The incidence and clinical significance of non-isolation of the pulmonary vein carina after encircling ipsilateral pulmonary veins isolation for paroxysmal atrial fibrillation: a pitfall of the double-Lasso technique

Role of Sleep-Disordered Breathing and Epicardial Connections in the Recurrence of Atrial Fibrillation

The presence of epicardial connections (ECs) between the pulmonary veins (PVs) and atrium may contribute to atrial fibrillation (AF) recurrence. This study aimed to determine the impact of sleep-disordered breathing (SDB) on the presence of ECs and the interplay between SDB and ECs on AF recurrence.We retrospectively reviewed 400 consecutive non-valvular AF patients. Among them, 235 patients exhibiting a 3% oxygen desaturation index (ODI) of ≥ 10 events/hour underwent polysomnography to evaluate the SDB severity, measured by the apnea-hypopnea index (AHI). To facilitate the ablation of AF and ECs, a high-density mapping catheter (HDMC) was employed. AF recurrence was evaluated over a 12-month period post-AF ablation.The key findings included: 1) 63% of AF patients with ECs had SDB with an AHI ≥ 20 events/hour. 2) Despite achieving complete PV isolations and precise EC ablation using an HDMC, SDB presence was associated with an increased AF recurrence. 3) Continuous positive airway pressure therapy for SDB improved AF recurrence among the AF patients with both ECs and SDB (57% versus 73%; P = 0.016). 4) AHI (odds ratio [OR] = 1.91, ≥ 28.4 events/hour) and left atrial volume (LAV) (OR = 1.42, ≥ 128.3 mL) were independent predictors of the presence of ECs, and AHI (OR = 1.44, ≥ 27.8 events/hour) was an independent predictor of the presence of AF recurrence.It is essential for physicians to recognise the potential complexity of ECs and SDB in AF patients. Thus, screening and treating SDB in AF patients presenting with ECs might play a pivotal role in suppressing AF recurrence.

Laser balloon ablation of atrial fibrillation in a patient with a large common inferior trunk: a case report

Background

A balloon-based visually guided laser balloon (LB) ablation (LBA) is as effective and safe as radiofrequency ablation and cryoballoon ablation in curing patients with atrial fibrillation (AF). The third-generation LB is so compliant that it can be inflated to any pressure and size change of up to 41 mm with its maximal expansion, which enables maximum balloon/tissue contact regardless of the size or shape of each pulmonary vein (PV) ostium. A large common inferior trunk (CIT) with a structured, completely independent common ostium of both the right and the left inferior PVs completely conjoined prior to the junction with the left atrium is an extremely rare anatomical variant and an important triggering focus in paroxysmal AF.

Case summary

We present a case of an LBA of AF in a patient with a large CIT of 34 mm in diameter. The laser energy was individually deployed to the right-sided and left-sided antra of the large CIT with the LB positioned at the ostium of the CIT's right and left branches. The complete electrical isolation of the three PVs was achieved. The patient remained stable without any symptoms or AF recurrence 1 year post ablation.

Discussion

The LBA, which is individually deployed to the right-sided and left-sided antra of the large CIT with the third-generation LB positioned at the ostium of the right and left branches of the CIT without laser energy deployment to the posterior wall of the CIT, may be one of the effective strategies for patients with large CITs.

Detection of a unidirectional epicardial connection between the right-sided pulmonary venous carina and the right atrium by pacing from a high-density mapping catheter

We report a case of recurring, persistent atrial fibrillation (AF) in a patient with a unidirectional epicardial connection (EC) between the right-sided pulmonary venous (PV) carina and the right atrium detected using a high-density mapping catheter with a steerable introducer support, but not a conventional circular mapping catheter. This unidirectional EC could be steadily abolished by a radiofrequency delivery. Finally, we were able to successfully achieve complete PV antrum isolation. Thereafter, he has remained well without any AF.

The Impact of Regional Maximum Tolerated Interlesion Distance on the Long-Term Ablation Outcomes in Ablation Index Guided Pulmonary Vein Isolation for Atrial Fibrillation

BACKGROUND

An adequate interlesion distance (ILD) applied during point-by-point pulmonary vein (PV) isolation for atrial fibrillation (AF) has never been established. We hypothesized that maximum tolerated ILD may differ between PV regions and may influence long-term ablation outcomes.

METHODS

A total of 260 AF patients underwent PV isolation with 3D electroanatomical platform. Postablation, ILD values were classified into 5 groups (6-5.5 mm, 5.5-5.0 mm, 5.0-4.5 mm, 4.5-4.0 mm and <4.0 mm); the number of tags in each group was calculated and correlated with postablation AF recurrence (AFR). All measurements were performed globally for the entire encirclement around each individual PV and regionally for designated PV anatomic segments.

