Dual linear lesions for right atrial flutter after mitral valve surgery via the superior transseptal approach.

BACKGROUND: The superior transseptal approach (STA) for mitral valve surgery is associated with a higher risk of developing macroreentrant incisional atrial flutter (AFL) than the left atrial approach. This study aimed to describe the linear lesions for the complex AFL circuit after the STA and to propose an option for the linear ablation target site. METHODS: Of the 26 patients who underwent radiofrequency catheter ablation for AFL after mitral valve surgery, data from seven patients with STA incisions were retrospectively analyzed. RESULTS: All patients who had undergone the STA had incisional AFL rotated in a long loop within the right atrium (RA) and cavo-tricuspid isthmus (CTI)-dependent AFL. The linear lesions were created in the CTI, the superior RA vestibule, and between the RA-free wall incision or the septal incision and the inferior vena cava. Procedural success was achieved with dual linear lesions in the CTI and superior RA vestibule. Two of seven patients had AFL recurrence during a mean observation period of 22.5 ± 16.7 months. The circuits of recurrent AFL were CTI-dependent AFL and perimitral AFL, respectively. No AFL recurrence was noted with reconduction of the superior RA vestibular lesion. CONCLUSION: Dual linear lesions in the CTI and superior RA vestibule are an effective treatment option for RA macroreentrant AFL after the STA.

A novel approach to typical atrioventricular nodal reentrant tachycardia with high-resolution mapping using the CARTO 3 cardiac mapping system.

BACKGROUND: We hypothesized that high-resolution activation mapping during sinus rhythm (SR) in Koch's triangle (KT) can be used to describe the most delayed atrial potential around the atrioventricular node and evaluated whether ablation targeting of this potential is safe and effective for the treatment of patients with typical atrioventricular nodal reentrant tachycardia (AVNRT). METHODS: We conducted a prospective, non-randomized, observational study using high-resolution activation mapping from the sinus node to KT with a PENTARAY or OCTARAY catheter using the CARTO 3 cardiac mapping system (Biosense Webster) during SR in 62 consecutive patients (22 men; age [mean ± standard deviation] = 55 ± 14 years) treated for typical AVNRT at our institution from August 2021 to March 2023. RESULTS: In all cases, the most delayed atrial potential was observed near the His potential within KT. Ablation targeting of this potential helped successfully treat each case of AVNRT, with a junctional rhythm observed at the ablation site. Initial ablation was deemed successful in 55/62 patients (89%); in the remaining seven patients, lesion expansion resolved AVNRT. One procedural complication occurred, namely, a transient atrioventricular block lasting 45 s. One patient experienced a transient tachycardic episode by the 1-month follow-up, but no further episodes were noted up to the 1-year follow-up. CONCLUSION: Activation mapping at KT during SR with the high-resolution CARTO system clearly revealed the most delayed atrial potential near the His potential within KT. Targeting this potential was a safe and effective treatment method for patients with typical AVNRT in our study.

Predicting the clinical course in hypertrophic cardiomyopathy using thallium-201 myocardial scintigraphy.

AIMS: This study aimed to evaluate the changes in left ventricular remodelling with time in patients with hypertrophic cardiomyopathy (HCM) using thallium-201 myocardial scintigraphy. METHODS AND RESULTS: Forty-eight patients with HCM participated in the study. The extent score (ES) and a newly devised index termed the 'mean count change' (MCC) were used to evaluate the myocardial perfusion defects. Using the amount of thallium-201 uptake (TU), MCC (%) was calculated using the following formula: (last TU - initial TU)∕initial TU × 100. To confirm the site of the lesion, the left ventricle was divided into five segments: anterior, septal, inferior, lateral, and apex. Cardiovascular complications and deaths were recorded. The mean follow-up period was 8.6 ± 2.0 years. ES increased from 17.4 ± 13.7% to 44.0 ± 22.3% (P < 0.0001). MCC increased from 0% to 12.0 ± 9.0% (P < 0.0001). The apex was the most frequent site of lesion. Twenty-seven patients (56.3%) had experienced left ventricular heart failure (LVHF). Both ES and MCC were greater in patients with LVHF than in those without LVHF. An overlap between the two groups was greater in ES than in MCC. Patients with LVHF had a higher incidence of atrial fibrillation and apoplexy. Nineteen patients (39.6%) died during the study period; 14 died from LVHF, 3 from sudden cardiac death, and 2 from cancer. CONCLUSIONS: Thallium-201 myocardial scintigraphy is useful for detecting the severity of myocardial damage and for confirming the lesion site in patients with HCM. MCC may be superior to ES in the evaluation of these changes with time.

