A paucity of data exists about long-term outcomes after catheter ablation of persistent atrial fibrillation (AF). The mechanisms of AF are still unclear.
The purpose of this study was to evaluate the ...5-year outcome after persistent AF ablation using sequential defragmentation approaches and to identify the prognostic factors.
One hundred thirty-five patients with persistent AF (age 62 ± 9 years, 76 longstanding persistent AF) underwent catheter ablation using biatrial linear defragmentation approaches consisting of substrate modification for eliminating AF after pulmonary vein antrum isolation. Procedures were stopped when AF terminated; however, AF termination was not pursued after predetermined substrate modification.
AF terminated in 69 patients (51%). Total procedural and fluoroscopic times were 145.4 ± 36.1 minutes and 35.1 ± 14.3 minutes, respectively. Median 25th, 75th percentiles follow-up was 60 26.0-64.0 months, with 1.9 ± 0.8 procedures per patient. Arrhythmia-free survival after multiple procedures was 86.8%, 73.1%, 62.6%, and 53.8% (39 patients on antiarrhythmic drug therapy) at 1, 2, 3, and 5 years, respectively. Multivariate analyses revealed that AF termination (hazard ratio HR 3.043, 95% confidence interval CI 1.605-5.767, P = .001) was the sole independent predictor of long-term arrhythmia freedom, and arrhythmia freedom at 5 years was 70.0% and 31.8% in patients with and without AF termination (P = .0007). Five-year freedom from crossover to rate control strategies was 86.5%, and AF termination (HR 3.558, 95% CI 1.171-10.812, P = .025) was also the sole predictor.
Catheter ablation of persistent AF using the sequential defragmentation approach provided limited long-term freedom of arrhythmias often requiring multiple procedures. AF termination was the sole factor predicting freedom from both arrhythmia recurrence and crossover to rate control strategies during long-term follow-up.
Sick sinus syndrome (SSS) frequently coexists with atrial fibrillation (AF). The results of AF ablation in patients with SSS have not been fully evaluated. We retrospectively investigated 65 patients ...with paroxysmal AF (PAF) and SSS who underwent AF ablation using either radiofrequency (
n
= 50) or cryoballoon ablation (
n
= 15) in our institute. Forty-nine (75.4%) patients had a median of 5.6 (4.8–6.0) s of documented sinus pauses prior to the procedure (42 patients on antiarrhythmic drugs), and were observed when AF terminated in 47 patients. Successful pulmonary vein isolation was achieved in all, and substrate modification was added in 3 patients. Freedom from recurrent atrial arrhythmias after single procedures was 58.7, 45.2, and 38.9% at 1, 2, and 3 years after the initial procedure. During a 23.4 (11.1–40.7) month median follow-up and after 1.4 ± 0.6 sessions, 80.6% of patients were free from arrhythmia recurrence; however, permanent pacemaker implantations were required in 9 (13.8%) patients at a median of 5.3 (2.9–21.0) months after initial procedures. The average heart rate did not significantly differ before or a median of 2.5 (1.2–5.3) months post-procedure (76.7 ± 17.4 vs. 73.5 ± 14.6 bpm,
p
= 0.90). Multivariate analyses revealed that larger left atrial diameters odds ratio (OR) 1.21, 95% confidential interval (CI) 1.01–1.45,
p
= 0.042 were independent predictor of AF recurrence, and SSS type 1 was the sole predictor of pacemaker implantations (OR 10.30, 95% CI 1.38–76.7,
p
= 0.023), respectively. AF ablation obviated permanent pacemaker implantations in the majority of the patients with SSS and PAF, and SSS type 1 was a sole factor predicting pacemaker implantations.
Cryoablation is a safe alternative to radiofrequency (RF) ablation for slow-fast atrioventricular reentrant tachycardia (AVNRT); however, optimal electrogram parameters for site selection remain ...unknown. We retrospectively investigated local electrograms for slow pathway (SP) modification in cryoablation.
