Quantitative electrocardiography for predicting postoperative atrial fibrillation after cardiac surgery

Abstract

Background: Atrial fibrillation (AF) after cardiac surgery is a common marker of poor outcomes. Quantitative electrocardiographic (ECG) measurements may be valuable predictors of postoperative AF.

Methods: We evaluated clinical and ECG predictors of postoperative AF in 13,356 patients who underwent cardiac surgery in sinus rhythm.

Results: A total of 4724 patients (35%) developed postoperative AF. P-wave amplitude in leads aVR and V(1) were the strongest ECG predictors. A less negative P-wave amplitude in lead aVR was associated with increased risk for postoperative AF (odds ratio, 1.46; 95% confidence interval, 1.32-1.61), as was a more positive or a more negative P-wave amplitude in lead V(1) (odds ratio, 1.25; 95% confidence interval, 1.16-1.36) after adjusting for clinical and procedural predictors of postoperative AF. Reclassification analysis showed a 7% discrimination improvement (P < .0001).

Conclusions: P-wave amplitude in lead aVR and lead V(1) are powerful predictors of postoperative AF and, in combination with other clinical predictors, can guide application of prophylactic interventions.

Figure 1

Adjusted probability of postoperative atrial fibrillation (AF) according to P-wave amplitude in leads aVR and V1. Less negative P-wave amplitude in lead aVR and more negative or more positive P-wave amplitude in lead V1 (bimodal distribution) was linked to greater risk of postoperative AF. Positive and negative P-wave amplitude in V1 are mutually exclusive on an individual patient level. Dashed lines represent 95% confidence intervals.

Figure 2

P-wave amplitude in lead aVR: Strata with patient number and their associated risk of postoperative AF. OR indicates odds ratio.

Figure 3

Nomogram for risk of developing postoperative atrial fibrillation (AF) with preoperative variables only: Find for each patient variable the associated score in the first line and add them to get “Total Points.” Total point score can then be extrapolated to determine the probability of developing postoperative AF after cardiac surgery (e.g., 0.5 indicates a 50% risk)