RESULTS

Single-procedure freedom from AF was 81% for paroxysmal and 66% for persistent AF at 12 months. Global analysis showed that AFR was not related to median ILD nor the number of lesions within each ILD tag group for any PV. Segmental analysis showed that AFR was not related to median ILD. However, the presence of tags from the 5.5-6.0 mm ILD group located on the posterior aspect of right upper PV (RUPV) correlated with AFR. This was confirmed in a multivariable logistic regression model.

CONCLUSIONS

Maximum tolerated ILD of 6.0 mm translated into well-accepted ablation results. However, the study suggests that it may be inadequate at the posterior aspect of RUPV.

Epicardial Connections After a Conventional Pulmonary Vein Antrum Isolation in Patients With Atrial Fibrillation

BACKGROUND

The existence of epicardial connection(s) (ECs) between the pulmonary veins (PVs) and atrium may hinder establishing a complete PV antrum isolation (AI) (PVAI) in patients with atrial fibrillation (AF). Thus, the purpose of this study was to determine the prevalence and location of ECs inside the conventional PVAI lines.Methods and Results: Three-hundred consecutive patients with non-valvular AF were evaluated. This study revealed that: (1) the prevalence of patients with ECs and the number of ECs per patient between the PVs and atrium became significantly greater, respectively, in accordance with the progression of paroxysmal to long-lasting AF and left atrial enlargement; (2) some ECs were located at sites far distal to the PVAI lines; (3) 25% of ECs could be detected only by high-density mapping catheters, but not by conventional circular mapping catheters; (4) a B-type natriuretic peptide (BNP) level of 176.6pg/mL and left atrial volume (LAV) of 129.0 mL may be important predictors of the presence of ECs; and (5) the rate of conduction of ECs from the right PVs was dominantly to the atrium and His-bundle, and that from the left PVs to the coronary sinus was most dominant.

CONCLUSIONS

The PVAI may not be completed by using only a conventional PVAI method, and additional EC ablation inside the PVAI lines detected using high-density mapping may be able to achieve a more complete PVAI.

Left atrial wall thickness and its relationship with reconnection after pulmonary vein isolation in patients with atrial fibrillation evaluated using a three-dimensional wall thickness map

Background

The major cause of recurrence after pulmonary vein (PV) isolation for atrial fibrillation (AF) is PV reconnection, and thicker wall could be associated with reconnection.

Objectives

This study aimed to evaluate the wall thickness of the PV antrum in reconnection sites using a three-dimensional (3D) wall thickness map.

Methods

A total of 91 patients who underwent a second ablation procedure due to AF recurrence were evaluated. The locations of the PV reconnection sites were confirmed in electroanatomical maps. A 3D atrial wall thickness (AWT) map was created using computed tomography scan data. The AWT values of the ablation lines of the index procedure were graded in each segment of the PV antrum: grade 1, 0.5 < AWT ≤ 1.0 mm; grade 2, 1.0 < AWT ≤ 1.5 mm; grade 3, 1.5 < AWT ≤ 2.0 mm; grade 4, 2.0 < AWT ≤ 2.5 mm; grade 5, AWT > 2.5 mm.

Results

A total of 281 PV reconnection sites among 1256 segments of the PV antrum in 79 patients were detected. The average AWT grades were 2.7 ± 1.0 and 2.2 ± 1.0 in the reconnected and non-reconnected segments, respectively (P < 0.01). Higher AWT grades were observed in the reconnected superior segments of the left superior PV, carina and inferior segments of the left inferior PV, superior and posterior segments of the right superior PV, and posterior and inferior segments of the right inferior PV.

Conclusion

The reconnected segments of the PV antrum showed thicker myocardium than the non-reconnected ones in patients with recurrent AF after catheter ablation. A wall thickness map for PV isolation could be considered for customized ablation in order to reduce PV reconnection.

Fast anatomical mapping of the carina and its implications for acute pulmonary vein isolation

BACKGROUND

Fast anatomical mapping (FAM) of the left atrium and pulmonary veins (PV) during PV isolation (PVI) generates anatomical information about the carina region additionally. We aimed to investigate the utility of these data in relation to conduction abilities of the intervenous carina.

METHODS

We investigated 71 patients with drug-refractory atrial fibrillation (AF) who underwent first-time circumferential PVI using an electroanatomical mapping system. Carina width between ipsilateral PV was measured using FAM and an integrated distance measurement tool. Encirclings were divided into carina ablation and noncarina ablation groups based on the necessity of carina ablation to achieve PVI.

