Mapping and ablation of left atrial roof-dependent tachycardias using an ultra-high resolution mapping system.

BACKGROUND: Left atrial roof-dependent tachycardias (LARTs) are common macroreentrant atrial tachycardias (ATs). We sought to characterize clinical LARTs using an ultra-high resolution mapping system. METHODS: This study included 22 consecutive LARTs in 21 patients who underwent AT mapping/ablation using Rhythmia systems. RESULTS: Three, 13, 4, and 2 LART patients were cardiac intervention naïve (Group-A), post-roof line ablation (Group-B), post-atrial fibrillation ablation without linear ablation (Group-C), and post-cardiac surgery (Group-D), respectively. The mean AT cycle length was 244 ± 43 ms. Coronary sinus activation was proximal-to-distal or distal-to-proximal in 16 (72.7%) ATs. The activation map revealed 13 (59.1%) clockwise and 9 (40.9%) counter-clockwise LARTs. A 12-lead synchronous isoelectric interval was observed in 10/19 (52.6%) LARTs. The slow conduction area was identified on the LA roof, anterior/septal wall, and posterior wall in 18, 6, and 2 ATs, respectively. Twenty concomitant ATs among 13 procedures were also eliminated, and peri-mitral AT coexisted in 7 of 9 non-group-B patients. In group-B, the conduction gap was predominantly located on the mid-roof. Sustained LARTs were terminated by a single application and linear ablation in 6 (27.3%) and 9 (40.9%), while converting to other ATs in 7 (31.8%) LARTs. Complete linear block was created without any complications in all, however, ablation at the mid-posterior wall was required to achieve block in 4 (18.2%) procedures. During 14.0 (6.5-28.5) months of follow-up, 17 (81.0%) and 19 (90.5%) patients were free from any atrial tachyarrhythmias after single and last procedures. CONCLUSIONS: The LART mechanisms were distinct in individual patients, and elimination of all concomitant ATs was required for the management.

Cryoballoon left atrial roof ablation for persistent atrial fibrillation-Analysis with high-resolution mapping system.

BACKGROUND: Additional benefit of cryoballoon left atrial roof line ablation (CB-RA) beyond cryoballoon pulmonary vein isolation (CB-PVI) is suggested in patients with persistent atrial fibrillation (PsAF). We sought to investigate the feasibility of CB-RA for PsAF and to determine the ablation area. METHODS AND RESULTS: Fifty-three PsAF patients (67[58.5-75.5] years, 36 men, 11 longstanding PsAF) underwent CB-PVI. Subsequently, 44(83.0%) out of 53 patients underwent additional CB-RA. Voltage maps were created in all patients with a high-resolution mapping system. The total number and duration of CB-RAs were 3.9 ± 0.7 and 468 ± 84 s. LA roof areas were complete low voltage areas (LVAs) /scar in 37/44(84.1%) patients ("complete roof modification"). The normal LA posterior wall (LAPW) voltage area was 6.1(4.1-8.4) cm2 , and the %LAPW isolation area was 61.0(47.2-71.7)%. The %LAPW isolation area was significantly greater in CB-RA patients than those without (64.0[54.2-73.2] vs. 45.0[39.5-50.5]%, p = .041) despite significantly larger LAs in the former group. The %LAPW isolation area was significantly greater in patients with transverse LA diameters < 45 mm than those ≥ 45 mm (p < .0001). The single procedure 1-year AF freedom was 87.4% (22.5% on antiarrhythmic drug) and tended to be higher in CB-RA patients than those without. Among the 44 CB-RA patients, it was significantly higher in patients with a complete roof modification than those without (94.4% vs. 75.0%, p = .0049). One CB-RA patient experienced a delayed cardiac tamponade requiring drainage at 4-months post-procedure. CONCLUSIONS: CB-RA significantly expanded the LAPW isolation area, and a complete roof modification resulted in a high arrhythmia freedom in PsAF patients.

The advantages and disadvantages of the novel fourth-generation cryoballoon as compared to the second-generation cryoballoon in the current short freeze strategy.

