LAUSR

INTRODUCTION Interventional cardiology together with interventional electrocardiology are nowadays one of the fastest developing branches of medicine and latterly, indications for transcatheter interventions have been extended to more and more folded cases. In recent decades, rapid progression in treatment of various types of atrial arrhythmias, particularly atrial fibrillation and atrial flutter, has been observed. Ablation within the cavotricuspid and other parts of the right atrium, as well as cardiac resynchronisation therapy, has become a standard approach. The right atrium (RA) and the interatrial septum are not only the direct targets of various interventions but also enable access to left heart chambers. The RA consists of many unique anatomical structures whose presence and morphology not only may trigger the abnormal electric activity of the heart, but also hinder the course of procedures. Precise understanding of heart anatomy and the most frequently observed anatomical variants of atrial structures seems to be crucial for achieving satisfying results, and minimising or avoiding complications during interventional procedures. This comprehensive summary presents in a thorough but uncomplicated way a detailed macroscopic morphology of RA and interatrial septum. It also provides the anatomical background for the most common atrial arrhythmias and invasive cardiological procedures.