Takatsugu Kajiyama

Estimation of the origin of ventricular outflow tract arrhythmia using synthesized right-sided chest leads

AIMS For successful ablation of ventricular outflow tract arrhythmia, estimation of its origin prior to the procedure can be useful. Morphology and lead placement in the right thoracic area may be useful for this purpose. Electrocardiography using synthesized right-sided chest leads (Syn-V3R, Syn-V4R, and Syn-V5R) is performed using standard leads without any additional leads. This study evaluated the usefulness of synthesized right-sided chest leads in estimating the origin of ventricular outflow tract arrhythmia. METHODS AND RESULTS This retrospective study included 63 patients in whom successful ablation of ventricular outflow tract arrhythmia was performed. Numbers of arrhythmias originating from the left ventricle, the septum of the right ventricle, and the free wall of the right ventricle were 11, 40, and 13, respectively. In one patient, two different left ventricular outflow tract origins were found. Electrocardiographic recordings from right-sided chest leads were divided into three types as follows: those in which an R > S concordance, a transitional zone, or an R < S concordance were detected. In all left arrhythmia cases, R > S concordance was observed. A transitional zone was evident in 34 of 40 cases of right ventricular outflow tract arrhythmia originating in the ventricular septum, and an R < S concordance was observed in 6 of the 40 cases. However, an R < S concordance was found in all cases of right ventricular outflow tract arrhythmia originating in the free wall. CONCLUSION Synthesized right-sided chest lead electrocardiography may be useful for estimating the origin of ventricular outflow tract arrhythmia.

Gastric hypomotility after second-generation cryoballoon ablation—Unrecognized silent nerve injury after cryoballoon ablation

BACKGROUND Few data are available on gastric hypomotility (GH) after cryoballoon pulmonary vein isolation. Also, the use of esophageal temperature monitoring for the prevention of endoscopically detected esophageal lesions (EDELs) is not well established. OBJECTIVE The purpose of this study was to investigate GH and the impact of an esophageal probe on EDELs during second-generation cryoballoon ablation. METHODS One hundred four patients with paroxysmal atrial fibrillation undergoing second-generation cryoballoon ablation under conscious sedation followed by esophagogastroscopy were prospectively included. Temperature probes were used in the first 40 (38.5%) patients, but not in the latter 64 (61.5%). Pulmonary vein isolation was performed with one 28-mm balloon using single 3-minute freeze techniques. RESULTS Clinical and procedural characteristics were similar between the groups. Esophagogastroscopy 1.4 ± 0.5 days postablation demonstrated GH and EDELs in 18 (17.3%) and 9 (8.7%) patients. The incidence of GH was similar (7 of 40 vs 11 of 64; P = .967) between the groups, while that of EDELs was significantly higher in the former than in the latter group (8 of 40 vs 1 of 64; P < .0001). In multivariate analyses, the esophagus-right inferior pulmonary vein ostium distance (hazard ratio 0.870; 95% confidence interval 0.798-0.948; P = .002) was the sole predictor of GH, and the optimal cutoff for the prediction was 18.2 mm (sensitivity 88.1%; specificity 77.8%). The use of esophageal probes was the sole predictor of EDELs (hazard ratio 15.750; 95% confidence interval 1.887-131.471; P = .011). All collateral damage was asymptomatic and healed on repeat esophagogastroscopy at a mean of 2 ± 1 months postprocedure. CONCLUSION Second-generation cryoballoon ablation is associated with an increased incidence of silent periesophageal nerve injury even using short freeze times, and anatomical information aids identifying high-risk populations. The use of esophageal probes increases the risk of EDELs.

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.

Evaluation of periesophageal nerve injury after pulmonary vein isolation using the 13C-acetate breath test

Pulmonary vein isolation (PVI) has become an important option for treating patients with atrial fibrillation (AF). Periesophageal nerve (PEN) injury after PVI causes pyloric spasms and gastric hypomotility. This study aimed to clarify the impact of PVI on gastric motility and assess the prevalence of gastric hypomotility after PVI.

