Transcranial measurement of cerebral microembolic signals during left-sided catheter ablation with the use of different approaches- the potential microembolic risk of a transseptal approach.

Aims: Subclinical brain damage due to microembolization could occur during catheter ablation procedures. We evaluated the microembolic signals (MESs) detected by transcranial Doppler during ablation of supraventricular tachycardias (SVTs) or idiopathic ventricular arrhythmias (VAs) with the use of different approaches. Methods and results: This study included 36 patients (23 men, 49 ± 21 years) who underwent catheter ablation of SVTs (n = 27) or idiopathic VAs (n = 9). Left-sided ablation was performed by either a transaortic (Group 1, n = 11) or transseptal approach (Group 2, n = 9). A sole right-sided ablation was performed in the remaining 16 patients (Group 3). The MESs were counted throughout the procedure, and then analysed offline with a frequency analysis. The mean number of radiofrequency applications, total energy delivery time, total application energy, and total procedure time were 5.8 ± 5.0, 4.3 ± 3.3 min, 6625 ± 4633 J, and 81 ± 40 min, respectively, and there was no significant difference in the parameters between the three groups. The mean total number of MESs was 3.8 ± 3.1 in Group 1, 75 ± 58 in Group 2, and 0.3 ± 0.6 in Group 3 (P = 0.001). Few MESs were detectable during the radiofrequency energy deliveries in all groups. In Group 2, 19 ± 18 MESs were detected during the transseptal puncture period, and subsequently a relatively even distribution of emboli formation was observed. A frequency analysis suggested that 99, 91, and 100% of MESs were gaseous, in Group 1, Group 2, and Group 3, respectively. No neurological impairment was observed in any patients after the procedure. Conclusion: The retrograde aortic approach might potentially have a lower risk of subclinical brain damage than the transseptal approach during left-sided catheter ablation.

Management of cardiac tamponade in catheter ablation of atrial fibrillation: single-centre 15 year experience on 5222 procedures.

Aims: Cardiac tamponade during atrial fibrillation (AF) ablation is infrequent but potentially fatal. This study aimed to retrospectively investigate the incidence, management, and outcomes of tamponade in large patient series. Methods and results: The study analysed 5222 AF ablation procedures in 3483 patients between 2002 and 2016 under a heparin-bridge anticoagulation protocol. Cardiac tamponade occurred in 51 procedures/patients, and the incidence was 0.98% per procedure and 1.46% per patient and was noted during the procedure in 42 patients and in the ward in the remaining 9 patients. No clinical factors were associated with the occurrence, but it was lower during cryoballoon than radiofrequency ablation (P = 0.025). Pericardiocentesis was required in 44 (86.3%) patients, and the haemodynamic state stabilized after a total of 377 (260-530) mL of pericardial blood drainage except for in 2 (3.9%) patients requiring subsequent emergent surgical repairs. The pericardial drain was successfully removed after a median of 1.0 (1.0-2.0) days. In 44 patients, anticoagulation therapy was restarted a median of 3.0 (1.0-7.0) days after the procedure. Thirty (58.8%) patients experienced early recurrent AF with low-grade fevers (37.4 ± 0.5 °C) and an elevated C-reactive protein [2.4 (1.1-8.5) mg/dL]. After successful management of tamponade, 2 (3.9%) patients exhibited cerebral infarctions despite restarting anticoagulation therapy. One patient died, and the other completely recovered without any neurological deficit. Recurrent post-cardiac injury syndrome (PCIS) occurred on post-procedural Day 13 in another patient, requiring oral prednisone administration for 10 months. During a median follow-up of 23 (5.4-46.1) months, 34 (66.7%) patients were arrhythmia free. Conclusions: Despite an infrequent incidence, surgical backup is essential for performing AF ablation. Even after successful management of tamponade, care should be taken for subsequent complications.

Persistence of an iatrogenic atrial septal defect after a second-generation cryoballoon ablation of atrial fibrillation.

