Double atrial septum and transseptal puncture: An unusual obstacle to pulmonary vein isolation

Incidental Finding of a Double Interatrial Septum in a Patient Undergoing Atrial Fibrillation Ablation

“…In these adult cases, communication between the IAC and adjacent atria is highly variable. Three cases 1 , 6 showed no communication with either atrium, five showed communication with both atria, 2 , 3 , 7 and five 5 , 8 , 9 , 10 , 11 were similar to the present one in having the IAC communicate only with the left atrium. Association with systemic thromboembolism was noted in five of these cases (38%).…”

Correspondence on “Possible spontaneous PFO closure after thrombus trapped in PFO”, Antonia Schulz et al., Clin Res Cardiol 2014; 103:333-335

“…Later several other case reports and clinical studies confirmed this initial description [4][5][6] and an extensive autopsy study on 115 postmortem adults found such a left-sided ''atrial septal pouch'' in 36 % of autopsies, while in contrast a classic PFO could only be confirmed in 28 % of the autopsies [2]. This pathology may not only be a risk factor for thrombus formation outside the left atrial appendage but also present as an unexpected obstacle during cardiac interventions which require transseptal puncture for left atrial access [7]. An invasive attempt to close (or open) a suspected PFO is certainly not warranted in such cases.…”

An unusual interatrial septum

“…In most reported cases, double interatrial septum is an isolated anomaly, but it may be associated with obstructive left‐sided heart lesions and, possibly, increased risk of systemic thromboembolism if communication between the interatrial space and the atria is present . It may also represent an obstacle to transseptal puncture during catheter procedures . Some controversy exists with regard to terminology: Initially, similar anomalies with an interatrial chamber were described by pathologists as cor triatriatum, type C, that is, the interatrial chamber was considered as a midline (third) atrium, while Faletra et al believe the description of a double atrial septum is consistent with a large septal pouch .…”

“…We suppose that our cases are those of a double atrial septum phenotype which along with the cases of septal pouch represent different patterns of septum primum and septum secundum fusion. Due to increasing use of catheter‐based interventions requiring a transseptal puncture, the recognition of this anomaly is essential for performing safe and effective procedures …”