Utility of noninvasive electrocardiographic imaging in the localization of nonpulmonary vein triggers of atrial fibrillation determined by pacing common trigger sites.

INTRODUCTION: Identifying the origin of nonpulmonary vein atrial fibrillation (AF) triggers (NPVTs) after pulmonary vein isolation (PVI) can be challenging. We aimed to determine if noninvasive electrocardiographic imaging (ECGi) could localize pacing from common NPVT sites. ECGi combines measured body surface potentials with heart-torso geometry acquired from computed tomography (CT) to generate an activation map. METHODS: In 12 patients with AF undergoing first time ablation, the ECGi vest was fitted for preprocedural CT scan and worn during the procedure. After PVI, we performed steady-state pacing from 15 typical anatomic NPVT sites at a cycle length of 700-800 ms. We co-registered the invasive anatomic map with the CT-based ECGi epicardial activation map to compare ECGi predicted to true pacing origin. RESULTS: In the study cohort (67% male, 58% persistent AF, and 67% with left atrial dilation), 148 (82%) pacing sites had both capture and adequate anatomy acquired from the three-dimensional mapping system to co-register with ECGi activation map. Median distance between true pacing sites and point of earliest epicardial activation derived from the ECGi maps for all sites was 17 mm (interquartile range, 10-22 mm). Assuming paced sites treated as regions with a radius of 2.5 cm, the earliest activation site on ECGi map falls within the region with 94% accuracy. CONCLUSION: ECGi can approximate the origin of paced beats from common NPVT sites to within a median distance of 17 mm. A rapidly identified region may then be the focus of more detailed catheter-based mapping techniques to facilitate successful localization and ablation of NPVTs.

Ablation of atrial fibrillation beyond pulmonary vein isolation: Do additional ablation lesions impact left atrial function?

INTRODUCTION: Electrical isolation of pulmonary veins (PVI) is a cornerstone for atrial fibrillation (AF) ablation. The overall effect of AF ablation, and especially lesions beyond PVI, on left atrial (LA) function is currently poorly understood. Our aim was to determine if LA function is different in patients after extensive LA ablation compared to PVI only. We performed non-inferiority analysis of LA function after PVI with additional nonpulmonary vein ablation lesions in LA (PVI+) and PVI alone. METHODS: We studied 68 patients consecutive patients who underwent AF ablation and who had complete transthoracic echocardiogram (TTE) within 12 months before AF ablation and 1-12 months after the procedure. Patients were stratified into two groups: PVI only and PVI+. Primary outcome was change in LA reservoir strain (LASr). Noninferiority margin was defined at 6%. RESULTS: The PVI only group had a higher proportion of patients with paroxysmal AF (70% vs. 30%). The PVI+ group was observed to have a slightly higher increase in LASr compared to PVI alone (5.0% vs. 4.3%, p < .01 for noninferiority). LASr noninferiority was confirmed when adjusted for age, sex, coronary artery disease, hyperlipidemia, and AF type, rhythm at preprocedure TTE in a multivariable linear regression model, 90% CI (-5.46 to 2.04), p < .01. CONCLUSION: LA functional improvement evaluated by LASr was noninferior after PVI with additional LA ablation lesions compared to PVI alone. These findings were confirmed when adjusted for confounding clinical variables, suggesting that more extensive ablation does not negatively affect LA function.

Approach to ablative management of patient with persistent atrial fibrillation and enduring pulmonary vein isolation.

Enduring isolation of the pulmonary veins (PV) is becoming increasingly common in patients undergoing repeat catheter ablation for atrial fibrillation. We describe our approach to ablation strategy in a patient with enduring isolation of PV and briefly discuss the role of non-PV triggers.

Arrhythmogenecity and thrombogenicity of the residual left atrial appendage stump following surgical exclusion of the appendage in patients with atrial fibrillation.

