Objective The prognostic value of left atrial (LA) dimensions may differ between patients with and without atrial fibrillation (AF).
Methods MEDLINE and EMBASE were searched for studies that investigated the association between LA echocardiographic parameters measured by transthoracic echocardiography and cardiovascular outcomes in patients with or without AF. Data were independently abstracted by two reviewers and pooled using random-effects meta-analysis. The primary outcome was incident stroke or thromboembolic events. Secondary outcomes were heart failure, all-cause mortality and major adverse cardiac events (MACE).
Results Twenty-three studies of patients with AF (14 939 patients) and 68 studies of patients without AF (50 720 patients) in this systematic review. Increasing LA diameter was significantly associated with stroke and thromboembolic events in patients without AF (risk ratio (RR) 1.38, 95% CI 1.02 to 1.87; p=0.03), but not in patients with AF (RR 1.02, 95% CI 0.98 to 1.07; p=0.27; p for difference=0.05). Increasing LA diameter index was significantly associated with MACE in patients with AF (RR 1.13, 95% CI 1.09 to 1.17; p<0.001) and in patients without AF (RR 2.98, 95% CI 1.90 to 4.66; p<0.001), with stronger effects in non-AF populations (p for difference <0.001). Greater LA volume index was significantly associated with the risk of MACE in patients with AF (RR 1.01, 95% CI 1.00 to 1.02; p=0.03) and in non-AF populations (RR 1.08, 95% CI 1.05 to 1.10; p<0.001), the association being stronger in individuals without AF (p for difference <0.001).
Conclusions Larger LA parameters were associated with various adverse cardiovascular events. Many of these associations were stronger in individuals without AF, highlighting the potential importance of LA myopathy.
- atrial fibrillation
- left atrial dimensions
- systematic review
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Contributors The study concept and design was developed by LF, PM and DC. Search strategy and data acquisition was conducted by LF and PM. The statistical analyses were performed by LF and PM. LF, PM and DC drafted the manuscript. LF, PM, SA, SB, DD, MK, SO, BAK and DC contributed to data interpretation and provided critical revision of the manuscript for important intellectual content. DC has been the study supervisor and is the corresponding author.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Patient consent for publication Not required.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement All data relevant to the study are included in the article or uploaded as online supplementary information.