 These findings led to the organization of the Occluded Artery Trial OAT, an international, NHLBI-funded, randomized trial of 2,200 participants. OAT is testing the hypothesis that mechanical reperfusion of an occluded IRA with PTCA and percutaneous coronary intervention PCI 3 to 28 days after a heart attack in high-risk individuals will reduce mortality, recurrent heart attacks, and hospitalization for class IV congestive heart failure. Enhancement of electrical stability is one of the major mechanisms that has been proposed to explain the association of an open IRA with an improved prognosis independent of myocardial salvage. 