Simple and novel technique to confirm complete mitral isthmus block.

BACKGROUND: Differential pacing technique to confirm mitral isthmus (MI) block is sometimes challenging due to destroyed tissues after extensive ablation. The purpose of this study is to set an endpoint of MI ablation using conduction time around the mitral annulus (MA). METHODS: Forty-five consecutive patients with persistent atrial fibrillation who received MI linear ablation were included. The geometry and activation times of the left atrium around the MA were collected using a multipolar catheter before ablation. During coronary sinus (CS) pacing, the time between the stimulus and the wave-front collision at the opposite side of the MA (defined as T/2) was calculated, and the doubled value was defined as the estimated perimitral conduction time (E-PMCT). The endpoint for complete MI block was when the stimulus (at distal CS) minus the maximal delayed potential (St-MDP) on the MI interval reached the E-PMCT. RESULTS: St-MDP reached E-PMCT during MI ablation in 44/45 patients. Among these 44 patients, differential pacing revealed bidirectional block in 39/44 (88.6%), whereas in 5/44 (11.4%), the differential pacing was not possible because of the loss of capture of local potentials due to extensive applications around the linear line. In one patient, the St-MDP did not reach E-PMCT (E-PMCT: 148 ms, St-MDP :130 ms) and differential pacing revealed no MI block. E-PMCT values (median 176 ms) correlated strongly with St-MDP (median 185 ms, P < 0.0001, R = 0.98). CONCLUSIONS: Although E-PMCT differs between individuals, the value is significantly correlated with the St-MDP. This technique may be useful in providing an individual endpoint of MI ablation as an alternative to differential pacing.

The proportion of asymptomatic recurrence after catheter ablation of atrial fibrillation in patients with a pacemaker for sick sinus syndrome.

BACKGROUND: Catheter ablation (CA) of paroxysmal atrial fibrillation (PAF) is an effective treatment. However, the frequency of asymptomatic AF recurrence after CA in patients with PAF and sick sinus syndrome (SSS) is not clear. The aim of this study was to elucidate the real AF recurrence after CA in patients with PAF and a pacemaker for SSS. METHODS AND RESULTS: Fifty-one consecutive patients (mean age 66.6 ± 7.0 years, male 34) with PAF and SSS and pacemakers underwent CA. All patients were followed at 1, 3, 6, 9, and 12 months after the CA using a 12-lead ECG, Holter-ECG, and 1-month event recorder as a conventional follow-up. In addition, the pacemakers were interrogated every 12 months. During a 5-year follow-up after the final CA procedure, AF recurrences were observed in 7 patients (13.7%) with a conventional follow-up, including 1 (2.0%) asymptomatic patient. Pacemaker-interrogation revealed another 10 patients (19.6%) with asymptomatic AF recurrences. Ultimately, the conventional follow-up plus pacemaker-interrogation provided a higher incidence of AF recurrences (P = 0.009). Multiple CA procedures contributed to a significant increase in the AF-free survival rate at 5 years: 58.6% after a single CA and 86.0% after multiple CA procedures with a conventional follow-up, but which decreased to 40.6% and 60.9% with a conventional follow-up plus a pacemaker interrogation, respectively. CONCLUSIONS: One-third of PAF patients with SSS and pacemakers recurred after multiple CA sessions. However, 65% of them were asymptomatic and difficult to be identified with conventional follow-up. Pacemaker interrogation significantly increased the detection rate of AF-recurrence.