BACKGROUND: The novel fourth-generation cryoballoon (4th-CB) is characterized by a shorter-tip that potentially facilitates better time-to-isolation (TTI) monitoring. We sought to clarify the advantages and disadvantages of the 4th-CB compared to the second-generation cryoballoon (2nd-CB) in pulmonary vein isolation (PVI). METHODS: Forty-one and 49 consecutive atrial fibrillation patients underwent 2nd-CB and 4th-CB PVIs using 28-mm balloons and short freeze strategies. When effective freezing was not obtained, the CB was switched to the other CB. RESULTS: The rate of successful PVIs was significantly higher for 2nd-CBs than 4th-CBs (162/162[100%] vs. 178/193[92.2%] PVs, p < 0.0001). The difference was significant for lower PVs, especially right inferior PVs (RIPVs)(p = 0.005). In a total of 15 PVs in 11 patients, 4th-CBs were switched to 2nd-CBs, and 14/15(93.3%) PVs were successfully isolated. The balloon temperature tended to reach -55℃ more frequently with 2nd-CBs than 4th-CBs during RIPV ablations (15/41[36.6%] vs. 12/49[24.5%], p = 0.21). The TTI monitoring capability was significantly higher with 4th-CBs than 2nd-CBs (131/188[69.7%] vs. 83/160[51.9%] PVs, p = 0.0007). The difference was significant for right superior and left inferior PVs, but not for left superior PVs. Even if PVs requiring crossover were excluded, the total freeze duration (715±152 vs. 755±215 seconds, p = 0.31) tended to be shorter for 2nd-CBs than 4th-CBs. The incidence of phrenic nerve injury was similar for 2nd-CB and 4th-CB ablation (0/41 vs. 2/49, p = 0.12) CONCLUSIONS: The 4th-CB's shorter balloon tip enabled a significantly higher capability of TTI monitoring; however, it resulted in significantly lower rates of successful PVIs than the 2nd-CB, especially for the RIPVs.

Superior vena cava isolation using a novel ablation catheter incorporating local impedance monitoring.

BACKGROUND: A novel technology able to measure the local impedance (LI) during radiofrequency ablation has become available for clinical use. We investigated the change in the LI characteristics during superior vena cava isolations (SVCIs) using a novel catheter equipped with mini-electrodes. METHODS: Twenty paroxysmal atrial fibrillation patients (68 ± 9 years; 14 males) underwent an SVCI by targeting breakthroughs. Subsequently, dormant conduction provoked by adenosine triphosphate (ATP) was evaluated. RESULTS: Electrical SVCIs were successfully achieved in all with 7.2 ± 3.0 radiofrequency applications (RFA) without any complications. The procedure and fluoroscopic times were 13.1 ± 8.1 and 2.8 ± 2.3 min. No ablation was required at the anteroseptal SVC in 19 (95.0%) patients. The baseline LI and generator impedance (GI) were 125 ± 23 and 105 ± 14Ω. LI drops during RFA were significantly greater than GI drops (17 ± 12 vs. 4 ± 4Ω, p < 0.001). The correlation between the LI drops and GI drops was relatively high (R = 0.69, p < 0.001). LI drops were highest at the septal SVC and lowest at the lateral followed by antero-lateral SVC. The baseline electrogram amplitude between the mini-electrodes and tip-ring electrodes was 1.2 ± 1.4 and 0.8 ± 0.6 mV. The mini-electrode amplitude is more sharply attenuated with a greater magnitude than the tip-ring amplitude (p < 0.001). ATP-provoked dormant conduction was exposed in 10/17 (58.8%) patients and antero-lateral SVC gap locations in 7. Antero-lateral SVC LI drops were similar between patients with and without dormancy. CONCLUSIONS: The LI drop magnitude during RFA significantly differed among the SVC segments. Antero-lateral SVC ATP-provoked dormant conduction was often exposed, and additional applications are recommended following the isolation for a robust SVCI.

Predictive impacts of chronic kidney disease and cardiac sympathetic nervous activity on lethal arrhythmic events in chronic heart failure.

