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Background: Optimal overlap ratio remains unclear in point-by-point laser balloon (LB) ablation. Objective: This study sought to determine the optimal overlap strategy with target energies on the acute and chronic outcomes in LB pulmonary vein (PV) isolation (PVI). Methods: Consecutive 38 patients (148 PVs) with atrial fibrillation underwent the first-generation LB PVI with the following protocols based on the overlap ratios for each PV anterior/posterior wall: 50%/50% (13 patients [49 PVs], group A), 50%/25% (15 patients [60 PVs], group B), and 25%/25% (10 patients [39 PVs], group C). High energies (240–255 J: 12 W / 20 seconds, 8.5 W / 30 seconds), moderate energies (200–210 J: 10 W / 20 seconds, 7 W / 30 seconds), and low-to-moderate energies (low, 165–170 J: 5.5 W / 30 seconds, 8.5 W / 20 seconds) were targeted for left PV anterior walls, right PV anterior walls, and bilateral PV posterior walls, respectively. First-pass PVI, the other procedure-related data, and atrial tachyarrhythmia recurrences were analyzed. Results: First-pass PVI rate per PV was higher in group A (94%) than in group B (88%) and group C (62%) (P < .001). All PVs were finally isolated. First-pass time, total LB PVI time, complications, and atrial tachyarrhythmia recurrences during a mean follow-up of 11 ± 5 months did not differ between the groups. A few residual gaps after first-pass LB ablations were found for PV anterior walls even in group A and group B. Conclusion: Sufficiently overlapped LB ablation promises a high rate of first-pass PVI without adverse outcomes. High energy could be required for PV anterior walls.

The lesion formation properties of a motorized rotational delivery (RAPID) mode, third-generation laser balloon (LB3) ablation compared to point-by-point laser ablation in patients with atrial fibrillation remain unclear.The purpose of this study was to assess lesion characteristics and thermodynamics in LB3 ablation with a RAPID modeChicken muscles were cauterized using LB3 in RAPID mode with 13 W and 15 W and 50% overlapped point-by-point fashion with 7 W/30 seconds, 8.5 W/20 seconds, 10 W/20 seconds, and 12 W/20 seconds. Lesion depth, width, and continuity were compared. Lesion continuity was classified by the visible gap degree categorized from 1 (perfect) to 3 (poor). Thermodynamics and maximum tissue temperatures were assessed under infrared thermographic monitoring. Fifteen and 5 lesions were evaluated per ablation protocol for measurement of lesion size and continuity and for thermographic assessment, respectively.Lesion depth and width were smaller in RAPID mode laser ablation than point-by-point laser ablation (RAPID mode LB3 ablation could provide fast, gapless, and acceptable lesion formation with thermal stacking and moderate tissue temperature rise.

An 83-year-old male with complete atrioventricular block underwent dual-chamber pacemaker implantation. Venography showed normal anatomy of the left axillary vein. Following sedation with intravenous propofol, local anesthesia, and skin incision, we punctured the left axillary vein on the first limb. However, the guidewire could not be advanced despite blood backflow after the initial puncture. On venography, left axillary vein on the first limb totally disappeared with dilated collaterals. We diagnosed axillary vein spasm and injected 1000 μg of intravenous nitroglycerin. After 15 min, repeated venography showed slight contrast flow in the axillary vein. We alternatively punctured the axillary vein on the second limb. However, the axillary vein was spasmodically occluded again. We considered the possibility that puncture of the right axillary vein could also result in venous spasm. Since the left cephalic vein was identified after waiting time, we partially cut down the left cephalic vein and inserted guidewires into the vein. The ventricular and atrial leads were successfully implanted through sheaths in the right ventricular septum and right atrial appendage, respectively. LEARNING OBJECTIVE: Pacemaker implantation complicated with puncture-related axillary vein spasm is challenging. Severe venous spasms refractory to waiting time or nitroglycerin sometimes require conversion of access site. However, the bail-out technique from ipsilateral access remains unclear. Cut-down technique of the ipsilateral cephalic vein is one alternative to manage severe axillary vein spasm refractory to nitroglycerin and waiting time.