Persistent iatrogenic atrial septal defects (iASDs) can be observed after intervention requiring a left atria (LA) access, including pulmonary vein isolation (PVI) of atrial fibrillation (AF). We investigated the incidence of iASDs post-second-generation cryoballoon ablation and the pre-procedural predictors. Eighty-three paroxysmal AF patients underwent PVI using second-generation cryoballoons. The LA was accessed with single 15-Fr steerable sheaths following a radiofrequency transseptal puncture, and the iASD was evaluated with transthoracic echocardiography (TTE), a median of 9.3 (7.1-13.3) months post-procedure. All patients underwent pre-procedural contrast-enhanced multi-detector computed tomography (CT) to evaluate the LA and PV anatomy. iASDs were detected by TTE in 7 (8.4%) patients, a median of 15.5 (6.8-17.3) months post-procedure. Patients with iASDs had significantly larger LA volumes and smaller atrial septal angles, defined as the angle between the atrial septum and sagittal line on the horizontal section at the height of the fossa ovalis, which could be the transseptal puncture site measured on CT, and more likely hypertension than those without. Multivariate analyses revealed that the atrial septal angle was the sole predictor of iASDs [odds ratio 0.764, 95% confidence interval (CI) 0.624-0.935, p = 0.009], and the optimal cut-off value was 57.5° (sensitivity 85.7%, specificity 88.2%, 95% CI 0.873-0.995, p < 0.0001). Patients with iASDs were asymptomatic and had no adverse clinical events during a 17.7 (14.4-25.8) month median follow-up. iASDs were still detectable in 8.4% of patients a median of 15.5 months after the second-generation CB ablation, and the atrial septal angle might aid in predicting persistent iASDs.

Autonomic nervous system modulation and clinical outcome after pulmonary vein isolation using the second-generation cryoballoon.

BACKGROUND: The intrinsic cardiac autonomic nervous system (ANS) plays a significant role in atrial fibrillation (AF) mechanisms. This study evaluated the incidence and impact of intraprocedural vagal reactions and ANS modulation by pulmonary vein isolation (PVI) using second-generation cryoballoons on outcomes. METHODS: One hundred three paroxysmal AF patients underwent PVI with one 28-mm second-generation balloon. The median follow-up was 15.0 (12.0-18.0) months. ANS modulation was defined as a >20% cycle length decrease on 3-minute resting electrocardiograms at 1, 3, 6, and 12 months postindex procedure relative to baseline if sinus rhythm was maintained. RESULTS: Marked sinus arrests/bradycardia and atrioventricular block (intraprocedural vagal reaction) occurred in 14 and 2 patients, and all sinus arrest/bradycardia occurred in 44 patients with left superior pulmonary veins (PVs) targeted before right PVs. ANS modulation was identified in 66 of 95 (69.5%) patients, and it persisted 12-month postprocedure in 36 (37.9%) patients. Additional ß-blocker administration was required in 9 patients for sinus tachycardia. ANS modulation was similarly observed in patients with and without intraprocedural vagal reactions (P = 0.443). Forty-eight (46.6%) patients experienced early recurrences, and the single procedure success at 12 months was 72.7%. Neither intraprocedural vagal reactions nor ANS modulation predicted AF freedom within or after the blanking period. Thirty-three patients underwent second procedures, and reconnections were detected in 39 of 130 (30.0%) PVs among 23 (69.7%) patients. The incidence of reconnections was similar in patients with and without ANS modulation. CONCLUSIONS: Increased heart rate persisted in 37.9% of patients even at 12-month post-second-generation cryoballoon PVI. Neither intraprocedural vagal reactions nor increased heart rate predicted a single procedure clinical outcome.

Validation of electrical ostial pulmonary vein isolation verified with a spiral inner lumen mapping catheter during second-generation cryoballoon ablation.

BACKGROUND: Achieve catheters are cryoballoon guidewires that enable pulmonary vein (PV) potential mapping. The single catheter approach in conjunction with the Achieve catheter is currently standard practice in second-generation cryoballoon ablation, yet circumferential mapping catheters are the gold standard for evaluating PV isolation (PVI). The study sought to validate the ostial PVI verified by an Achieve catheter alone. METHODS: One hundred fifty-one paroxysmal atrial fibrillation patients undergoing PVI using exclusively 28-mm second-generation cryoballoons were enrolled. PV recordings were analyzed during (real-time recordings) and after cryoballoon applications with 20-mm Achieve mapping catheters, and subsequently validated by 20-mm conventional circumferential mapping catheters. RESULTS: Out of 596 PVs, 576 (96.6%) were isolated using cryoballoons, and 20 required touch-up ablation. PVI was verified during cryoballoon applications with real-time monitoring in 299, and after applications in 280 PVs by Achieve catheters alone. The time-to-isolation was 27.2 ± 22.0 seconds. Validation with standard circumferential mapping catheters confirmed ostial PVIs in 296 of 299 (99.0%) PVs that real-time PVI was obtained during applications, and in 242 of 280 (86.5%) PVs that PV activities were not visible during applications and PVI was verified after the applications. The accuracy of ostial PVIs with Achieve catheters in PVs without obtaining real-time PV recordings was 40/47 (85.1%), 58/65 (89.2%), 77/79 (97.5%), 61/81 (75.3%), and 6/8 (75.0%) in left superior, left inferior, right superior, right inferior, and left common PVs, respectively. CONCLUSIONS: In second-generation 28-mm cryoballoon ablation, verification of ostial PVIs using Achieve mapping catheters alone might not be sufficient to accurately confirm an ostial PVI when real-time PVI was not obtained.