BACKGROUND: The clinical implications of chronic kidney disease (CKD) and cardiac sympathetic nervous activity (CSNA) regarding lethal arrhythmic events have not yet been fully elucidated in patients with chronic heart failure (CHF). We hypothesized that the combination of CKD and abnormal CSNA, assessed by 123 I-metaiodobenzylguanidine (123 I-MIBG) scintigraphy, may provide useful prognostic information for lethal arrhythmic events. METHODS: We studied 165 consecutive hospitalized CHF patients without dialysis. Cardiac 123 I-MIBG scintigraphy was performed in a clinically stable condition, and abnormal CSNA was defined as a late heart-to-mediastinum ratio of <1.6. CKD was defined as an estimated glomerular filtration rate of <60 ml/min/1.73 m2 . We then investigated the incidence of lethal arrhythmic events (sustained ventricular tachyarrhythmia, appropriate implantable cardioverter-defibrillator therapy, or sudden cardiac death). RESULTS: During a median follow-up of 5.3 years, lethal arrhythmic events were observed in 40 patients (24.2%). The patients were divided into four groups according to the presence of CKD and CSNA abnormality: non-CKD/normal CSNA (n = 52), CKD/normal CSNA (n = 39), non-CKD/abnormal CSNA (n = 33), and CKD/abnormal CSNA (n = 41). Kaplan-Meier analysis showed that CKD/abnormal CSNA had the highest event rate (log-rank p = .004). Additionally, the Cox proportional hazard analysis revealed that CKD/abnormal CSNA was a predictor for lethal arrhythmic events compared with non-CKD/normal CSNA (hazard ratio, 5.368, p = .001). However, the other two groups did not show significant differences compared with the non-CKD/normal CSNA group. CONCLUSIONS: The combination of CKD and abnormal CSNA, assessed by 123 I-MIBG scintigraphy, had a high predictive value for lethal arrhythmic events in patients with CHF.

The impact of electrical connections between left ipsilateral pulmonary veins on the time-to-isolation values in cryoballoon ablation.

BACKGROUND: The time-to-isolation (TTI) may be a physiological predictor of durable isolations, and TTI-guided dosing strategies are widely performed in cryoballoon ablation. We sought to investigate the impact of the order of targeting the pulmonary veins (PVs) on the TTI values of left ipsilateral PVs. METHODS: This study included 144 atrial fibrillation patients who underwent PV isolations using 28-mm fourth-generation cryoballoons. In 101 patients, the left superior PV (LSPV) was targeted and followed by the left inferior PV (LIPV) (group 1), and the LIPV was targeted and followed by the LSPV in the remaining 43 (group 2). RESULTS: The total LSPV and LIPV freeze durations were 193 ± 60 and 171 ± 40 s, respectively. Real-time PV isolation monitoring was capable in 137 (95.1%) LSPVs and 119 (82.6%) LIPVs and in 112 (77.8%) patients (78 in group 1 and 34 in group 2) in both LSPVs and LIPVs. Among them, the LSPV TTI was significantly longer in group 1 than that in group 2 (54.8 ± 32.1 vs. 34.1 ± 17.3 s, p < 0.0001), while the LIPV TTI was significantly shorter in group 1 than that in group 2 (23.7 ± 11.8 vs. 39.2 ± 19.4 s, p < 0.0001). The ΔTTI ((TTI in LSPV)-(TTI in LIPV)) was significantly greater in group 1 than that in group 2 (31.1 ± 31.4 vs. - 5.0 ± 25.9 s, p < 0.0001). In 5 patients (3 in group 1 and 2 in group 2), initially targeted left PVs were not isolated despite complete vein occlusions, while they were by subsequent applications at the other ipsilateral PVs. CONCLUSIONS: In CB ablation, the order of targeting PVs highly influenced the TTI of the left PVs owing to the presence of electrical connections between left ipsilateral PVs.

The feasibility and safety of substrate modification on the left atrial roof area using a cryoballoon in atrial fibrillation ablation.

BACKGROUND: Data on additional substrate modification using a cryoballoon beyond cryoballoon pulmonary vein isolation (CB-PVI) is limited. We sought to evaluate the efficacy and safety of substrate modification on the left atrial roof area using CBs (LAR-CBs) for atrial fibrillation (AF) patients. METHODS: Eighty-one AF patients (70.0[62.5-77.0] years, 33 paroxysmal AF[PAF], 48 non-PAF) underwent LAR-CBs following CB-PVIs. Voltage maps were created with a high-resolution mapping system. Roof line conduction block was evaluated during the repeat procedure. RESULTS: The total number of applications for the CB-PVI and LAR-CB were 5.0 ± 1.2 and 3.8 ± 0.7, and both were significantly greater in non-PAF than PAF patients. LA roof areas had continuous scar in 61/79(77.2%) patients, and the mean balloon temperature was significantly lower in patients with continuous scar than those without (-39.3 ± 3.8 vs. -36.0 ± 4.6 °C, p = 0.004). The single procedure 1-year AF freedom was 87.6% (7.5% on antiarrhythmic drug) and was similar between PAF and non-PAF patients (p = 0.14). Twelve (14.8%) patients underwent a second procedure 5.5(2.2-7.5) months later, and a mean of 1.3 ± 0.5 PVs were reconnected in 7/12(58.3%) patients. Electrical conduction block across the roof line was proven in 3/12(25.0%) patients. There were 6(7.4%) complications related to the procedures, including iatrogenic roof dependent atrial tachycardia, takotsubo cardiomyopathy, and severe pericarditis in 1, 1, and 2 patients, respectively. CONCLUSIONS: LA roof area substrate modification using CBs yielded a high arrhythmia freedom after single procedures. However, a low incidence of electrical conduction block across the line during the chronic phase and delayed complications were the major concerns.