INTRODUCTION: It is common to find residual stump after the amputation or clip exclusion of the left atrial appendage (LAA). We evaluated the arrhythmogenic and thrombogenic potential of LAA stumps in atrial fibrillation (AF) patients. METHODS: Consecutive patients undergoing catheter ablation for AF recurrence with LAA stump detected at baseline transesophageal echocardiogram (TEE) were included in the analysis. Nonpulmonary vein (non-PV) triggers were ablated based on operator's discretion. RESULTS: A total of 213 patients with LAA stump were included in the analysis. Firing from the LAA stump was detected in 186 cases, of which 145 received stump isolation (group I) and the stump was not targeted for isolation in 41 (group II) patients. In 27 patients with no firing from the stump (group III) only non-PV triggers from sites other than the LAA stump were targeted for ablation. At 16.7 ± 8.5 months of follow-up, 126 (86.9%) patients from group I, eight (19.5%) from group II, and eight (33.3%) from group III remained arrhythmia-free off antiarrhythmic drugs (AAD) (P < 0.001). Sixty out of 70 patients underwent redo procedure; electrical isolation of the stump and ablation of other non-PV triggers was done in all 60 cases. At 1 year after the repeat procedure, 55 (91.7%) patients remained arrhythmia-free off-AAD. A total of four (1.88%) thromboembolic (TE) events reported, three of which were transient ischemic attacks and all three patients had "smoke" detected in the left atrium. CONCLUSION: LAA stump is arrhythmogenic and electrical isolation improves clinical outcome. TE events are rare and mostly associated with left atrial smoke in this subset of AF population.

Predictors of nonpulmonary vein triggers for atrial fibrillation: A clinical risk score.

BACKGROUND: Targeting non-pulmonary vein triggers (NPVTs) after pulmonary vein isolation may reduce atrial fibrillation (AF) recurrence. Isoproterenol infusion and cardioversion of spontaneous or induced AF can provoke NPVTs but typically require vasopressor support and increased procedural time. OBJECTIVE: The purpose of this study was to identify risk factors for the presence of NPVTs and create a risk score to identify higher-risk subgroups. METHODS: Using the AF ablation registry at the Hospital of the University of Pennsylvania, we included consecutive patients who underwent AF ablation between January 2021 and December 2022. We excluded patients who did not receive NPVT provocation testing after failing to demonstrate spontaneous NPVTs. NPVTs were defined as non-pulmonary vein ectopic beats triggering AF or focal atrial tachycardia. We used risk factors associated with NPVTs with P <.1 in multivariable logistic regression model to create a risk score in a randomly split derivation set (80%) and tested its predictive accuracy in the validation set (20%). RESULTS: In 1530 AF ablations included, NPVTs were observed in 235 (15.4%). In the derivation set, female sex (odds ratio [OR] 1.40; 95% confidence interval [CI] 0.96-2.03; P = .080), sinus node dysfunction (OR 1.67; 95% CI 0.98-2.87; P = .060), previous AF ablation (OR 2.50; 95% CI 1.70-3.65; P <.001), and left atrial scar (OR 2.90; 95% CI 1.94-4.36; P <.001) were risk factors associated with NPVTs. The risk score created from these risk factors (PRE2SSS2 score; [PRE]vious ablation: 2 points, female [S]ex: 1 point, [S]inus node dysfunction: 1 point, left atrial [S]car: 2 points) had good predictive accuracy in the validation cohort (area under the receiver operating characteristic curve 0.728; 95% CI 0.648-0.807). CONCLUSION: A risk score incorporating predictors for NPVTs may allow provocation of triggers to be performed in patients with greatest expected yield.

Bipolar Ablation for an Intramural Septal Atrial Tachycardia.

A 70-year-old man with recurrent atrial fibrillation (AF) underwent transcatheter radiofrequency ablation after an earlier unsuccessful attempt. Although typical AF triggers were ablated, the patient's condition persisted, leading to the identification of the interatrial septum (IAS) as the probable source of the tachycardia trigger. Given the depth and thickness of the IAS, traditional radiofrequency ablation proved ineffective. However, using the alternative method of bipolar radiofrequency catheter ablation (B-RFCA), the atrial tachycardia was successfully terminated. B-RFCA demonstrates potential for effectively terminating tachycardias originating from deep intramural locations, suggesting its potential as a pivotal technique for complex cases with septal atrial tachycardia.