Forty-five consecutive patients with slow-fast AVNRT who underwent cryoablation using a 6-mm-tip catheter were enrolled. Electrogram parameters for sites of successful SP modification (success-sites) were investigated; these included the interval between atrial activation at His and the last deflection of SP potential, defined as the His(A)-SPP interval. In 8 patients, 3-dimensional mapping by multi-electrode catheter was performed pre-ablation for more detailed SP assessment.
Twenty-seven of 45 patients had successful SP modification by 1 cycle of freeze-thaw-freeze cryoablation at a single site with a low amplitude and fragmented SP potential. Among a total of 76 cryoablation sites in all patients, the His(A)-SPP interval at success-sites (45 sites) was significantly longer than that at unsuccess-sites (31 sites) (86 ± 9 vs.78 ± 10 msec, p < 0.0001). The AV amplitude ratio was not significantly different between success-and unsuccess-sites (0.21 ± 0.22 vs.0.25 ± 0.23, p = 0.429). The cutoff value of the His(A)-SPP interval for successful cryoablation was 82 msec with a sensitivity of 0.67 and specificity of 0.71 (AUC: 0.739; 95%CI: 0.626–0.852; p < 0.0001). Three-dimensional mapping in all 8 patients showed that sites with the most delayed atrial activation and the last deflection of the fragmented SP potential within the Koch's triangle coincided with success-sites.
A longer His(A)-SPP interval and fractionated SP potential were characteristics of successful cryoablation for SP modification in slow-fast AVNRT.
•Outcome after CB and RF PVI was comparable in the patients with a LCPV.•The ovality index and configuration of LCPV might predict the procedural difficulty.•The total procedure time was ...significantly shorter with the CB than RF ablation.
Adaptability of cryoballoons to anatomic pulmonary vein (PV) variations is limited due to the fixed geometrical shape, and use for left common PVs (LCPVs) is controversial. We compared the procedural and clinical outcomes in patients with LCPVs after cryoballoon and radiofrequency ablation, and explored the morphological parameters associated with procedural difficulty in LCPV isolations using cryoballoons.
Eighty-nine consecutive atrial fibrillation patients with LCPVs undergoing PV isolation using either 28-mm second-generation cryoballoons (n=30) or irrigated-tip catheters (n=59) were included. The patient characteristics except for the left atrial diameter (p=0.05) or morphological parameters obtained from cardiac computed tomography were similar between the two groups. The number needed to disconnect the LCPVs (NND) in the cryoballoon-group was ≦3 applications in 22 patients, but ≧4 in the remaining 8, including 1 requiring touch-up ablation. The PV isolation procedure time was significantly shorter in the cryoballoon-group than radiofrequency-group (43.0±19.5min vs. 68.2±31.4min, p<0.001), whereas the single procedure 1-year atrial fibrillation freedom was similar between the groups (74% vs. 67%, p=0.73). A multivariate logistic regression analysis revealed that the ovality index in the cryoballoon-group (odds ratio=1.474; 95%confidence interval=1.020–2.128; p=0.039) and orientation difference between the LCPV and lower branch in the frontal plane (odds ratio=1.071; 95%confidence interval=1.008–1.137; p=0.026) were independent predictors of an NND≧4. The incidence of LCPV reconnections was similar between the cryoballoon- and radiofrequency-groups during the second procedure (50.0% vs. 58.3%, p=0.73).
Cryoballoon ablation was similarly as effective as radiofrequency ablation in patients with LCPVs, and morphological evaluations aided in predicting procedural difficulty in LCPV isolations.
Background
The concept of ablation index (AI) was introduced to evaluate radiofrequency (RF) ablation lesions. It is calculated from power, contact force (CF), and RF duration. However, other factors ...may also affect the quality of ablation lesions. To examine the difference in RF lesions made during sinus rhythm (SR) and atrial fibrillation (AF).
Methods
Sixty patients underwent index pulmonary vein isolation during SR (n = 30, SR group) or AF (n = 30, AF group). All ablations were performed with a power of 50 W, a targeted CF of 5–15 g, and AI of 400–450 using Thermocool Smarttouch SF. The CF, AI, RF duration, temperature rise (Δtemp), impedance drop (Δimp), and the CF stability of each ablation point quantified as the standard deviation of the CF (CF‐SD) were compared between the two groups.