Pulmonary Vein Stenosis After Second-Generation Cryoballoon Ablation.

BACKGROUND: Pulmonary vein stenosis (PVST) can occur after first-generation cryoballoon ablation. This study aimed to evaluate the incidence, severity, and characteristics of PVST after second-generation cryoballoon ablation. METHODS: In total, 103 patients underwent PV isolation of paroxysmal atrial fibrillation using second-generation cryoballoons with a single big-balloon 3-minute freeze technique. Cardiac enhanced multidetector computed tomography (MDCT) was performed both before and a median of 6.0 (4.0-8.0) months after the procedure in all. PVST was classified as follows: minimal (<25%), mild (25-50%), moderate (50-70%), or severe (>70%). RESULTS: In total, 406 PVs were analyzed. MDCT demonstrated PV stenosis in 10(2.5%) PVs among 8(7.8%) patients. In detail, minimal and mild PVSTs were observed in 6 and 4 PVs, respectively. PVST occurred in the left superior (LSPV), left inferior, and right superior PVs in 6, 1, and 3 PVs, respectively. No stenosis was observed in 15 PVs with active balloon deflations during freezing. All PVSTs had concentric patterns except for 2 PVs with minimal stenosis. Balloon deformities were observed during freezing of 2 PVs with mild stenosis. When the PVST was defined as a >25% decreased diameter, the incidence was 0.98% (4/406; including 3 LSPVs). PVST did not progress further during the follow-up period. CONCLUSIONS: Although the incidence of PVST was low, it could occur even if a single big-balloon short freeze technique was applied. The risk of PV stenosis significantly differed among the 4 PVs, and reaching balloon temperatures of -60 °C and active balloon deflations during freezing were not associated with any PV stenosis.

[A Case of Cardiopulmonary Arrest due to Difficult Mask Ventilation and Difficult Laryngoscopy in the Ward after Operation: A Case Report].

A 77-year-old man with paroxysmal atrial fibrillation and hypertrophic obstructive cardiomyopathy was scheduled for cervical laminoplasty. He was predicted difficult mask ventilation combined with difficult laryn- goscopy (CICV) because of short thyromental distance. After induction of general anesthesia, we attempted tracheal intubation using McGRATHO and Gum-elastic Bougie and the intubation was successful. After opera- tion, in ward, atrial fibrillation occurred. Because anti- arrhythmic agents were not effective, cardioversion was planned. While under sedation, his breathing stopped. The attending physician could not ventilate with mask and intubate with Macintosh laryngoscope. The patient went into cardiopulmonary arrest After successful intubation using McGRATH? and Gum- elastic Bougie by anesthesiologist The attending physi- cian did not recognize CICV. We should convey infor- mation of CICV surely and perform education about difficult airway management.

Pulmonary Vein Isolation Using a Second-Generation Cryoballoon in Patients With Paroxysmal Atrial Fibrillation: One-Year Outcome Using a Single Big-Balloon 3-Minute Freeze Technique.

BACKGROUND: The second-generation cryoballoon (CB) has been recently introduced into clinical use for pulmonary vein isolation (PVI). Data on the feasibility, long-term outcome, and optimal freeze cycle are still limited. We assessed the 1-year clinical outcome after second-generation CB ablation with single 3-minute freeze techniques, and clinical variables associated with AF recurrence. METHODS: A total of 108 paroxysmal atrial fibrillation (PAF) patients undergoing cryothermal PVI were enrolled. PVI was performed with one 28-mm CB using single 3-minute freeze techniques without bonus applications. Fourteen-day consecutive monitoring was done after discharge to detect early AF recurrences (ERAFs). RESULTS: Out of 425 PVs, 409 (96.2%) were isolated using exclusively CBs, and 16 required touch-up ablation. Transient phrenic nerve injury, pericardial tamponade, and 50% PV stenosis occurred in 9, 1, and 1 patients, respectively. No PV stenosis >50% was observed in any patients. The total procedure and fluoroscopic times were 82.9 ± 26.4 and 26.2 ± 14.8 minutes, respectively. ERAFs were detected in 51 (47.2%) patients. At 1-year after single and repeat procedures, 71.6% and 84.3% of the patients were free from recurrent AF off antiarrhythmic drugs (AADs), respectively. Eighteen patients underwent repeat procedures (median 6.0 [4.0-9.3] months post procedure), and 68.6% of PVs were still isolated. Cox's proportional models determined that ERAFs were significantly associated with AF recurrence (HR = 7.236; 95%CI = 2.753-19.016; P < 0.0001). AF-freedom off AADs at 1-year after single procedures was 90.8% and 50.3% in patients without and with ERAFs. CONCLUSIONS: Second-generation CB ablation using single 3-minute freeze techniques appears feasible in PAF patients. ERAFs were significant factors for predicting clinical outcomes.