Airway support using a pediatric intubation tube in adult patients with atrial fibrillation: A simple and unique method to prevent heart movement during catheter ablation under continuous deep sedation.

BACKGROUND: The present study aimed to elucidate the safety and effectiveness of a noble and unique airway management technique in which a pediatric intubation tube is used in adult patients with atrial fibrillation (AF) undergoing catheter ablation (CA) under continuous deep sedation. METHODS: In total, 246 consecutive patients with AF (mean age, 65±10 years; 60 women) underwent CA under dexmedetomidine-based continuous deep sedation. A 4-mm pediatric intubation tube guided by a 10-French intratracheal suction tube was inserted smoothly, and the tip of the tube was located at the base of the epiglottis. The maximum shifting distance of the heart (MSDH) was measured with the 3D mapping system (Ensite NavX system) before and after inserting the pediatric intubation tube. RESULTS: At baseline, the MSDH of patients under continuous deep sedation was 23±14 mm. The pediatric intubation tube reduced the MSDH to 13±6 mm (mean reduction from baseline, 38.4±21.7%; P<0.0001). In contrast, oxygen saturation was significantly increased from 89±8% to 95±3% (P<0.0001). The mean distance between the nostril and base of the epiglottis was 16.6±0.5 mm. Major periprocedural complications occurred in 9 (3.6%) patients including 3 (1.2%) cardiac tamponade and 6 (2.4%) phrenic nerve injury cases. Larger MSDH (odds ratio, 1.13; 95% confidence interval, 1.04-1.25; P=0.007) was a significant predictor of major periprocedural complications. No major airway complications occurred, except in 3 patients (1.2%) who had minor nasal bleeding. CONCLUSION: This unique airway management technique using a pediatric intubation tube for CA procedures performed in adult patients with AF under continuous deep sedation was easy, safe, and effective.

A case of ventricular fibrillation as a consequence of capecitabine-induced secondary QT prolongation: A case report.

Capecitabine is an oral fluoropyrimidine which can prolong QT interval. However, there have been no reports that capecitabine induced ventricular fibrillation (VF) due to secondary QT prolongation in patients with no structural heart disease. A 39-year-old woman developed VF during the chemotherapy of capecitabine for colon cancer. At the administration, corrected QT interval (QTc) was prolonged to 559 ms despite no evidence of organic heart disease. Discontinuation of capecitabline normalized the QTc (414 ms). During the follow-up of eight years, neither the QTc prolongation nor the recurrent VF has been detected. We report the rare case of capecitabine-related VF without any organic heart disease. .

Impact of anteroinferior transseptal puncture on creation of a complete block at the mitral isthmus in patients with atrial fibrillation.

PURPOSE: Achieving complete mitral isthmus (MI) conduction block for atrial fibrillation (AF) ablation remains challenging. We hypothesized that transseptal puncture (TSP) at the anteroinferior aspect of the atrial septum (anteroinferior TSP) could shorten the distance to the MI and improve catheter contact and stability, enabling complete MI block. This study investigated the efficacy of anteroinferior TSP for MI ablation in AF patients. METHODS: Three hundred and twenty consecutive patients (mean age: 62 ± 9 years, 84 % male) with persistent AF undergoing AF ablation, including MI ablation, were enrolled. MI ablation was performed through the conventional (posterior) TSP site (group C, n = 170) or the anteroinferior TSP site (group A, n = 150). RESULTS: Left atrial diameter (LAD) enlargement was greater in group A than in group C (45.8 ± 5.3 mm vs. 44.1 ± 5.0 mm, p = 0.002). Complete MI block at the initial session was significantly higher in group A than in group C (141/150 [94 %] vs. 144/170 [85 %], p = 0.011). At the repeat session for AF recurrence, the rate of persistent complete MI block was significantly higher in group A than in group C (36/48 [75 %] vs. 28/67 [42 %], p < 0.001). LAD (p = 0.011) and left ventricular diastolic dimension (p = 0.037) were significant predictors of failed MI block, while anteroinferior TSP was significantly associated with successful MI block (p < 0.001). CONCLUSION: Anteroinferior TSP could improve the initial success rate and long-term persistence of complete MI block for AF ablation.

