Electrical isolation of the superior vena cava using second-generation cryoballoon in patients with atrial fibrillation.

BACKGROUND: The safety and efficacy of superior vena cava (SVC) isolation using second-generation cryoballoon (CB) ablation remain unknown. METHODS: A total of 26 (3.2%) patients with SVC-related paroxysmal atrial fibrillation (AF) from a consecutive series of 806 patients who underwent second-generation CB were included. Pulmonary vein isolation was initially achieved by CB ablation. If the SVC trigger was determined, the electrical isolation of SVC isolation was performed using the second-generation CB. RESULTS: Real-time SVC potential was observed in all patients. Isolation of the SVC was successfully accomplished in 21 (80.8%) patients. The mean number of freeze cycles in each patient was 2.1 ± 1.1. The mean time to isolation and ablation duration were 22.5 ± 14.2 seconds and 94.5 ± 22.3 seconds, respectively. A transient phrenic nerve (PN) injury was observed in five patients (19.2%). There were two patients (7.7%) experienced reversible sinus node injury during the first application. During a mean follow-up period of 13.2 ± 5.8 months, four patients (15.4%) had atrial arrhythmia recurrences. CONCLUSION: Isolation of SVC using the second-generation 28-mm CB is feasible when SVC driver during AF is identified. Vigilant monitoring of PN function during CB ablation of SVC is needed to avoid PN injury.

Safety and efficacy of superior vena cava isolation using the second-generation cryoballoon ablation in a canine model.

BACKGROUND: The safety and efficacy of superior vena cava (SVC) isolation (SVCI) using second-generation cryoballoon (CB) ablation remains unknown. METHODS: Electrical isolation of SVC was attempted using the second-generation CB ablation catheter in 14 canines. Ablation duration was randomized to either 90 s (7 canines) or 120 s (7 canines). SVC venography was performed to identify the SVC-right atrium (RA) junction. The 28-mm CB was positioned above SVC-RA junction. Repeat electrophysiological assessment in the live animals was conducted 40-60 days post-ablation, after which animals were euthanized for histological examination. RESULTS: Acute SVCI was successfully performed in all canines. No significant differences in numbers of freezes (1.7 ±â€¯0.8 vs. 1.5 ±â€¯0.5, p = 0.658), time to isolation (TTI) (24.3 ±â€¯8.1s vs. 22.7 ±â€¯9.0s, p = 0.297), temperature at isolation (-23.4 ±â€¯12.5 °C vs. -21.5 ±â€¯11.1 °C, p = 0.370), and nadir temperature (-51.2 ±â€¯6.2 °C vs. -53.3 ±â€¯7.0 °C, p = 0.195) were observed between the 90-s and 120-s groups. There were no procedural complications except one transient sinus bradycardia in the 120-s group. After ablation, animals survived for 51 ±â€¯5 days. Chronic SVCI was achieved in 6 of 7 (85.7%) SVCs in the 90-s group and 7 of 7 SVCs (100%) in the 120-s group (p = 0.299). Histological analysis revealed that a circumferential transmural lesion was achieved in all isolated SVCs. No sinus node (SN) and phrenic nerve injuries were observed. The minimum distance between ablation lesion and SN was 5.1 ±â€¯3.0 mm. CONCLUSIONS: The second-generation CB ablation catheter is both safe and effective in achieving SVC isolation in a canine model. Effective SVCI was found in the 90-s dosing strategy.

Long-term outcome of cryoballoon ablation versus radiofrequency ablation for focal atrial tachycardias originating from the pulmonary veins.

