Case Report:
A 40-year-old man was admitted to our institution because of paroxysmal atrial fibrillation. At the age of 24, he had been diagnosed with a secundum ASD, which was 19mm in diameter with the left to right shunt and was corrected with percutaneous atrial septal defect closure. During the last 7 years, the patient complained of palpitations, and a follow-up electrocardiogram demonstrated the atrial flutter in September 2016. A further electrophysiological mapping revealed the CTI-dependent atrial flutter. Subsequently, he had undergone the tricuspid isthmus ablation. His symptoms were relieved but reported with transient palpitations sometimes. AF was diagnosed on an electrocardiogram in 2019, and the patient then opted for AF ablation. The patient had undergone 1 attempt to perform AF ablation in 2019, and TSP which was attempted initially at a site posteroinferior to the ASD occlude guided by intracardiac echocardiography (ICE) failed. Moreover, the occluder with 11mm thickness and a 34 mm diameter, which was oversized with respect to the native interatrial septum further increased the risks of direct TSP through the occluder. Finally, the ablation was terminated due to unsuccessful access to the LA. The patient’s paroxysmal atrial arrhythmias were treated initially with propafenone, followed by dronedarone. However, AF became aggravated and the condition transformed into a drug-refractory stage. The patient was referred to our institution for a second attempt at LA ablation.
The LA ablation procedure was performed under general anesthesia. An ICE was performed to rule out the left atrial appendage thrombus and for visual assistance during transseptal puncture. A 7-F multipolar electrode catheter was placed in the coronary sinus via the left femoral vein. TSP using a Brockenbrough needle was guided by fluoroscopy and ICE. We performed the direct TSP through the occluder device posteroinferior to its waist. Initially, the transseptal needle succeeded to traverse the device confirmed by contrast injection and a guidewire was positioned in the left superior pulmonary vein. Repeated attempts to pass through the 8.5F long sheath into the LA were unsuccessful because of significant resistance induced by severe fibrosis, which indicated a change to be made in the strategy. We could successively advance a 2.0-, 3.0-, 4.5-mm percutaneous coronary intervention (PCI) balloon over the guidewire across the septum. Moreover, the position of the non-compliant balloon on either side of the septum was confirmed by fluoroscopy and ICE, which also ensured that the balloon was placed perpendicularly to the transseptal access site created by the needle and the dilator. The sequential dilatation was performed by an inflation pressure of up to 12atm, whereas the thickened occluder prevented the balloon from further enlarging the access site. The PCI balloon was then withdrawn and a Passeo-35 (Biotronik AG ) peripheral balloon with a 6mm diameter was advanced through the puncture site. Subsequently, we inflated the peripheral balloon to its maximum size as the inflation pressure reached 10 atm. Finally, the 8.5F transseptal sheath could easily be passed into the mid-cavity of the LA without any resistance. After successful TSP, the patient was continuously anticoagulated by intravenous heparin to maintain an activated clotting time of 250-300 seconds. A saline-irrigated ablation catheter was then advanced through the sheath, and the patient could tolerate the procedure well without any further complications. An electroanatomical mapping was made of the LA and pulmonary veins and showed successful isolation of the pulmonary veins. The total procedure time and transseptal time were 360 minutes, and 215 minutes, respectively. No interatrial shunt or device deformation was seen and was confirmed by ICE at the end of the ablation procedure and by the transthoracic echocardiography the next day. At 3 months of follow-up, the patient remained in sinus rhythm and showed no residual shunt.