Long-term outcome after catheter ablation of paroxysmal atrial fibrillation: Impact of different atrial fibrillation foci.

BACKGROUND: We aimed to determine whether differing foci in paroxysmal atrial fibrillation (PAF) affected the long-term outcome of catheter ablation (CA). METHODS: A total of 865 consecutive PAF patients (age, 61±10years; 670 male) undergoing initial AF ablation were included. After pulmonary vein (PV) isolation, superior vena cava (SVC) isolation was performed for SVC foci; other non-PV foci were focally ablated. Long-term outcomes were compared among patients with SVC foci (Group SVC), other non-PV foci (Group Non-PV), and those without these foci (Group PV). RESULTS: Groups PV, SVC, and Non-PV contained 740 (85.8%), 57 (6.6%), and 68 (7.6%) patients, respectively. Structural heart disease (P=0.01) and duration of AF history (P=0.04) were significantly associated with Group Non-PV, and female sex (P=0.0002) was significantly associated with Group SVC. AF recurrence-free rates at 5years in Group PV, SVC, and Non-PV were 62.0%, 66.3%, and 49.3%, respectively (P=0.03), after the initial CA, and 84.7%, 83.9%, and 77.0%, respectively (P=0.02), after the final CA. The duration of AF history (HR, 1.04, P<0.0001) and left atrial dimension (HR, 1.37 per 10mm increase, P=0.0003) were significant predictors of AF recurrence after the initial CA. Although Group Non-PV was weakly associated (HR 1.38, P=0.08) with AF recurrence, Group SVC was not associated with AF recurrence. CONCLUSIONS: Long-term outcome of CA of PAF was significantly worse in patients with non-PV foci other than SVC foci. These foci may affect the outcome not independently but as an aspect of atrial remodeling.

HotBalloon Ablation of the Pulmonary Veins for Paroxysmal AF: A Multicenter Randomized Trial in Japan.

BACKGROUND: Point-by-point catheter ablation is an established treatment for drug-refractory paroxysmal atrial fibrillation (PAF). However, it is time consuming, requires excellent technique to achieve complete pulmonary vein (PV) isolation, and is associated with severe complications. OBJECTIVES: The purpose of this study was to evaluate the safety and effectiveness of a HotBalloon ablation (HBA) compared with antiarrhythmic drug therapy (ADT) for the treatment of PAF. METHODS: A prospective multicenter randomized controlled study was conducted in Japan. Patients with symptomatic PAF refractory to antiarrhythmic drugs (Class I to IV) were randomized to HBA or ADT at a 2:1 ratio and assessed for effectiveness in a comparable 9-month follow-up period. RESULTS: A total of 100 patients in the HBA group and 43 patients in the ADT group received treatment at 17 sites. HBA procedure produced acute complete PV isolation in 98.0% (392 of 400) of the PVs and in 93.0% (93 of 100) of patients in the HBA group. The chronic success rates after the 9-month effective evaluation period were 59.0% in the HBA group (n = 100) and 4.7% in the ADT group (n = 43; p < 0.001). The incidence of major complications was 11.2% (15 of 134 patients). The incidences of PV stenosis (>70%) and transient phrenic nerve injury were 5.2% and 3.7%, respectively. The mean fluoroscopy time was 49.4 ± 26.6 min (n = 134), and the mean procedure duration was 113.9 ± 31.9 min (n = 133). CONCLUSIONS: This study demonstrates the superiority of HBA compared with ADT for treatment of patients with PAF, and a favorable safety profile.

