Key result
Left atrial diverticula are distinct anatomical structures whose prevalence does not differ between patients with sinus rhythm and atrial fibrillation, making them unlikely arrhythmogenic substrates.
Why the study?
Prior studies reporting on left atrial diverticula lacked consistent definitions, causing confusion with structures like left atrial accessory appendages and atrial aneurysms, and their link to atrial tachyarrhythmias remained unclear.
Left atrial diverticula are distinct anatomical structures from accessory appendages and aneurysms, and are unlikely to be arrhythmogenic substrates for atrial fibrillation.
May aid CT differentiation of LAD from LAAA in AF patients; leaves open prospective validation of clinical relevance.
INTRODUCTION: The finding of left atria diverticula (LAD) on cardiac computed tomography images obtained from patients with atrial fibrillation (AF) referred for pulmonary vein isolation is not uncommon. Prior studies reporting on LAD do not always provide definitions of LAD resulting in confusion with other anatomical structures such as left atrial accessory appendages (LAAA) and atrial aneurysms. The aim of this review is to identify an accurate definition of LAD and to describe distinctive properties between LAD and other left atrial structures, such as LAAA and aneurysms. Also, the relation between LAD and development of atrial tachyarrhythmias is discussed. METHODS: PubMed was searched for studies reporting on atrial aneurysms, left atrial diverticula, left atrial accessory appendages and atrial congenital aneurysms, resulting in 36 papers. RESULTS: LAD can be distinguished from LAAA by taking into account embryologic origins of the left atrium and their locations, resulting in the following definitions: (a) LAAA are contractile, trabeculated structures with circumscriptive ostia and narrow necks, originating from the primitive atria, (b) LAD are contractile, sac like structures with either smooth or trabeculated inner surfaces, circumscriptive ostia, narrow necks, and variable morphologies, originating from the embryologic common pulmonary vein, that incorporates into the LA, and (c) atrial aneurysms are non-contractile structures with wide necks and sac like bodies. There are no differences in prevalences of LAD between patients with sinus rhythm and AF. CONCLUSION: The pathophysiology of LAD is not yet fully understood. It is unlikely, that LAD are related to the development of atrial tachycardia's and AF by either being a source of ectopic activity or being part of an arrhythmogenic substrate. No differences in LAD prevalences between patients with sinus rhythm and AF have been found. Thus, it is unlikely that LAD could potentially be wolves in sheep's clothing.
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Veen et al. (2020) conducted a review in Left atrial diverticula. Left atrial diverticula was evaluated on Prevalence of left atrial diverticula in sinus rhythm versus atrial fibrillation. Left atrial diverticula are distinct anatomical structures whose prevalence does not differ between patients with sinus rhythm and atrial fibrillation, making them unlikely arrhythmogenic substrates.
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