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

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.

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

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.

Impact of catheter ablation of atrial fibrillation on long-term clinical outcomes in patients with heart failure

BACKGROUND Heart failure (HF) promotes atrial fibrillation (AF) and AF worsens HF. This study aimed to investigate the long-term clinical outcomes after AF ablation in patients with HF. METHODS AND RESULTS A total of 106 consecutive HF patients, including 51 (48.1%) with a reduced left ventricular ejection fraction (LVEF) (HFrEF) and 55 (51.9%) with a preserved LVEF (HFpEF), underwent AF ablation. All patients underwent successful pulmonary vein antrum isolation, and substrate modification was added in 38 (35.8%). The mean follow-up period was 32.4±18.6 months, and mean number of procedures was 1.4±0.5 per patient. Low-dose antiarrhythmic drugs were combined in 29 (27.3%) patients. Freedom from recurrent atrial arrhythmias (ATa), HF-related hospitalizations, and the composite endpoint (all-cause death, stroke, HF-related hospitalizations) at 3 years was 88.7%, 97.6%, and 97.6% in HFrEF patients, and 79.3%, 96.2%, and 91.8% in HFpEF patients, respectively. LVEF normalization (≥50%) was observed in 37 (72.5%) HFrEF patients post-ablation, and a smaller LV diastolic diameter (LVDd) was the sole predictor [odds ratio (OR)=0.863; 95% confidence interval (CI)=0.779-0.955, p=0.005]. Shortening of the LVDd (≥5mm) was observed in 16 (29.1%) HFpEF patients post-ablation, and no recurrence after the initial procedure was the sole predictor (OR=6.229; 95% CI=1.524-25.469, p=0.011). CONCLUSIONS Catheter ablation of AF could be one of the important therapeutic options in the management of patients with HF combined with AF regardless of the type of HF.

Atrioventricular conduction disturbance during pulmonary vein isolation using the second-generation cryoballoon — Vagal impact of cryoballoon ablation

BACKGROUND Vagal reactions of the sinus node during pulmonary vein isolation (PVI) have been reported, however, data on intra-procedural atrioventricular conduction disturbances have been sparse. The present study aimed to investigate the clinical characteristics of atrioventricular conduction block (AVB) during PVI using second-generation cryoballoons. METHODS A total of 2252 PVs among 568 consecutive atrial fibrillation patients undergoing PVI with 28-mm cryoballoons were analyzed. In 44 patients, left superior PVs (LSPVs) were initially targeted (initial-LSPV-group). In the remaining 524 patients, LSPVs were targeted following right superior PVs (RSPVs) (initial-RSPV-group). RESULTS Marked sinus arrests/bradycardia occurred in 14 patients only in the initial-LSPV-group, and the incidence was significantly higher in the initial-LSPV than initial-RSPV-group (14/44 vs. 0/524, p < 0.001). Intra-procedural AVB with 3.6 [1.9-8.2] second maximal RR intervals appeared in 12 patients during freezing (n = 1) or after balloon deflation following freezing (n = 11). The targeted PVs were the LSPV, left common PV, right inferior PV, and RSPV in 8, 1, 2, and 1 patients, respectively. The incidence was similar between the initial-LSPV and initial-RSPV-groups (1/44 vs. 11/524, p = 0.938). Four patients exhibited complete AVB with more than a 6 s maximal RR interval. Three patients experienced AVB during atrial fibrillation. AVB was observed a median of 23.0 [15.0-70.0] seconds after balloon deflation and 76.0 [60.0-125.0] seconds after freezing termination. AVB persisted for 56.0 [36.0-110.0] seconds, and all recovered spontaneously with or without requiring back-up pacing. CONCLUSIONS A marked transient AV conduction disturbance could occur after balloon deflation, especially during LSPV ablation, regardless of the order of targeted PVs.

Silent cerebral events/lesions after second-generation cryoballoon ablation: How can we reduce the risk of silent strokes?