INTRODUCTION Lesion size and continuity in dragging laser balloon (LB) ablation, which may enable fast and durable pulmonary vein isolation for atrial fibrillation, are unknown. We evaluated the differences in size and continuity of linear lesions formed by dragging ablation and conventional point-by-point ablation using an LB in vitro model. METHODS AND RESULTS Chicken muscles were cauterized using the first-generation LB in dragging and point-by-point fashion. Dragging ablation was manually performed with different dragging speeds (0.5-2°/s) using an overlap ratio of the beginning and last site during one application at 12 W/20 s and 8.5 W/30 s. Point-by-point ablation was performed with 25% and 50% overlap ratios at six energy settings (5.5 W/30 s to 12 W/20 s). Lesion depth, width, and continuity were compared. Lesion continuity was assessed by the surface and deep visible gap degree categorized from 1 (perfect) to 3 (poor). Twenty lesions were evaluated for each ablation protocol. Lesion depth and width in dragging ablation at high power (12 W) were comparable with most measurements in point-by-point ablation. Lesion depth and width were smaller at faster-dragging speed and lower power (8.5 W) in dragging ablation. The surface visible gap degree was better in dragging ablation at all dragging speeds than a 25% overlapped point-by-point ablation (p

Identification of a conduction gap between the left atrium and pulmonary vein (LA-PV gap) and the circuit of atrial tachycardia after pulmonary vein isolation (PVI) is an important process during the second ablation for atrial fibrillation (AF). The high-density mapping system RHYTHMIA® is useful for identification of an LA-PV gap and the circuit of atrial tachycardia. Therefore, this study was performed to investigate the effect of RHYTHMIA® in terms of the outcome of the second ablation for AF. One hundred patients underwent a second ablation for AF in our institute from April 2015 to December 2018. We retrospectively evaluated 49 patients using RHYTHMIA® (group 1) and 51 patients using the conventional method with additional anatomical guide by CARTO® system. In group 1, we performed redo PVI for 41 patients with 49 LA-PV countable gaps and ablation for other atrial arrhythmias in 7 patients. In group 2, we performed redo PVI in 40 patients with 33 LA-PV countable gaps and ablation for other atrial arrhythmias in 9 patients. Three and two unstable arrhythmias in each group were not ablated. The final recurrence of atrial arrhythmia was significantly lower in group 1 than 2 (8/49 (16%) vs. 17/51 (33%), respectively; P = 0.017). Atrial arrhythmias other than AF after the second ablation occurred in only one patient in group 1 but seven patients in group 2. Using high-density mapping for the second ablation of AF was found to be superior to the conventional ablation method in terms of the suppression of atrial events in this study. This technique warrants further investigation.

Introduction: Cardiac sympathetic activity is involved in the initiation and maintenance of atrial fibrillation. A novel technique that evaluates the atrial accumulation of 123I-MIBG may be able to assess the atrial sympathetic innervation. The purpose of this study was to visually evaluate the modification of sympathetic innervation caused by multiple catheter ablations. Methods: The total study cohort comprised 32 patients with atrial fibrillation. 21 patients underwent only one ablation using a balloon catheter (cryoballoon in 10 patients; hot balloon in 11 patients) (group 1), while 11 patients underwent multiple radiofrequency catheter ablation procedures (three procedures in 6 patients; four procedures in 5 patients) (group 2). In all patients, the left atrial sympathetic activity was evaluated using MIBG images obtained using a novel solid-state whole-body scanner (VERITON). For local quantitative evaluation, the site with the strongest discrete MIBG accumulation was automatically recognized by the computer and compared in pre- and post-procedural images. Results: In all patients, the total left atrial MIBG accumulation value after ablation (6.64х10 4 ±1.65х10 4 PROPCNTS) was significantly lower than that before ablation (7.74х10 4 ±2.25х10 4 PROPCNTS, p=0.0289). At the site with the strongest discrete MIBG accumulation, the MIBG accumulation after ablation was decreased in 19 patients, unchanged in 9, increased in 3, and shifted in 1. The total left atrial MIBG accumulation value before ablation was significantly lower in group 2 (5.74х10 4 ±1.40х10 4 PROPCNTS) than group 1 (6.67х10 4 ±1.57х10 4 PROPCNTS, p=0.0485). Conclusions: The MIBG accumulation in the left atrium decreased after catheter ablation. Furthermore, preoperative evaluation revealed a significant decrease in MIBG accumulation after multiple ablation procedures. This suggests that multiple catheter ablation of the left atrium modifies the sympathetic innervation.

Heart rate information from a smartwatch can facilitate the diagnosis and treatment of SVT. Benefitting from long‐term HR trends, we performed successful RF catheter ablation of coexisting AVNRT and AVRT.

The prognostic predictors of death or heart failure hospitalization and the echocardiographic response after initial cardiac resynchronization therapy (CRT) device replacement (CRT-r) remain unclear. We evaluated the predictors and the echocardiographic time course in patients after CRT-r. Consecutive 60 patients underwent CRT-r because of battery depletion. Patients were divided into two groups depending on the chronic echocardiographic response to CRT (left ventricular end-systolic volume [LVESV] reduction of ≥ 15%) at the time of CRT-r: CRT responders (group A; 35 patients) and CRT nonresponders (group B; 25 patients). The primary endpoint was a composite of death from any cause or heart failure hospitalization. Changes in LVESV and left ventricular ejection fraction (LVEF) after CRT-r were also analyzed. During the mean follow-up of 46 ± 33 months after CRT-r, the primary endpoint occurred more frequently in group B (group A versus group B; 8/35 [23%] patients versus 19/25 [76%] patients, p

The techniques for successful pacemaker implantation via the PLSVC with the SelectSecure system (Medtronic, Minneapolis, Minnesota, USA) are unknown. Regarding the techniques, we presented a case in which we implanted a pacemaker via the PLSVC in patient with absent RSVC using the SelectSecure system.

