Catheter Ablation -> SVT/AVNRT/WPW/AT: -> Mapping & Imaging D-PO01 - Featured Poster Session (ID 11) Poster

D-PO01-192 - Is The Right Atrium A More Frequent Source Of Focal Atrial Tachycardias Than The Left Atrium? (ID 959)

 M. Sendra Ferrer: Nothing relevant to disclose.


Background: Prior studies have reported that focal atrial tachycardias (AT) originate more frequently from the right atrium than the left atrium with an average ratio of 66% to 33%.
Objective: We hypothesized that whenever early activation is recorded near the septum, detailed mapping of both atria may uncover a left atrial origin more frequently than previously reported.
Methods: We analyzed 135 consecutive patients (57 males; age 50±18 years) that underwent catheter ablation of focal AT, defined as a discrete source of activation with centrifugal spread. Thirteen patients had a prior ablation attempt. Ten patients had incessant tachycardia and had developed a tachycardia-induced cardiomyopathy. The other patients had normal LV function (EF 58±7%).
Results: In 135 patients we found 148 different ATs. Seventy-four tachycardias (50%) originated from the left atrium (Table). The ATs originated from a septal or para-septal region in 56 (38%) of patients. Right septal/paraseptal ATs (n=21) originated from the coronary sinus ostium (10), fast pathway area (5), slow pathway area (2), Tendon of Todaro (2), and fossa ovalis (2). Left septal/paraseptal ATs (n=35) originated from the mitral annulus-aorta junction (anterior leaflet-non coronary cusp) (17), right sided pulmonary vein (15), and fossa ovalis (3).
Conclusion: Septal or paraseptal sources account for 38% of all focal ATs and more frequently originate in the left atrium (63%) than in the right atrium (37%). This finding underscores the value of mapping both atria when early activation is found near the septum.
Anatomical Distribution of Focal Atrial Tachycardia
Right atrium74Left atrium74
Crista terminalis/sinus venosa31Left pulmonary veins20
Right septa/paraseptal22Left septal/paraseptal35
Tricuspid annulus13Mitral annulus13
Right atrial appendage5Posterior wall or roof4
Superior vena cava3left atrial appendage2