non-PV Foci Research Articles

Fibrillatory pattern of dissociated venous activity after pulmonary vein isolation: Novel characteristics for remnant foci of a trigger ectopy for atrial fibrillation

BackgroundDissociated pulmonary vein activity (DPVA), defined as isolated intrinsic ectopic beats observed after successful pulmonary vein (PV) isolation, indicates the presence of remnant foci of trigger ectopy but has yet to be extensively studied. We investigated the correlation between DPVA and the PV triggers of atrial fibrillation (AF). Method and resultsConsecutive 110 patients undergoing AF ablation were enrolled. We defined trigger ectopy as documented ectopic foci observed to spontaneously initiate AF. Trigger ectopy was detected in 62 (56%) patients. DPVA in at least one PV was detected in 95 (86%) patients. Of the 440 isolated PVs, we recognized trigger ectopy in 73 (16%) PVs (culprit PVs) and DPVA in 184 (42%) PVs. DPVA was more frequently observed in culprit PVs than in non-culprit PVs [59% vs. 39%; odds ratio (OR)=2.3; p=0.001]. The concordance ratio of culprit PV was 67% (8/12) in PV with fibrillatory DPVA, 20% (35/172) in PV with non-fibrillatory DPVA, and 12% (30/256) in PV without DPVA. Fibrillatory DPVA was more frequently observed in culprit PVs than non-fibrillatory DPVA (OR=7.8; p=0.001). Non-PV foci were observed in 10 (11%) of the 95 patients with DPVA and 5 (33%) of the 15 patients without DPVA (OR=4.3; p=0.02). No significant difference in the frequency of AF recurrence was observed between them. ConclusionsFibrillatory DPVA was found to be strongly associated with trigger ectopy of AF. Non-fibrillatory DPVA might merely indicate the existence of bystander ectopic foci located inside PVs. Non-PV ectopic foci were frequently observed in patients without DPVA.

176-23: Ectopies from the superior vena cava after pulmonary vein isolation in patients with atrial fibrillation

Purpose: Episodes of atrial fibrillation (AF) are mainly initiated by triggers from pulmonary veins (PVs). The superior vena cava (SVC) has been identified as a second major substrate of non-PV foci, but the electrophysiologic features of the SVC have not been fully investigated. We hypothesized that SVC ectopies are suppressed by predominant features of PV ectopies and tend to appear after PV isolation (PVI). Methods: We evaluated the electrophysiological characteristics and clinical implications of SVC ectopies in patients with AF during catheter ablation using high-dose isoproterenol and the atrial overdrive pacing maneuver. The manifestation patterns and modes of onset (coupling interval and appearance interval) of ectopies from both the PVs and SVC were investigated. Summary: 205 patients were enrolled [153 males and 52 females; mean age 64 ± 10 years; paroxysmal in 143 patients (69.8 %), persistent in 40 (19.5 %), and long-standing persistent in 22 patients (10.7 %)]. Before PVI, PV ectopies were detected in 182/205 patients (89 %). SVC ectopies were rarely observed before PVI but were significantly more frequent after the completion of PVI (3/205 vs. 14/205 patients, p = 0.011). The coupling interval (CI) and %CI (CI/preceding the A-A interval × 100) of PV ectopies were significantly shorter than those of SVC ectopies (211 ± 78 vs. 282 ± 106 ms, p = 0.021, and 34 ± 9 vs. 51 ± 17 %, p < 0.001, respectively). The appearance intervals of the PV ectopies were shorter than those of the SVC ectopies (6.3 ± 4.0 vs.10.7 ± 6.7 s, p =0.030). During repeat procedures, PVs with reconnection to the left atrium were less frequently observed in patients with SVC firing than in patients without SVC firing (1.7 ± 1.5 vs. 2.9 ± 1.1 PVs, p = 0.029). Conclusion: We demonstrated that PVI tends to manifest SVC ectopies with less spontaneous activity and that an elimination of predominant ectopies from the PVs may affect appearance of SVC ectopy.

Clinical recurrence and electrical pulmonary vein reconnections after second-generation cryoballoon ablation