INTRODUCTION The influence of power (Watt [W]) and total energy (Joule [J]) on lesion size and the optimal overlap ratio remain unclear in laser balloon (LB) ablation for atrial fibrillation. We aimed to evaluate lesion size and visible gaps after LB ablation with various energy settings and different overlap ratios in vitro model. METHODS AND RESULTS Chicken muscles were cauterized using the first-generation LB with single applications of full and a half duration of six energy settings (5.5 W/30 seconds [165 J] to 12 W/20 seconds [240 J]) and varying power (5.5-12 W) at the constant total energy (160 J). Three overlapped ablations with different ratios (25% and 50%) for each energy setting were also performed to evaluate the visible gap degree categorized from 1 (perfect) to 3 (poor). Twenty lesions were evaluated for each energy setting. In single applications of full duration, lesion depth, lesion volume, and maximum lesion diameter increased according to the total energy (all, P

AimsLeft atrial appendage electrical isolation (LAAI) may improve the rhythm outcome in selected patients with atrial fibrillation (AF). Controversy exists if LAAI is associated with an increased rate of thromboembolic complications. We sought to assess the feasibility, efficacy, and safety of interventional left atrial appendage closure (LAAC) in comparison to oral anticoagulation (OAC) after electrical LAAI.Methods and resultsWeeks after index LAAI using the cryoballoon or a linear maze like ablation strategy patients’ left atrial appendage was invasively remapped. In case of persistent LAAI, LAAC was performed. Patients who refused invasive remapping continued OAC. The primary endpoint was composed of any stroke or systemic embolism (SE) and the occurrence of intracardiac thrombus. Secondary endpoints included stroke/SE, major bleeding, and all-cause death. Of 166 patients (51% female; mean age 70 ± 8 years; mean CHAD2S2VASc score 3.4 ± 1.8) after LAAI, 94 patients received LAAC (LAAC group) and 72 continued OAC (no LAAC). After LAAC, 83% of patients received dual antiplatelet therapy for 6 weeks and aspirin thereafter. During a mean follow-up of 778 ± 630 days, 5 and 11 primary endpoint events were observed in the LAAC and no LAAC group, respectively [hazard ratio (HR) 0.27, 95% confidence interval (CI) 0.10–0.75; P = 0.010]. The calculated annual thromboembolic event rates were 6.9% (no LAAC) and 2.3% (LAAC), respectively. Left atrial appendage closure significantly reduced the incidence of stroke and SE (HR 0.31, CI 0.1–0.98; P = 0.04).ConclusionAfter electrical LAAI for rhythm control in AF patients, interventional LAAC was associated with fewer thromboembolic complications when compared with OAC.

Background The left atrial appendage (LAA) has been identified as a potential source of atrial fibrillation (AF) and has been described as the "fifth" pulmonary vein (PV). We report our initial experience in LAA isolation (LAAI) using the cryoballoon (CB) and data on durability of CB-LAAI. Methods Patients treated with a CB-LAAI were retrospectively identified. Six weeks after electrical LAAI, patients were scheduled for staged percutaneous LAA closure. During the second procedure, a subset of patients underwent invasive remapping of the LAA. Results A total of 32 patients (21 males, 68 ± 10 years old) were treated with CB-LAAI. Acute LAAI was achieved in 29 of 32 (91%) patients: single-shot LAAI was observed in 18 of 32 (56%) patients. Acute procedural sustained LAAI was related with a significantly shorter time to LAAI (sustained LAAI: 84 ± 50 s vs nonsustained LAAI: 166 ± 76 s, P = 0.004). Mean procedure and fluoroscopy time were 61 ± 29 and 8 ± 6 min, respectively. One left-sided phrenic nerve palsy occurred. In 25 of 32 (78%) patients, a second procedure for percutaneous LAA closure device implantation was performed. In 22 patients, persistency of LAAI was tested: durable LAAI was documented in 16/22 patients (73%). Conclusion In the present report, CB LAA isolation followed by staged LAA closure appeared to be safe and feasible but more data are required. Time to LAAI played a role in predicting acute sustained LAAI rate. CB LAA ablation leads to 73% of durable LAA isolation.

