Abstract
Background
It has been reported that left atrial (LA) phasic function, evaluated by LA strain, is associated with cardiogenic stroke in patients with atrial fibrillation (AF). There are no ...well-established echocardiographic findings to predict peri-operative stroke in AF ablation.
Purpose
The aim is to evaluate between LA strain and peri-operative stroke in AF ablation.
Methods
This study included 103 consecutive AF patients (90 paroxysmal and 13 non-paroxysmal AF cases) who underwent initial cryo-ablation without interruption of peri-operative anticoagulation from January 2019 to August 2022. Pre-operative echocardiography was used to measure the LA strain items: LA reservoir strain, contractile strain, and conduit strain in sinus rhythm. Twenty-three patients were excluded due to AF rhythm and atrial septal defect. Peri-operative stroke was detected by using magnetic resonance imaging on the day after ablation.
Results
Peri-operative stroke occurred in 9 patients (11.3%), and there was no symptomatic stroke. In univariate analysis, age (69.6 ± 4.8 years vs. 64.2 ± 10.9 years, p<0.05) and log brain natriuretic peptide (1.61 ± 0.26 vs. 1.32 ± 0.42 p<0.05) were significantly higher in the stroke group. On the other hand, LA reservoir strain (20.9 ± 5.6% vs. 29.8 ± 8.3%, p<0.01) and LA conduit strain (10.9 ± 2.3% vs. 15.9 ± 7.0%, p<0.01) in the stroke group was significantly lower compared with the non-stroke group. There were no significant differences in the rate of intra-operative electrical cardioversion and other clinical parameters between both groups. Receiver operating characteristic curve analysis revealed that LA reservoir strain cut-off value of 22.7% provided a c-statistic of 0.82 for predicting peri-operative stroke in AF ablation.
Conclusions
LA reservoir strain is closely associated with peri-operative stroke in AF ablation.ROC curve analysis
Abstract
Background
The QT interval, an electrocardiogram (ECG) parameter, can be corrected for heart rate, giving the QTc. The QTc is an indicator of ventricular repolarisation and is widely used as ...a predictor of ventricular arrhythmia. Recent studies have reported a relationship between prolonged QTc and atrial fibrillation (AF) development.
Purpose
We investigated whether a relationship between QTc prolongation and new-onset AF could be identified in the general Japanese population.
Methods
This retrospective study evaluated the annual health check-up data of 103,304 adults (50,438 males; age, 54±15 years) that did not have AF at baseline, from April 2005 to October 2018. Most participants underwent annual health examinations as recommended by the Japanese health welfare policy. The QTc times were calculated with the Bazett formula (QTc=QT/√RR), using the mean QT and RR intervals. Participants were grouped according to QTc time: long-QTc group (males, >440 ms; females, >460 ms) and normal-QTc group. AF was diagnosed using a 12-lead surface ECG. Logistic regression analyses were performed to determine the strength of the association between prolonged QTc and new-onset AF. Multivariate analyses were adjusted for clinical variables (age, sex, obesity, hypertension, dyslipidaemia, diabetes, estimated glomerular filtration rate, and habitual drinking).
Results
The median follow-up time for the total study population was 6 years. During follow-up, 341 (0.3%) new cases of AF were recorded. Univariate analysis revealed a significant increase in new-onset AF in the long-QTc group (odds ratio OR, 2.80; 95% confidence interval CI, 1.85–4.25; p<0.001). After adjusting for clinical variables, multivariate analysis revealed that a long QTc was significantly associated with new-onset AF (OR, 1.71; 95% CI, 1.12–2.61; p=0.013). In the multivariate analysis, age (OR, 1.06; 95% CI, 1.05–1.07; p<0.001), sex (OR, 2.55; 95% CI, 1.95–3.33; p<0.001), obesity (OR, 1.46; 95% CI, 1.16–1.84; p=0.001), and habitual drinking (OR, 1.90; 95% CI, 1.50–2.41; p<0.001) were also significant predictors of new-onset AF.
Conclusions
Prolonged QTc is associated with an increased risk of new-onset AF in the general Japanese population. The mechanism of this causal relationship requires further investigation.
Abstract
Background
Catheter ablation of atrial fibrillation (AF) is effective, but certain patients experience AF recurrences. Obstructive sleep apnea (OSA) is a risk factor for AF recurrence. Watch ...peripheral arterial tonometry (WP) has a good correlation with polysomnography (PSG) in terms of the apnea-hypopnea index (AHI) and is easier to perform than PSG. Patients in AF have a high prevalence of OSA. Whether all patients with AF should be evaluated for OSA before catheter ablation is still controversial.
Purpose
To elucidate the prevalence and predictors of OSA using WP as a home sleep apnea test in AF patients before catheter ablation.
