A new angle on atrial fibrillation risk prediction; the role of P-wave axis in future AF

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. Background/Introduction There is growing interest in the prediction of incident atrial fibrillation. This is driven by the vast amounts of data in electronic records that may act as a substrate for prediction, and has led to demographic, biochemical and electrophysiological strategies (figure 1a). The 12-lead ECG has been a particularly rich target for possible prediction strategies, with a variety of individual parameters and even artificial intelligence methods being examined. Purpose The P-wave axis is an ECG parameter that reflects the dominant vector of atrial depolarisation. The normal P-wave axis is considered to be 0-75º. There is a large body of literature suggesting that AF reflects structural and conduction abnormalities of the atria, and thus the P-wave axis may represent a sensitive parameter to detect such changes, prior to the onset of AF (figure 1b). Methods A systematic review and meta-analysis of published literature associating abnormal P-wave axis and the development of incident AF was performed. The electronic databases PUBMED, EMBASE, Web of Science and Cochrane were systematically searched using the key words "P-wave axis" and "P wave axis" from inception to October 2021. An initial titular analysis, followed by abstract and full text screening was performed. Data was extracted using a pre-specified collection form. A random-effects model with generic inverse variance weights was utilised to pool the most adjusted effect measure from each paper. A funnel plot was used to assess publication bias. Results After excluding duplicate studies, 568 studies were screened. A total of twelve studies were identified that associated an abnormal p-wave axis with the subsequent detection of atrial fibrillation. The eight studies that considered abnormal P-wave axis as being <0º or >75º were pooled for meta-analysis. In the pooled studies a total of 78,222 patients were included with 5656 cases of incident atrial fibrillation identified. The meta-analysis of the studies suggested that an abnormal P-wave axis was associated with a pooled risk ratio of 2.10 (95% CI 1.48 to 2.72) for the detection of incident atrial fibrillation (figure 2). Sensitivity analysis by removing one study at each time did not alter the results. Conclusion This comprehensive systematic review and meta-analysis including 78,327 patients from 8 studies, indicates the positive association of abnormal P wave axis and future detection of AF. It thus confirms a two-fold risk of abnormal p wave axis in parallel with other established factors such as hypertension, age and abnormal systolic heart function. Utilisation of abnormal p wave axis, can allow clinicians to better risk-stratify individuals at increased risk of AF. This may lead to more tailored and precision strategies for prolonged cardiac monitoring or targeted anticoagulation approaches.