Esophagus-Related Complications During Second-Generation Cryoballoon Ablation-Insight from Simultaneous Esophageal Temperature Monitoring from 2 Esophageal Probes.

BACKGROUND: Monitoring luminal esophageal temperatures (LETs) helps predict esophageal thermal lesions (ETLs) after catheter ablation. This study aimed to evaluate esophagus-related complications after second-generation cryoballoon ablation under simultaneous LETs monitoring from 2 esophageal probes. METHODS: Forty consecutive paroxysmal atrial fibrillation patients undergoing second-generation cryoballoon ablation under conscious sedation followed by esophagogastroscopy were prospectively included. Two temperature probes inserted bi-nasally (both non-deflectable in 13, non-deflectable and deflectable in 27 patients) were used for LET monitoring. Pulmonary vein isolation was performed with one 28-mm balloon using single 3-minute freeze techniques. RESULTS: The lowest LETs significantly correlated between different probes; however, deflectable probe showed significantly lower nadir LETs than non-deflectable probes (14.6 ± 9.2 vs. 20.0 ± 10.6 ℃, P<0.0001). Esophagogastroscopy post-ablation demonstrated ETLs and gastroparesis in 8 (20%) and 7 (17.5%) patients (total 13 [32.5%]), respectively. The optimal cutoff for the lowest LET measured on any probe for predicting no ETLs was 12.8 ℃ (sensitivity 78.1%, specificity 100%). When using deflectable and non-deflectable catheters, the optimal cutoff point for the lowest LET for predicting no ETLs was 11.4 ℃ (sensitivity 70.0%, specificity 100%) and 19.4 ℃ (sensitivity 63.6%, specificity 100%), respectively. No ETLs were detected in 12 (30%) patients with the esophagus located between the left atrium and spine. All esophagus-related complications were asymptomatic and had healed on repeat esophagogastroscopy by a mean of 53 ± 25 days after the procedure. CONCLUSIONS: The lowest LET highly depended on the temperature probe location. However, if a different cutoff value was applied, LET monitoring, regardless of the probe type, and anatomical information might help predict ETLs during second-generation cryoballoon ablation.

Prospective Evaluation of Electromyography-Guided Phrenic Nerve Monitoring During Superior Vena Cava Isolation to Anticipate Phrenic Nerve Injury.

BACKGROUND: Right phrenic nerve injury (PNI) is a major concern during superior vena cava (SVC) isolation due to the anatomical close proximity. The functional and histological severity of PNI parallels the degree of the reduction in the compound motor action potential (CMAP) amplitude. This study aimed to evaluate the feasibility of monitoring CMAPs during SVC isolation to anticipate PNI during atrial fibrillation (AF) ablation. METHODS: Thirty-nine paroxysmal AF patients were prospectively enrolled. Radiofrequency energy was delivered point-by-point for 30 seconds with 20 W until eliminating all SVC potentials after the pulmonary vein isolation. Right diaphragmatic CMAPs were obtained from modified surface electrodes by pacing from the right subclavian vein. Radiofrequency applications were applied without fluoroscopy under CMAP monitoring at sites with phrenic nerve capture by high output pacing. RESULTS: Electrical SVC isolation was successfully achieved with a mean of 9.4 ± 3.3 applications in all patients. In 3 (7.5%) patients, the SVC was isolated without radiofrequency delivery at phrenic nerve capture sites. Among a total of 346 applications in the remaining 36 patients, 71 (20.5%) were delivered while monitoring CMAPs. In 1 (1.4%) application, the RF application was interrupted due to a decrease in the CMAP amplitude. However, no PNI was detected on fluoroscopy, and the decreased amplitude recovered spontaneously. The remaining 70 (98.6%) applications exhibited no significant changes in the CMAP amplitude throughout the applications (from 1.01 ± 0.47 to 0.98 ± 0.45 mV, P = 0.383). CONCLUSIONS: Stable right diaphragmatic CMAPs could be obtained, and monitoring CMAPs might be useful for anticipating right PNI during SVC isolation.