PURPOSE: We aimed to investigate the characteristics of focal atrial tachycardias (ATs) arising from the pulmonary veins (PVs), as well as the safety and long-term efficacy of cryoballoon (CB) versus radiofrequency (RF) ablation in this population. METHODS: Eighty-three patients with ATs arising from PVs from a consecutive series of 487 patients who underwent CB and RF ablation were retrospectively reviewed. Patients who had a prior history of atrial fibrillation (AF) were excluded. The AT origin was confirmed during the conventional electrophysiological study and activation mapping. The ablation approach was at the discretion of the operators. RESULTS: Thirty-five patients were managed with focal ablation, 25 were ablated with unilateral PV isolation (PVI), and the remaining 23 were performed with CB ablation. All procedures were successfully ablated. There was no significant difference in procedure time between CB group and RF focal group (43.7 ± 11.8 min vs. 45.8 ± 11.2 min, P = 0.121), whereas the fluoroscopy time in CB group was longer than in RF PVI group (10.1 ± 2.5 min vs. 8.4 ± 2.8 min, P < 0.001). There was 1 recurrence in CB group, 4 recurrences of AT in RF focal group, and 2 recurrence in RF PVI group (P = 0.643). Repeat ablation was performed in 6 of 7 patients. Seventy-eight patients were available for long-term follow-up. At a mean of 5.4 ± 4.6-year follow-up, 77 of 78 patients were free from AT without antiarrhythmic medication after 1.1 ± 0.3 procedures. No patient had procedural complications and developed AF during the follow-up period. CONCLUSIONS: CB ablation is an effective and safe tool to treat ATs originating from the PVs. The ATs originating from the PVs represent an isolated clinical process and are not likely to be the forerunner of a more diffuse process leading to the development of PV AF.

Procedural findings and clinical outcome of second-generation cryoballoon ablation in patients with variant pulmonary vein anatomy.

INTRODUCTION: The procedural findings and clinical outcome of second-generation cryoballoon (CB2) ablation in patients with variant pulmonary vein (PV) anatomy have not been fully investigated. METHODS: A total of 424 consecutive patients who underwent PV isolation with CB2 were included. Computed tomographic (CT) scan was performed in all patients before the procedure. The study population was divided into common PV, accessory PV, and nonvariant PV groups according to the CT scan. Procedural findings and clinical outcome between the three groups were compared. RESULTS: Variant PV anatomy was observed in 118 of 424 (27.8%) patients. PV isolation was successfully achieved in all patients in three groups with low rates of need for touch-up ablation (P = 0.974). Total procedure time was longer in the accessory PV group compared with nonvariant PV group (53.7 ± 12.9 vs 49.5 ± 8.8 minutes; P < 0.001). More number of applications per patient were required in accessory PV group compared with the nonvariant PV and common PV groups (7.5 ± 2.1 vs 6.5 ± 1.6, P < 0.001; 7.5 ± 2.1 vs 6.8 ± 1.4, P = 0.027, respectively). No significant difference in phrenic nerve (PN) injury was observed between the three groups (P = 0.693). During mean follow-up duration of 16.1 ± 3.3 months, there was no significant difference in rates of atrial fibrillation (AF) recurrences in the three groups (13 of 43 common PV group, 21 of 75 accessory PV group, and 80 of 306 nonvariant PV group, P = 0.178). CONCLUSION: Variant PV patterns are common in patients undergoing ablation for drug-resistant AF. CB2 ablation appears to be a reasonable strategy in the setting of the variant PV anatomy with a small increase in procedure time and the number of cryoapplications.

Predictors of hemoptysis in the setting of pulmonary vein isolation using the second-generation cryoballoon.

INTRODUCTION: To assess the predictors of hemoptysis using second-generation cryoballoon (CB). METHODS: Thirty patients with hemoptysis after second-generation CB ablation and 60 age-, gender-, and body mass index-matched controls were recruited. Anatomic parameters were obtained from preprocedural cardiac computed tomography (CT). Pulmonary vein isolation was performed with 28-mm balloon using single 3-minute freeze technique. RESULTS: Clinical and procedural characteristics were similar between the groups. A shorter distance between left superior PV (LSPV) and left main bronchus (LMB) was associated with hemoptysis (7.8 ± 4.3 mm vs. 12.5 ± 3.5 mm, P < 0.001), whereas no significant difference in the distance between right superior PV (RSPV) and right main bronchus (RMB) was found between groups (11.9 ± 3.5 mm vs. 12.9 ± 4.6 mm, P = 0.089). Additionally, the mean thickness of the connective tissue interposed between RSPV and RMB was significantly thicker than that between LSPV and LMB in both groups (both P < 0.001). A stepwise logistic multivariate analysis identified only the LMB-LSPV distance as an independent predictor of hemoptysis (odd ratio [OR] 2.676; 95% CI 1.121-4.843, P < 0.001). A cutoff value ≤ 9.5 mm predicted hemoptysis after CB ablation with 93.8% sensitivity and 75.0% specificity. CONCLUSION: Hemoptysis is a relatively rare event following second-generation CB ablation. The bronchi location obtained from CT aids in identifying high-risk population for the complication.

Right atrial dual-loop reentrant tachycardia after cardiac surgery: Prevalence, electrophysiological characteristics, and ablation outcomes.