Electrical reconnections after pulmonary vein isolation (PVI) are less common after second-generation cryoballoon than radiofrequency ablation. The purpose of this study was to investigate the incidence and characteristics of pulmonary vein (PV) reconnections after second-generation cryoballoon ablation in patients with and those without clinical recurrences. Forty patients with paroxysmal atrial fibrillation undergoing second procedures after cryoballoon ablation were enrolled. Twenty-five patients experienced clinical recurrences, and the remaining 15 did not. All 158 PVs were reevaluated a median [25th, 75th percentiles] of 6.0 [4.0-9.0] months after the initial procedure. In total, reconnections were detected in 39 PVs (24.7%) among 25 patients (62.5%). Reconnected PVs included 6 left superior (LS) (15.8%), 7 left inferior (LI) (18.4%), 5 right superior (RS) (12.5%), 20 right inferior (RI) (50.0%), and 1 left common (LC) (50.0%) PV. Reconnected PV potential conduction delays were a median of 112 [76-130], 103 [82-133], 84 [66-96], 68 [49-73], and 204 ms in the LS, LI, RS, RI, and LC PV, respectively. There was no significant difference between those with and those without clinical recurrences with regard to clinical characteristics, procedural results, incidence of reconnections (25/98 vs 14/60, P = .758), and PV conduction delays in each PV. The most common gap location was the RI PV bottom in both groups. Among 5 patients with reconnections of arrhythmogenic PVs (with atrial fibrillation initiation), 2 experienced clinical recurrences, whereas 3 did not. Non-PV foci (with atrial fibrillation initiation) were identified in a second procedures in 10 of 25 patients with clinical recurrences. The incidence and characteristics of PV reconnections after second-generation cryoballoon ablation were similar between patients with and those without clinical recurrences. The results should be considered when discussing the optimal dose of cryoballoon applications.

Abstract 19031: Prediction and Incidence of Non-PV Trigger Foci of Atrial Fibrillation With Regard to Clinical Profile

Introduction: Non-PV triggers play significant roles in initiating atrial fibrillation (Af). We hypothesized that location of non-PV Af triggers is predictable to some extent from clinical background and may have influence on clinical outcome after ablation. Methods: We analyzed consecutive 109 patients (76 men) with Af who underwent catheter ablation and investigation of Af triggers. Af was induced under recordings of intra-cardiac electrograms before ablation procedure in the following ways (1) watching spontaneous firing, (2) induction with intravenous infusion of isoproterenol and adenosine, (3) burst atrial pacing and/or intentional defibrillation to watch immediate recurrence of Af. Af triggers were analyzed and compared to clinical profiles and therapeutic outcome. Results: Eighty-four were paroxysmal Af and 25 were persistent. Any ectopic trigger of Af was identified in 73 patients (66%) with 99 foci. Seventy-eight foci were PVs (79%) whereas 21 (21%) were non-PV triggers. In general, non-PV foci were notably identified in female (P&lt;0.01) whereas age, LA diameter or Af type was not significantly relevant to the presence of non-PV foci. Among non-PV foci, superior vena cava (SVC, n=5), crista terminals (CT, n=5) and left atrium (LA, n=5) were prevalent sites. CT was prevalently noted in younger females (P&lt;0.01), whereas SVC was regardless of age. Non-PV foci in the LA were preferably noted in patients with persistent Af (P&lt;0.05). Importantly, multiple or non-PV foci were not significantly correlated to Af recurrence after ablation, whereas LA diameter was weakly correlated. Conclusion: Presence and sites of non-PV foci are rather predictable by simple clinical profiles such as gender, age and type of Af. Multiple or non-PV foci may not be associated with worse clinical outcome as long as they can be successfully targeted and ablated.

Abstract 15628: Prevalence of Non-Pulmonary Vein Triggers in Patients With Previous History Of Coronary Artery Bypass Grafting Undergoing Catheter Ablation for Atrial Fibrillation

Introduction: Post-operative atrial fibrillation (AF) is reported in up to 5-40% of patients following coronary artery bypass graft (CABG) surgery. Age-related atrial dilatation and fibrosis, electrical remodeling, autonomic imbalance and post-operative inflammation are few of the many pathophysiological factors that play an important role in the genesis and persistence of post-CABG AF. Recent data on fibroblast-myocyte interaction indicates the central role of cardiac fibrosis in the origin of non-pulmonary vein (non-PV) drivers that serve as a source for maintenance of AF. Therefore, we sought to examine the prevalence of non-PV triggers and their impact on ablation outcome in post-CABG AF patients. Methods: Two-hundred sixty seven patients with history of CABG undergoing catheter ablation for atrial fibrillation were included in this analysis (61±11 years, 69% male, LVEF 50±10%, LA size 41.0±6.8mm, non-PAF 72%). All patients underwent pulmonary vein antrum (PVAI) and posterior wall isolation. Non-PV triggers were defined as ectopic triggers originating from sites other than pulmonary veins such as interatrial septum, superior vena cava, left atrial appendage, coronary sinus, ligament of Marshall, crista terminalis. Those were identified by isoproterenol challenge and were ablated based on operator choice. Results: During ablation, non-PV triggers were detected in 243 (91%) patients. The triggers were most commonly mapped to CS (62%) and LAA (70%). Additional sites of non-PV triggers were LA septum, superior vena cave, crista terminalis and mitral valve annulus. Based on operator choice, non-PV triggers were ablated in 118 of the 243 patients and not targeted in 125 patients. At the end of 32±7 month follow-up after a single procedure, overall success rate was 130 (53.5%). Of the 118 patients undergoing non-PV trigger ablation, 81(68.6%) patients remained arrhythmia-free off anti-arrhythmic drugs compared to 49 of 125 (39.2%) where non-PV ablation was not performed (log rank p &lt;0.001, hazard ratio 3.76 [95% CI 2-6.43]). Conclusion: Our results for the first time demonstrate that non-PV foci are highly prevalent in post-CABG AF patients and ablation of those triggers results in significantly better long-term outcome.

