Clinical Pacing Post-Conditioning During Revascularization After AMI

Intermittent dyssynchrony, induced by ventricular pacing, during early reperfusion reduces infarct size in pre-clinical studies. We evaluated cardioprotection by pacing post-conditioning (PPC) in ST-segment elevation myocardial infarction in a randomized, controlled, single-center, single-blinded, first-in-man study. Patients with first ST-segment elevation myocardial infarction received either PPC plus percutaneous coronary intervention (PCI) (n = 30) or PCI (n = 30). PPC consisted of 10 episodes of 30-s right ventricular pacing. Infarct size was measured as the area under the curve of creatine kinase (CK) (primary endpoint) and by contrast-enhanced cardiac magnetic resonance. The CK area under the curve was not significantly different between study groups. Adjusted contrast-enhanced cardiac magnetic resonance data showed similar to 25% smaller infarct size in PPC + PCI than in PCI patients after 4 days (p = 0.01), 4 months (p = 0.02), and 1 year of PCI (p = 0.08). In PPC + PCI, (uncomplicated) ventricular fibrillation (n = 3) and paroxysmal atrial fibrillation (n = 4) were observed as opposed to 1 and 0 cases in PCI, respectively. We conclude PPC is feasible and may induce cardioprotection during PCI treatment of ST-segment elevation myocardial infarction, but technical improvements are needed to improve safety. (PROTECT: Pacing to Protect Heart for Damage From Blocked Heart Vessel and From Re-opening Blocked Vessel[s]; NCT00409604