Results
A total of 3579 ablation points were analyzed, which included 1618 and 1961 points in the SR and the AF groups, respectively. Power, average CF, RF duration per point, and the resultant AI (389 ± 59 vs. 388 ± 57) were similar for the two rhythms. However, differences were seen in the CF‐SD (3.5 ± 2.2 vs. 3.8 ± 2.1 g, p < .01), Δtemp (3.8 ± 1.3 vs. 4.0 ± 1.3°C, p < .005), and Δimp (10.3 ± 5.8 vs. 9.4 ± 5.4 Ω, p < .005).
Conclusions
Despite similar AI, various RF parameters differed according to the underlying atrial rhythm. Ablation delivered during SR demonstrated less CF variability and temperature increase and greater impedance drop than during AF.
Differences in the radiofrequency effects were observed during atrial fibrillation (AF) and sinus rhythm (SR). The stability of the contact force and impedance drop was greater during SR, but the temperate rise was greater during AF.
Diaphragmatic compound motor action potential (CMAP) amplitude monitoring is a standard technique to anticipate phrenic nerve injury during cryoballoon ablation.
The purpose of this study was to ...evaluate the feasibility of a novel superior vena cava isolation (SVCI) technique using simultaneous pacing and ablation through the tip of a single mapping/ablation catheter.
Fifty-four patients with atrial fibrillation were included. Radiofrequency energy was delivered point by point uniformly for 20 seconds with a power of 20 W until achieving SVCI. Diaphragmatic CMAPs were obtained from modified surface electrodes by high-output pacing from the mapping/ablation catheter throughout the procedure (pace-and-ablate group). Applications were interrupted if CMAP amplitudes significantly decreased without fluoroscopy. The data were compared with those of the 54 patients undergoing conventional SVCI (conventional group).
Successful SVCI procedures were achieved in all with a mean of 10.3 ± 2.9 applications. In total, among 559 ablation sites, CMAPs were recorded at 95 (17.0%) with baseline amplitudes of 0.45 ± 0.23 mV. In 10 patients (18.5%), isolation was achieved without any radiofrequency deliveries at CMAP-recorded sites. Among the 95 applications, 6 (6.3%) were interrupted because of CMAP amplitude reductions. At the remaining 88 sites, 20-second radiofrequency applications were delivered without any amplitude decrease (from 0.45 ± 0.21 to 0.46 ± 0.23 mV; P = .885). Phrenic nerve injury occurred in 1 patient in the pace-and-ablate group, which recovered 3 months later, and in 3 conventional group patients, of whom 1 recovered 1 month later (P = .308). The total procedure time tended to be shorter (14.5 ± 6.3 minutes vs 16.7 ± 9.2 minutes; P = .153) and fluoroscopy time significantly shorter (3.9 ± 3.0 minutes vs 6.7 ± 5.7 minutes, P = .002) in the pace-and-ablate group than in the conventional group.
A novel and simple pace-and-ablate technique under diaphragmatic electromyography monitoring might be feasible for an electrical SVCI.
Introduction: Dormant pulmonary vein (PV) conduction can be provoked by adenosine triphosphate (ATP) after extensive encircling pulmonary vein isolation (EEPVI). However, the clinical implication of ...reconnection between the left atrium (LA) and isolated PVs provoked by ATP (ATP‐reconnection) remains unknown.