Abstract 17461: Clinical Significance of No Pulmonary Vein Potential at Redo-procedure After Catheter Ablation for Atrial Fibrillation

Introduction: Long-lasting pulmonary vein isolation (PVI) has been shown to be the key determinants for clinical outcome in both patients with paroxysmal and persistent atrial fibrillation (AF). Hypothesis: Although reconnected PV potential (PVP) has been regarded as a main mechanism of AF recurrence after catheter ablation, PVIs are well preserved in some patients at redo-procedure after recurrence. Therefore, we explored the characteristics and clinical outcome of the patients with negative PVP at redo-procedure. Methods: Among 1522 patients with AF who underwent catheter ablation, 143 patients (79.0% male, 56.1±10.0 years old, 65.0% paroxysmal AF) refractory to antiarrhythmic drug underwent redo-procedure. PVP was not shown in 52 patients (PVP- group, 36.4%), but remaining 91 patients showed PVP (PVP+ group, 234/364 (64.3%) of PVs). We mapped triggers with isoproterenol infusion in both groups (after PVI in PVP+ group). Depending on mapping finding, we ablated non-PV foci and added linear ablation or complex fractionated atrial electrogram (CFAE)-guided ablation. Results: 1. PVP- group was independently associated with female gender (OR 2.64 95%CI 1.13~6.21, p=0.026) and later de novo clinical recurrence timing (OR 1.02 95% CI 1.00~1.04, p=0.047). 2. Additional linear ablations were more likely to be performed in PVP- group (92.2% vs. 61.5%, p&lt;0.001), but total ablation time (2411.3±1082.8 vs. 3144.8 ± 1412.5 sec, p=0.003) and procedure time (164.2± 51.4 vs. 144.2±47.1 min, p=0.027) were shorter in PVP- group than in PVP+ group. 3. During 18.4±10.2 months follow-up after redo-ablation, PVP- group showed significantly higher clinical recurrence rate than PVP+ group regardless of redo-ablation strategies (Kaplan Meier, Log Rank p=0.011). The presence of recurred PV connection (PVP+) was independently associated with lower recurrence of AF after repeat ablation (HR 0.46, 95% CI 0.21 - 0.98, p=0.043). Conclusions: AF patients with well-preserved PVI recurred later timing after de novo ablation, but showed poor clinical outcome after redo-ablation procedure, suggesting a potential AF progression.

Ectopies from the superior vena cava after pulmonary vein isolation in patients with atrial fibrillation.

Episodes of atrial fibrillation (AF) are mainly initiated by triggers from pulmonary veins (PVs). The superior vena cava (SVC) has been identified as a second major substrate of non-PV foci, but the electrophysiologic features of the SVC have not been fully investigated. We hypothesized that SVC ectopies are suppressed by predominant features of PV ectopies and tend to appear after PV isolation (PVI). We evaluated the electrophysiological characteristics and clinical implications of SVC ectopies in patients with AF during catheter ablation using high-dose isoproterenol and the atrial overdrive pacing maneuver. The manifestation patterns and modes of onset (coupling interval and appearance interval) of ectopies from both the PVs and SVC were investigated. 205 patients were enrolled [153 males and 52 females; mean age 64±10years; paroxysmal in 143 patients (69.8%), persistent in 40 (19.5%), and long-standing persistent in 22 patients (10.7%)]. Before PVI, PV ectopies were detected in 182/205 patients (89%). SVC ectopies were rarely observed before PVI but were significantly more frequent after the completion of PVI (3/205 vs. 14/205 patients, p=0.011). The coupling interval (CI) and % CI (CI/preceding the A-A interval×100) of PV ectopies were significantly shorter than those of SVC ectopies (211±78 vs. 282±106ms, p=0.021, and 34±9 vs. 51±17%, p<0.001, respectively). The appearance intervals of the PV ectopies were shorter than those of the SVC ectopies (6.3±4.0 vs. 10.7±6.7s, p=0.030). During repeat procedures, PVs with reconnection to the left atrium were less frequently observed in patients with SVC firing than in patients without SVC firing (1.7±1.5 vs. 2.9±1.1 PVs, p=0.029). We demonstrated that PVI tends to manifest SVC ectopies with less spontaneous activity and that an elimination of predominant ectopies from the PVs may affect appearance of SVC ectopy.

