Jin Iwasawa

Impact of the order of the targeted pulmonary vein on the vagal response during second-generation cryoballoon ablation.

BACKGROUND Radiofrequency applications around pulmonary vein (PV) ostia often induce vagal reflexes. OBJECTIVE This study aimed to evaluate the impact of the order of the targeted PV on the vagal response during second-generation cryoballoon ablation. METHODS Eighty-one consecutive paroxysmal atrial fibrillation (AF) patients undergoing cryoballoon ablation were prospectively enrolled. PV isolation was performed with one 28-mm second-generation balloon using a 3-minute freeze technique. In the first 39 patients, the left superior PV (LSPV) was initially targeted. In the second 42, the LSPV was targeted following the right PVs. RESULTS Baseline rhythms were sinus rhythm and AF in 34 and 5 patients in the first group, and 34 and 8 in the second group, respectively. In the first group, sinus bradycardia/arrest requiring back-up pacing occurred in 13 patients (38.2%) at a median of 41.0 (10.0-55.5) seconds after balloon deflation (90 [60-100] seconds post freezing), and pauses requiring pacing in 1 (20.0%) with AF. In the second group, no sinus bradycardia/arrest occurred throughout the procedure; however, atrioventricular block requiring back-up pacing occurred 21 seconds after balloon deflation in 1 patient in whom right superior PV (RSPV) ablation was performed for only 60 seconds owing to right phrenic nerve injury. The cycle length was similar at baseline and post PV isolation between the 2 groups, and significantly shorter during RSPV ablation (P < .0001) in both. In total, marked vagal responses were significantly higher in the first than second group (14/39 vs 1/42, P < .0001). CONCLUSIONS LSPV cryoballoon ablation often provoked marked vagal responses; however, preceding RSPV ablation markedly suppressed this response.

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. METHODSANDRESULTS 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.

Quantitative Analysis of the Isolation Area During the Chronic Phase After a 28-mm Second-Generation Cryoballoon Ablation Demarcated by High-Resolution Electroanatomic Mapping

Background—The post–second-generation cryoballoon (CB) ablation isolation area during the chronic phase has not been described. The aim of this study was to quantitatively evaluate the chronic-phase isolation area after 28-mm second-generation CB ablation and compare it to the estimated conventional radiofrequency circumferential pulmonary vein isolation (CPVI) line. Methods and Results—Thirty-two patients with paroxysmal atrial fibrillation underwent pulmonary vein (PV) isolation using second-generation CB. After a median of 6.0 (4.0–9.0) months, the PV isolation area was evaluated using high-resolution mapping (1-mm electrode, 2-mm interelectrode spacing; 527±99 points per map) and pacing techniques in all patients (17 with and 15 without arrhythmia recurrence beyond blanking period) and compared with estimated conventional radiofrequency CPVI area. PV reconnections were observed in 34 of 126 PVs (27.0%) among 21 of 32 patients (65.6%), which were eliminated by a median of 1.0 (1.0–3.0) focal radiofrequency application. The left- and right-sided PV antrum isolation area and nonablated posterior wall areas were 9.8±1.7, 8.1±2.3, and 17.0±6.1 cm2, respectively. The cryoablated areas were significantly smaller than the estimated conventional radiofrequency CPVI areas in all but the right inferior PV. The difference was highest in the left superior PV. In 2 patients (6.3%), recurrent atrial fibrillation originated from the foci identified at the left superior PV antrum outside the CB isolation area but inside the estimated conventional radiofrequency CPVI line. Conclusions—Although the PV isolation areas during the chronic phase after the second-generation CB ablation were generally wide, they were significantly smaller than the area encircled by the CPVI line except at the right inferior PV antrum. Recurrent atrial fibrillation could originate from the left superior PV antrum and could be isolated by a CPVI but not by a CB.

Clinical Significance of Early Recurrence After Pulmonary Vein Antrum Isolation in Paroxysmal Atrial Fibrillation – Insight Into the Mechanism –

BACKGROUND Early recurrence of atrial fibrillation (ERAF) is common after pulmonary vein antrum isolation (PVAI); however, the definition, study population, and lesion set are not uniform in prior studies. We examined ERAF for paroxysmal AF while complying with the definition in the latest guidelines. METHODSANDRESULTS We included 471 patients undergoing empirical PVAI for paroxysmal AF. ERAF was observed in 180 patients (38.2%) including 49, 16, and 115 within 3, 4-7 days, and 8-90 days, respectively, after the index procedure. ERAF (hazard ratio 6.872; 95% confidence interval 4.803-9.382; P<0.0001) was the strongest factor associated with recurrence beyond 3 months (LR) in the multivariable model, and ERAF patients had worse outcomes than those without, regardless of the time to the first ERAF episode. There were no significant differences in the prevalence of PV reconnections and non-PV foci among 29 and 62 patients, respectively, who underwent redo procedures for ERAF within and more than 3 months after the index procedure, and 21 who underwent redo procedures for LR. Re-ablation was associated with a greater freedom from LR (HR 0.443; 95% CI 0.230-0.854; P=0.015). CONCLUSIONS ERAF occurred in 38.2% of patients and was strongly associated with LR regardless of the time to the first ERAF episode. Re-ablation for ERAF significantly improved the freedom from recurrent atrial arrhythmias, regardless of the time to the first ERAF episode.

