Atrial fibrillation in patients with permanent VVI pacemakers: risk factors for atrial fibrillation

The predictive value of abnormal P-wave axis for the detection of incident atrial fibrillation: A systematic review with meta-analysis

INTRODUCTION

There is growing interest in the prediction of incident atrial fibrillation (AF). The 12-lead electrocardiogram (ECG) has been a particularly rich target for possible prediction strategies.

PURPOSE

The P-wave axis is an ECG parameter that reflects the dominant vector of atrial depolarisation and is usually 0° -75°. 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.

METHODS

A systematic review and meta-analysis of published literature associating abnormal P-wave axis and the development of incident AF was performed. Electronic databases were systematically searched from inception to October 2021. 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 eleven studies were identified that associated an abnormal P-wave axis with the subsequent detection of AF. The eight studies that considered abnormal P-wave axis as being <0° or >75° 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 2.12 (95% CI 1.49 to 3.01) for the detection of incident atrial fibrillation.

CONCLUSION

This comprehensive systematic review and meta-analysis, indicates the positive association of abnormal P wave axis and future detection of AF. Utilisation of abnormal P-wave axis, alongside other parameters, may allow clinicians to better risk-stratify individuals at increased risk of AF, and thus identify those who may benefit most from prolonged cardiac monitoring or targeted anticoagulation.

Intra-Atrial Block: Definition and Relationship to Atrial Fibrillation and Other Adverse Outcomes

In 1916, Bachmann first reported on the inter-auricular time interval. However relatively little attention was paid to this ECG measurement for decades. Then, in 1956, Samuel Bradley and Henry JJ Marriott reported on intra-atrial block (IAB) in 4,500 ECGs.As defined by them, IAB was a P wave duration of 0.12 sec or longer. Since that time, others have defined IAB as 0.11 sec or longer or 0.12 sec or longer. Several authors have suggested subcategories, such as first-, second-, and third-degree patterns and some have defined specific intra-atrial and inter-atrial pathways. These are of electrocardiographic interest but have not been substantiated as related to different clinical outcomes. Many disorders have been associated with IAB. More importantly, however, IAB has been associated with several adverse outcomes, including sinus node dysfunction, atrial tachyarrhythmias - especially atrial fibrillation, thromboembolic events, and increased mortality. This brief review will detail the above to emphasize to ECG readers the importance of not overlooking IAB in their interpretations.

How should left atrial size be reported? Comparative assessment with use of multiple echocardiographic methods

BACKGROUND

Determination of left atrial (LA) size is important in clinical decision-making. The LA anteroposterior dimension (APD) has been routinely reported as LA size assessment. Early studies indicated that the APD may have limited accuracy in quantification. Conventional 3-dimensional reconstruction (C3DR) of the LA has been validated. However, its process is time-consuming and not applicable for daily practice. To explore an accurate and practical approach, we compared different echocardiographic measurements with C3DR in 141 patients with different LA sizes.

METHODS AND RESULTS

LA size was measured with (1) the cubic equation with APD (Cub); (2) the ellipsoidal formula (Ellp); (3) biplane modified Simpson rule (biplane); and (4) simplified 3-dimensional reconstruction from 3 standard apical views with B spline interpolation (S3VR). All four methods were compared with C3DR. S3VR and biplane methods provided a close agreement to C3DR (y = 0.94x + 3.6, r = 0.95, SEE = 7.6 mL, mean difference = -1.3% for S3VR; y = 0.87x + 2.9, r = 0.91, SEE = 9.0 mL, mean difference = -9.4% for biplane). The Cub and Ellp calculations were less accurate, with significant volume underestimation (P <.001).

CONCLUSIONS

LA single dimension is not accurate for LA size measurement. Among four different methods of LA size measurement, biplane and S3VR provide the closest agreement to C3DR. The biplane, which is readily applicable with current echocardiographic equipment, should be routinely applied in clinical practice.