Impact of Alcohol Consumption on the Outcome of Catheter Ablation in Patients With Paroxysmal Atrial Fibrillation.

BACKGROUND: Although several studies have reported an association between atrial fibrillation (AF) and alcohol, the impact of alcohol consumption on the outcome after catheter ablation (CA) for AF has not been discussed. We aimed to elucidate the effect of alcohol consumption on the outcome of CA for paroxysmal AF. METHODS AND RESULTS: We examined 1361 consecutive patients with paroxysmal AF (mean age, 61±11 years, 334 women) who underwent CA, including 623 (45.8%) patients who consumed alcohol. The clinical characteristics and outcomes of CA were compared between patients who did and did not consume alcohol. No significant differences were seen in the left atrial size, duration of AF history, and incidence of nonpulmonary vein foci between 2 groups (P=NS). Although the AF recurrence-free rate after the initial CA was higher in patients who did not consume alcohol (261/623 [41.9%] versus 252/738 [34.1%]; mean follow-up, 44.4±30.7 months; P=0.003), the outcome after the final CA was similar between 2 groups (patients who consumed alcohol: 111/628 [17.7%] versus patients who did not consume alcohol: 138/738 [18.7%]; mean follow-up, 53.1±25.8 months; P=0.67). The frequency (hazard ratio 1.07 per 1 day/week increase, CI 1.00-1.15, P=0.04) of alcohol consumption was significantly associated with AF recurrence after CA. CONCLUSIONS: The frequency of alcohol consumption may be associated with AF recurrence after the initial CA for paroxysmal AF, but it may not affect the outcome after the final CA.

Reversible Atrial Fibrillation with Bradycardia Associated with Primary Cardiac B-Cell Lymphoma.

Primary cardiac lymphoma (PCL) only rarely occurs and it is defined as a lymphoma in which the bulk of the tumor is located within the heart and pericardium. A 53-year-old woman was referred due to dyspnea, and an electrocardiogram exhibited atrial fibrillation (AF). Echocardiography revealed no abnormal findings. Scintigraphy and a lymph node biopsy led to a diagnosis of PCL. After the start of chemotherapy, AF was converted to atrial tachycardia prior to sinus rhythm with a first-degree atrioventricular block, which was finally restored to a normal sinus rhythm. PCL is only rarely encountered, but it should be included in the differential diagnosis as a possible cause of AF, and such AF could be reversible if the patient can be treated in a timely manner.

The mechanism of mitral regurgitation assessed by preprocedural echocardiography is associated with the outcome of catheter ablation in patients with paroxysmal atrial fibrillation.

BACKGROUND: Mitral regurgitation (MR) is generally classified as either primary (organic) or secondary (functional). Although patients with atrial fibrillation (AF) often exhibit MR, the relation between the etiology of MR and the outcome of catheter ablation (CA) remains unknown. We conducted this study in order to elucidate this association. METHODS: Among 1330 consecutive paroxysmal AF patients who underwent initial catheter ablation in our institution, 92 patients (62 men, mean age 65 ± 7 years) who had moderate or severe MR were included in this study; 46 were classified to have primary and the remaining 46 to have secondary MR by preoperative echocardiography. These patients were prospectively monitored after the CA. RESULTS: During a mean follow-up period of 27.9 ± 28.8 months, AF recurred in 26/46 (56.6 %) of primary MR patients and in 15/46 (32.6 %) of those with secondary MR (P < 0.02). Although univariate analysis found that diabetes, left atrial volume indexed by body surface area (LAVI), and primary MR were significantly associated with AF recurrence, primary MR (hazard ratio (HR), 2.47; 95 % confidence interval (CI), 1.30-4.88; P = 0.006) and LAVI (HR, 1.03/1 mL/m(2) increase; 95 % CI, 1.00-1.06; P = 0.03) remained significant predictors on multivariate analysis. The AF recurrence-free rate was lower in patients with primary MR after both the initial and final CA. CONCLUSION: In patients with paroxysmal AF and moderate or severe MR, primary MR may increase the risk of AF recurrence after the initial and final CA.