Introduction Pulmonary vein isolation (PVI) is the cornerstone ablation strategy for treatment of atrial fibrillation (AF). Ablation outside the PVs is sometimes needed particularly in persistent or longstanding AF. This study reported left atrial appendage isolation (LAAI) using cryoballoon (CB) focusing on technical data and short-term clinical follow-up. Methods and results Patients with recurrent persistent AF after multiple AF procedures were enrolled. LAAI was performed using the second generation CB guided by compound motor action potential (CMAP) and 240 seconds plus bonus freeze (ICE-B) protocol. Ten patients were included, median age was 69.5 (56-73) years, CHA2 DS 2 -VASc score was 3 (1.8-4), LA diameter was 44 (38.8-46.5) mm. All patients had a mean of three AF procedures before the LAAI procedure. All patients were under successful CMAP guidance. During the CB LAAI procedure, the median time to LAA isolation was 100 (76-270) seconds, minimal freeze temperature was -50 (-57 to -47)°C. A "pull-down (or pull-away)" CB maneuver was performed in all patients. Median fluoroscopic time was 4.8 (3.4-6.8) minutes and acute LAAI success rate was 100%. No phrenic nerve injury or other major complications were observed. At 6-week follow-up, remapping of the LAA showed durable isolation of all PVs (100%), all patients were scheduled for LAA occlusion. Six-month follow-up showed that 80% of patients were free from AF/AT recurrence. Conclusion CMAP plus ICE-B guided LAAI using cryo-technology appears feasible and safe, results in durable LAAI, and shows promising clinical results in patients with recurrent persistent AF.

application/pdf, The body surface area (BSA) of animals has generally been estimated by multiplying the k value by the measured body weight (BW) raised to the power of 2/3 (Meeh’s formula). In mathematical terms, the assumption that the density and body shape of animals are essentially constant means that the BSA is proportional to BW2/3. In this study, we measured the BSA and volume of 50 male Japanese White rabbits (JW) at 10 to 54 weeks of age using a computed tomography scanner, then calculated the k value, density, and sphericity. The variations in these parameters were then analyzed in relation to growth. The obtained results indicated that the k value was negatively correlated to BW, and that this negative correlation was mainly due to the variation in density. Based on the regression analysis, we propose the following linear regression equation for calculating the k value in male JW at 10–54 weeks of age: the k value = 14.602 − 0.959 × BW [kg]. The calculated values ranged from 10.9 to 12.7 (working BW range: 1.98 to 3.81 kg). The k value of male New Zealand White rabbits (NZW) determined in our previous study and that of male JW in the present study were compared. It was revealed that the k value of male JW was larger than that of male NZW. We concluded that different breeds of rabbits express different k values.

Background: Pulmonary vein isolation (PVI) represents the cornerstone in atrial fibrillation ablation. Cryoballoon and laserballoon catheters have emerged as promising devices but lack randomized comparisons. Therefore, we sought to compare efficacy and safety comparing both balloons in patients with persistent and paroxysmal atrial fibrillation (AF). Methods: Symptomatic AF patients (n=200) were prospectively randomized (1:1) to receive either cryoballoon or laserballoon PVI (cryoballoon: n=100: 50 paroxysmal atrial fibrillation + 50 persistent AF versus laserballoon: n=100: 50 paroxysmal atrial fibrillation + 50 persistent AF). All antiarrhythmic drugs were stopped after ablation. Follow-up included 3-day Holter-ECG recordings and office visits at 3, 6, and 12 months. Primary efficacy end point was defined as freedom from atrial tachyarrhythmia between 90 and 365 days after a single ablation. Secondary end points included procedural parameters and periprocedural complications. Results: Patient baseline parameters were not different between both groups. In all (n=200) complete PVI was obtained and the entire follow-up accomplished. Balloon only PVI was obtained in 98% (cryoballoon) versus 95% (laserballoon) requiring focal touch-up in 2 and 5 patients, respectively. Procedure but not fluoroscopy time was significantly shorter in the cryoballoon group (50.9±21.0 versus 96.0±20.4 minutes; P P =0.083). Overall, the primary end point of no atrial tachyarrhythmia recurrence was met in 79% (cryoballoon: 80.0% versus laserballoon: 78.0%, P =ns). No death, atrio-esophageal fistula, tamponade, or vascular laceration requiring surgery occurred. In the cryoballoon group, 8 transient but no persistent phrenic nerve palsy were noted compared with 2 persistent phrenic nerve palsy and one transient ischemic attack in the laserballoon group. Conclusions: Both balloon technologies represent highly effective and safe tools for PVI resulting in similar favorable rhythm outcome after 12 months. Use of the cryoballoon is associated with significantly shorter procedure but not fluoroscopy time.

