Left-to-right differences in the histopathologic patterns of transthyretin-derived amyloid (ATTR) deposition in the atria of older adults have not yet been investigated. Hence, this study evaluated heart specimens from 325 serial autopsy subjects. The amount of ATTR deposits in the seven cardiac regions, including both sides of atria and atrial appendages, was evaluated semiquantitatively. Using digital pathology, we quantitatively evaluated the immunohistochemical deposition burden of ATTR in the myocardium. We identified 20 sporadic ATTR cardiac amyloidosis cases (9 males). All patients had ATTR deposition in the left atrial regions of the myocardium. In the semiquantitative analysis, 14 of the 20 cases showed more severe ATTR deposition on the left atrial regions than on the right side, with statistically significant differences in the pathology grading (p < 0.01 for both the atrium and atrial appendage). Quantitative analysis further supported the difference. Moreover, six had ATTR deposition in the epineurium and/or neural fibres of the atria. Cluster analysis revealed that ATTR deposition in the myocardium was significantly more severe in males than in females. The heterogeneous distribution of amyloid deposits between atria revealed in this study may impair the orderly transmission of the cardiac conduction system and induce arrhythmias, which may be further aggravated by additional neuropathy in the advanced phase. This impairment could be more severe among males. These findings emphasise that atrial evaluation is important for individuals with sporadic ATTR cardiac amyloidosis, particularly for early detection.

Transseptal puncture is an established technique for achieving left atrium access during cardiac procedures. It is associated with low overall complication rate and high success rates. Although being almost a century old technique, recent years brought a substantial development in the field, allowing for faster and safer left atrium catheterization. In this paper we discuss its history, complications, available techniques and current state of the art.

Atrial fibrillation (AF) is a common cardiac arrhythmia associated with significant morbidity and mortality. The role of epicardial adipose tissue (EAT), particularly in the left atrium, has garnered attention in the pathophysiology of AF. This review aims to provide an overview of the association between the thickness of left atrial epicardial adipose tissue (LA-EAT) and the incidence of AF, while exploring the arrhythmogenic effects of LA-EAT and the impact of epicardial fat tissue changes with age and in pathological conditions. A comprehensive search of PubMed was conducted, and relevant studies were selected based on their inclusion criteria. The findings suggest that increased LA-EAT thickness is associated with an elevated risk of AF, potentially mediated through inflammatory and proarrhythmic effects. Age-related changes in epicardial fat tissue and alterations in pathological conditions, such as obesity, metabolic syndrome, and cardiovascular diseases, further contribute to the development and progression of AF. Further research is needed to deepen our understanding of these mechanisms and their clinical implications.