BACKGROUND: Right atrial (RA) dual-loop reentrant tachycardia has been described in patients who have undergone open heart surgery. However, the prevalence, electrophysiological (EP) substrate, and ablation outcomes have been poorly characterized. OBJECTIVE: The purpose of this study was to investigate the prevalence, EP substrate, and ablation outcomes for RA dual-loop reentrant tachycardia after cardiac surgery. METHODS: We identified all patients with atrial tachycardia (AT) after cardiac surgery. We compared EP findings and outcomes of those with RA dual-loop reentrant tachycardia to a control group of patients with RA macroreentrant arrhythmias in the setting of linear RA free-wall (FW) scar. RESULTS: Of the 127 patients with 152 postsurgical ATs, 28 of the ATs (18.4%) had RA dual-loop reentry and 24 of 28 (85.7%) had tricuspid annular reentry combined with FW incisional reentry. An incision length >51.5 mm along the FW predicted the substrate for a second loop. In 22 of 23 patients (95.7%) with initial ablation in the cavotricuspid isthmus, a change in the interval between Halod to CSp could be recorded, and 15 of 23 patients (65.2%) had coronary sinus activation pattern change. Complete success was achieved in 25 of 28 patients (89.3%) in the dual-loop reentry group and in 64 of 69 patients (92.8%) in the control group. After mean follow-up of 33.9 ± 24.2 months, 24 of 28 patients (85.7%) and 60 of 69 patients (86.95%) were free of arrhythmias after the initial procedure in the 2 groups, respectively. CONCLUSION: The prevalence of RA dual-loop reentry is 18.4% of ATs with prior atriotomy scar. A long incision should alert physicians to the possibility of a second loop at the FW. Halo and coronary sinus activation patterns provide important clues to circuit transformation.

"Crosstalk" technique: A comparison between two generations of cryoballoon catheter.

INTRODUCTION: The "Crosstalk" technique: if pulmonary vein isolation (PVI) of the superior one is not achieved due to a gap in the inferior part, it could be done during inferior vein cryoablation. This maneuver minimizes the total energy delivery time and number of lesions. We aimed to correlate the likelihood of crosstalk phenomenon with certain anatomic characteristics. METHODS: A total of 676 patients undergoing a first ablation procedure for paroxysmal or persistent atrial fibrillation (470 first-generation cryoballoon [CB] and 206 second-generation CB) between June 2014 and December 2016 were included. RESULTS: "Crosstalk" phenomenon occurred in 32 patients (18 first-generation CB, 14 second-generation CB). Compared to 54 control patients without crosstalk, the angle between left superior pulmonary vein (LSPV) and left atrial (LA) roof-plane, left pulmonary common ostia were significant parameters associated with crosstalk (odds ratio [OR] = 1.20, ±95% confidence interval [CI]: 1.11-1.31, P < 0.001; OR = 5.67, ±95% CI: 1.08-28.69, P = 0.04). As for angle between LSPV and LA roof-plane, the cut-off value was 28.68° with a sensitivity of 72.22%, a specificity of 81.25%, and an area under the receiver operating characteristic curve of 0.87 to predict the possibility of crosstalk technique application to get isolated in LSPV. Among the crosstalk group, there was no statistical difference between first-generation CB and second-generation CB in pulmonary anatomic characteristics. CONCLUSION: Crosstalk technique can be effective in patients with AF undergoing CB ablation using with both first and second-generation CBs. Anatomic characteristics predictive of crosstalk include a left common ostia and smaller angle between the LSPV and LA roof-plane.

Pulmonary vein isolation with real-time pulmonary vein potential recording using second-generation cryoballoon: Procedural and biophysical predictors of acute pulmonary vein reconnection.

