Project description:BackgroundTypical isthmus-dependent atrial flutter (AFL) is traditionally treated through radiofrequency (RF) ablation to create a bidirectional conduction block across the cavo-tricuspid isthmus (CTI) in the right atrium. While this approach is successful in many cases, certain anatomical variations can present challenges, making CTI ablation difficult.MethodsWe enrolled four patients with typical counter-clockwise AFL who displayed an epicardial bridge at the CTI. Patients underwent high-resolution mapping of the right atrium and CTI ablation.ResultsPost-mapping identified areas of early focal activation outside the lesion line which suggested the presence of an epi-endocardial bridge with an endocardial breakthrough, confirmed by recording a unipolar rS pattern on electrograms at that site. A stable CTI block was achieved in all patients only after ablation at the site of the epi-endocardial breakthrough.ConclusionsThe presence of an epicardial bridge at the CTI, allowing conduction to persist despite endocardial ablation, should be considered in challenging cases of CTI-dependent AFL. Understanding this phenomenon and utilizing appropriate mapping and ablation techniques are essential for achieving successful and lasting CTI block.

| S-EPMC11338790 | biostudies-literature

Differentiation between epicardial and endocardial conduction gaps for left atrial posterior wall isolation using peak frequency annotation algorithm.

Project description: Not available

| S-EPMC11781886 | biostudies-literature

Surprises and pitfalls arising from (pseudo)symmetry.

Project description:It is not uncommon for protein crystals to crystallize with more than a single molecule per asymmetric unit. When more than a single molecule is present in the asymmetric unit, various pathological situations such as twinning, modulated crystals and pseudo translational or rotational symmetry can arise. The presence of pseudosymmetry can lead to uncertainties about the correct space group, especially in the presence of twinning. The background to certain common pathologies is presented and a new notation for space groups in unusual settings is introduced. The main concepts are illustrated with several examples from the literature and the Protein Data Bank.

| S-EPMC2394827 | biostudies-literature

Mitral annular flutter with epicardial coronary sinus conduit following mitral valve surgery.

Project description: Not available

| S-EPMC9391398 | biostudies-literature

Pseudo-reentry due to automatic annotation of dissociated activity unmasked by the new Lumipoint™ algorithm.

Project description:The new Lumipoint™ algorithm based on map analysis with several features is a valuable aid to understanding complex circuits, particularly as it can unmask areas with dissociated activity misleadingly annotated by an automatic mapping system.

| S-EPMC6982517 | biostudies-literature

Postoperative right atrial flutter following mitral valve surgery

Project description: Not available

| S-EPMC10123931 | biostudies-literature

All that quivers is not real: recognising pseudo-atrial flutter.

Project description: Not available

| S-EPMC9251261 | biostudies-literature