Atrial fibrillation after non-cardiac surgery: P-wave characteristics and Holter monitoring in risk assessment.

BACKGROUND: We investigated the role of 12-lead ECG P-wave duration and dispersion and of Holter monitoring as predictors of post-thoracic surgery atrial fibrillation.
METHODS: One hundred and five consecutive patients (88 males-17 females; age 60+/-9), undergoing thoracic surgery at National Cancer Institute between 2001 and 2003, were enrolled and both standard ECG and Holter monitoring were obtained from each patient. P-wave study was made on a magnified ECG paper copy. Holter monitoring was performed 1-3 days before surgery; patients were divided into three classes according to number and complexity of premature supra ventricular complexes (0: <30/h and no repetitive forms; 1: >30/h or couplets; 2: run of supraventricular tachycardia or atrial fibrillation).
RESULTS: Atrial fibrillation was detected in 12 patients (11%) within 96 h from surgery. In univariable logistic model, P-wave duration was not associated with postoperative atrial fibrillation while P-wave dispersion and Holter monitoring demonstrated a statistically significant association with the occurrence of atrial fibrillation (OR of 30 vs 20 ms=2.06; CI: 1.17-3.64; p=0.012, OR of class 1-2 vs class 0=8.16; CI: 2.04-35.59; p=0.003, respectively). In the multivariable model, both P-wave dispersion and Holter were shown to be significantly associated with the end-point. Holter monitoring enhanced the predictive ability of P-wave dispersion (area under the ROC curve increased from 0.64 to 0.80).
CONCLUSIONS: P-wave dispersion, but not duration, was associated with atrial fibrillation after thoracic surgery. Preoperative Holter monitoring adds further information and could be used to enhance the P-wave predictive power.