REEVALUATION OF THE ROLE OF P-WAVE DURATION AND MORPHOLOGY AS PREDICTORS OF ATRIAL-FIBRILLATION AND FLUTTER AFTER CORONARY-ARTERY BYPASS-SURGERY

To evaluate the significance of P-wave duration and morphology for the development of post-operative atrial fibrillation/flutter, we investi gated 189 consecutive patients scheduled for elective coronary artery bypass surgery. The longest pre-operative total P-wave duration was me asured from the standard electrocardiogram at a paper speed of 50 mm.s (-1) (mean of two independent observers). By the signal averaging tech nique we determined the pre-operative total P-wave duration, and root- mean square voltage of the last 10, 20, and 30 ms of the filtered (40- 250 Hz) P-wave from a vector composite of three orthogonal leads at no ise level 0 . 2 mu V. Forty-two (22%) of the patients developed atrial fibrillation/flutter. Older age (mean+/-SD) 62+/-8 vs 56+/-8 years (P <0 . 000), increasing body weight 83+/-11 vs 79+/-12 kg (P=0 . 05), tr eatment for hypertension 26 vs 13% (P=0 . 04), and a longer P-wave dur ation in the standard electrocardiogram 129+/-12 vs 124+/-12 ms (P=0 . 01) were associated with development of atrial fibrillation/flutter d ocumented by a 12-lead electrocardiogram. Logistic regression analysis identified independent predictors, estimated adjusted relative risk ( 95% confidence interval) of atrial fibrillation/flutter: with age >60 years, the relative risk was 4 . 46 (2 . 05-9 . 73), and body weight > 80 kg, the relative risk was 3 . 81 (1 . 71-8 . 46). Thus, P-wave dura tion and morphology did not provide significant information on the ris k of atrial fibrillation/flutter when controlling for the effects of i ncreasing age and body weight.