RESULTS

In total, 142 encirclings were analyzed and first-pass isolation was observed in 102 (72%) encirclings. Nonfirst-pass PVI solely due to a gap on the line or persistent carina conduction was observed in 10 (7%) and 30 (21%) encirclings, respectively. Encirclings were classified into a carina ablation group (n = 30, 21%) and noncarina ablation group (n = 112, 79%). Carina width was significantly larger in the carina ablation vs nonarina ablation group (right: 11.9 ± 1.5 mm vs 8 ± 1.4 mm, P < .001/left: 12.1 ± 1.3 mm vs 8.1 ± 1.1 mm, P < .001) requiring additional carina ablation.

CONCLUSION

Carina-related PV conduction is a common finding after the first-pass ablation during PVI. Measurement of carina width using FAM is feasible and its value correlates with the necessity of carina ablation to achieve PVI.

Contrast-enhanced computed tomography for optimizing the outcomes of pulmonary vein isolation with cryoablation -the role of isolation of PVs including carina

Purpose

Compared with conventional pulmonary vein isolation (PVI) with radiofrequency ablation, PVI with cryoballoon is an easier and shorter procedure without reconnection, particularly in the superior pulmonary vein. However, the durability of the cryoballoon may be reduced due to anatomical factors and the position of the pulmonary vein (PV). Further, inadequate isolation of the carina leads to recurrence of atrial fibrillation (AF). We aimed to determine whether using contrast-enhanced computed tomography (CT) for patient selection improves the early success rate and prevents the recurrence of AF in PVI with cryoballoon.

Methods

We evaluated patients who underwent ablation for paroxysmal atrial fibrillation in our hospital between July 2019 and November 2020. After excluding patients with contraindications for cryoablation, 50 patients were selected through visual inspection of the results of preoperative contrast-enhanced CT. A treatment plan was established, and the clinical course and outcomes were followed up.

Results

Of the 200 PVs of the 50 patients, only 8 PVs (4%) were incompletely isolated with a single cryoablation. Six of the eight PVs were successfully isolated with additional cryoablation. Only 2 patients (4%) underwent additional PVI with radiofrequency ablation. Four patients had AF recurrence within a mean follow-up period of 14.3 ± 5.1 months. The rate of sinus rhythm maintenance was 92%. PV reconnection was observed in 2 patients. None of the patients had postoperative atrial flutter.

Conclusions

Selecting patients for cryoablation according to contrast-enhanced CT findings made the procedure easier to perform, leading to improved early success rates and clinical course.

Cryoballoon Ablation for Patients With Paroxysmal Atrial Fibrillation

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia in clinical practice and induces cardiac dysfunction and stroke. The development of AF requires a trigger and also an electroanatomic substrate capable of both initiating and perpetuating AF. In the past decade, ectopic beats originating from the pulmonary veins (PV) have been identified as a source of paroxysmal AF. Thus, strategies that target the PV, including the PV antrum, are the cornerstone of most AF ablation procedures. Recently, alternative technologies to radiofrequency catheter ablation for paroxysmal AF such as balloon ablation modalities have been developed. The purpose of this review is to discuss cryoballoon ablation for paroxysmal AF.

Left Ventricular Unloading Using an Impella CP Improves Coronary Flow and Infarct Zone Perfusion in Ischemic Heart Failure

Background

Delivering therapeutic materials, like stem cells or gene vectors, to the myocardium is difficult in the setting of ischemic heart failure because of decreased coronary flow and impaired microvascular perfusion (MP). The aim of this study was to determine if mechanical left ventricular (LV) unloading with the Impella increases coronary flow and MP in a subacute myocardial infarction.

Methods and Results

Anterior transmural myocardial infarction (infarct size, 26.0±3.4%) was induced in Yorkshire pigs. At 2 weeks after myocardial infarction, 6 animals underwent mechanical LV unloading by Impella, whereas 4 animals underwent pharmacological LV unloading using sodium nitroprusside for 2 hours. LV unloading with Impella significantly reduced end‐diastolic volume (−16±11mL, P=0.02) and end‐diastolic pressure (EDP; −32±23 mm Hg, P=0.03), resulting in a significant decrease in LV end‐diastolic wall stress (EDWS) (infarct: 71.6±14.7 to 43.3±10.8 kdynes/cm² [P=0.02]; remote: 66.6±20.9 to 40.6±13.3 kdynes/cm² [P=0.02]). Coronary flow increased immediately and remained elevated after 2 hours in Impella‐treated pigs. Compared with the baseline, MP measured by fluorescent microspheres significantly increased within the infarct zone (109±81%, P=0.003), but not in the remote zone. Although sodium nitroprusside effectively reduced LV‐EDWS, 2 (50%) of sodium nitroprusside–treated pigs developed profound systemic hypotension. A significant correlation was observed between the infarct MP and EDWS (r²=0.43, P=0.03), suggesting an important role of EDWS in regulating MP during LV unloading in the infarcted myocardium.