Discrepancy between CARTO and Rhythmia maps for defining the left atrial low-voltage areas in atrial fibrillation ablation.

Reported mapping procedures of left atrial (LA) low-voltage areas (LVAs) vary widely. This study aimed to compare the PentaRay®/CARTO®3 (PentaRay map) and Orion™/Rhythmia™ (Orion map) systems for LA voltage mapping. This study included 15 patients who underwent successful pulmonary vein isolation (PVI) for atrial fibrillation. After PVI, PentaRay and Orion maps created for all patients were compared. LVAs were defined as sites with ≥ 3 adjacent low-voltage points < 0.5 mV. LVAs were indicated in 8 (53%) among 15 patients, and the average values of the measured LVAs was comparable between the systems (PentaRay map = 5.4 ± 8.7 cm2; Orion map = 4.3 ± 6.4 cm2, p = 0.69). However, in 2 of 8 patients with LVAs, the Orion map indicated LVAs at the septum and posterolateral sites of the LA, respectively, whereas the PentaRay map indicated no LVAs. In those patients, sharp electrograms of > 0.5 mV were properly recorded at the septum and posterolateral sites during appropriate beats in the PentaRay map. The PentaRay map had a shorter procedure time than the Orion map (12 ± 3 min vs. 23 ± 8 min, respectively; p < 0.01). Our study results showed a discrepancy in the LVA evaluation between the PentaRay and Orion maps. In 2 of 15 patients, the Orion map indicated LVAs at the sites where > 0.5-mV electrograms were properly recorded in the PentaRay map.

Mapping and ablation of clinical spontaneous perimitral atrial tachycardias using an ultra-high-resolution mapping system.

BACKGROUND: Perimitral atrial tachycardias (PMATs) are common atrial tachycardias (ATs), yet their mechanisms vary. OBJECTIVE: The purpose of this study was to characterize clinical spontaneous PMATs using an ultra-high-resolution (UHR) mapping system. METHODS: The study included 32 consecutive PMATs in 31 patients who had undergone AT mapping/ablation using a UHR mapping system. RESULTS: Six, 10, 11, and 5 PMATs occurred in cardiac intervention-naïve (group A), post-lateral/posterior mitral isthmus linear ablation (group B), post-atrial fibrillation ablation without mitral isthmus linear ablation (group C), and post-cardiac surgery (group D) patients, respectively. Group A patients tended to be older, more likely were female, and had sinus node or atrioventricular conduction disturbances more frequently. A 12-lead synchronous isoelectric interval was observed in 15 PMATs (46.9%). Coronary sinus activation was proximal to distal or distal to proximal except in 3 PMATs with straight patterns due to epicardial gaps. Left atrial anterior/septal wall (LAASW) low-voltage areas were smallest in group B. Slow conduction areas (SCAs) were identified in 26 PMATs (81.2%) and were located on the LAASW in all group A and group D patients. Conduction velocity in the SCAs was slowest in group B. In group B, all PMATs were terminated by single applications, and the gaps were located epicardially in 5 of 10 (50%). Anterior (n = 23) or lateral/posterior (n = 9) mitral isthmus linear block was successfully created without any complications in all. Twenty-five concomitant ATs among 18 patients (58.1%) also were eliminated. During a median of 20.0 (11.0-40.0) months of follow-up, 28 patients (90.3%) were free from any atrial tachyarrhythmias. CONCLUSION: An UHR mapping-guided approach with identification of the individual tachycardia mechanism should be the preferred strategy given the distinct and complex arrhythmia mechanisms.

