Search

Daily fetal movement counting based on maternal perception is widely deployed to monitor fetal wellbeing. However, the counting performed by the mother is prone to errors for various reasons. There are limited devices on the market that can provide reliable and automatic counting. This paper presents a prototype of a novel fetal movement monitoring device based on fibre Bragg grating sensors. Deformation of the skin caused by a fetal movement can lead to a change of the strain and stress on the optical fibre sensors, therefore can induce distortions to the breathing pattern of the mother. In the study data was gathered by the sensors through strain measurement and was post-processed using independent component analysis (ICA) and high-pass filtering to show the instances of the fetal movements. Information gathered during user trials with the prototype suggests that the system detects significantly higher numbers of fetus movements than that observed based on the mother’s perception. Among the various techniques available for fetal movement monitoring, fibre optic sensing provides many advantages including multiplex capability, flexibility and minimal size, making the concept an attractive solution for reliable monitoring of antenatal fetal movements.

PurposeSites of highest dominant frequency (HDF) are implicated by many proposed mechanisms underlying persistent atrial fibrillation (persAF). We hypothesized that prospectively identifying and ablating dynamic left atrial HDF sites would favorably impact the electrophysiological substrate of persAF. We aim to assess the feasibility of prospectively identifying HDF sites by global simultaneous left atrial mapping.MethodsPersAF patients with no prior ablation history underwent global simultaneous left atrial non-contact mapping. 30 s of electrograms recorded during AF were exported into a bespoke MATLAB interface to identify HDF regions, which were then targeted for ablation, prior to pulmonary vein isolation. Following ablation of each region, change in AF cycle length (AFCL) was documented (≥ 10 ms considered significant). Baseline isopotential maps of ablated regions were retrospectively analyzed looking for rotors and focal activation or extinction events.ResultsA total of 51 HDF regions were identified and ablated in 10 patients (median DF 5.8Hz, range 4.4–7.1Hz). An increase in AFCL of was seen in 20 of the 51 regions (39%), including AF termination in 4 patients. 5 out of 10 patients (including the 4 patients where AF termination occurred with HDF-guided ablation) were free from AF recurrence at 1 year. The proportion of HDF occurrences in an ablated region was not associated with change in AFCL (τ = 0.11, p = 0.24). Regions where AFCL decreased by 10 ms or more (i.e., AF disorganization) after ablation also showed lowest baseline spectral organization (p < 0.033 for any comparison). Considering all ablated regions, the average proportion of HDF events which were also HRI events was 8.0 ± 13%. Focal activations predominated (537/1253 events) in the ablated regions on isopotential maps, were modestly associated with the proportion of HDF occurrences represented by the ablated region (Kendall’s τ = 0.40, p < 0.0001), and very strongly associated with focal extinction events (τ = 0.79, p < 0.0001). Rotors were rare (4/1253 events).ConclusionTargeting dynamic HDF sites is feasible and can be efficacious, but lacks specificity in identifying relevant human persAF substrate. Spectral organization may have an adjunctive role in preventing unnecessary substrate ablation. Dynamic HDF sites are not associated with observable rotational activity on isopotential mapping, but epi-endocardial breakthroughs could be contributory.