Novel association of polymorphic genetic variants with predictors of outcome of catheter ablation in atrial fibrillation: new directions from a prospective study (DECAF)

Non-pulmonary vein (non-PV) triggers and left atrial (LA) scars perpetuate atrial fibrillation (AF) and limit the success rate of catheter ablation. In order to understand the genetic basis of these risk factors, we examined the association of selected single nucleotide polymorphisms (SNPs) with scar and non-PV triggers. Four hundred AF patients (67 %male, 62±12 years, LA size 45.3±7 mm, 64%non-paroxysmal) undergoing catheter ablation were prospectively enrolled. DNA extractions for16 AF-related SNPS from blood samples were performed of which 371 DNA samples were available for genotyping. Multivariate logistic regression analysis was used for assessing predictive role of individual SNP, and logistic kernel-machine approach was applied to test the cumulative effect of multiple SNPs as a group with non-PV triggers and LA scar. False discovery rate (FDR) was computed for all candidate SNPs to address multiple testing. SNPs rs6599230 and rs6843082 were inversely associated (OR 0.68, p=0.04, and 0.62, p=0.01, respectively) whereas rs1448817 (OR 1.74, p=0.04) and rs7193343 (OR 1.66, p=0.02) predicted higher risk of non-PV triggers. Genotypes for rs6599230 and rs6843082 conferred 51 % reduction in the odds for non-PV triggers (combined OR 0.49, p=0.019), while rs1448817 and rs7193343 demonstrated a combined OR of 1.93, p=0.025. FDR was controlled at 16 % to adjust for multiple testing. For LA scar, inverse association was observed with rs1448817 (OR 0.29, p=0.006), rs17042171 (OR 0.27, p=0.032), rs3807989 (OR 0.54, p=0.017), and rs6843082 (OR 0.56, p=0.009). Two SNPs were associated with increased scar risk: rs17375901 (OR 3.68, p=0.03) and rs7193343 (OR 1.74, p=0.037). For global association of SNPs with left atrial scar FDR was controlled at ≤10 % to adjust for multiple testing. This study has a strong clinical significance as it provides important insights into the molecular basis of pertinent therapeutic targets. Our findings demonstrate that the presence of certain genetic polymorphisms increases the risk of scar and non-PV triggers in AF patients. Therefore, PVAI alone will not be enough to eliminate the arrhythmia and the operators may need to identify and isolate the non-PV foci to maximize procedural success in patients carrying these risk variants. Clinical trial registration clinicaltrials.gov (NCT01751607).

History of hyperthyroidism and long-term outcome of catheter ablation of drug-refractory atrial fibrillation

Hyperthyroidism is a known reversible cause of atrial fibrillation (AF). However, some patients remain in AF despite restoration of euthyroid status. The purpose of this study was to compare the electrophysiologic characteristics and long-term ablation outcome in AF patients with and without history of hyperthyroidism. The study enrolled 717 consecutive patients with AF who underwent first AF ablation, which involved pulmonary vein (PV) isolation in paroxysmal AF and additional substrate modification in nonparoxysmal AF patients. Eighty-four patients (12%) with hyperthyroidism history were compared to those without. Euthyroid status was achieved for ≥3 months before ablation in hyperthyroid patients. Patients with hyperthyroid history were associated with older age, more female gender, lower mean right atrial voltage, higher number of PV ectopic foci (1.3 ± 0.4 vs 1.0 ± 0.2, P < .01), and higher prevalence of non-PV foci (42% vs 23%, P < .01). Ectopic foci from ligament of Marshall were demonstrated more often in hyperthyroid patients (7.1% vs 1.6%, P < .01) in whom alcohol ablations were required. After propensity score matching for potential covariates, history of hyperthyroidism was an independent predictor of AF recurrence after single procedure (hazard ratio 2.07, 95% confidence interval 1.27-3.38). AF recurrence rates after multiple procedures were not different between patients with and those without hyperthyroid history. Patients with hyperthyroid history had a significantly higher number of PV ectopies and higher prevalence of non-PV ectopic foci compared to euthyroid patients, which resulted in a higher AF recurrence rate after a single procedure.

