Atrial time and voltage dispersion are both needed to predict new-onset atrial fibrillation in ischemic stroke patients

Background: Atrial fibrillation (AF) is a known risk factor for ischemic stroke. Electrocardiographic predictors of AF in population studies such as the Framingham Heart Study, as well as in hypertensive patients have demonstrated a predictive value of the P-wave duration for development of AF. QRS vector magnitude has had a predictive value in ventricular arrhythmia development. We aimed to assess the value of the three-dimensional P-wave vector magnitude and its relationship to P-wave duration for prediction of new-onset AF after ischemic stroke. Methods: First-ever ischemic stroke patients without AF at inclusion in the Lund Stroke Register were included. Measurements of P wave duration (Pd), QRS duration, corrected QT interval, and PQ interval were performed automatically using the University of Glasgow 12-lead ECG analysis algorithm. The P-wave vector magnitude (Pvm) was calculated automatically as the square root of the sum of the squared P-wave magnitudes in leads V6, II and one half of the P-wave amplitude in V2 ( PV 6 2 + PII 2 + 0.5 PV 2 2 $$ \sqrt(PV(6)^2+(PII)^2+(\left((0.5)^(\ast )PV2\right))^2) $$ ), based on the P-wave magnitude (Pvm) as defined by the visually transformed Kors' Quasi-orthogonal method. Results: The median age was 73 (IQR 63-80) years at stroke onset (135 males, 92 females). Multivariate predictors of new-onset atrial fibrillation included age>65years, hypertension, and Pd/Pvm. A cut-off value of 870ms/mV gave sensitivity, specificity, positive and negative predictive values of 51, 79, 30 and 87%, respectively. The Pd/Pvm was the only ECG predictor of AF with a significant multivariate hazard ratio of 2.02 (95% CI 1.18 to 3.46, p=0.010). Conclusion: P-wave dispersion as measured by the Pd/Pvm was the only ECG parameter measured which independently predicted subsequent AF identification in a cohort of stroke patients. Further prospective studies in larger cohorts are needed to validate its clinical usefulness.