Methods
This study was conducted under a retrospective, single-center, observational design. Patients who received AF ablation without a prior diagnosis of sleep apnea and assessment of their AHI using WP were included in this analysis. The patients were mounted with a WP device by themselves at their own home. Twenty-two patients who were already diagnosed with OSA were excluded.
Results
Seven hundred seventy-four (65±11 years, 567 males, 440 paroxysmal AF) out of 776 patients were successfully mounted with WP devices on their own and underwent an OSA assessment. Their mean body mass index (BMI) was 24.1±3.5 kg/m2. The mean AHI was 20.1±15.6. Only 88 (11.4%) patients had a normal AHI (AHI<5). Mild OSA (5≤AHI<15), moderate OSA (15≤AHI<30), and severe OSA (AHI≥30) were observed in 274 (35.4%), 252 (32.6%), and 160 (20.7%) patients, respectively. A BMI≥25 (odds ratio OR; 2.42, 95% confidence interval CI; 1.74–3.37, p<0.001), male sex (1.70, 1.19–2.44, p=0.0037), non-paroxysmal AF (1.90, 1.35–2.66, p=0.0002), hypertension (1.70, 1.24–2.33, p=0.009), and left atrial volume index ≥30 (OR=1.51, CI 1.06–2.16, p=0.022) were significant predictors of moderate or severe OSA by a multivariate analysis, while an Epworth sleepiness scale ≥11 was not a predictor of moderate or severe OSA (OR=0.99, CI 0.66–1.49, p=0.95). However, 44.2% of non-obese patients (BMI <25) had moderate-severe OSA.
Conclusion Almost
All patients successfully underwent WP to diagnose OSA. AF patients had a high prevalence of OSA, and screening OSA would be important in AF patients receiving ablation even if patients do not have sleepiness or are obese. We cannot deny OSA in AF patients before catheter ablation without performing screening tests for OSA.
Funding Acknowledgement
Type of funding source: None
Abstract
Background
Preoperative left atrial (LA) function is associated with paroxysmal atrial fibrillation (PAF) ablation outcome. The presence of left atrial low voltage zone (LVZ) is also ...associated with recurrence. We hypothesized that reduced pre-ablation LA function reflects the presence of LVZ.
Purpose
We investigated the association between baseline LA function and the presence of LVZ in patients undergoing initial PAF ablation. Further, we sought to create the new predictive scoring for the presence of LVZ.
Methods
Consecutive 305 patients who underwent LA voltage mapping during initial PAF ablation from January 2017 to October 2019 in our institute were retrospectively analyzed. We performed 256-slice MDCT at baseline. As the representative of LA function, we calculated LA emptying fraction (LAEF), where LAEF = {(maximum LAV) − (minimum LAV)/(maximum LAV)} x 100. LVZ was defined as regions where bipolar peak-to-peak voltage was <0.5mV. We performed the univariate and multivariate analysis to assess the association between LAEF and the presence of LVZ. Second, we performed receiver operating characteristic (ROC) analysis for the prediction of LVZ. We combined multivariate predictors and created the predictive scoring for LVZ.
Results
Out of 305 pts, 56 pts (18%) had LVZ in LA. In univariate analysis, low body mass index, higher percentage of female sex, higher age, higher E/e', larger maximum LA volume and lower LAEF (29.3±11.8% vs. 41.2±9.7, P<0.0001) was associated with the presence of LVZ. In multivariate logistic regression analysis, Low LAEF revealed the strongest predictor for LVZ (LAEF; Odds ratio OR/10% increase: 0.54, 95% CI: 0.39–0.82, P=0.0016). High age and female sex also remained as the independent predictors (Age; OR/10 y.o. increase: 1.80, 1.23–3.03, P=0.0042, Female; OR: 2.51, 1.15–5.49, P=0.0213). In ROC analysis, LAEF had moderate predictive accuracy for the presence of LVZ. (Area under the ROC curve: 0.77, Best cut-off value: 31%, P<0.0001) (Figure 1). We created OLAF-LVZ predictive score by combining Old age (1 point, ≥65), LAEF (2 points, LAEF ≤31%) and Female sex (1 point). OLAF score had gradient effect on the incidence of LVZ (2%, 11%, 25%, 45%, 71%, OLAF score; 0, 1, 2, 3, 4, respectively, P<0.0001) (Figure 2).
Conclusions
In PAF patients, preoperative LAEF was strongly associated with the presence of LVZ. LVZ might reflect the myocardial injury causing LA dysfunction. OLAF-LVZ predictive score: combination of Old age (≥65), Female sex, and LAEF (≤31%) could be useful to stratify the risk of the presence of LVZ.
