VALUE OF THE SIGNAL-AVERAGED P-WAVE ANALYSIS IN PREDICTING ATRIAL-FIBRILLATION AFTER CARDIAC-SURGERY

Atrial fibrillation (AF) is the most common sustained arrhythmia occur ring after cardiac surgery. Beside important implications regarding pa tient recovery, AF has been shown to substantially lengthen hospital s tay-our recent study found a 3-day prolongation after adjusting for al l other significant factors. Identification of those at highest risk o f AF by clinical or noninvasive characteristics may be a useful strate gy for targeted prophylactic therapy. Our data have shown that prolong ed atrial conduction as assessed by analysis of the P wave duration fr om the signal-averaged electrocardiogram (SAECG) imparts a four fold i ncrease in risk for postoperative AF, independently of other measured variables. Ln addition, abnormal conduction was present on the preoper ative P wave ECG (P-SAECG), implying a prexisting substrate that is tr iggered by surgery. The use of combination abnormal noninvasive variab les (eg, abnormal P-SAECG and lo iv left ventricular ejection fraction ) can identify groups with a 50% risk of AF, which is nine times as hi gh as when both tests are normal. Thus, the P-SAECG is a useful and ac curate predictor of AF after cardiac surgery.