PREMATURE ATRIAL BEAT ELICITING ATRIAL-FIBRILLATION AFTER CORONARY-ARTERY BYPASS-GRAFTING

Of patients undergoing coronary artery bypass grafting 30% develop atr ial fibrillation (AF) or nutter. To determine if AF is initiated from the right or left atrium, atrial electrograms were continuously record ed in patients undergoing this procedure. In addition, to study whethe r the prematurity index of premature atrial contractions (PACs) elicit ing AF differs from PACs not provoking AF, the distribution of prematu rity indices was evaluated from R-R interval analysis. The right and l eft atrial recording electrodes were first activated by the ectopic be at provoking AF in six and eight patients, respectively. The prematuri ty index of the PAC eliciting AF was located in the middle (in half of the patients) or to the left of the median distribution of prematurit y indices. The variability in activation of the atrial electrodes sugg ests that the PAC provoking AE can have its origin in the right, the s eptal, or the left region of the atrium. The initiation of AF depends on the prematurity index of the PAC.