The body surface area (BSA) of animals is generally estimated by multiplying the k value (constant) by the measured body weight (BW) raised to the power of 2/3 (Meeh's formula). Computed tomography (CT) scanners generate detailed 3-dimensional (3D) images of objects, and image analysis does not depend on operator skill. Therefore, the analysis of CT images provides accurate and reproducible BSA measurements. In this study, we measured the BSA of 25 male Hartley guinea pigs from 3 to 36 weeks of age (working BW range: 0.233 to 1.160 kg) using a CT scanner and 3D analysis software. We concluded that the k value for male Hartley guinea pigs was 8.37, based on the mean k value of the 25 animals.

BACKGROUND Time-to-isolation (TTI) guided second-generation cryoballoon (CB2) ablation has been shown to be effective for pulmonary vein isolation (PVI). OBJECTIVE The objective of this paper is to compare the safety and clinical outcome of CB2 PVI using the TTI guided 4 minutes vs 3 minutes freeze protocol. METHODS This was a propensity-matched study based on an institutional database. Symptomatic atrial fibrillation (AF) patients who underwent CB2 PVI and systematic follow-up were consecutively included. RESULTS A total of 573 patients were identified, of them 214 (107 matched-pairs) symptomatic AF (paroxysmal AF: 61%, persistent AF: 39%) patients (age: 67.7 ± 11.2 years) were analyzed. The baseline characteristics were comparable between the two groups. Procedural time was significantly longer in the 4 minutes group compared to 3 minutes group (67.2 ± 21.8 vs 55.9 ± 16.9 minutes, P

Aims We aimed to assess the feasibility, efficacy and safety of short-term dual antiplatelet therapy (DAPT) for six weeks after left atrial appendage closure (LAAC). Methods and results Data of the Cardioangiologisches Centrum Bethanien-LAAC registry were analysed. DAPT (aspirin 100 mg plus clopidogrel 75 mg) was administered until transoesophageal echocardiography (TEE) evaluation six weeks after LAAC. In the absence of significant peri-device flow or device-related thrombus (DRT), the medication was decreased to single antiplatelet therapy (SAPT). Outpatient visits were timed at six-month intervals. The incidences of major bleeding (BARC ≥3) and of thromboembolic events were investigated. A total of 298 patients (76±8 years; 62% male; CHA2DS2-VASc 4.3±1.5; HAS-BLED 3.5±1.0; 61% with history of bleeding) with successful LAAC were included. TEE revealed DRT in 7/298 (2.3%) patients (five at six-week follow-up [FU] 45±10 days after implant, two during a median long-term FU of 731 days). Non-procedure-related bleeding events occurred in 25/298 (8.4%) patients and non-procedure-related thromboembolic events in 11/298 (3.7%) patients. This translated into 3.9 bleeding events/100 patient-years and 1.7 thromboembolic events/100 patient-years, respectively. Procedure-related events consisted of major bleeding in 7/298 (2.3%) patients and stroke in 2/298 (0.7%) patients. Age ≥75 years (OR 3.2; CI: 1.2-8.0; p=0.015) and renal impairment (OR 2.5; CI: 1.1-5.7; p=0.027) were identified as independent predictors for major bleeding after LAAC. Conclusions Short-term DAPT for six weeks appears to be a viable alternative for patients after LAAC. Age ≥75 years and renal impairment increase major bleeding events threefold.

application/pdf, The body surface area (BSA) of an organism is one of the important parameters for evaluating physiological functions. In drug development, normalization by BSA is an appropriate method for extrapolating doses between species. The BSA of animals has generally been estimated by multiplying the k value by 2/3 of the power of the body weight (BW) (Meeh’s formula). In mathematics, if it is assumed that the density and body shape of the animals are essentially constant, the BSA is proportional to BW2/3. In this study, we measured the BSA and volume (V) of 72 laboratory rabbits (48 males and 24 females of New Zealand White rabbits [NZW]), using a computed tomography scanner. After BSA and V determination, the k value, density, and sphericity were calculated. We analyzed variations in the k value, density, and body shape of laboratory rabbits. The mean k value of the 72 NZW was 11.0. We advocate using Meeh’s formula, as follows, for estimating BSA of laboratory rabbits (NZW): 100 × BSA [m2] = 11.0 × BW [kg]2/3. © 2018 Japanese Association for Laboratory Animal Science.