Conclusions

LV unloading using an Impella decreased EDWS and increased infarct MP without hemodynamic decompensation. Mechanical LV unloading is a novel and efficient approach to increase infarct MP in patients with subacute myocardial infarction.

Strategy and Outcome of Catheter Ablation for Persistent Atrial Fibrillation - Impact of Progress in the Mapping and Ablation Technologies

Pulmonary vein (PV) antrum isolation (PVAI) is effective in treating paroxysmal atrial fibrillation (AF) but is less so for persistent AF. A recent randomized study on the ablation strategies for persistent AF demonstrated that 2 common atrial substrate modifications, creation of linear lesions in the left atrium and ablation of complex fractionated electrogram sites, in addition to PVAI did not improve the outcome compared with stand-alone PVAI, suggesting the necessity of a more individualized, selective approach to persistent AF. There are emerging technologies, including high-resolution mapping with the use of multi-electrode catheter and auto mapping system and contact force (CF) guide ablation; the former allows rapid and accurate confirmation of the completeness of PVAI, and the latter enhances the achievement of durable ablation lesions more securely. Ablation for fibrotic area(s) has been proposed as a new approach for substrate modification, and high-resolution mapping is useful to define the area with low-voltage electrograms, a surrogate marker for atrial fibrosis. Ablation for non-PV triggers in addition to PVAI improves the outcome of persistent AF. Further, durable isolation of the left atrial posterior wall may reduce AF recurrence. These ablation strategies with concomitant use of the emerging technologies are strongly expected to enhance the effectiveness of catheter ablation for persistent AF.

Difference Between Dormant Conduction Sites Revealed by Adenosine Triphosphate Provocation and Unipolar Pace-Capture Sites Along the Ablation Line After Pulmonary Vein Isolation

Dormant pulmonary vein (PV) conduction revealed by adenosine/adenosine triphosphate (ATP) provocation test and exit block to the left atrium by pacing from the PV side of the ablation line ("pace and ablate" method) are used to ensure durable pulmonary vein isolation (PVI). However, the mechanistic relation between ATP-provoked PV reconnection and the unexcitable gap along the ablation line is unclear.Forty-five patients with atrial fibrillation (AF) (paroxysmal: 31 patients, persistent: 14 patients; age: 61.1 ± 9.7 years) underwent extensive encircling PVI (EEPVI, 179 PVs). After completion of EEPVI, an ATP provocation test (30 mg, bolus injection) and unipolar pacing (output, 10 mA; pulse width, 2 ms) were performed along the previous EEPVI ablation line to identify excitable gaps. Dormant conduction was revealed in 29 (34 sites) of 179 PVs (16.2%) after EEP-VI (22/45 patients). Pace capture was revealed in 59 (89 sites) of 179 PVs (33.0%) after EEPVI (39/45 patients), and overlapping sites, ie, sites showing both dormant conduction and pace capture, were observed in 22 of 179 (12.3%) PVs (17/45 patients).Some of the ATP-provoked dormant PV reconnection sites were identical to the sites with excitable gaps revealed by pace capture, but most of the PV sites were differently distributed, suggesting that the main underling mechanism differs between these two forms of reconnection. These findings also suggest that performance of the ATP provocation test followed by the "pace and ablate" method can reduce the occurrence of chronic PV reconnections.

Simultaneous isolation of superior and inferior pulmonary veins on both the left and right sides could yield better outcomes in patients with paroxysmal atrial fibrillation

AIMS

This study investigated whether disappearance patterns of pulmonary vein (PV) potentials (PVPs) during PV isolation (PVI) affect the outcome of catheter ablation (CA) in patients with paroxysmal atrial fibrillation (PAF).

