Transseptal Access to the Left Atrium: A Narrative Review of Techniques, Indications, and Device Innovations.

Transseptal puncture (TSP) is a critical technique for accessing the left atrium in various structural and electrophysiological cardiac procedures. Originally introduced for diagnostic catheterization in the mid-20th century, it has evolved into a cornerstone of modern interventional cardiology. This article was designed as a targeted narrative review, rather than a systematic or comprehensive review, and synthesizes selected peer-reviewed evidence spanning 1955 to 2025, retrieved through a targeted literature search. We explore the anatomical foundations of TSP, its historical development, and modern refinements such as radiofrequency-assisted puncture, balloon septoplasty, and fluoroless or image-fusion-guided access. Clinical applications-including mitral valve interventions, left atrial appendage closure, and decompression during extracorporeal membrane oxygenation (ECMO)-are reviewed alongside safety considerations and complication management strategies. Advances in imaging modalities, including three-dimensional echocardiography and computed tomography, have enhanced precision and safety. Because of the narrative design, the review emphasizes clinical relevance, procedural applicability, and evidence synthesis without formal risk-of-bias scoring or quantitative evidence grading. Overall, TSP demonstrates a high success rate and low complication profile when performed with appropriate imaging and operator expertise. Ongoing innovation in technique and technology continues to expand its utility across cardiac disciplines.