Introduction The ablation strategy for atrial fibrillation (AF) despite pulmonary vein isolation (PVI) is controversial. Left atrial appendage isolation (LAAI) may contribute to improve outcome. We describe an ablation approach (“Maze-like”-LAAI) that (1) modifies the underlying LA substrate by linear ablation (2) eliminates the LAA as a putative AF trigger site and (3) incorporates an unambiguous procedural endpoint. The role of LAA closure (LAAC) after LAAI was investigated. Methods Patients with atrial tachyarrhythmias non-responsive to PVI underwent a LAAI ablation procedure. LAAI was achieved by combining a) an anterior line, b) a LA roof line and c) a mitral isthmus line. Patients continued oral anticoagulation (OAC) therapy or underwent LAAC ≥6 weeks after LAAI. Results Maze-like LAAI was attempted in our center in 107/3611 AF ablation procedures (2.9%) and achieved in 88/107 patients (82%). In 8/107 (7%) patients cardiac tamponade occurred, all managed conservatively. During follow-up sinus rhythm was established in 65% at one year. After LAAI, 45 patients remained on OAC and 40 underwent LAAC. In both groups 1 patient experienced a bleeding complication. Thromboembolism exclusively occurred in the OAC group in 3 (7%) patients. Conclusion LAA isolation by Maze-like substrate modification may be considered a viable option for PVI non-responders. It offers a reproducible approach with an unambiguous procedural endpoint and leads to a favorable clinical outcome. However, extensive LA ablation increased the risk of tamponade. Consecutive LAA occlusion may offer a non-pharmacologic strategy to overcome the high thromboembolic risk associated with absent mechanical LAA contraction. This article is protected by copyright. All rights reserved

application/pdf, The use of miniature pigs in non-clinical studies for medical drugs or devices has gradually been increasing in recent years. It is anticipated that the use of juvenile miniature pigs in laboratory practice will also increase. Therefore, it is important to investigate various parameters of juvenile miniature pigs. The body surface area (BSA) of an organism is one of the important parameters for evaluating physiological functions. In drug development, normalization by BSA is an appropriate method for extrapolating doses between species. The BSA of animals has generally been estimated by multiplying the k value by 2/3 of the power of the body weight (BW) (Meeh’s formula). To our knowledge, the BSA of juvenile miniature pigs has not as yet been reported. In this study, we measured the BSA of 13 miniature pigs less than 1 month old, using a computed tomography scanner and 3-dimensional analysis software. The measurement results showed the BSAs of these 13 juvenile miniature pigs to be in the range of 386 to 1,672 cm2(working BW range: 278 to 3,200 g). After BSA determination, the k values were calculated from the BSA and the BW. The mean calculated k value was 8.58. We advocate using Meeh’s formula, as follows, for estimating the BSA of juvenile miniature pigs less than 1 month old (before weaning): BSA (cm2)=8.58 × BW (g)2/3. © 2017 Japanese Association for Laboratory Animal Science.

Background The ablation index (AI) is reported to be useful for a durable pulmonary vein isolation (PVI). However, there have been no studies investigating the relationship between the power, contact force (CF), AI, and steam pops. Methods Using an in vitro model, ablation energy was delivered until a steam pop occurred and the time to the steam pop and AI when the steam pop occurred were measured. The experiment was performed with a combination of various powers (20, 30, 40, and 50 W) and contact forces (CFs) (10, 30, and 50 g) 20 times for each setting. The analysis consisted of two protocols. The first protocol was a comparison between the ablation power and several parameters under the same CF (10, 30, and 50 g). The second protocol was a comparison between the CF and several parameters under the same power (20, 30, 40, and 50 W). The correlation between the lesion formation and ablation parameters was evaluated. Results The AI value when steam pops occurred varied depending on the ablation settings. All AI median values were

application/pdf, The body surface area (BSA) of an organism is an important parameter for evaluating physiological functions. In drug development, normalization by BSA is an appropriate method for extrapolating doses between species. The BSA of animals has generally been estimated by multiplying a constant by the power of the body weight (BW). Recently, the use of miniature pigs in non-clinical studies for medical drugs or devices has gradually been increasing. However, verification of their BSA is not as yet sufficient. In this study, we measured the BSAs of 40 laboratory miniature pigs (11 males and 9 females of Göttingen minipig and 14 males and 6 females of Nippon Institute for Biological Science [NIBS] miniature pig) by analyzing computed tomography (CT) images, since measurements using a CT scanner were expected to more precisely determine BSA than classical measuring techniques. The measurement results showed the BSAs of the 20 Göttingen minipigs to range from 0.4358 to 0.8356 m2 (the working BW range: 12.7-37.0 kg) and 20 NIBS miniature pigs to range from 0.2906 to 0.8675 m2 (the working BW range: 7.9-41.5 kg). Since accuracy and reproducibility were confirmed by measuring the surface area of an acrylic cuboid, we concluded the measurement method employed in this study to be very reliable. We propose the following estimating formula for BSA of laboratory miniature pigs: 100 × BSA [m2] = 7.98 × BW [kg]2/3. © 2016, Japanese Society of Toxicology. All rights reserved.