Impact of Catheter Contact Force on Superior Vena Cava Mapping and Localization of the Right Phrenic Nerve by High Output Pacing.

BACKGROUND: Right phrenic nerve injury (PNI) is a major concern during superior vena cava (SVC) isolation. Phrenic nerve (PN) localization by high-output pacing is a standard technique for anticipating PNI. This study evaluated the impact of catheter contact force (CF) on SVC mapping and PN localization. METHODS: Twenty-one atrial fibrillation patients undergoing cardiac enhanced computed tomography (CT) were prospectively enrolled. SVC geometries were created at the SVC-right atrium junction level with low (<10 × g) and high (>10 × g) CFs. The PN was localized by high-output pacing (10 V, 2 milliseconds) at the SVC and anterior right superior pulmonary vein (RSPV) with different CFs. RESULTS: The SVC cross-sectional area was significantly greater when created with high (22.1 ± 4.9 × g) compared with low CFs (4.2 ± 1.3 × g) (5.3 ± 1.4 cm2 vs. 2.3 ± 0.7 cm2 , P < 0.0001). High CFs distorted the SVC and anterior RSPV by a mean of 4.8 ± 2.5 and 4.4 ± 1.7 mm, with minimal distortion at the anteroseptal SVC. The PN was more frequently captured with a high compared with low CF at the SVC (95.2% vs. 71.4%, P = 0.038) and RSPV (66.7% vs. 14.3%, P = 0.0005). The PN capture area was also wider with a high compared with low CF at the SVC (9.0 ± 4.1 mm vs. 4.5 ± 2.8 mm, P = 0.001). The PN location was at the anterolateral, lateral, and posterolateral SVC in 3 (14.3%), 13 (61.9%), and 5 (23.8%) patients, respectively, which was identical to that identified on CT. No PNs located >1.98 mm from the RSPV were captured by RSPV pacing. CONCLUSIONS: CF impacted the SVC mapping and PN localization. Cardiac CT identified the PN location, and the distance from the pacing site influenced PN capture.

Cavotricuspid isthmus ablation using a catheter equipped with mini electrodes on the 8 mm tip: a prospective comparison with an 8 mm dumbbell-shaped tip catheter and 8 mm tip cryothermal catheter.

AIMS: The mini electrodes (ME) placed on the tip of the ablation electrode provide more precise local signal. We evaluated whether ME catheter was effective for the ablation of cavotricuspid isthmus (CTI)-dependent atrial flutter. METHODS AND RESULTS: Eighty-five consecutive patients (68 men; 62 ± 10 years) underwent CTI ablation either using a catheter equipped with ME on the 8 mm tip (ME catheter) in 25 patients (Group A), 8 mm dumbbell-shaped (DS) tip catheter (DS catheter) in 30 patients (Group B), or 8 mm tip cryothermal catheter (Cryo catheter) in 30 patients (Group C). In cases of failed isthmus block, the catheter was changed to the other catheter, but patients remained in the original group following intention-to-treat analysis. The endpoint was achieved in all patients after 13 ± 7 applications in Group A, 9 ± 4 applications in Group B, and 5 ± 2 applications in Group C (P < 0.001). The fluoroscopic and procedure times were significantly longer in Group A (9 ± 7 and 28 ± 17 min, P = 0.001, and P = 0.002, respectively) when compared with Groups B (6 ± 4 and 13 ± 6 min) and C (4 ± 3 and 14 ± 7 min). A crossover was performed in 14 (56%) Group A patients, and 3 (10%) Group C patients. The mean power delivered in Group A was significantly lower than in Group B (31.3 ± 9.1 vs. 38.6 ± 7.6 W, P = 0.015). CONCLUSION: The ME catheter was found to be less effective than the Cryo catheter and a DS catheter for the CTI ablation.

Early Recurrence After Pulmonary Vein Isolation of Paroxysmal Atrial Fibrillation With Different Ablation Technologies - Prospective Comparison of Radiofrequency vs. Second-Generation Cryoballoon Ablation.