Apixaban versus Warfarin for the Prevention of Periprocedural Cerebral Thromboembolism in Atrial Fibrillation Ablation: Multicenter Prospective Randomized Study.

INTRODUCTION: Stroke can be a life-threatening complication of atrial fibrillation (AF) catheter ablation. Uninterrupted warfarin treatment contributes to minimizing the risk of stroke complications. METHODS AND RESULTS: This was a prospective, open-label, randomized, multicenter study assessing the safety and efficacy of apixaban for the prevention of cerebral thromboembolism complicating AF catheter ablation. Two hundred patients with drug-resistant AF were equally assigned to take either apixaban (5 mg or 2.5 mg twice daily) or warfarin (target international normalized ratio, 2-3) for at least 1 month before AF ablation. Neither drug regimen was interrupted throughout the operative period. Diffusion-weighted magnetic resonance imaging was performed for all patients to detect silent cerebral infarction (SCI) after the ablation. Primary outcomes were defined as the occurrence of stroke, transient ischemic attack, SCI, or major bleeding that required intervention. The secondary outcome was minor bleeding. The groups did not statistically differ in patients' backgrounds or procedural parameters. During AF ablation, the apixaban group required administration of more heparin to maintain an activated clotting time > 300 seconds than the warfarin group (apixaban, 14,000 ± 4,000 units; warfarin, 9,000 ± 3,000 units). Three primary outcome events occurred in each group (apixaban, 2 SCI and 1 major bleed; warfarin, 3 SCI, P = 1.00), and 3 and 4 secondary outcome events occurred in the apixaban and warfarin groups (P = 0.70), respectively. CONCLUSION: Apixaban has similar safety and effectiveness to warfarin for the prevention of cerebral thromboembolism during the periprocedural period of AF ablation.

Rapid Mapping of Right Atrial Tachycardia Using a New Multielectrode Basket Catheter.

INTRODUCTION: The mapping of atrial tachycardia (AT) can often be challenging and time-consuming, especially in patients with ATs that develop following cardiac surgery or are concomitant with atrial fibrillation. Recently, a new multielectrode basket catheter (MBC) has become available; we hypothesized that the MBC could be utilized to diagnose AT circuits. METHODS AND RESULTS: This study included 51 consecutive patients undergoing catheter ablation of clinically documented right-sided ATs (including 17 cases following cardiac surgery). Using a NavX system, 2 activation maps of the ATs were created, one using the new MBC (32 mm, 31 poles) and the other using a circular catheter. The time needed to complete the activation maps and the points acquired with both mapping catheters were compared. In all 64 ATs, including 34 non-cavotricuspid isthmus-dependent ATs, the AT activation maps created by both catheters were essentially identical. The number of points acquired to complete the activation maps did not differ significantly between the MBC and the circular catheter (387 [285-511] vs. 374 [269-533], P = 0.19), but the mapping time was significantly shorter using the MBC (4.0 [3.0-6.0] minutes vs. 8.0 [6.5-10.0] minutes, P < 0.0001). Inadvertent mechanical AT termination (n = 6) was observed only during mapping with the circular catheter. CONCLUSION: In patients with right-sided ATs, the use of an MBC could save mapping time.

Sudden manifestation of sinus arrest nine months after catheter ablation treatment for persistent atrial fibrillation.