Adenosine-Provoked Atrial Fibrillation Originating From Non–Pulmonary Vein Foci: The Clinical Significance and Outcome After Catheter Ablation

ObjectivesThe goal of this study was to systematically investigate the incidence and clinical significance of non–pulmonary vein (PV) foci revealed by adenosine/adenosine triphosphate (ATP) testing during atrial fibrillation (AF) ablation. BackgroundATP is reported to provoke AF. MethodsA total of 464 patients with consecutive paroxysmal AF undergoing ATP testing after PV antrum isolation were included. ResultsAF originating from non-PV foci was provoked in 26 (5.6%) total patients during first (n = 20) or repeat (n = 8) ablation procedures. Dormant PV conduction was also revealed by ATP testing in 6 patients. Non-PV foci were located in the superior vena cava (SVC) (i.e., the SVC group) and atria (i.e., the atria group) in 10 and 18 (9 each in the right and left atria) patients, respectively. In the multivariable analysis, being female was the sole independent predictor of ATP-provoked AF originating from non-PV foci (hazard ratio [HR]: 2.52 [95% confidence interval (CI): 1.069 to 5.929]; p = 0.034). After additional ablation targeting non-PV foci, freedom from recurrent AF after the last procedure was similar between the SVC group and patients without ATP-provoked AF but was significantly lower in the atria group than in others (p = 0.0008). Atria group membership (HR: 3.725 [95% CI: 1.692 to 8.199]; p = 0.001) and being female (HR: 1.538 [95% CI: 1.189 to 1.989]; p = 0.001) were significant independent predictors associated with recurrence after the last procedure in the multivariable Cox regression model. ConclusionsATP provoked AF originating from non-PV foci under isoproterenol in 5.6% of patients undergoing paroxysmal AF ablation. ATP testing might be useful for identifying and eliminating AF originating from the SVC. The atria group was associated with a poor outcome after the last procedure despite efforts to eliminate non-PV foci.

Importance of nonpulmonary vein foci in catheter ablation for paroxysmal atrial fibrillation.

Pulmonary vein (PV) isolation is an established treatment strategy for paroxysmal atrial fibrillation (PAF). However, the recurrence rate of PAF is 8% to 37%, despite repeated procedures, and the catheter ablation strategy for PAF with non-PV foci is unclear. The purpose of this study was to assess the PAF ablation strategy for non-PV foci. The study included 304 consecutive patients undergoing PAF ablation (209 males, age 63.0 ± 10.4 years) divided into 3 groups: group 1 (245 patients) with no inducible non-PV foci; group 2 (34 patients) with atrial fibrillation (AF) originating from non-PV foci and all the foci successfully ablated; and group 3 (25 patients) with AF originating from non-PV triggers, but without all foci being ablated or with persistently inducible AF. Mean follow-up period was 26.9 ± 11.8 months, and AF recurrence rates since the last procedure were 9.8%, 8.8%, and 68.0% in groups 1, 2, and 3, respectively. There was no statistically significant difference in recurrence rate between groups 1 and 2 (P = .89); however, there were statistically significant differences between groups 3 and 1 (P <.0001) and groups 3 and 2 (P <.0001). The patients in group 2 had an AF-free outcome to equivalent to those who had PV foci in group 1 (P = .83). Success rates can be improved for PAF ablation if non-PV foci are detected and eliminated.

Recurrence after “long-term success” in catheter ablation of paroxysmal atrial fibrillation

The latest guidelines define "long-term success" as freedom from atrial arrhythmia recurrence more than 36 months after procedures without any antiarrhythmic drug therapy. The purpose of this study was to investigate the clinical outcomes and procedural findings in patients with recurrence beyond "long-term success." Among patients who underwent pulmonary vein (PV) antrum isolation for drug-refractory symptomatic paroxysmal atrial fibrillation (AF), 37 in whom recurrent arrhythmias were observed during annual follow-up after "long-term success" and who underwent repeat procedures for recurrent arrhythmias were included in the study. The time from the latest procedure to recurrence was a median of 61 ([25th, 75th percentiles]: [51-77.5]) months. Recurrent arrhythmia type was paroxysmal in 22 patients (59.5%) and persistent in 15 (40.5%). Recurrent arrhythmias were atrial tachycardia (AT) in 13 patients (35.1%), including 8 with AT unrelated to PVs. Repeat procedures were performed a median of 2.0 [1.0-4.0] months after identifying recurrent episodes. Recovered PV conduction was found in 29 patients (78.4%) and non-PV foci in 4 (10.8%). Freedom from recurrence 1 year after repeat procedures was 63.3%. Seven patients (18.9%) underwent further repeat procedures a median of 7.0 [2.0-28.0] months after repeat procedures and had no PV reconnections. In total, AF/AT unrelated to PVs was present in 24 patients (64.9%). In contrast, arrhythmias related to PVs were observed in 2 patients (5.4%) during a total of 46 repeat procedures after "long-term success." Although PV reconnections were commonly found even after "long-term success," AF/AT unrelated to PVs was assumed to be present in the majority of this population.