BACKGROUND Atrial fibrillation (AF) ablation is associated with a substantial risk of silent cerebral events/lesions (SCEs/SCLs) detected on magnetic resonance imaging (MRI). OBJECTIVE The purpose of this study was to investigate the factors associated with the incidence of SCEs/SCLs during second-generation cryoballoon ablation. METHODS Two hundred fifty-six AF patients underwent brain MRI 1 day after pulmonary vein (PV) isolation using second-generation cryoballoons with a single 28-mm balloon and short freeze strategy. RESULTS Overall, 991 of 1016 PVs (97.5%) were successfully isolated by 4.9 ± 1.3 cryoballoon applications per patient, and 25 PVs required touch-up radiofrequency ablation. The total procedure time was 72.7 ± 26.1 minutes. SCEs and SCLs were detected in 68 (26.5%) and 27 (10.5%) patients, respectively. None of the patients reported any neurologic symptoms. Reinsertion of once withdrawn cryoballoons and subsequent applications significantly increased the incidence of SCEs (odds ratio [OR] 2.057; 95% confidential interval [CI] 1.051-4.028; P = .035), and additional left atrial mapping with a multielectrode catheter significantly increased the incidence of SCLs (OR 3.317; 95% CI 1.365-8.056; P = .008). Transient coronary air embolisms were significantly associated with the incidence of SCLs (OR 3.447; 95% CI 1.015-11.702; P = 0.047). On the contrary, an uninterrupted anticoagulation regimen, use of radiofrequency deliveries for transseptal access, cryoballoon air removal with extracorporeal balloon inflations, strength of the MRI magnet, internal electrical cardioversion, and touch-up ablation were not associated with the incidence of SCEs/SCLs. CONCLUSION A significant number of SCE/SCL occurrences was observed after second-generation cryoballoon ablation procedures. These results suggest that air embolisms are the main mechanism of SCEs/SCLs, and the injected air volume might determine the lesion type.

Circulatory Dynamics During Pulmonary Vein Isolation Using the Second‐Generation Cryoballoon

Background Circulatory dynamics change during pulmonary vein (PV) isolation using cryoballoons. This study sought to investigate the circulatory dynamics during cryoballoon‐based PV isolation procedures and the contributing factors. Methods and Results This study retrospectively included 35 atrial fibrillation patients who underwent PV isolation with 28‐mm second‐generation cryoballoons and single 3‐minute freeze techniques. Blood pressures were continuously monitored via arterial lines. The left ventricular function was evaluated with intracardiac echocardiography throughout the procedure in 5 additional patients. Overall, 126 cryoapplications without interrupting freezing were analyzed. Systolic blood pressure (SBP) significantly increased during freezing (138.7±28.0 to 148.0±27.2 mm Hg, P<0.001) and sharply dropped (136.3±26.0 to 95.0±17.9 mm Hg, P<0.001) during a mean of 21.0±8.0 seconds after releasing the occlusion during thawing. In the multivariate analyses, the left PVs (P=0.008) and lower baseline SBP (P<0.001) correlated with a larger SBP rise, whereas a higher baseline SBP (P<0.001), left PVs (P=0.017), lower balloon nadir temperature (P=0.027), and female sex (P=0.045) correlated with larger SBP drops. These changes were similarly observed regardless of preprocedural atropine administration and the target PV order. PV occlusions without freezing exhibited no SBP change. PV antrum freezing without occlusions similarly increased the SBP, but the SBP drop was significantly smaller than that with occlusions (P<0.001). The SBP drop time‐course paralleled the left ventricular ejection fraction increase (66.8±8.1% to 79.3±6.7%, P<0.001) and systemic vascular resistance index decrease (2667±1024 to 1937±513 dynes‐sec/cm2 per m2, P=0.002). Conclusions With second‐generation cryoballoon‐based PV isolation, SBP significantly increased during freezing owing to atrial tissue freezing and dropped sharply after releasing the occlusion, presumably because of the peripheral vascular resistance decrease mainly by circulating chilled blood.