Clinically Manifesting Air Embolisms in Cryoballoon Ablation: Can Novel Water Buckets Reduce the Risk?

Air embolisms can lead to lethal results; however, few reports have systemically investigated this issue. Of 348 consecutive patients with atrial fibrillation who underwent cryoballoon ablation, procedures were performed conventionally in 251 patients. In the remaining 97 patients, a water bucket was used while inserting the cryoballoon into the sheath. A total of 10 coronary air embolisms with ST-segment elevation in the inferior leads were observed among 9 (2.6%) patients. Multiple air bubbles were identified in 2 patients on emergent coronary angiography. All recovered under conservative treatment without any sequela. The incidence decreased when using the water bucket (1 of 97 [1.03%] vs. 8 of 251 [3.2%], p = 0.454).

Cryothermal atrial linear ablation in patients with atrial fibrillation: An insight from the comparison with radiofrequency atrial linear ablation.

BACKGROUND: Atrial linear lesions are generally created with radiofrequency energy. We sought to evaluate the feasibility of cryothermal atrial linear ablation. METHODS AND RESULTS: Twenty-one atrial fibrillation (AF) patients underwent linear ablation on the left atrial (LA) roof, mitral isthmus (MI), and cavotricuspid isthmus (CTI) with 8-mm-tip cryocatheters following pulmonary vein isolation. The data were compared with those of 31 patients undergoing linear ablation with irrigated-tip radiofrequency catheters. Conduction block was successfully created in 18 of 20 (90%), 9 of 21 (43%), and 20 of 20 (100%) on the LA roof, MI, and CTI by endocardial cryoablation alone with 19.0 (12.0-24.0), 30.0 (23.0-34.0), and 14.0 (14.0-16.0) minute cryo applications, respectively. The presence of either an interposed circumflex artery or pouch at the MI was significantly associated with failed MI block (P = .04). Conduction block was created in 25 of 31 (83.9%), 27 of 31 (87.1%), and 30 of 31 (96.8%) on the roof, MI, and CTI, respectively, by radiofrequency ablation. During the 17.5 (13.0-31.7) months of follow-up, freedom from AF/atrial tachycardia (AT) was significantly higher in the cryo group (P = .05); especially, recurrent AT was more frequent in the RF group (8/31 vs 1/21; P = .03). Conduction block across the roof, MI, and CTI was durable in 6 of 12 (50.0%), 4 of 12 (33.3%), and 9 of 12 (75.0%) patients during second procedures. All nine patients (except one) with recurrent ATs had at least one roof or MI conduction resumption. CONCLUSIONS: Cryoablation is effective for creating a roof and CTI linear block, however, creating MI block by endocardial ablation alone was often challenging. Conduction resumption of LA linear block is common and recurrent arrhythmias, especially iatrogenic ATs, are more frequently observed after radiofrequency linear ablation.

The mechanisms of recurrent atrial arrhythmias after second-generation cryoballoon ablation.

BACKGROUND: In patients with paroxysmal atrial fibrillation (PAF), 10%-15% of patients require repeat procedures after second-generation cryoballoon pulmonary vein isolation (CB-PVI). We sought to explore the mechanisms of recurrences after cryoballoon ablation. METHODS: The data of 122 PAF patients who underwent second procedures for recurrent arrhythmias 7.0 (4.0-12.0) months after the CB-PVI were analyzed. During second procedures, non-PV AF foci were explored with isoproterenol, adenosine, and repetitive cardioversions. RESULTS: In total, 378/487 (77.6%) PVs remained isolated, and reconnections were not observed in any PVs in 59 (48.4%) patients. PV reconnections were associated with recurrences in 38 (31.1%) patients, of whom 33 (86.8%) had reconnections of at least 1 upper PV. In 6 (4.9%) patients, non-PV AF foci were identified in the upper PV antra where cryoballoons cannot isolate but within the circumferential radiofrequency PVI line. Non-PV AF foci were identified in the superior vena cava, right atrial body, left atrial body, and atrial septum in 28 (23.0%), 18 (14.7%), 4 (3.3%), and 5 (4.1%) patients, respectively. Twelve (9.8%) patients had multiple non-PV AF foci. Four (3.3%), 3 (2.4%), and 8 (6.5%) patients underwent second procedures for atrioventricular nodal reentrant tachycardia, atrial flutter, and atrial tachycardias. During 16.0 (8.0-24.0) months of follow-up, freedom from any atrial arrhythmia at 1 year and 2 years after the second procedure was 79.2% and 60.6%. Nineteen (15.5%) patients had antiarrhythmic drug therapy at the last follow-up. CONCLUSIONS: Our study suggested that improvement in the upper PV PVI durability, eliminating arrhythmogenic superior vena cavae and coexisting atrial arrhythmias, and bonus cryoballoon applications at PV antra might improve the single procedure outcome in cryoballoon ablation.