Clinical significance of early recurrence after pulmonary vein antrum isolation in paroxysmal atrial fibrillation -- insight into the mechanism.

Early recurrence of atrial fibrillation (ERAF) is common after pulmonary vein antrum isolation (PVAI); however, the definition, study population, and lesion set are not uniform in prior studies. We examined ERAF for paroxysmal AF while complying with the definition in the latest guidelines. We included 471 patients undergoing empirical PVAI for paroxysmal AF. ERAF was observed in 180 patients (38.2%) including 49, 16, and 115 within 3, 4-7 days, and 8-90 days, respectively, after the index procedure. ERAF (hazard ratio 6.872; 95% confidence interval 4.803-9.382; P<0.0001) was the strongest factor associated with recurrence beyond 3 months (LR) in the multivariable model, and ERAF patients had worse outcomes than those without, regardless of the time to the first ERAF episode. There were no significant differences in the prevalence of PV reconnections and non-PV foci among 29 and 62 patients, respectively, who underwent redo procedures for ERAF within and more than 3 months after the index procedure, and 21 who underwent redo procedures for LR. Re-ablation was associated with a greater freedom from LR (HR 0.443; 95% CI 0.230-0.854; P=0.015). ERAF occurred in 38.2% of patients and was strongly associated with LR regardless of the time to the first ERAF episode. Re-ablation for ERAF significantly improved the freedom from recurrent atrial arrhythmias, regardless of the time to the first ERAF episode.

Origin and Ablation of the Adenosine Triphosphate Induced Atrial Fibrillation After Circumferential Pulmonary Vein Isolation: Effects on Procedural Success Rate

Adenosine triphosphate (ATP) has been used to provoke dormant pulmonary vein (PV) conduction after circumferential PV isolation (CPVI). However, there have been no systematic studies examining the incidence and the mechanism of ATP-induced atrial fibrillation (AF) following CPVI in paroxysmal AF. In this study, we explore the mechanism of ATP-induced AF and assess the feasibility of eliminating this response by additional radiofrequency (RF) ablation. A total of 300 consecutive patients with paroxysmal AF underwent CPVI. After all PVs were isolated, intravenous ATP (40 mg) was administered during an intravenous isoproterenol (ISP) infusion (5 μg/min). AF was reproducibly induced by ATP in 39 patients. Non-PV foci were confirmed and located in 29 of these patients at the onset of AF, including 27 foci in the superior vena cava (SVC), 1 focus in the crista terminalis, and 1 focus near the antrum of the PV. In all these cases, ATP-induced AF was eliminated after the non-PV foci were successfully ablated. For the other 10 patients, the foci triggering AF could not be confirmed or located due to the transient effect of ATP, thus no further ablation was performed. After a mean follow-up period of 18.7 ± 6.4 (8-24) months, the success rate in the ATP-induced AF group was not significantly different compared with the conventional treatment group who did not exhibit ATP-induced AF (76.9% vs 67.3%; P = 0.25). But in the subgroup of which the ATP-induced AF could be eliminated by additional RF ablation, the success rate was significantly higher than the non-ATP inducible group (86.2% vs 67.3%; P = 0.04). A large proportion of the ATP-induced AF post CPVI were initiated by rapid firing in the SVC. Eliminating this response by additional ablation may have an influence on clinical results of paroxysmal AF ablation.

Administration of Isoproterenol and Adenosine to Guide Supplemental Ablation After Pulmonary Vein Antrum Isolation

Pulmonary vein antrum isolation (PVAI) remains associated with atrial fibrillation (AF) recurrence. We administered adenosine and isoproterenol (ISP) after PVAI to uncover non-PV atrial triggers and PV reconnection, potentially increasing ablation success rate. One hundred and ninety-two consecutive patients with symptomatic AF presenting for PVAI were prospectively studied (group 1). Following PVAI, adenosine (18-24 mg) and ISP (20-30 mcg/min) were administered intravenously. Supplemental ablation was performed in patients with non-PV triggers that induced AF (group 1A). Other subgroups included patients with (group 1B) or without (group 1C) consistent non-PV atrial foci that did not induce AF. A cohort of 196 matched control patients undergoing PVAI without drug challenge was used for comparison (group 2). A total of 132 atrial non-PV foci were revealed (31 inducing AF). The majority of atrial foci were observed with ISP (113/132, 86%). Less than 5% of patients had persistent PV recovery during the drug challenge. During a mean follow-up of 22 ± 8 months, PVAI was successful in 110/192 (57%, group 1) versus 100/196 (52%, group 2), P = 0.038. Furthermore, the success rate was statistically different between group 1A (25/32, 78%), group 1B (28/83, 34%), and group 1C (57/74, 74%), P < 0.001. After PVAI, ablation guided by the administration of adenosine and ISP to target non-PV triggers inducing AF increased AF ablation outcomes. Patients with non-PV foci that did not induce AF had no further ablation, with the lowest ablation success rate. This group may likely benefit from further ablation after PVAI.