A 39-year-old man with a seemingly non-remodeled, small heart suffered persistent atrial fibrillation (AF). Extensive isolation of the pulmonary vein, superior vena cava, and posterior left atrium, in conjunction with right atrium focal ablation, was performed to ablate multiple AF foci during two catheter ablation sessions. Sinus arrest occurred suddenly during follow-up, despite the absence of recurrent AF, ultimately necessitating pacemaker implantation. This case underscores the necessity of careful follow-up after catheter ablation, highlighting the risk of sudden, severe sinus node dysfunction, even in young AF patients with small hearts.

Relation between dabigatran concentration, as assessed using the direct thrombin inhibitor assay, and activated clotting time/activated partial thromboplastin time in patients with atrial fibrillation.

Dabigatran is a direct thrombin inhibitor that has been approved for preventing stroke in patients with atrial fibrillation. In this study, we aimed to assess the associations between the dabigatran concentration (calculated through plasma-diluted thrombin time, as assessed using the Hemoclot assay) and the activated partial thromboplastin time (aPTT) and activated clotting time (ACT). We recruited 137 patients with atrial fibrillation who were receiving a normal dose of dabigatran (300 mg/d) or a reduced dose of dabigatran (220 mg/d, usually administered to patients who were elderly, had moderate renal dysfunction, or who were also receiving verapamil). We then assessed the aPTT, ACT, and Hemoclot results of the patients and calculated the plasma dabigatran concentration. The mean plasma concentration of dabigatran was 127 ± 88 ng/ml, although no significant differences in dabigatran concentration, ACT, or aPTT were observed when we compared the 2 doses of dabigatran (300 or 220 mg/d). The dabigatran concentration was within the therapeutic levels in most patients, although a high value (>300 ng/ml) was observed in several patients, which indicated a high risk of bleeding. The dabigatran concentration was strongly and positively correlated with ACT and aPTT (r = 0.87, p <0.001; and r = 0.76, p <0.001; respectively). Multivariate analysis revealed that verapamil use was independently associated with elevated dabigatran concentrations (p <0.001). Therefore, ACT and aPTT may be useful for bedside assessment of the anticoagulant activity of dabigatran, and verapamil use may be a risk factor for elevated dabigatran concentrations.

Impact of Non-Pulmonary Vein Foci on the Outcome of the Second Session of Catheter Ablation for Paroxysmal Atrial Fibrillation.

BACKGROUND: Paroxysmal atrial fibrillation (AF) is primarily triggered by pulmonary veins (PVs). However, non-PV AF foci may also trigger AF. METHODS: We examined 207 patients (mean age, 62 ± 11 years; 166 men) who underwent a second catheter ablation (CA) and evaluated the clinical significance of non-PV AF foci on the outcomes. RESULTS: Electrical reconnections between the PVs and left atrium (LA) were observed in 162 patients (78.3%). Non-PV AF foci were identified in 95 patients (45.9%, 60 patients with successfully ablated non-PV AF foci and 35 with unmappable non-PV AF foci). During a median follow-up period of 22.7 months, 61 patients (29.5%; 18/112 [16.1%] without non-PV AF foci vs. 20/60 [33.3%] with successfully ablated non-PV AF foci vs. 23/35 [65.7%] with unmappable non-PV AF foci, P < 0.0001) developed AF recurrence; 52 (85.2%) developed recurrence within 1 year. The presence of non-PV AF foci was a significant clinical predictor of AF recurrence after the second CA; successfully ablated non-PV AF foci increased the AF recurrence risk by 2.24 times (95% confidence interval [CI], 1.12-4.54; P = 0.02), and unmappable AF foci increased this risk by 5.58 times (95% CI, 2.73-11.63; P < 0.0001). CONCLUSION: Nearly half of the patients had non-PV AF foci at the second CA session. AF recurred after the second CA session in approximately 30%, with most recurrences happening within 1 year. The presence of non-PV AF foci significantly increased the AF recurrence risk after a second CA. When non-PV AF foci were unmappable, the AF recurrence rate was extremely high.