Identifying Origin of Nonpulmonary Vein Triggers Using 2 Stationary Linear Decapolar Catheters: A Novel Algorithm.

BACKGROUND: Targeting nonpulmonary vein triggers (NPVTs) of atrial fibrillation (AF) after pulmonary vein isolation can be challenging. NPVTs are often single ectopic beats with a surface P-wave obscured by a QRS or T-wave. OBJECTIVES: The goal of this study was to construct an algorithm to regionalize the site of origin of NPVTs using only intracardiac bipolar electrograms from 2 linear decapolar catheters positioned in the posterolateral right atrium (along the crista terminalis with the distal bipole pair in the superior vena cava) and in the proximal coronary sinus (CS). METHODS: After pulmonary vein isolation in 42 patients with AF, pacing from 15 typical anatomic NPVT sites was conducted. For each pacing site, the electrogram activation sequence was analyzed from the CS catheter (simultaneous/chevron/inverse chevron/distal-proximal/proximal-distal) and activation time (ie, CSCTAT) between the earliest electrograms from the 2 decapolar catheters was measured referencing the earliest CS electrogram; a negative CSCTAT value indicates the crista terminalis catheter electrogram was earlier, and a positive CSCTAT value indicates the CS catheter electrogram was earlier. A regionalization algorithm with high predictive value was defined and tested in a validation cohort with AF NPVTs localized with electroanatomic mapping. RESULTS: In the study patient cohort (71% male; 43% with persistent AF, 52% with left atrial dilation), the algorithm grouped with high precision (positive predictive value 81%-99%, specificity 94%-100%, and sensitivity 30%-94%) the 15 distinct pacing sites into 9 clinically useful regions. Algorithm testing in a 98 patient validation cohort showed predictive accuracy of 91%. CONCLUSIONS: An algorithm defined by the activation sequence and timing of electrograms from 2 linear multipolar catheters provided accurate regionalization of AF NPVTs to guide focused detailed mapping.

Association of fragmented QRS with left atrial scarring in patients with persistent atrial fibrillation undergoing radiofrequency catheter ablation.

BACKGROUND: Fragmented QRS (fQRS) on 12-lead electrocardiography is a noninvasive marker of intramyocardial conduction delay due to ventricular scarring that has not previously been studied in atrial fibrillation. OBJECTIVE: The purpose of this study was to assess the association of fQRS with left atrial (LA) scarring in patients with persistent atrial fibrillation (PsAF) undergoing first catheter ablation. METHODS: A total of 376 patients with PsAF were enrolled. Severity of LA scarring was assessed using electroanatomic mapping. Narrow fQRS was defined by the presence of an additional R wave (R') or notching in the nadir of the S wave, or the presence of >1 R' in 2 contiguous leads corresponding to inferior, lateral, or anterior myocardial regions. RESULTS: Both any degree (97.3% vs 63.3%) and severe (42.2% vs 6.3%) LA scarring were higher in patients with fQRS. Age and fQRS were found to be independent predictors of severe LA scarring. At multiple ventricular regions, fQRS had diagnostic accuracy of 79.8% for prediction of severe LA scarring. Nonpulmonary vein triggers were more often detected and ablated in patients with fQRS and severe LA scarring (84.4% vs 70%; P = .001). Atrial tachyarrhythmia recurrence was observed in 131 patients (34.8%) during 18.9 ± 7.7 months of follow-up, which was significantly higher in patients with fQRS (53.2% vs 16.8%). In multivariate analysis, fQRS was found to be a significant predictor of recurrence (hazard ratio 4.65; 95% interval confidence 2.91-7.42; P <.001). CONCLUSION: The study results showed that fQRS is a simple, available, and noninvasive marker, and that fQRS at multiple ventricular regions is significantly associated with the severity of LA scarring in PsAF patients.

Recurrent Atrial Fibrillation with Isolated Pulmonary Veins: What to Do.