Long-term outcomes after radiofrequency catheter ablation of paroxysmal and persistent atrial fibrillation

Background : Short-term oucomes of radiofrequency (RF) catheter isolation of the pulmonary veins (PVs) in patients with paroxysmal or persistent atrial fibrillation (PAF/PEAF) are encouraging. However, long-term outcomes are not well defined. Therefore, we evaluated 3–5-year outcomes in our series of patients. Freedom from symptomatic AF/flutter/tachycardia recurrences with patients off antiarrhythmic drugs (AAD) was considered a treatment success. Methods : Consecutive patients with symptomatic PAF/PEAF and AAD failure, without significant structural heart disease, were prospectively recruited between September 2003 and November 2009. Irrigated-tip RF ablation catheter and Lasso catheter were used after standard trans-septal approach with X-ray fluoroscopic guidance. Ablation endpoints were: complete segmental/circumferential ostial and antral electrical PV isolation, non-PV foci ablation, and bi-directional flutter isthmus (FI) block when indicated. The procedure was repeated if AF/flutter/tachycardia recurred after 3-month blanking period. The suspected arrhythmia recurrences were evaluated by series of ECG/Holter recordings. Data were analyzed by t-, chi-square, and Fisher’s exact tests. P < 0.05 was considered statistically significant. Results : In 126 patients, median age 55 years (range 19–75), 94 men (75 %), 86 with PAF and 40 with PEAF (31 %), 207 procedures were performed: single in 63 (50 %), double in 48 (38 %), and multiple in 15. FI was ablated in 53 patients (42 %). Tamponade occurred in 4 (3 %). No PV stenosis, esophageal injury, or stroke were detected clinically in 115 patients (91 %) during 36-month (13–89) follow-up. We achieved treatment success in 69 patients (61 %), partial success with a significant reduction of AF/flutter/tachycardia recurrences on AAD in 13 patients (12 %), and in 33 patients (27 %) the procedure was not successful. Overall, 73 % of our patients had long-term benefit. Outcomes were better in patients with PAF vs. PEAF (84 % vs. 48 %, p < 0,001), in younger age, in those without concomitant diseases, and in those with normal PV anatomy. These results were maintained in the subgroup of 58 patients over 56 months of follow-up: 35 (60 %), 6 (11 %), and 17 (29 %), respectively. Conclusions : Lasso-guided RF irrigated-tip segmental/circumferential PV isolation is a safe and long-term successful treatment of PAF in the majority of our patients. The method needs improvements in patients with PEAF, possibly with the introduction of new technologies.

Anatomical basis of minimally invasive epicardial ablation of atrial fibrillation

Minimally invasive atrial fibrillation surgery (MIAFS) has become a well established and increasingly used option for managing patients with stand-alone arrhythmia. Pulmonary veins (PVs) isolation continues to be the cornerstone of ablation strategies. Indeed, in most cases, atrial fibrillation (AF) is triggered in or near the PVs. Nevertheless, ectopic beats initiating AF may occasionally arise from non-PV foci. The knowledge of the anatomy and underlying morphology of PVs and non-PV foci is essential for cardiac surgeons treating AF patients with epicardial minimally invasive procedures. The anatomical structures relevant to the pathogenesis and the epicardial treatment of AF include the PVs, the pericardial space, the pericardial sinuses, the phrenic nerve, the left atrium, the retro-atrial and caval ganglionated plexuses, the ligament of Marshall, the caval veins and the left atrial appendage. In this review, we briefly describe the basic anatomy of these structures and discuss their specific correlations for cardiac surgeons interested in performing MIAFS.