BACKGROUND It remains unclear whether left atrial low-voltage area (LALVA) affects atrial tachyarrhythmia recurrence after laser balloon pulmonary vein isolation (PVI) for atrial fibrillation (AF). We prospectively evaluated the outcome of laser balloon PVI in patients with and without LALVA (≤ 0.5 mV) together with surface/intracardiac electrophysiological criteria. METHODS One hundred consecutive paroxysmal/persistent AF patients underwent laser balloon PVI. The relative extent of LALVA (extent of LALVA/left atrial surface area × 100 [%]: rLALVA), total p-wave duration in lead II (PWD), and time interval from the beginning of p-wave to the local activation in left atrial appendage (TTLAA) were assessed. Patients were divided into patients with LALVA (group A: 23 patients) and those without LALVA (group B: 77 patients). The primary endpoint was freedom from atrial tachyarrhythmia after the blanking periods. RESULTS Complete PVI was achieved in 99/100 (99%) patients. PWD and TTLAA were longer in group A (both, P

Background Left atrial appendage closure (LAAC) has been suggested as an alternative to anticoagulation in non-valvular atrial fibrillation (AF). The present study aimed to compare a LAmbre LAA occluder system [Lifetech Scientific (Shenzhen) Co. Ltd., Shenzhen, China] with the most investigated Amulet (St. Jude Medical Inc., St. Paul, MN, USA) and Watchman (Boston Scientific, Plymouth, MN, USA) devices in terms of peri-procedural and short-term outcomes. Methods This is a prospective observational study. Results Overall, 140 patients (50 female, mean age 76.2 ± 8.4 years) were consecutively enrolled. Mean CHA2DS2-VASc score was 3.8 ± 1.5, and mean HAS-BLED score was 3.9 ± 1.1. Baseline clinical characteristics were comparable between the three groups (LAmbre, n = 30; Amulet, n = 74; Watchman, n = 36); the LAmbre group had significantly more patients with complicated LAA morphology (p = 0.006). The implant success rate was 100% in LAmbre, 99% in Amulet, and 100% in Watchman group (p = 0.638). The number of device repositions was not significantly different between groups (0.7 ± 1.1 in LAmbre, 1.0 ± 2.0 in Amulet, and 1.4 ± 1.8 in Watchman group, p = 0.345). Fluoroscopic and procedural times were similar between groups. Major peri-procedural adverse events did not differ between groups (0% vs. 0% vs. 2.8%, p = 0.233). Six months’ follow-up showed good device stability and patients’ clinical condition in all groups. Conclusion LAmbre, Amulet, and Watchman exhibit remarkable implant success rate, low risk of peri-procedural adverse events, and good clinical outcomes.

BACKGROUND The incidence of pulmonary vein stenosis (PVS) after AF ablation following contemporary procedures remains unclear. We compared the incidence of PVS/narrowing (PVS/N) after PV isolation (PVI) for (1) 3-D mapping-guided wide-area encircling irrigated radiofrequency current (RFC) ablation; (2) first-third-generation big cryoballoon (CB1-3) ablation; and (3) laser balloon (LB) ablation.Methods and Results:All patients undergoing a second procedure between January 2012 and November 2016 were subgrouped according to index ablation (PVI): RFC; CB; or LB. PVS/N was classified using PV diameter ratio (second/index procedure) on selective PV angiogram performed before ablation: mild, 25-49%; moderate, 50-74%; or severe, ≥75%. A total of 344 patients (1,362 PV) were analyzed (RFC, n=211; 840 PV; CB1, n=21; 82 PV; CB2,3, n=64; 250 PV; LB, n=48; 190 PV). In the LB group, 45 patients (94%) were treated with dose ≥8.5 W. Second procedures were performed on average 14.9±14.1 months after the index procedure. Mild PVS/N was observed in 18.4%, 9.5% and 3.6% of PV in the LB, RFC and CB groups, respectively (P

Detailed substrate mapping is important for catheter ablation. However, the influence of the electrode spacing of the mapping catheter on the substrate map has not been well clarified. The aim of this study was to investigate the influence of the electrode spacing of the mapping catheter on the voltage of the substrate map.Protocol 1: We recorded the local atrial potentials of the left atrium (LA) using the ablation catheter during sinus rhythm in six atrial fibrillation (AF) patients. The voltage of each atrial potential was compared between a close-bipolar (1-2 electrode) recording and wide-bipolar (1-4 electrode) recording. Protocol 2: Two voltage-maps of the LA were constructed separately using a 20-pole circular catheter and 10-pole circular catheter during sinus rhythm in 42 AF patients. The low voltage zone (LVZ) (0.5mV) areas obtained by 2 voltage maps using the 10-pole and 20-pole circular catheters were compared.Protocol 1: The close-bipolar voltage of the local potentials was significantly smaller than that of the wide-bipolar voltages (0.76±0.39mV vs. 0.63±0.41mV, p0.0001). Protocol 2: The size of the LVZ areas identified by the 10-pole and 20-pole catheters was 1.12±1.92cmThe voltage of the local atrial potential using the close-bipolar catheter was significantly smaller than that using the wide-bipolar catheter. Care should be given to the electrode spacing of mapping catheters when analyzing the voltage of the atrial myocardial potentials.