Temperature drop in thawing phase reflects sufficient ice formation and better outcome of pulmonary vein isolation using second-generation cryoballoon.

BACKGROUND: Few reports exist regarding the details of ice formation on second-generation cryoballoon (CB) surface during pulmonary vein isolation (PVI). We propose a new parameter "temperature drop" in thawing phase for predicting sufficient ice formation and CB-PVI outcome. METHODS: Consecutive 106 patients who underwent successful CB-PVI for atrial fibrillation (AF) were analyzed. We defined "temperature drop" as a temperature drop of more than 3 °C just after CB catheter bending. We compared the previously known parameters predicting durable PVI between PVs with or without temperature drop. Then, we compared the PVI outcome among three groups: group 1 with temperature drop in all PVs, group 2 with temperature drop in 1-3 PVs, and group 3 without temperature drop in any PV. RESULTS: Temperature drop was present in 206 out of 424 isolated PVs. In those, PV occlusion score was significantly higher (3.7 ± 0.5 vs. 3.5 ± 0.6, P <0.001), and thawing time was significantly longer (55 ± 20 vs. 46 ± 21 s, P < 0.001) in PVs with temperature drop than those without. With a mean follow up period of 376 ± 217 days, Kaplan-Meier survival analysis revealed that no patients in group 1 experienced AF recurrence, 14 out of 86 patients (16%) experienced AF recurrence in group 2, and 5 out of 10 (50%) patients experienced AF recurrence in group 3 (Log-Rank P = 0.003). CONCLUSION: The temperature drop in thawing phase might reflect the state of ice formation and can be used to predict clinical outcome after CB-PVI.

Predicting factors of transmural thermal injury after cryoballoon pulmonary vein isolation.

PURPOSE: Transmural thermal injury (TTI), such as esophageal erosion/ulcer and periesophageal nerve injury leading to gastric hypomotility, is not rare complications associated with pulmonary vein isolation (PVI). However, the mechanism and predicting factors of TTI have not yet been fully elucidated with second-generation cryoballoon (CB) PVI. METHODS: One hundred ten consecutive patients, who underwent CB PVI for atrial fibrillation and received esophagogastroduodenoscopy 2 days later, were investigated. The relationships between TTI and both clinical and anatomical parameters were examined. We measured the following parameters based on the computed tomography data: the angle of the left atrial (LA) posterior wall to the descending aorta (Ao) (LA-Ao angle); the branching angle of the left inferior pulmonary vein (LIPV) to the coronal plane (LIPV angle); and the minimum distance between the LA posterior wall and descending Ao enclosing the esophagus (LA-Ao distance). RESULTS: TTIs occurred in 19 patients (esophageal erosion in 2 and gastric hypomotility in 17). The patients with TTI were significantly older than those without TTI. In the anatomical parameters, the LIPV angle was larger and the LA-Ao distance was shorter in the TTI (+) group compared to the TTI (-) group. With the multivariate logistic regression analysis, the age (odds ratio [OR] 2.148, P = 0.022) and LA-Ao distance (OR 0.430, P = 0.013) were independent predictors of TTI. CONCLUSIONS: The occurrence of TTI in CB PVI was associated with aging, suggesting compromised periesophageal circulation, and the anatomical proximities between the LA and the descending Ao, which enclose the esophagus.

Clinical impact of insulin resistance on pulmonary vein isolation outcome in patients with paroxysmal atrial fibrillation.

