Atrial fibrillation increases production of superoxide by the left atrium and left atrial appendage: role of the NADPH and xanthine oxidases.

Background: Atrial fibrillation (AF) is associated with an increased risk of stroke due almost exclusively to emboli from left atrial appendage (LAA) thrombi. Recently, we reported that AF was associated with endocardial dysfunction, limited to the left atrium (LA) and LAA and manifest as reduced nitric oxide (NO*) production and increased expression of plasminogen activator inhibitor-1. We hypothesized that reduced LAA NO* levels observed in AF may be associated with increased superoxide (O2*-) production.

Comparison of outcomes of percutaneous coronary intervention of ostial versus nonostial narrowing of the major epicardial coronary arteries.

Outcomes of percutaneous coronary intervention (PCI) of the ostia of the major epicardial coronary arteries in the modern era of stenting have not been clearly defined. We evaluated data from all PCIs performed from 1998 to 2001 in the proximal segments of the major epicardial coronary arteries entered into a large cardiac database and compared ostial with nonostial PCI outcomes. Of 2,484 patients who underwent PCI of a proximal coronary artery (left anterior descending, left circumflex, or right coronary), 223 patients had ostial narrowing and 2,261 patients had proximal, nonostial narrowing.