OBJECTIVE: The study sought to evaluate the procedural and biophysical factors related to acute pulmonary vein isolation (PVI) guided by real-time pulmonary vein (PV) potential recordings. METHODS: A total of 180 consecutive patients with drug-resistant atrial fibrillation (AF) undergoing CB2 (second-generation version of cryoballoon) ablation were enrolled. Real-time monitoring of PV potentials was obtained using an inner lumen spiral mapping catheter. RESULTS: Acute isolation was achieved in all PVs without touch-up ablation. Real-time assessment of PV disconnection was possible in 611 of 711 (85.9%) PVs. A total of 617 (86.8%) PVs were isolated during the initial freeze. Longer time cycle integration (TCI) (TTI * freeze cycle, TCI) (254.6 ± 112.8 seconds vs 74.1 ± 59.7 seconds, P < 0.001), time to isolation (TTI) (94.3 ± 34.0 seconds vs 46.3 ± 26.2 seconds, P < 0.001), higher nadir temperature (-45.5 ± 5.3°C vs -50.4 ± 5.5°C, P < 0.001), longer time to -40°C (77.3 ± 22.7 seconds vs 55.7 ± 23.2 seconds, P < 0.001), faster interval rewarming time at 0°C (9.4 ± 4.3 seconds vs 12.4 ± 4.9 seconds, P = 0.008), and total balloon rewarming time (38.1 ± 11.6 seconds vs 47.7 ± 14.0 seconds, P = 0.003) were observed in PVs with acute reconduction. TTI ≤ 65 seconds predicted absence of acute reconnection with 84.2% sensitivity and 75.7% specificity, whereas TCI ≤ 119 seconds presented 94.7% sensitivity and 80.2% specificity. At a mean follow-up of 4.7 ± 1.4 months, 82.2% of patients were free of AF. None of those with PV reconnections suffered from AF recurrences. CONCLUSIONS: The ablation using CB2 is effective in achieving acute PVI. Real-time assessment of PVI could be achieved during CB application in 86% of PVs. The incidence of spontaneous PV reconnection is very low, observed in just 3% of isolated PVs. TTI ≤ 65 seconds and TCI ≤ 119 seconds predicted absence of acute PV reconnection. Although they may identify effective cryoapplications in the acute phase, their performance still needs to be verified in the long term.

Electrocardiographic and electrophysiologic differentiation between atriofascicular, long atrioventricular, and short atrioventricular decrementally conducting accessory pathways.

Aims: We aimed to examine the electrocardiographic and electrophysiologic characteristics of anterograde-conducting decremental accessory pathways (DAP) and to identify surrogate criteria to distinguish short atrioventricular (SAV) DAP from atriofascicular (AF) AP and long atrioventricular (LAV) DAP. Methods and results: We identified all patients with DAPs and analysed electrocardiographic and electrophysiologic characteristics. Distal insertion sites were examined using existing criteria, including V-H interval, ventricular activation at the right ventricular apex, and around tricuspid annulus during antidromic atrioventricular re-entrant tachycardia (A-AVRT) or complete pre-excitation and evaluated the AV node-like properties according to the response to adenosine and radiofrequency ablation. Out of 45 patients with DAPs, 28 (62.2%) had SAV-DAP (13 with definite AF-AP, 2 with definite LAV-DAP, 2 indeterminate). In all, 50% of SAV-DAPs and 53.3% of AF-AP/LAV-DAPs had 'rS' pattern in lead III. Longer QRS duration (159.9 ± 17.4 ms vs. 139.2 ± 14.3 ms, P < 0.0001) during full pre-excitation or A-AVRT differentiated SAV-DAP from AF-AP. The QRS-V(His) interval was longer for those with SAV-DAP compared vs. AF-AP/LAV-DAP (45.3 ± 2.4 ms vs. 22.9 ± 2.5 ms, P < 0.0001) and a cut-off value of 33.0 ms differentiated the two (sensitivity 81.3%, specificity 87.5%). Conclusion: The majority of the SAV-DAPs are located at the TA free wall. An 'rS' pattern in lead III is frequently seen in SAV-DAP as well as AF-AP/LAV-DAPs. Measuring the QRS-V(His) interval would be helpful to distinguish SAV-DAP from AF-AP/LAV-DAP.

Focal atrial tachycardias from the parahisian region: Strategies for mapping and catheter ablation.