INTRODUCTION: The relationship between insulin resistance and atrial fibrillation (AF) recurrence after pulmonary vein isolation (PVI) remains unclear. METHODS: Drug-refractory 114 paroxysmal AF patients (89 males, 62 ± 8 years) who underwent successful PVI were enrolled. Homeostasis model assessment of insulin resistance (HOMA-IR) was calculated and a value of ≥2.5 was defined as insulin resistant. The left atrial volume index (LAVI) was measured using echocardiography before and 1 year after PVI. Tumor necrosis factor-α (TNF-α) and TGF-ß1 serum levels were measured before PVI, and the left atrium (LA) conduction velocity was calculated. The patients were divided into two groups (group 1: HOMA-IR < 2.5, n = 81; group 2: HOMA-IR ≥ 2.5, n = 33). RESULTS: The LAVI between the two groups before PVI did not significantly differ (P > 0.05), nor did TNF-α (7.7 ± 2.0 vs 7.5 ± 1.0 pg/mL; P = 0.149) or TGF-ß1 (28.4 ± 12.0 vs 27.6 ± 10.3 ng/mL; P = 0.757). LAVI before and 1 year after PVI in each group did not change. The conduction velocity of group 2 was slower than that of group 1 (0.7 ± 0.1 vs 1.1 ± 0.3 m/s, P < 0.001). Kaplan-Meier analysis showed significantly higher AF recurrence in group 2 than that in group 1 ( P = 0.019). Cox multivariable analysis revealed that insulin resistance was an independent predictor of recurrence (hazard ratio 1.287, P = 0.004). CONCLUSION: Our results suggest that insulin resistance promotes LA electrical remodeling and might be related to AF recurrence after PVI.

Anatomical predisposing factors of transmural thermal injury after pulmonary vein isolation.

Aims: Transmural thermal injury (TTI), such as oesophageal erosion/ulcer and perioesophageal nerve injury leading to gastric hypomotility, is an important complication associated with pulmonary vein isolation (PVI). However, a predictor of TTI concerning anatomical structures surrounding the oesophagus has not yet been fully elucidated. Therefore, we sought to identify the predisposing factors of TTI after PVI. Methods and results: Consecutive 110 patients, who underwent PVI for atrial fibrillation, received oesophagogastroduodenoscopy 2 days later, were investigated. The relationships between TTI and clinical and anatomical parameters were examined. Based on the computed tomography data, we measured the angle of the left atrial (LA) posterior wall to the descending aorta (Ao) (LA-Ao angle), the branching angle of the left inferior pulmonary vein (LIPV) to the coronal plane (LIPV angle), and the minimum distance between the LA posterior wall and descending Ao enclosing the oesophagus (LA-Ao distance). Transmural thermal injuries occurred in 21 patients (oesophageal erosion in 5 and gastric hypomotility in 16). Age, gender, body mass index, LA diameter, and LA volume index in echocardiography were not associated with TTI. However, the LIPV angle was larger and the LA-Ao distance was shorter in the TTI (+) group compared to the TTI (-) group. With multivariate logistic regression analysis, the LIPV angle [odds ratio (OR): 2.144, P = 0.0031] and LA-Ao distance (OR: 0.392, P = 0.0229) were independent predictors of TTI. Conclusion: The anatomical proximities of the LA posterior wall, LIPV, and descending Ao surrounding the oesophagus are strongly associated with the prevalence of TTI.

Mapping Strategy Associated with QRS Morphology for Catheter Ablation in Patients with Idiopathic Ventricular Outflow Tract Tachyarrhythmia.

BACKGROUND: In catheter ablation of idiopathic ventricular arrhythmia (VA), it is still unclear whether pace mapping or activation mapping is more useful for successful catheter ablation. The depth of origin in the ventricular wall especially affects the success rate of endocardial-approached catheter ablation. Thus, we examined the relationship between these tactics and QRS morphology. METHODS: We evaluated the relationship among pace mapping score, activation time, and peak deflection index (PDI) in 28 patients, with a total of 30 origins, who underwent successful catheter ablation of idiopathic VA. RESULTS: All origins were located in the ventricular outflow tract area, including three in the left coronary cusp (LCC). PDI, activation time, and pace mapping score at successful ablation sites were 0.60 ± 0.08, 26.3 ± 9.9 ms, and 19.1 ± 4.6, respectively. The pace mapping score inversely correlated with the PDI (R = -0.540, P = 0.0017), but the activation time did not correlate with the PDI. When excluding the three VAs originating from the LCC, in which perfect pace mapping was obtained from epicardial sites despite high PDI, this correlation coefficient became more intensive (R = -0.734, P < 0.0001). CONCLUSIONS: Our study suggests that pace mapping with an endocardial approach could not reproduce the precise QRS morphology for VA originating from the intramural site of the ventricular wall. With such origins, we should rely on activation mapping to detect the optimal ablation site.