BACKGROUND: Inflammation plays a prominent role in the etiology of the early recurrence of atrial fibrillation (ERAF). We prospectively compared the proportion of ERAF and time-course patterns of biomarkers between radiofrequency (RF) and cryoballoon (CB) ablation. METHODS AND RESULTS: We enrolled 82 consecutive paroxysmal AF patients undergoing pulmonary vein (PV) isolation, performed with either a 28-mm 2nd-generation CB and 3-min freeze technique or point-by-point RF ablation. Each group had 41 patients. In the RF group, all PVs were successfully isolated with 28.9 ± 6.5 min of RF delivery. In the CB group, a mean of 5.3 ± 1.4 applications/patient was delivered. The proportion of ERAF was similar between the groups. The time-course patterns significantly differed between the groups for high-sensitivity C-reactive protein (hs-CRP) value (P=0.006) and myocardial injury markers (P<0.0001). Greater myocardial injury was observed in the CB than in the RF group (P<0.0001), whereas the peak hs-CRP value was comparable between the groups. The 2-day post-procedure hs-CRP value was the sole factor correlating with ERAF as identified by the multivariable analysis (hazard ratio 1.697; 95% confidence interval, 1.005-2.865; P=0.048) in the RF, but not the CB group. CONCLUSIONS: The proportion of ERAF was comparable after RF and 2nd-generation CB ablation. Despite CB ablation exhibiting greater myocardial injury than RF ablation, the inflammatory responses were comparable between the groups. The inflammatory response extent predicted ERAF post-RF ablation but not post-CB ablation.

Left atrial appendage flow velocity after successful ablation of persistent atrial fibrillation: clinical perspective from transesophageal echocardiographic assessment during sinus rhythm.

BACKGROUND: Left atrial appendage flow velocity (LAAFV) is a predictor of thromboembolism in atrial fibrillation (AF) patients, as well as CHA2DS2-VASc score. However, little is known about LAAFV in sinus rhythm (SR) after catheter ablation. The aim of this study was to determine clinical predictors of low LAAFV in patients in whom stable SR had been maintained after catheter ablation for persistent AF. METHODS: The study comprised 104 patients with persistent AF (median AF duration 24 months) in whom SR had been achieved and maintained for at least 6 months after the final ablation procedure. Transesophageal echocardiography was performed to assess LAAFV during SR after ablation. Lower LAAFV was defined as ≤40 cm/s. RESULTS: Mean LAAFV before ablation was 29 ± 11 cm/s (range 10-67 cm/s). In 23 (22%) patients, LAAFV remained low even after being in SR for at least 6 months. Multiple logistic regression analysis showed that CHA2DS2-VASc scores of ≥2 (odds ratio 2.18, 95% CI 1.19-3.99, P = .012) was an independent predictor of lower LAAFV after successful ablation. Seventeen (74%) of the 23 patients with low LAAFV during SR presented CHA2DS2-VASc scores of ≥2 complicated by spontaneous echo contrast during AF. CONCLUSIONS: Long-term maintenance of SR after catheter ablation for persistent AF does not guarantee LAAFV recovery. The CHA2DS2-VASc score appears to predict poor recovery of LAAFV. Further studies are necessary to confirm the usefulness of LAAFV during SR as a surrogate marker predicting thromboembolism in patients after AF ablation.

Impact of Pulmonary Vein Isolation on Superior Vena Cava Potentials With a Second-Generation Cryoballoon.

BACKGROUND: Radiofrequency ablation of the right superior pulmonary vein (RSPV) can lead to inadvertent superior vena cava (SVC) isolation due to the close anatomical proximity. This study aimed to evaluate the impact of PV isolation on SVC potentials with a second-generation cryoballoon. METHODS: Thirty-one consecutive paroxysmal atrial fibrillation patients who underwent PV isolation exclusively with a 28 mm second-generation cryoballoon and single 3-minute freeze technique were prospectively enrolled. The produced SVC potential conduction delay during the RSPV isolation was prospectively evaluated using circular mapping catheters placed in the SVC throughout the cryoballoon procedure. RESULTS: Stable SVC potentials were recorded in 28 (90.3%) patients. The produced SVC potential conduction delay during the RSPV isolation was a median of 6.0 (0.5-7.6) milliseconds, and >5.0 milliseconds in 16 (57.1%) patients. Among them, the delay had shortened by >5.0 milliseconds in 7 (43.8%) patients within 5 minutes after the RSPV application. The distance between the RSPV ostium and SVC was the sole parameter correlated with the produced delay (R = 0.77, P < 0.0001). For the association between the distance and a produced delay of >5 milliseconds, the area under the curve was 0.896 (95% confidential interval = 0.775-1.000). The optimal cutoff point for the distance predicting the occurrence of the conduction delay (>5 milliseconds) was 2.5 mm (sensitivity 83.3%, specificity 81.2%). CONCLUSIONS: RSPV isolation with a second-generation cryoballoon could produce an SVC potential conduction delay. The anatomical distance between the RSPV and SVC significantly correlated with the impact.

Evaluation of diaphragmatic electromyograms in radiofrequency ablation of atrial fibrillation: prospective study comparing different monitoring techniques.

