P Wave Indices-Advancing Our Understanding of Atrial Fibrillation-Related Cardiovascular Outcomes

Abstract

Atrial fibrillation (AF) is associated with an increased risk of ischemic stroke, heart failure, cognitive decline, dementia, myocardial infarction, sudden cardiac death (SCD), and all-cause death. Although these associations are firmly established, our understanding of the underlying mechanisms remains incomplete. Accumulating evidence suggests that left atrial (LA) abnormality or atrial cardiomyopathy may explain the relationship of AF to the aforementioned outcomes. P-wave indices (PWIs) reflect underlying atrial remodeling. In this mini review, we define representative PWIs, discuss state-of-the-art knowledge on the relationship between abnormal PWIs and AF-related cardiovascular outcomes (focusing on ischemic stroke and sudden cardiac death), and propose directions for future research. Our ultimate goal is to present a practical way forward to advance the emerging field of LA abnormality or atrial cardiomyopathy.

Keywords: P wave axis; P wave duration; P wave indices; atrial fibirillation; stroke.

Figure 1

Representative ECG tracings of abnormal P-wave indices. A through (D), Prolonged P-wave duration (A), abnormal P-wave axis (B), abnormal P-wave terminal force in V1 (C), and advanced interatrial block (D). (A) The maximal P-wave duration is seen in lead II (136 ms). (B) The gray area on the hexaxial reference system (lead I 0°, lead II 60°, aVF 90°, aVR −150°, aVL −30°) represents normal P-wave axis (0–75°). The P-wave axis on B is −27°. (C) The P-wave terminal force is −9,632 μV*ms (amplitude −112 μV, duration 86 ms). (D) The maximal P-wave duration is seen in lead III (136 ms). Biphasic P-waves can be seen in III and aVF. This figure has been republished from Maheshwari et al. (30). Chen and Soliman are allowed to republish this figure, per American Heart Association Journal Policy.