METHODS AND RESULTS

Extensive PVI was performed in 1149 PAF patients (age, 61 ± 10 years). Clinical and demographic characteristics, ablation data, and follow-up outcomes were prospectively collected. During an initial CA, simultaneous disappearance of superior and inferior PVPs in both right and left PVs was observed in 464 (40.4%) patients (Group S). Atrial fibrillation-recurrence free rates at 1, 3, and 5 years after the initial CA in Group S were 78.9, 71.9, and 68.1%, respectively, which were higher than those in Group Non-S (P = 0.004). However, those were similar after the final CA between both groups. The incidence of PV-left atrium (LA) electrical reconnection was significantly lower in Group S than in Group Non-S in the second (Group S, 65.6% vs. Group Non-S, 82.1%; P = 0.004) and third (Group S, 8.3% vs. Group Non-S, 47.6%; P = 0.03) CAs. Furthermore, the reconnections more frequently occurred on the side of PVs where simultaneous PVP elimination had not been achieved at the initial CA. Simultaneous disappearance of superior and inferior PVPs in both right and left PVs independently reduced the risk of AF recurrence after the initial CA by 26%.

CONCLUSIONS

The simultaneous disappearance of superior and inferior PVPs in both right and left PVs is associated with less frequent PV-left atrium reconnection and may yield a better clinical outcome after the initial CA.

Comparison of the change in the dimension of the pulmonary vein ostia immediately after pulmonary vein isolation for atrial fibrillation-open irrigated-tip catheters versus non-irrigated conventional 4 mm-tip catheters

INTRODUCTION

A difference in the lesion formation between open irrigated-tip (OITC) and non-irrigated 4-mm-tip catheters (NITC) may result in a difference in the dimension of the pulmonary vein (PV) ostia after PV isolation of atrial fibrillation (AF). This study evaluated the difference using intracardiac echocardiography (ICE) before and immediately after an extensive encircling PV isolation (EPVI) with an OITC and with an NITC.

METHODS AND RESULTS

We studied 100 consecutive patients (OITC group, 54; NITC group, 46) who received EPVI. Changes in the vessel, lumen, and wall thickness areas of the PVs were evaluated at the PV ostia by ICE. There were no significant differences in the baseline characteristics and acute success rate of the EPVI between the OITC and NITC groups. The energy delivered to achieve EPVI was higher in the OITC group than that in the NITC group (34,967 ± 13,222 J vs. 28,300 ± 10,614 J; p=0.01). After the ablation, the reduction in the vessel and lumen cross-sectional areas was significantly smaller in the OITC group than that in the NITC group (-9.05 ± 28.4 % vs. -21.2 ± 28.8 %, p<0.001; -8.76 % vs. -17.7 ± 26.9 %, p=0.003). The wall thickness area slightly decreased in the OITC group, but increased in the NITC group (-2.96 ± 38.4 % vs. 10.5 ± 76.6 %, p=0.591). During a median follow-up of 234 days, there was no significant difference in the AF recurrence after the initial ablation procedure between the two groups.

CONCLUSION

Greater PV ostial narrowing occurred with the NITC than OITC immediately after the EPVI. PV ostial wall edema was noted with only the NITC. These findings suggested that an OITC might reduce any acute PV narrowing and wall edema as compared with an NITC.

Patterns of pulmonary vein potential disappearance during encircling ipsilateral pulmonary vein isolation can predict recurrence of atrial fibrillation

BACKGROUND

The relationship between pulmonary vein (PV) potential (PVP) disappearance patterns during encircling ipsilateral pulmonary vein isolation (EIPVI) of atrial fibrillation (AF), and outcome was examined.

METHODS AND RESULTS

A total of 352 consecutive AF patients (age, 61±12 years; 269 men, 76.4%; paroxysmal AF, n=239; persistent AF, n=73; and long-standing persistent AF, n=40) who underwent initial AF ablation were studied. After EIPVI with a double Lasso technique, pacing was performed from the PV carina to confirm isolation of the carina. PVP disappearance patterns were classified into 3 types: A, both superior and inferior PVP disappeared simultaneously; B, superior and inferior PVP disappeared separately; and C, additional RF applications were required inside the encircling lesions to eliminate the PVP after creating anatomical encircling lesions. The relationship between these patterns and outcome was examined. Six groups were defined according to the combination of right and left ipsilateral PVP disappearance patterns. The incidence of A-A, A-B, B-B, A-C, B-C, and C-C was 7.1%, 14.2%, 16.2%, 15.3%, 27.3%, and 19.9%, respectively. AF recurrence-free rate at 2 years for these 6 groups was 96%, 81%, 78%, 64%, 64%, and 59%, respectively (P<0.02). The incidence of a carina isolation was 153/154 (99.4%) for type A, 221/259 (85.3%) for type B, and 145/290 (50.0%) for type C.

CONCLUSIONS

PVP disappearance pattern during EIPVI was significantly associated with the incidence of residual PV carina conduction and AF recurrence.