Funding Acknowledgement
Type of funding source: None
Abstract
Background
It has been reported that low voltage areas and conduction abnormalities detected by electrophysiology catheters in the left atrium (LA) represent regional degeneration and ...fibrosis of the atrium and are related to a poor atrial fibrillation (AF) ablation outcome. Assessment of the local atrial function is clinically useful because atrial degeneration does not occur uniformly throughout the atrium. Though evaluating the global atrial function using speckle tracking imaging (STI) by transthoracic echocardiography (TTE) has been attempted, TTE does not have a sufficient image quality to assess local atrial STI.
Purpose
To evaluate the local atrial function by STI using intracardiac echocardiography (ICE) and to elucidate the characteristics of the STI in normal and abnormal voltage regions in the LA.
Methods
We included 9 patients undergoing AF ablation with written informed consent for this prospective observational study. After pulmonary vein isolation, we performed voltage mapping of the LA in sinus rhythm using a CARTO system (Biosense). Abnormal regions and normal regions were defined as those with low voltage areas (<0.5 mV) and those with normal voltages, respectively. Echo images were recorded by an ACUSON SC2000 (Siemens) and SOUNDSTAR catheter (Biosense). We inserted the SOUNDSTAR catheter into the LA to obtain clear images, recorded the STI of the anterior and inferior wall, and performed an offline analysis of the atrial strain with an eSie VVI work station (Siemens) and the LA voltage data with CARTO system at each site simultaneously (left figure). We compared the strain during the atrial contraction phase (Sct) between the normal and abnormal regions.
Results
Among the study population, 5 patients had low voltage areas in the LA. We evaluated the STI at 26 normal regions and 44 abnormal regions. The typical regional speckle tracking waveform in the normal region was similar to a jugular vein pressure waveform (right figure). There was a difference in the amplitude of the Sct between the groups; it was significantly smaller in the abnormal regions (normal and abnormal regions, 9.8±5.0% and 5.6±3.8%, p=0.0001). The duration of the Sct was significantly more prolonged in the abnormal regions than normal regions (98.8±26.3ms and 118.2±33.9ms, p=0.015).
Conclusions
This pilot study demonstrated that the local atrial function was evaluable by STI using ICE and that the regional strain tracking waveform during the atrial contraction phase in abnormal voltage regions was smaller and more prolonged than that in normal regions. An evaluation of the regional STI with an ICE may be useful to detect regional abnormalities of the atrium.
Representative case
Funding Acknowledgement
Type of funding source: None
Abstract
Background
While multiple catheter ablation for recurrent atrial fibrillation (AF) is effective for the maintenance of sinus rhythm, some of patients have ablation-refractory AF. Left atrial ...(LA) dysfunction and the presence of low voltage zone (LVZ) are associated with recurrence after AF ablation. The association between recurrence and LA dysfunction/ LVZ among patients undergoing multiple AF ablation remains unclear.
Purpose
We aimed to compare (i)LA function, (ii)the prevalence of LVZ among patients undergoing first, second and third or more AF ablation procedures. Further, we investigated whether LA dysfunction and LVZ are associated with recurrence after multiple procedures.
Methods
We retrospectively analyzed 460 patients undergoing AF ablation procedures including first, second and third or more sessions from January 2017 to October 2019 in our institute. Before each session, 256-slice MDCT was performed under sinus rhythm to measure pre-ablation LA emptying fraction (LAEF) as the representative of LA function. At the end of each session, we checked the presence of LVZ, which was defined as regions where bipolar peak-to-peak voltage was <0.5mV. All patients underwent pulmonary vein isolation (PVI). If necessary, additional ablation (e.g. linear ablation, non-PV foci ablation and LVZ ablation) was performed.
Results
Out of 460 sessions, 295 were first (follow-up years: 1.5 0.8, 2.0), 134 were second (1.0 0.5, 1.8), and 31 were third or more sessions (1.2 0.7, 2.0). As the number of sessions increased, the recurrence rate was increased (19% vs. 31% vs. 61%, first vs. second vs. ≥third, P<0.0001), LAEF decreased (39.7±10.5% vs. 32.6±10.1% vs. 25.3±11.8%, P<0.0001) and the incidence of LVZ increased (18% vs. 34% vs. 68%, P<0.0001) (Figure 1). In patients with recurrence (N=104) after multiple ablation (second or more sessions), LAEF was lower and the prevalence of LVZ was higher than those without recurrence (N=61) (LAEF: 27.3±10.3% vs. 33.5±10.5%, with vs. without, P=0.0003; LVZ: 57% vs. 31%, P=0.0014).
Conclusions
As the number of sessions increased, the recurrence rate was increased. The prevalence of LA dysfunction and LVZ was high in patients requiring multiple ablation procedure. LA dysfunction and LVZ possibly reflect arrhytmogenic substrate causing recurrence of ablation-refractory AF. We should carefully consider repeated AF ablation in patients with severe LA dysfunction and extensive LVZ.