When patients have symptomatic recurrent atrial tachyarrhythmias after 2 months following pulmonary vein antral isolation, a repeat ablation should be considered. Patients might present with isolated pulmonary veins posterior wall. In these patients, posterior wall isolation is extended, and non-pulmonary vein triggers are actively sought and ablated. Moreover, in those with non-paroxysmal atrial fibrillation or a known higher prevalence of non-pulmonary vein triggers, empirical isolation of the superior vena cava, coronary sinus, and/or left atrial appendage might be performed. In this review, we will focus on ablation of non-pulmonary vein triggers, summarizing our current approach for their mapping and ablation.

Pulmonary vein isolation plus left atrial posterior wall isolation and additional nonpulmonary vein trigger ablation using high-dose isoproterenol for long-standing persistent atrial fibrillation.

BACKGROUND: Little evidence exists regarding the endpoint and optimum approach to catheter ablation for long-standing persistent atrial fibrillation (LSPAF). We examined the efficacy of pulmonary vein isolation (PVI) plus left atrium posterior wall isolation (PWI) and additional non-PV trigger ablation using high-dose isoproterenol for LSPAF. METHODS: One-hundred and fifty-five patients (median AF duration, 36 months) underwent catheter ablation for LSPAF; After PVI plus PWI, they underwent provocation of non-PV triggers by high-dose isoproterenol and were divided into 3 groups based on the results: group A, PVI plus PWI alone, without induced non-PV triggers (single procedure: 105 patients, multiple procedures: 90 patients); group B, mappable non-PV triggers demonstrated and ablated (single procedure: 41 patients, multiple procedures: 45 patients); group C, if non-PV triggers were unmappable or could not be induced in repeated procedures, adjunctive complex fractionated atrial electrogram ablation was performed (single procedure: 9 patients, multiple procedures: 20 patients). RESULTS: The Kaplan-Meier estimate of the 1-year freedom from atrial tachyarrhythmias without antiarrhythmic drugs was 65% in all patients, (73%, 56%, and 11% in groups A, B, and C, respectively) after a single procedure, which improved to 86% in all patients (93%, 86%, and 53% in groups A, B, and C, respectively) after multiple procedures. CONCLUSION: Even for LSPAF, in approximately 60% of patients, non-PV triggers were not elicited, and PVI plus PWI alone achieved good outcomes. Although the inducibility of non-PV triggers was associated with recurrence of atrial tachyarrhythmias, additional non-PV trigger ablation may improve the outcome after multiple procedures.

Lack of prognostic value of atrial arrhythmia inducibility and change in inducibility status after catheter ablation of atrial fibrillation.

BACKGROUND: Previous studies have suggested a role of atrial arrhythmia inducibility as an endpoint of catheter ablation of atrial fibrillation (AF). The prognostic value of noninducibility after ablation and of a change in inducibility status has not been investigated in large studies. OBJECTIVE: The purpose of this study was to evaluate the prognostic role of noninducibility and of a change in inducibility status after ablation of AF. METHODS: We studied 305 consecutive patients with AF (66% paroxysmal) undergoing antral pulmonary vein (PV) isolation plus non-PV triggers ablation. All patients underwent a standardized induction protocol before and after ablation from the coronary sinus and right atrium: 15-beat burst pacing at 250 ms and decrementing to 180 ms (up to 20 µg/min isoproterenol). Inducibility was defined as any sustained AF or organized atrial tachycardia (AT) lasting >2 minutes. RESULTS: A total of 197 patients (65%) had inducible AF/AT at baseline compared to 118 (39%) after ablation. One hundred seven patients (57%) changed their inducibility status from inducible preablation to noninducible postablation. After 19 ± 7 months of follow-up, 212 patients (70%) remained free from any recurrent AF/AT. Noninducibility of AF/AT postablation (log-rank P = .236) or change in inducibility status (log-rank P = .429) was not associated with reduced risk of recurrent AF/AT. Results were consistent across the paroxysmal and nonparoxysmal subgroups. CONCLUSION: Noninducibility of atrial arrhythmia or change in inducibility status after PV isolation and non-PV trigger ablation is not associated with long-term freedom from recurrent arrhythmia and should not be used as an ablation endpoint or to support the appropriateness of additional ablation lesion sets.