Left Atrial Size and Left Atrial Volume Index as Predictors of Atrial High-Rate Episodes

Recent studies have shown that atrial high-rate episodes (AHREs) are associated with adverse cardiovascular outcomes, including an increased risk of stroke, cardiovascular mortality, and future atrial fibrillation. Despite efforts to identify predictors for AHRE, the relationship between left atrial morphology and AHRE remains unclear.

We systematically reviewed MEDLINE and EMBASE from inception to May 2024 to assess the association between left atrial morphology, measured as left atrial diameter (mm) and left atrial volume index (LAVI, mL/m²) via transthoracic echocardiography, and the occurrence of AHRE in patients without a prior history of atrial fibrillation at device implantation. Means and standard deviations of LAD and LAVI were extracted to calculate pooled mean differences using the generic inverse variance method.

A total of 18 cohort studies were included in the meta-analysis. The results showed that patients with AHRE had significantly higher left atrial diameter and LAVI compared to those without AHRE. The pooled mean difference for left atrial diameter was 2.19 mm (95% CI: 1.11-3.28; I² = 80%, p < 0.001), while for LAVI, it was 4.88 mL/m² (95% CI: 2.55-7.21; I² = 55%, p < 0.001).

Our study demonstrated that patients with AHRE had greater left atrial diameter and LAVI than those without AHRE. Further research is needed to clarify the underlying mechanism.