Atrial fibrillation (AF) affects 1-2% of the population, and its prevalence is estimated to double in the next 50 years as the population ages. AF results in impaired patients' life quality, deteriorated cardiac function, and even increased mortality. Antiarrhythmic drugs frequently fail to restore sinus rhythm. Catheter ablation is a valuable treatment approach for AF, even as a first-line therapy strategy in selected patients. Effective electrical pulmonary vein isolation (PVI) is the cornerstone of all AF ablation strategies. Use of radiofrequency (RF) catheter in combination of a three-dimensional electroanatomical mapping system is the most established ablation approach. However, catheter ablation of AF is challenging even sometimes for experienced operators. To facilitate catheter ablation of AF without compromising the durability of the pulmonary vein isolation, "single shot" ablation devices have been developed; of them, cryoballoon ablation, is by far the most widely investigated. In this report, we review the current knowledge of AF and discuss the recent evidence in catheter ablation of AF, particularly cryoballoon ablation. Moreover, we review relevant data from the literature as well as our own experience and summarize the key procedural practical techniques in PVI using cryoballoon technology, aiming to shorten the learning curve of the ablation technique and to contribute further to reduction of the disease burden.

Background The LAmbre™ occluder is a novel device for percutaneous left atrial appendage closure (LAAC). The presented study aimed to report the initial experience in implantation of the novel LAmbre for LAAC in patients with nonvalvular AF. Methods We conducted a prospective, observational, cohort registry study to evaluate the feasibility of percutaneous LAAC using the LAmbre system. Results Thirty patients (15 female, mean age 77.6 ± 8.9 years) who had high risks of stroke and contraindications for oral anticoagulation were prospectively enrolled in this registry study. The mean CHA2DS2-VaSc was 3.9 ± 1.5, and the mean HAS-BLED score was 4.1 ± 1.0. Twenty (66.7%) patients had chicken-wing LAA morphology. The implant success rate was 100%. The mean fluoroscopic time and procedure time were 3.5 ± 1.9 and 29.0 ± 10.1 minutes, respectively. No significant procedure-related complications were observed during in-hospital and acute clinical follow-up. Conclusion In this preliminary study, the LAmbre occluder showed an excellent implant success rate, favorable implant property, and very low incidence of complications. Larger sample, randomized studies are further warranted.

Although left atrial function index is reportedly a possible predictor of hospitalization for heart failure and of stroke irrespective of the presence or not of atrial fibrillation (AF), the effects of catheter ablation on left atrial function index have not yet been reported. We performed catheter ablation on 55 patients (age 56.6 ± 9.6 years; 44 men; 30 with paroxysmal and 25 with persistent, long-standing AF) and evaluated them by transthoracic echocardiography preoperatively and 3 monthly for 12–24 months after catheter ablation. We then compared clinical characteristics and echocardiographic variables before catheter ablation between two groups: the 42 subjects with the most recent left atrial function index

Aims Vagal responses such as marked bradycardia or a rapid blood pressure decrease are often observed during pulmonary vein (PV) isolation of atrial fibrillation (AF) using a cryoballoon (CB). However, the relationship between the marked vagal response and change in the heart rate variability (HRV) as a marker of the autonomic tone is not well understood. Methods and results Fifty-four paroxysmal AF patients underwent CB ablation. The CB ablation was started from the right sided PVs in 25 patients (R group) and left sided PVs in 29 (L group). The HRV and haemodynamic status during the procedure were analysed. A vagal response was observed in 16 L group patients (61.5%) during the ablation of the different PVs (RSPV:1, RIPV:5, LSPV:15, LIPV:5), while it was observed in only 2 R group patients (9.5%) (RSPV:0, RIPV:0, LSPV:1, LIPV:1) (P = 0.0002). The HRV in the L group was significantly higher than that in the R group just after the CB ablation especially for the left sided PVs (L group vs. R group, total power of the HRV, median; RSPV, 11184.7 vs. 4360.0, P = 0.21; RIPV, 9044.3 vs. 2115.1, P = 0.01; LSPV, 21186.0 vs. 1314.2, P = 0.0002; LIPV 10265.9 vs. 1236.2, P = 0.0007). Conclusion A marked increase in the HRV parameters was observed just after the CB ablation. An initial CB ablation of the right PVs decreased the change in the autonomic tone during the right PV ablation and subsequent left PV ablation. It prevented an excessive vagal response during the CB ablation and might be a safe procedure.