Figure 1
Funding Acknowledgement
Type of funding source: None
Abstract
Funding Acknowledgements
Type of funding sources: None.
Background
Quantification of left ventricular (LV) dyssynchrony is of great interest for resynchronization therapy (CRT). Recently, ...cardiac computed tomography (CCT) is feasible for evaluation of dyssynchrony. Our aim was to assess a novel simplified approach using CCT to quantify LV dyssynchrony.
Methods
We studied 346 consecutive patients with a wide range of QRS width and ejection fractions (EF). Electrocardiogram-gated contrast-enhanced 256-slice multidetector CT (Brilliance 256 iCT, Philips Medical Systems) was performed before CRT. After CCT scan, the LV endocardial boundaries from short-axis images reconstructed at 5% increments of cardiac cycle were automatically detected, and a time from R-wave to maximal wall motion was calculated for each of the 16 standardized segments for all slices using software "Myocardial Contraction Map" (Argus, Inc Ehime, Japan). The standard deviation of all segments modified by mean heart rate (%SD) was respectively calculated as the global parameter of dyssynchrony. LVEF was also measured using MDCT.
Results
%SD was feasible in all patients, respectably. %SD was significantly different between the different QRS duration groups; narrow QRS (<120ms): 9 ± 5%, relatively wide QRS (120-150 ms): 11 ± 6%, and significantly wide QRS (>150 ms): 14 ± 7% (p <0.001). Moreover, there was significantly difference in %SD between the different morphology groups; normal: 9 ± 7%, Non-left bundle branch block (Non-LBBB): 10 ± 6%, LBBB: 17 ± 7% (p <0.001).
Conclusion
This novel simplified approach by CCT can quantify dyssynchrony in different QRS duration and morphology groups. This method has promise for clinical applications to the evaluation of patients for CRT.
Abstract Figure.
For all engineers and students coming to finite element analysis or to ANSYS software for the first time, this powerful hands-on guide develops a detailed and confident understanding of using ANSYS's ...powerful engineering analysis tools. The best way to learn complex systems is by means of hands-on experience. With an innovative and clear tutorial based approach, this powerful book provides readers with a comprehensive introduction to all of the fundamental areas of engineering analysis they are likely to require either as part of their studies or in getting up to speed fast with the use of ANSYS software in working life. Opening with an introduction to the principles of the finite element method, the book then presents an overview of ANSYS technologies before moving on to cover key applications areas in detail.Key topics covered: Introduction to the finite element method Getting started with ANSYS software stress analysis dynamics of machines fluid dynamics problems thermo mechanics contact and surface mechanics exercises, tutorials, worked examples With its detailed step-by-step explanations, extensive worked examples and sample problems, this book will develop the reader's understanding of FEA and their ability to use ANSYS's software tools to solve their own particular analysis problems, not just the ones set in the book.* Develops a detailed understanding of finite element analysis and the use of ANSYS software by example * Develops a detailed understanding of finite element analysis and the use of ANSYS software by example * Exclusively structured around the market leading ANSYS software, with detailed and clear step-by-step instruction, worked examples, and detailed, screen-by-screen illustrative problems to reinforce learning
Dental rehabilitation using osseointegrated implants is a routine for dentists. Maxillary sinus lift surgery is essential in expanding the indications for dental implants, as it re-establishes ...adequate bone volume for the installation of implants in the ideal areas in the middle posterior portion of maxillae that have undergone the physiological process of pneumatization. This article describes the chronology of this technique and its increase over time.
Accelerator design at SuperKEKB Ohnishi, Yukiyoshi; Abe, Tetsuo; Adachi, Toshikazu ...
Progress of theoretical and experimental physics,
03/2013, Letnik:
2013, Številka:
3
Journal Article
Recenzirano
Odprti dostop
The SuperKEKB project requires a positron and electron collider with a peak luminosity of 8 × 1035 cm−2 s−1. This luminosity is 40 times that of the KEKB B-factory, which operated for 11 years up to ...2010. SuperKEKB is an asymmetry-energy and double-ring collider; the beam energy of the positron (LER) is 4 GeV and that of the electron (HER) is 7 GeV. An extremely small beta function at the interaction point (IP) and a low emittance are necessary. In addition, in order to achieve the target luminosity, a large horizontal crossing angle between two colliding beams is adopted, as is a bunch length much longer than the beta function at the IP. This method is called the "nano-beam scheme". The beam-beam parameter is assumed to be similar to KEKB, the beta function at the IP is 1/20, and the beam currents are twice those of KEKB in the nano-beam scheme. Consequently, the luminosity gain of 40 with respect to KEKB can be obtained.
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