BACKGROUND: The utility of compound motor action potential (CMAP) monitoring for anticipating phrenic nerve injury (PNI) during cryoballoon ablation has been reported. We sought to compare two different CMAP recording techniques and evaluated the feasibility during pulmonary vein antrum isolation (PVAI) and superior vena cava isolation (SVCI) using radiofrequency energy. METHODS AND RESULTS: Forty-two patients undergoing paroxysmal atrial fibrillation ablation were prospectively enrolled. SVCI was performed following PVAI if SVC potentials were observed. CMAPs were recorded 3 times (before and after PVAI, and after SVCI) simultaneously from surface electrodes (CMAPsuf) and a decapolar catheter in the subdiaphragmatic hepatic vein (CMAPabd). The baseline CMAPsuf and CMAPabd were 0.92 ± 0.36 and 0.65 ± 0.43 mV except in one case with catheter inaccessibility. The CMAPsuf did not correlate with the body mass index, or CMAPabd. In 2 and 9 patients, the CMAPsuf and CMAPabd amplitudes were < 0.5 and < 0.3 mV, respectively. The diaphragm to catheter distance was significantly longer in cases with a CMAPabd < 0.3 mV than one > 0.3 mV (39.2 ± 10.8 vs. 21.5 ± 6.6 mm, P < 0.0001). Two cases with a CMAPsuf < 0.5 mV had larger amplitudes on the CMAPabd. In 1 patient, apparent PNI occurred during the SVCI, and the CMAP disappeared after the SVCI in both techniques. The CMAPs did not significantly decrease after the PVAI and SVCI; however, a >30% decrease was observed in 2 patients in both techniques. In both, no PNI was apparent on fluoroscopy or chest X-ray. CONCLUSIONS: Stable evaluable CMAPs were obtained with the CMAPsuf in most patients. Monitoring with the CMAPabd could be an alternative and complementary method.

Prospective Evaluation of Bilateral Diaphragmatic Electromyograms During Cryoballoon Ablation of Atrial Fibrillation.

BACKGROUND: Left phrenic nerve injury (PNI) can occur during cryoballoon ablation of the left pulmonary veins (PVs). This study aimed to evaluate the feasibility of monitoring the bilateral phrenic nerve function during cryoballoon ablation of atrial fibrillation (AF). METHODS: Fifty consecutive paroxysmal AF patients undergoing cryoballoon ablation using one 28-mm second-generation balloon were prospectively enrolled. Bilateral diaphragmatic compound motor action potentials (CMAPs) were obtained from modified surface electrodes by pacing from the bilateral subclavian veins, and monitored during 3-minute cryoballoon applications at the ipsilateral PVs. RESULTS: One hundred ninety of 202 PVs were successfully isolated exclusively using 28-mm cryoballoons. CMAPs could be obtained in all except 3 cases with catheter inaccessibility in the left subclavian vein. The left and right CMAP amplitudes were similar at baseline (1.04 ± 0.41 mV vs. 1.01 ± 0.43 mV, P = 0.49). Among 105 left and 132 right PV applications while monitoring CMAPs, 2 (1.9%) and 13 (9.8%) applications were interrupted for a decreased CMAP amplitude (P = 0.01). Among them, CMAPs decreased due to right PNI in 4 applications/patients and to catheter dislodgement in the remaining applications. PNI remained in 1 and recovered in the remaining 3 patients one day after the procedure. Applications without requiring interruptions exhibited no significant CMAP amplitude changes throughout the applications, and the time-course pattern was similar between the bilateral CMAPs (P = 0.292). CONCLUSIONS: A stable bilateral diaphragmatic CMAP could be similarly obtained during cryoballoon applications in the vast majority of patients. Monitoring CMAPs might be useful to anticipate not only right but also left PNI during cryoballoon ablation.

Adenosine Triphosphate Test After Cryothermal Pulmonary Vein Isolation: Creating Contiguous Lesions Is Essential for Eliminating Dormant Conduction.

