One hundred forty-four patients underwent PVAI with posterior wall and septum debulking for the treatment of AF. Of these patients, forty-two (28.2%) experienced recurrence of AF after their ablation procedure. Average time to AF recurrence was 5.11± 2.84 months. The average follow-up in this study was 10.23 ± 5.14 months (range = 6 to 20 months). There was no statistical difference between the two groups with regards to gender, age, AF type, radiofrequency burn time, as well as other baseline patient characteristics ().
Eighteen patients underwent a repeat ablation procedure. There were 14 males and 4 females, with an average age of 66.0 years ± 8.7 among males and 70.0 years ± 2.5 among females (). Three patients had paroxysmal and fifteen patients had persistent atrial fibrillation. Average ejection fraction was 51.1 % ± 7.8. Of the 18 patients, five (27.8%) had recurrence of atrial fibrillation following the second procedure. Although all patients have varying degrees of pre-ablation enhancement, no patients had significant enhancement to register with the scar quantification code used to detect post-ablation scarring.
Ablation-Scarring after the First Procedure and Outcome
Following the initial procedure, patients with 4 completely scarred PVA (ten patients) had 100% procedure success, whereas patients with 3 PVA (16 patients, 76.9% successful outcome), 2 PVA (19 patients, 84.2% procedure success), 1 PVA (45 patients, 73.3% procedure success, and zero PVA (54 patients, 55.5% procedure success) all had lower success rates. depicts this relationship.
A) Correlation of Circumferential PVA Scar from First Ablation Procedure and Recurrence. B) Patients with PVA Isolated Following Initial and Repeat Ablation Procedures.
Patients with successful AF termination had higher average total LA wall scar of 16.4% ± 9.8 (p = 0.004) and percent PVA scar of 66.2 ± 25.4 (p = 0.01) compared to patients with AF recurrence who had an average total LA wall scar 11.3% ± 8.1 and PVA percent scar 50.0 ± 24.7.
Frequency of Complete Circumferential PVA Lesions
Only 10/144 (6.9%) patients had circumferential scarring of all four PVA, 16/144 (11.1%) had 3 completely scarred PVA, 19/144 (13.2) had 2 completely scarred PVA, 45/144 (31.3%) had 1 completely scarred PVA and 54/144 (37.5%) had no completely scarred PVA (). shows the frequency of PVA scarring. The LIPV was most frequently circumferentially scarred PV occurring in 71/144 (49.3%) patients. The LSPV had complete scarring in 43/144 (29.9%) patients. The RIPV had complete scar in 32/144 (22.2%) patients. The RSPV was the most difficulty PV to achieve circumferential scarring occurring in only 17/144 (11.8%) patients.
Pulmonary Vein Antrum Scar Analysis
Ablation Lesions Prior to and Following Repeat Procedure
Eighteen patients underwent repeat ablation. Following the initial ablation, complete circumferential scarring was demonstrated around no PVA in four patients (22.2%), one PVA in eleven patients (61.1%), around 2 PVA in two patients (11.1%), and around three PVA in one patient (5.5%). No patients had complete scarring of all four PVA after the initial procedure. Following the repeat procedure, all patients had increased number of completely scarred PVA with five patients (27.8%) experiencing complete circumferential scarring of all four PVA and three patients (16.7%) with complete circumferential scarring of three PVA. Five patients (33.3%) had complete circumferential scarring in two PVA and four patients (22.2%) had complete scarring of one PVA. The numbers of veins scarred after the first and second procedures are demonstrated in .
depicts a patient with incomplete isolation of all four PVA (top row) after his first procedure. Prior to the repeat ablation the regions of interrupted ablation lesions were targeted (yellow arrows) and given to the electrophysiologists prior to the procedure. Electrical recovery was present in all four PVA. Following the procedure, DE-MRI was obtained (bottom row) which demonstrated complete circumferential lesions around all four PVA.
Figure 2 3D MRI model of the LA following failed PVAI (1) and repeat successful PVAI (2). After the initial failed ablation, all four PV’s showed incomplete PVA scar as evident by lack of continuous scar (orange/white) around each pulmonary vein ostia (more ...)
In the study, all patients had an increase in total LA scar percentage following the second procedure. The average circumferential PV antral scar after first ablation was 56.1% ± 21.4, while the average PV antral scar after the second ablation was 77.2% ± 19.5. The average total LA scar after the first ablation was 11.0% ± 4.1, while the average total LA scar after second ablation was 21.2% ± 7.4. The increase in posterior wall scarring of three patients is shown in . Thirteen of the eighteen patients (72.2%) had successful suppression of AF following the second ablation procedure. All five patients with AF recurrence after the second procedure demonstrated at least one incomplete circumferential PVA lesion. demonstrates two patient examples of patients with incomplete ablation lesion sets who suffered AF recurrence following the second ablation procedure.
Increased Posterior Wall Scar Formation
Identification of Gap Lesions following Procedure Failure
Correlation of DE-MRI Scar with Electroanatomical Mapping and Recovery of Conduction
A qualitative correlation between regions of enhancement on DE-MRI and low voltage regions on EA maps was seen in all patients. demonstrates three patients. Patients one and three had DE-MRI scar (red) located along the posterior wall and right PVA, which correlated with the distribution of low voltage tissue (red) on EA maps. Patient 2 had minimal scar following the first procedure and had normal voltage tissue on the EA map. Quantitative analysis of this relationship demonstrated a positive correlation of R2 = 0.57 ().
Figure 5 Correlation between DE-MRI following a failed ablation procedure with the electroanatomical map (EAM) obtained during the repeat procedure for three patients. The images on the left demonstrate PA (top) and AP (bottom) views of the DE-MRI color model (more ...)
Quantitative Correlation between DE-MRI Scar and Low-Voltage Tissue on Electroanatomical Mapping
Recovery of Electrical Potential and Gap Lesions
All patients with incomplete ablation sets marked by identifiable gap lesions had recovery of electrical activity on repeat electrophysiological (EP) study. shows recovery of conduction into the left superior PV as demonstrated by pulmonary vein potentials within the PV, which was abolished during the initial procedure. This recovery occurs in a vein with only minimal scarring and incomplete circumferential lesions. In contrast, represents a patient with complete circumferential lesion (orange/white) of the right inferior PV with no evidence of electrical activity during the repeat EP study. No patients in the series had complete circumferential scar around the PVA and electrical recovery.
Recovery of Electrical Potentials that Correlate with Incomplete Scar Lesions
Complete Anatomical and Electrical Isolation