Improved Ablation Efficiency in PVI Guided by Contact Force and Local Impedance: Chronic Canine Model

Background: The purpose of this study was to assess the effect local impedance (LI) has on an ablation workflow when combined with a contact force (CF) ablation catheter.Methods: Left pulmonary vein isolation was performed in an in vivo canine model (N = 8) using a nominal (30 W) or an elevated (50 W) power strategy with a CF catheter. The catheter was enabled to measure LI prior to and during ablation. LI was visible for only one of the vein isolations.Results: Chronic block was achieved in all animals when assessed 30 ± 5 days post-ablation procedure with a median LI drop during RF ranging from 23.0 to 34.0 Ω. In both power cohorts, the median radiofrequency (RF) duration decreased if LI was visible to the operator (30 W only CF: 17.0 s; 30 W CF + LI: 14.0 s, p = 0.009; 50 W only CF: 6.0 s; 50 W CF + LI: 4.0 s, p = 0.019). An inverse relationship between the LI prior to RF delivery and the RF duration required to achieve an effective lesion was observed. There was no correlation between the magnitude of the applied force and the drop in LI, once at least 5 g was achieved.Conclusions: An elevated power strategy with the context of CF and LI led to the most efficient titration of successful RF energy delivery. The combination of feedback allows for customization of the ablation strategy based on local tissue variation rather than a uniform approach that could potentially lead to overtreatment. Higher LI drops were more readily achievable when an elevated power strategy was utilized, especially in conditions where the catheter was coupled against tissue with low resistivity. Clinical study is warranted to determine if there is an additive safety benefit to visualizing the dynamics of the tissue response to RF energy with LI when an elevated power strategy is used.

Usefulness of a Radiofrequency Transseptal Needle in the Second Puncture of Fontan Extracardiac Conduit

We performed a second puncture of the extracardiac conduit in an 11-year-old Fontan patient to assess the patency of the stent previously deployed in the left pulmonary vein. For the first puncture, a mechanical Brockenbrough needle was selected to puncture the Gore-Tex conduit, an electrical insulator. For the second puncture, the location of that previous hole was detected as an indentation covered with atrial tissue, which is an electrical conductor. The second puncture was performed safely using a radiofrequency transseptal needle.

A case of catheter ablation for atrial fibrillation in a very young patient without structural heart disease

The patient was an 18-year-old man who suffered frequent supraventricular premature complexes (SVPCs) and atrial fibrillation. Catheter ablation was performed and left pulmonary vein had been isolated, although firing from within the left inferior pulmonary vein remained. After that, the patient did not exhibit SVPCs and atrial fibrillation.

Effectiveness of posterior aortopexy for the left pulmonary vein obstruction between the left atrium and the descending aorta

Background: Left pulmonary vein (PV) obstruction can occur due to compression between the left atrium (LA) and the descending aorta (DA). One of the effective solutions for this problem is posterior aortopexy. In this study, we have reported five cases of posterior aortopexy to relieve left PV obstruction between the LA and the DA. Methods: Since August 2012, five patients have undergone posterior aortopexy for compression of the left PV between the LA and the DA. The median age and weight of the patients at the time of operation were 5.5 months (range, 1-131 months) and 5.2 kg (range, 4.2-29.5 kg), respectively. The left PV obstruction was initially diagnosed on echocardiography in four patients and computed tomography angiography in one patient. The median peak pressure gradient across the obstructed left PV was 7.3 mmHg (range, 4-20 mmHg). Concomitant procedures were ventricular septal defect closure in one patient and patent ductus arteriosus ligation in one patient. Results: There was no PV obstruction on echocardiography in any of the patients after the operation except in the case of one patient who had diffuse pulmonary vein stenosis. The median follow-up duration was 34 months (range, 14-89 months), and during follow-up no incidence of the left PV obstruction was observed in any of the surviving patients. Conclusions: The posterior aortopexy technique could be a good surgical option for the left PV obstruction caused by compression between the LA and the anteriorly positioned DA.

Effectiveness of Ethanol infusion into the vein of Marshall combined with a fixed anatomical ablation strategy (the ‘upgraded 2C3L’ approach) for catheter ablation of persistent atrial fibrillation

Introduction: Linear ablation in addition to pulmonary vein antrum isolation (PVAI) has failed to improve the success rate for persistent atrial fibrillation (PeAF), due to incomplete block of ablation lines, especially in the mitral isthmus (MI). Methods and results: The study enrolled 191 patients (66 in group 1 and 125 in group 2). In group 1, EI-VOM was firstly performed, followed by radiofrequency (RF) applications targeting bilateral PVAI and bidirectional block in the roofline, cavotricuspid isthmus, and MI. In group 2, PVAI and the three linear ablations were completed using only RF energy. MI block was achieved in 63(95.5%) and 101(80.8%) patients in group 1 and 2, respectively (p=0.006). Patients in group 1 had shorter ablation time for left pulmonary vein antrum (8.15 min vs 12.59 min, p<0.001) and MI (7.0 min vs 11.8 min, p<0.001) and required less cardioversion (50(78.5%) vs 113(90.4%), p=0.007). During the 12-month follow-up, 58 (87.9%) patients were free from AF/AT in group 1 compared with 81 (64.8%) in group 2 (p<0.001). In multivariate cox regression, the ‘upgraded 2C3L’ procedure is associated with a lower recurrence rate (HR 0.27, 95%CI 0.12-0.59). Conclusion: Compared with the conventional ‘2C3L’ approach, the ‘upgraded 2C3L’ approach has higher effectiveness for ablation of PeAF.

Anomalous Connection of the Left Pulmonary Vein to the Coronary Sinus With Intact Atrial Septum in a Young Woman

The authors have requested that this preprint be withdrawn due to erroneous posting.

Anomalous Connection of the Left Pulmonary Vein to the Coronary Sinus With Intact Atrial Septum in a Young Woman

Background: Left sided Partial anomalous pulmonary venous connection (PAPVC) is a rare congenital abnormal cardiac defect. An intact atrial septum is more uncommon. To our knowledge, connection of the left pulmonary vein (LPV) to the coronary sinus (CS) with intact atrial septum was no previous reported.Case report: We report an 18-years-old woman who had this rare anomaly. She exhibited no obvious clinical symptoms. An echocardiogram revealed the primary diagnosis and this diagnosis confirmed during operation. This patient underwent a successful surgical repair. Artificial atrial septal defect (ASD) and coronary sinus orifice were inserted into left atrium by patch. postoperative recovery was recuperated.Conclusion: Given the high risk of developing Congestive heart failure, like many other centers, we advocate for intervention during the preschool age. Surgical techniques depend on the number and location of abnormal veins or veins.