Simple Minimal Sedation for Catheter Ablation of Atrial Fibrillation

BACKGROUND Deep sedation or general anesthesia is generally used during atrial fibrillation (AF) ablation. The aim of this study was to report the safety and feasibility of minimal sedation during AF ablation. METHODS AND RESULTS One thousand and fifty-two AF ablation procedures in 819 patients (62 ± 11 years, 621 men, 506 paroxysmal) were included. Boluses of intravenous hydroxyzine pamoate and pentazocine were administered, with a maximal dose of 100 mg of hydroxyzine and 60 mg of pentazocine in response to pain. If the pain was intolerable or patients requested deeper sedation, moderate sedation using dexmedetomidine or propofol was introduced. Among 819 consecutive first procedures, the procedure was completed under minimal sedation in 795 (97.1%) patients without inotropic drugs or respiratory support, whereas in 20 (2.4%) patients, anesthesia was switched to moderate sedation due to pain. Patients requiring a switch to moderate sedation were significantly younger than those without (53.6 ± 2.3 vs. 62.6 ± 10.4, P<0.01). No procedures were abandoned due to adverse effects of sedation. Significant intra-procedural blood pressure decreases requiring inotropic drugs were not observed in any patients. Among 233 patients who underwent repeat procedures, 6 (2.6%) requested moderate sedation before the procedure. The mean procedure time was 151 ± 54 min. Cardiac tamponade, unrelated to sedation, was observed in 7 (0.66%) procedures. CONCLUSIONS Minimal sedation might be acceptable anesthesia in the vast majority of AF ablation procedures performed in electrophysiological laboratories.

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

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.

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.

Thromboembolic Risks of the Procedural Process in Second-Generation Cryoballoon Ablation Procedures: Analysis From Real-Time Transcranial Doppler Monitoring

Background Atrial fibrillation ablation is associated with substantial risks of silent cerebral events (SCEs) or silent cerebral lesions. We investigated which procedural processes during cryoballoon procedures carried a risk. Methods and Results Forty paroxysmal atrial fibrillation patients underwent pulmonary vein isolation using second-generation cryoballoons with single 28-mm balloon 3-minute freeze techniques. Microembolic signals (MESs) were monitored by transcranial Doppler throughout all procedures. Brain magnetic resonance imaging was obtained pre- and post-procedure in 34 patients (85.0%). Of 158 pulmonary veins, 152 (96.2%) were isolated using cryoablation, and 6 required touch-up radiofrequency ablation. A mean of 5.0±1.2 cryoballoon applications was applied, and the left atrial dwell time was 76.7±22.4 minutes. The total MES counts/procedures were 522 (426–626). Left atrial access and Flexcath sheath insertion generated 25 (11–44) and 34 (24–53) MESs. Using radiofrequency ablation for transseptal access increased the MES count during transseptal punctures. During cryoapplications, MES counts were greatest during first applications (117 [81–157]), especially after balloon stretch/deflations (43 [21–81]). Pre– and post–pulmonary vein potential mapping with Lasso catheters generated 57 (21–88) and 61 (36–88) MESs. Reinsertion of once withdrawn cryoballoons and subsequent applications produced 205 (156–310) MESs. Touch-up ablation generated 32 (19–62) MESs, whereas electric cardioversion generated no MESs. SCEs and silent cerebral lesions were detected in 11 (32.3%) and 4 (11.7%) patients, respectively. The patients with SCEs were older than those without; however, there were no significant factors associated with SCEs. Conclusions A significant number of MESs and SCE/silent cerebral lesion occurrences were observed during second-generation cryoballoon ablation procedures. MESs were recorded during a variety of steps throughout the procedure; however, the majority occurred during phases with a high probability of gaseous emboli.

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.

Outcomes of Ventricular Tachycardia Ablation Using Percutaneous Left Ventricular Assist Devices

Background— Although percutaneous left ventricular assist devices (pLVADs) facilitate mapping and ablation of hemodynamically unstable ventricular tachycardia (VT), there is limited data whether clinical outcomes are improved. We sought to retrospectively compare the outcomes of patients undergoing scar-related VT ablation with and without pLVAD support. Methods and Results— The study population comprised 194 patients (109 pLVAD and 85 non-pLVAD). The pLVAD group more often had dilated cardiomyopathy (33% versus 13%; P=0.001), New York Heart Association heart failure class ≥III (51% versus 25%; P<0.001), lower left ventricular ejection fractions (26±10% versus 39±16%; P<0.001), and electrical storm (49% versus 34%; P=0.04). Procedure times (422±112 versus 330±92 minutes; P<0.001), postablation VT inducibility (20% versus 7%; P=0.02), and length of subsequent hospitalization (median 6 versus 4 days; P=0.001) were all higher in the pLVAD group. During median follow-up of 215 days, the primary end point (recurrent VT, heart transplantation, or death) occurred in 36% of the pLVAD versus 26% of the non-pLVAD groups (P=0.14). After propensity matching for differences between groups, no differences were seen between groups for both acute procedural outcomes and the primary end point. Conclusions— In this large single-center scar-related VT ablation experience, despite the worse clinical status of the patients selected for pLVAD support, clinical outcomes were better than expected and were similar to healthier patients not receiving hemodynamic support. Patients with dilated cardiomyopathy presenting with electrical storm, advanced heart failure, and severe left ventricular dysfunction most frequently received hemodynamic support during VT ablation.