshold by Transcoronary Pacing
Background: Transcoronary pacing has recently been proposed as a safe and reliable method to treat severe bradycardia during percutaneous coronary intervention. However, few data are reported on the effects of acute ischemia/reperfusion on the performance of transcoronary pacing.
Methods: Acute ischemia/reperfusion was induced in 10 York pigs by percutaneous balloon angioplasty technique with the over-the-wire (OTW) balloon system. A 0.014 inch BMW (Cordis) guidewire together with the OTW balloon was inserted deeply into the distal left anterior descending artery or its branch and as a pacing lead. Pacing thresholds were measured at baseline, 5, 10, 20, 30 and 40 minutes after LAD occlusion by balloon inflation, as well as 5, 10, 20, 30, 60, 90, and 120 minutes after reperfusion by balloon deflation, which were demonstrated by coronary angiography.
Results: The pacing threshold at baseline was 0.71±0.24 V. The pacing threshold did not change significantly until 30 minutes after ischemia. The pacing threshold significantly increased 30 minutes after ischemia and reached peak value at 40 minutes after ischemia (1.99±1.36 V). The pacing threshold decreased significantly, but a little bit higher to the baseline level 5 minutes after reperfusion (1.06±0.46 V) and remained similar level throughout the reperfusion period.
Conclusions: Acute ischemia more than 30 minutes could increase transcoronary pacing threshold almost 3 folds to the baseline level, but reperfusion could decrease the increased pacing threshold induced by persistent severe acute ischemia. This study further demonstrated the reliability of transcoronary pacing even during severe ischemia and reperfusion.