Fibroblasts, Focal Triggers, and Persistent Atrial Fibrillation

Ablation of persistent atrial fibrillation (AF) remains challenging, particularly as the duration of continuous AF before the procedure increases. Attainment of durable pulmonary vein (PV) isolation remains a fundamental goal in this population; continuous retriggering from focal peri-PV sources (both automaticity and localized reentry) as a potential mechanism for maintaining persistent AF was documented more than a decade ago.1 An area of continuing debate centers on the extent of additional atrial ablation outside the PV antra required for long-term maintenance of sinus rhythm. Two studies published in this issue of Circulation: Arrhythmia and Electrophysiology highlight important clinical aspects of this debate. Articles see p 287, 295, and 442 Inoue and colleagues2 report long-term follow-up of catheter ablation in 263 patients with persistent AF (mean duration of continuous AF, 11 months; >1 year in 50%). To identify triggers that may perpetuate AF, cardioversion was performed at procedure onset, followed by short-duration isoproterenol infusion if needed, to provoke immediate recurrence of AF. The immediate recurrence of AF occurred in 70 (27%) of 263 patients, one third arising from non-PV foci. These triggers were then targeted for ablation (successful in all peri-PV foci, but in only 6 of 23 patients with non-PV triggers). All patients subsequently underwent PV isolation, and 72% had additional non-PV left atrial ablation. At the last follow-up of 17 months (38% of patients receiving antiarrhythmic drugs [AADs], multiple procedures in ≈30%), 90% of patients were in sinus rhythm, although 16% continued to have paroxysmal episodes. Immediate recurrence of AF was associated with a greater risk of recurrent persistent AF during follow-up, predominantly a result of inability to localize and eliminate non-PV focal triggers. In a randomized trial of ablation for persistent AF, Dixit and coworkers3 evaluate 3 strategies for ablation of persistent AF: (1) …

Catheter Ablation of Atrial Fibrillation in Patients With Chronic Lung Disease

Chronic lung disease (CLD) is one of the important underlying diseases of atrial fibrillation (AF). The outcomes after radiofrequency catheter ablation of AF in patients with CLD have not yet been reported. We investigated the electroanatomic alterations in pulmonary veins (PVs) in CLD patients with AF and assessed their effect on the outcomes of radiofrequency catheter ablation of AF. We assessed 15 patients who had CLD and underwent radiofrequency catheter ablation of AF. CLD included chronic obstructive pulmonary disease, a tuberculosis-destroyed lung, and interstitial lung disease. For controls, we selected 60 sex-, age-, and procedure era-matched non-CLD patients who received radiofrequency catheter ablation for AF (4 controls for each CLD patient). Eight patients had chronic obstructive pulmonary disease, 6 had a tuberculosis-destroyed lung, and 1 had interstitial lung disease. PV morphology in the affected lung was altered significantly, ie, obliteration, pulling of the PVs toward the destroyed lung, or compensatory bulging of the PV antrum. These alterations were related to arrhythmogenicity in 6 (40%) of 15 patients with CLD. Non-PV foci were more common in the CLD group (4/15, 26.7%) than in the control group (3/60, 5.0%; P=0.025). All non-PV foci were located in the right atrium. The AF recurrence rate in the CLD group (26.7%, 4/15) was similar to that in the control group (18.3%, 11/60; P=0.45). Significant alteration of PV anatomy was related to arrhythmogenicity, and non-PV foci from the right atrium were commonly observed in the CLD group. Radiofrequency catheter ablation can be performed safely for AF in CLD patients with a comparable success rate to that in patients with normal lungs.

Early Recurrences after Paroxysmal Atrial Fibrillation Ablation: When is the Proper Timing for Reablation?

Early recurrences (ERs) within 1 month after paroxysmal atrial fibrillation (AF) ablation are common and may subside in a considerable proportion of patients. Although late reablation after 3 months is recommended, the proper timing for reablation remains undetermined. One hundred and seventeen (31.2%) from the pool of 375 patients experienced ERs at 7.5 ± 5.5 days postablation. They were allocated into two groups randomly: early reablation group (ERe+) (n = 57) and nonearly reablation group (ERe-) (n = 60). Forty patients (70.2%) in ERe+ group underwent early reablation at 28.1 ± 2.7 days postablation. Forty patients (66.7%) in ERe- group underwent late reablation at 98.2 ± 5.2 days postablation. The proportion of reablation was comparable (P = 0.68). ERs subsided in 17 (29.8%) in ERe+ group and in 20 (33.3%) in ERe- group. In ERe+ group, PV reconnection in 36 (80.0%), non-PV foci in six (10.5%), and right or left atrial flutter in five (8.8%) was abolished by ablation. In ERe- group, pulmonary vein (PV) reconnection in 29 (72.5%), non-PV foci in eight (13.3%), and right or left atrial flutter in eight (13.3%) was ablated successfully. The proportion of PV reconnection, nonfoci, and atrial flutter was comparable, P = 0.45, 0.64, and 0.56, respectively. At the end of 16.5 ± 2.0 (ERe+ group) and 15.2 ± 2.6 (ERe- group) months' follow-up, 47 (82.5%) in ERe+ group and 51 (85%) in ERe- group were free of atrial tachyarrhythmias, P = 0.70. Compared with reablation 2 months later after initial ablation, early reablation at ≈1 month had similar clinical effectiveness. The proper timing for reablation can be set at ≈1 month after initial paroxysmal AF ablation.