Methods and Results: We studied the clinical consequences of ATP‐reconnection during intravenous isoproterenol infusion (ISP‐infusion). EEPVI severs conduction between the LA and ipsilateral PVs at their junction. Radiofrequency energy is applied at a distance from the PV ostia guided by double Lasso catheters placed within the ipsilateral superior and inferior PVs. This study comprised 82 patients (67 men, 56 ± 9 years old) with atrial fibrillation (AF) who underwent injection of ATP during ISP infusion after successful EEPVI (ATP(+) group). We compared clinical characteristics of 170 patients who underwent earlier EEPVI prior to our use of ATP injection after successful EEPVI (ATP(N/D) group) with those of ATP(+) group patients who underwent one session of EEPVI. ATP‐reconnection occurred in 34 (41%) of 82 ATP(+) group patients. Additional radiofrequency applications were performed to eliminate ATP‐reconnection in all ipsilateral PVs. Continuous ATP‐reconnection of more than 20 seconds duration occurred in six (7.3%) of 82 patients. A total of 102 (60%) of 170 patients in the ATP(N/D) group had no recurrence of AF, whereas 60 (73%) of 82 ATP(+) group patients who underwent only one EEPVI session have had no recurrence of AF in a 6.1 ± 3.3‐month follow‐up period (P = 0.04).
Conclusion: Radiofrequency application for provoked ATP‐reconnection may reduce clinical AF recurrence.
Radiofrequency catheter ablation (RFCA) for pulmonary artery ventricular arrhythmia (PAVA) can be difficult because of the occasional existence of PAVA with preferential conduction.This study ...described the characteristics of PAVA that demonstrate preferential conduction.We analyzed electrocardiographic and electrophysiological data from 8 patients found to have PAVAs with preferential conduction out of 183 patients (4.4%) with right ventricular outflow tract (RVOT) arrhythmias who underwent RFCA at our hospitals. The PAVA with preferential conduction were classified into two types. In type 1 PAVA, successful ablation sites (success-sites) exhibited discrete prepotentials with an isoelectric line, in which the activation time (AT) was ≥ 50 milliseconds. In type 2 PAVA, excellent pace mapping was achieved at two sites separated by ≥ 20 mm: one in the RVOT free wall and the other at the success-site in the pulmonary artery. Type 1 and 2 PAVA features were considered signs of a short and long preferential conduction pathway, respectively.There were four patients each with type 1 and 2 PAVA. Type 1 PAVA was distinguished by the isoelectric line at success-sites with the mean AT of 78 ± 25.1 milliseconds. In type 2 PAVAs, although the AT at RVOT sites was very short (18.5 ± 10.1 milliseconds), the AT at success-sites was longer than that at the RVOT by 42.3 ± 36.2 milliseconds. Type 2 PAVAs displayed distinct electrocardiogram (ECG) features (R wave in lead I, RR′ in inferior leads, and transitional zone in V4) not found in typical PAVA ECGs.PAVA with preferential conduction can manifest in distinct ways on the ECG and intracardiac mapping. Knowledge of these features may facilitate successful RFCA of such PAVA cases.
Arrhythmogenic SVC and AF
Background
It is well known that superior vena cava (SVC) is one of the important non‐pulmonary vein (PV) foci of atrial fibrillation (AF). However, little is known ...regarding the role of arrhythmogenic SVC in AF.
Methods and Results
Among 1,425 patients who underwent AF ablation in 2 centers, PV antrum isolation was performed in all and SVC isolation was added in 74 (5.2%) patients with arrhythmogenic SVC (58 ± 10 years; 54 males) when the latter was identified as an AF source. The arrhythmogenicity was identified at the 1st, 2nd, and 3rd procedures in 62 (83.8%), 7 (9.5%), and 5 (6.7%) patients, respectively. In 7 (9.5%), 26 (35.1%), and 14 (18.9%) patients, it was identified following adenosine injection, isoproterenol infusion, and electrical cardioversion, respectively. SVC triggering AF was identified in 58 out of 74 (78.4%) patients. In this subset, AF initiated from SVC; however, AF cycle length was longer in SVC than in the right atrium once AF persisted, which suggested its role as an initiator. In 24 (32.4%) patients following the isolation of SVC, AF terminated or converted to atrial flutter and/or confined SVC tachycardia/fibrillation was observed, which suggested its role as a perpetuator. Sixty‐four (86.5%) of 74 patients were free from any atrial tachyarrhythmias without antiarrhythmic drugs mean 12.1 ± 9.4 months after the last ablation procedure (mean 1.38 procedures/patient).
Conclusions
In a subset of patients, SVC plays a role in AF not only as an initiator/trigger but also as a driver/perpetuator.
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