BACKGROUND: Focal atrial tachycardias (ATs) from the parahisian region can be successfully ablated from the right atrial septum (RAS), noncoronary cusp (NCC), and right middle septum (RMS). The optimal mapping and ablation strategy for ATs from these sites remains unclear. OBJECTIVE: The purpose of this study was to investigate the electrophysiologic characteristics and optimal ablation sites of parahisian ATs from the RAS, RMS, and NCC. METHODS: A total of 362 patients with ATs undergoing radiofrequency catheter ablation of ATs were included. A detailed examination including ECG analysis and electrophysiologic study was performed. RESULTS: Overall, 91 patients had a parahisian site of AT origin, and ablation was successful in 86 (94.5%). ATs were successfully eliminated from the RAS in 23, RMS in 19, and NCC in 44. The earliest "A" potential was recorded at the distal His catheter in 69.4% of NCC ATs vs the proximal His catheter in 83.3% of RAS ATs and 86.7% of RMS ATs. Mean timing of the "A" potential of RMS ATs recorded at the His-bundle catheter was -18.25 ± 7.20 ms, which was later than ATs from the RAS (-24.59 ± 8.73 ms) or NCC (-27.08 ± 5.63 ms). For ATs originating from the RAS and RMS, an A/V ratio <1.22 predicted safe and successful ablation (sensitivity 88.4%, specificity 91.7%). CONCLUSION: For parahisian ATs, activation sequence and timing of the "A" on the His catheter can provide clues for the origin of ATs. When ablating at the RAS and RMS, an A/V ratio >1.22 identified safe and effective ablation sites.

Very long-term outcome of catheter ablation of post-incisional atrial tachycardia: Role of incisional and non-incisional scar.

BACKGROUND: The arrhythmogenicity of right atrial (RA) incisional scar after cardiac surgery could result in atrial tachycardia (AT). Radiofrequency catheter ablation is effective in the treatment of such tachycardia. However, data regarding long-term outcomes are limited. METHODS AND RESULTS: A total of 105 patients with prior RA incision who underwent radiofrequency catheter ablation of AT were included. In the first procedure, electroanatomic mapping (EAM) revealed a total of 139 ATs in 105 patients, including 88 cavotricuspid isthmus dependent atrial flutters (IDAFs), 5 mitral annulus reentrant tachycardias (MARTs), 44 intra-atrial reentrant tachycardias (IARTs) and 2 focal ATs (FATs). AT was successfully eliminated in 101 (96.1%) patients. During a mean follow-up period of 90 ± 36 months, recurrent AT was observed in 23 patients and 21 underwent a second ablation. A total of 23 ATs were identified in redo procedures including 4 IDAFs, 2 MARTs, 12 IARTs and 5 FATs. The time to recurrence was significantly different among various AT types. Acute success was achieved in 20 of 23 redo procedures. Taking a total of 21 patients presenting atrial fibrillation during follow-up into account, 85 patients (81.9%) were in sinus rhythm. No complications except for a case of RA compartmentation occurred. CONCLUSION: RA incisional scar played an essential role in promoting both IDAF and IART, while non-incisional scar contributed to a substantial rate of late recurrent AT in forms of both macroreentry and small reentry. Catheter ablation using EAM system resulted in a high success rate during long-term follow-up.

Pulmonary Vein Isolation Using the First-Generation Cryoballoon Technique in Chinese Patients.

BACKGROUND: Cryoballoon ablation is an alternative for the treatment of atrial fibrillation (AF). We assess the relationship among pulmonary vein (PV) electrophysiology, balloon temperature, and persistent PV isolation (PVI), and report procedural properties, safety, and efficacy of this technique in a Chinese center for the first time. METHODS: A total of 70 patients with paroxysmal (n = 57) and persistent (n = 13) AF were consecutively enrolled. PVI was performed with cryoballoon catheter. Real-time recording of dissociation of PV potentials was attempted using a circumferential mapping catheter. RESULTS: Successful PVI was achieved in 274 of 282 (97.2%) PVs. Procedural duration was 115.2 ± 24.8 minutes and fluoroscopy time was 29.6 ± 8.9 minutes. Real-time PV potential recording was achieved in 232 (84.3%) PVs. Regarding time to isolation, a cut-off value of less than 60 seconds was predictive of persistent PVI with a sensitivity of 0.76 and specificity of 0.82 (area under curve = 0.835; P < 0.0001). The nadir balloon temperature was significantly lower in PVs without early reconduction (-46.3 ± 0.5°C vs -40.2 ± 1.3°C, P < 0.0001). However, there was an insignificant trend that the balloon temperature at isolation was higher in PVs without reconduction (-33.9 ± 0.7°C vs -36.4 ± 2.0°C, P = 0.14). The overall complication rate was 5.7%. After a median follow-up of 6.5 (range 3.2-14.9) months, 76% of patients were free of AF recurrence with a blanking period of 3 months. CONCLUSIONS: Real-time PV potentials can be recorded in most PVs. The time to isolation is predictive of the persistency of PVI. The nadir balloon temperature, not the balloon temperature at isolation, is significantly lower in PVs without reconduction.