Idiopathic ventricular arrhythmia originating from the vicinity of lateral tricuspid annulus: The precise origin and anatomic concerns.

Background: Although the electrocardiographic and electrophysiological properties of ventricular arrhythmias (VAs) from the vicinity of the lateral tricuspid annulus (TA) have been reported in previous studies, their precise site of origin have not been addressed.
Objective: The purpose of this study was to describe the precise origin of lateral TA-VA and the relevant anatomy.
Methods: Consecutive patients with idiopathic lateral TA-VAs were reviewed and analyzed. Three-dimensional mapping system combined with intracardiac echocardiography (ICE) was used for anatomic reconstruction, mapping, and ablation.
Results: During the study period, 63 patients with lateral TA-VAs were included. Under ICE view, a prominent enfoldment structure was observed under the valve along the lateral TA. The muscular bundle was documented in all patients (100%) within the subvalvular enfoldment with an average number and diameter of 4 ± 2 and 4.10 ± 0.73 mm, respectively. Initial ablation was attempted via the anterograde approach in 15 patients but succeeded in none. To reach the ventricular side of the TA, the catheter needed to enter the ventricular chamber and retroflexed toward the atrial side with a reverse curve. The earliest activation site was found at the valvular end of muscular bundles in 51 of the 63 patients (80.9%) with a local activation time of -26.78 ± 4.63 ms. The VAs were eliminated after an average of 4 ± 2 seconds of ablation.
Conclusion: The ventricular side adjacent to the lateral TA exhibits a subvalvular enfoldment-like structure, which is rich in muscular bundles and serves as the origin of TA-VAs in most patients. To reach the origins, a reverse technique is required.
Competing Interests: Disclosures Dr Ma has received honoraria for presentations from AstraZeneca, Bayer Healthcare, Boehringer Ingelheim, Bristol Myers Squibb, Johnson & Johnson, and Pfizer. Dr Long and Dr Dong have received honoraria for presentations from Johnson & Johnson and Abbott. All other authors have no conflicts of interest to disclose.
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