BACKGROUND: Adenosine triphosphate (ATP) testing reveals dormant pulmonary vein (PV) conduction after electrical PV isolation (PVI). This study aimed to evaluate the incidence of latent PV conduction after cryothermal PVI. METHODS: Fifty-four consecutive paroxysmal atrial fibrillation patients undergoing cryothermal PVI were prospectively enrolled. PVI was performed with one 28-mm second-generation balloon using a 3-minute freeze technique, and touch-up lesions were created by focal cryothermal applications. ATP testing was performed following PVI with a 20-mm circular mapping catheter placed in each PV. RESULTS: Of 217 PVs, 205 (94.5%) were isolated using a cryoballoon, and 12 required additional focal ablation. ATP testing was performed in 46 patients for 173 and 8 PVs, which were isolated by cryoballoons and focal ablation, respectively. No dormant PV conduction was provoked in any PVs, which were isolated by cryoballoons, whereas 4 (50.0%) out of 8 PVs requiring focal ablation had transient ATP-provoked reconnections (0 vs. 50.0%, P < 0.0001) with a median duration of 11.3 (10.7-17.1) seconds. The latent PV conduction site was identical to the residual conduction gap site after cryoballoon ablation in all. All latent conduction was successfully eliminated by 2 (2.0-9.5) additional focal applications. At a mean follow-up of 7.7 ± 1.6 months, 81.5% of the patients were arrhythmia free after a single procedure. CONCLUSIONS: No dormant PV conduction was provoked in PVs, which were isolated by 28-mm second-generation cryoballoons, but was provoked in 50% of PVs, which were isolated by focal cryoablation. These findings suggest that creating contiguous lesions is essential for eliminating dormant conduction in cryothermal ablation.

Ventricular arrhythmias with superior axis originating from the left ventricular septum: electrocardiographic characteristics predicting successful ablation and insights into their mechanism-observations from a small series of patients.

AIMS: This study aimed to evaluate the electrocardiographic characteristics and predictors of successful ablation for ventricular arrhythmias (VAs) with superior axis originating in the ventricular septum. METHODS AND RESULTS: This study included 385 consecutive patients with VAs undergoing radiofrequency ablation (RFA). Of these, 14 patients (3.7%) were identified who had VAs with superior axis that were mapped to and ablated at the left ventricular (LV) septum. These patients were classified into two groups, successful (n = 9, Success-RFA) and failed (n = 5, Fail-RFA) ablation. The QRS duration of the VAs was longer in the Success-RFA than the Fail-RFA [median (25%, 75% quartile), 140 (134, 149) vs. 128 (116, 132) ms; P = 0.007]. In the Success-RFA, the QRS morphology in lead V1 exhibited qR or rSR (r < 0.2 mV) pattern. In the Fail-RFA, QRS in lead V1 demonstrated an initial R-wave of ≥0.2 mV except for one patient who demonstrated a qR pattern. The initial R-wave amplitude of <0.2 mV in lead V1 identified successful ablation cases with 100% sensitivity and 80% specificity. The magnitude of the initial R-wave amplitude in lead V1 could be related to the originating site's depth within the septal tissue, which could also explain the RFA results. CONCLUSION: Four percent of VA patients had superior axis on electrocardiogram and foci that mapped to the LV septum, two-thirds of which were successfully ablated. The initial R-wave amplitude of <0.2 mV in lead V1 identified RFA success with high sensitivity and specificity.

Catheter ablation of atrial tachyarrhythmias causing inappropriate implantable cardioverter-defibrillator shocks.

AIMS: Inappropriate shocks have been an important issue post-implantable cardioverter-defibrillator (ICD) implantation. Moreover, inappropriate ICD shocks are associated with increased mortality. The objective of this study was to evaluate the feasibility of catheter ablation therapy for atrial tachyarrhythmias (ATa) responsible for inappropriate ICD shocks. METHODS AND RESULTS: Among 108 consecutive patients who underwent ICD implantations, 22, 5, and 3 experienced inappropriate ICD shocks due to ATa, sinus tachycardia, and T-wave oversensing, respectively. Among the 22 patients with ATa, 18 patients (55 ± 10 years, 15 men, structural heart disease in 9) underwent catheter ablation of ATa causing inappropriate shocks. The median duration between the ICD implantation and first inappropriate shock was 10.0 (3.0-24.5) months. The ATa were atrial fibrillation (AF), atrial flutter (AFL), and atrioventricular nodal reentrant tachycardia in 14, 2, and 2 patients, respectively. One patient underwent an atrioventricular nodal ablation for persistent AF associated with a venous anomaly. Among 13 patients who underwent pulmonary vein antrum isolation, 10 (76.9%) were free from AF for a median of 21.0 (13-37.3) months after an average of 1.3 ± 0.5 procedures. In four patients with AFL or a supraventricular tachycardia, none had any arrhythmia recurrence for a median of 6.0 (3.3-93.5) months after a cavotricuspid isthmus or slow pathway ablation, respectively. There were no procedural complications. During the median follow-up of 19.0 (9.5-37.3) months after the last procedure, no patients experienced any inappropriate shocks. CONCLUSION: Catheter ablation is a feasible therapeutic option for treating ATa responsible for inappropriate shock(s) in patients with ICD.