[EN] Electrocardiographic imaging (ECGI) is a technique to reconstruct non-invasively the electrical activity on the heart surface from body-surface potential recordings and geometric information of the torso and the heart. ECGI has shown scientific and clinical value when used to characterize and treat both atrial and ventricular arrhythmias. Regarding atrial fibrillation (AF), the characterization of the electrical propagation and the underlying substrate favoring AF is inherently more challenging than for ventricular arrhythmias, due to the progressive and heterogeneous nature of the disease and its manifestation, the small volume and wall thickness of the atria, and the relatively large role of microstructural abnormalities in AF. At the same time, ECGI has the advantage over other mapping technologies of allowing a global characterization of atrial electrical activity at every atrial beat and non-invasively. However, since ECGI is time-consuming and costly and the use of electrical mapping to guide AF ablation is still not fully established, the clinical value of ECGI for AF is still under assessment. Nonetheless, AF is known to be the manifestation of a complex interaction between electrical and structural abnormalities and therefore, true electro-anatomical-structural imaging may elucidate important key factors of AF development, progression, and treatment. Therefore, it is paramount to identify which clinical questions could be successfully addressed by ECGI when it comes to AF characterization and treatment, and which questions may be beyond its technical limitations. In this manuscript we review the questions that researchers have tried to address on the use of ECGI for AF characterization and treatment guidance (for example, localization of AF triggers and sustaining mechanisms), and we discuss the technological requirements and validation. We address experimental and clinical results, limitations, and future challenges for fruitful application of ECGI for AF understanding and management. We pay attention to existing techniques and clinical application, to computer models and (animal or human) experiments, to challenges of methodological and clinical validation. The overall objective of the study is to provide a consensus on valuable directions that ECGI research may take to provide future improvements in AF characterization and treatment guidance., JS was supported by Grants #2020/12841-3, #2020/13017-2, and #2018/25606-2, Sao Paulo Research Foundation (FAPESP). FS was supported by research grants from the Medical Research Council UK (MR/S037306/1), and from the British Heart Foundation (BHF Project Grant No. PG/18/33/33780). JR-A was supported by the projects (PID2019-106623RBC41) and meHeart (PID2019-104356RB-C42 and PID2019104356RB-C43) from the Spanish Government. JP was funded by Program of Alliances for Education and Training (Scholarship Brazil-PAEC OEA-GCUB-2017). RM, AC, and MG were supported by the Instituto de Salud Carlos III, and Ministerio de Ciencia, Innovacion y Universidades (supported by the FEDER Fondo Europeo de Desarrollo Regional PI17/01106 and RYC2018-024346B-750), EIT Health (Activity code 19600, EIT Health was supported by the EIT, a body of the European Union), received funding from the European Union's Horizon research and Innovation programme under the Marie Sklodowska-Curie grant agreement no. 860974 and the Generalitat Valenciana Grants (ACIF/2020/265). BZ and RM were supported by the NIH NHLBI Grant No. 1F30HL149327; NIH NIGMS Center for Integrative Biomedical Computing (www.sci.utah.edu/cibc), NIH NIGMS Grants P41GM103545 and R24 GM136986; and the Nora Eccles Treadwell Foundation for Cardiovascular Research. OB was supported in part by research grants from the National Institutes of Health (R01-HL118304 and R21-HL153694), Abbott, Medtronic, and CoreMap. MC was supported by a Veni Grant from the Netherlands Organization for Scientific Research (TTW 16772). FA was supported by the Instituto de Salud Carlos III (PI17/010559 and PI20/01618) and the Consorcio de Investigacion Biomedica en Red de Enfermedades Cardiovasculares (CIBERCV), the Ministerio de Ciencia e Innovacion (cofound by FEDER: Fondo Europeo de Desarrollo Regional), EIT Health (AFFINE 19600, EIT Health was supported by EIT, a body of the European Union).

[EN] [Background] Identification of arrhythmogenic regions remains a challenge in persistent atrial fibrillation (persAF). Frequency and phase analysis allows identification of potential ablation targets. [Objective] This study aimed to investigate the spatiotemporal association between dominant frequency (DF) and reentrant phase activation areas. [Methods] A total of 8 persAF patients undergoing first-time catheter ablation procedure were enrolled. A noncontact array catheter was deployed into the left atrium (LA) and 2048 atrial fibrillation electrograms (AEGs) were acquired for 15 seconds following ventricular far-field cancellation. DF and phase singularity (PS) points were identified from the AEGs and tracked over consecutive frames. The spatiotemporal correlation of high DF areas and PS points was investigated, and the organization index at the core of high-DF areas was compared with that of their periphery. [Results] The phase maps presented multiple simultaneous PS points that drift over the LA, with preferential locations. Regions displaying higher PS concentration showed a degree of colocalization with DF sites, with PS and DF regions being neighbors in 61.8% and with PS and DF regions overlapping in 36.8% of the time windows. Sites with highest DF showed a greater degree of organization at their core compared with their periphery. After ablation, the PS incidence reduced over the entire LA (36.2% ± 23.2%, P < .05), but especially at the pulmonary veins (78.6% ± 22.2%, P < .05). [Conclusion] Multiple PS points drifting over the LA were identified with their clusters correlating spatially with the DF regions. After pulmonary vein isolation, the PS¿s complexity was reduced, which supports the notion that PS sites represent areas of relevance to the atrial substrate., This work was supported by the Leicester NIHR Cardiovascular Biomedical Research Unit, UK. Dr. Salinet was supported by Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq, Brasil, N. 200598/2009-0) and Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP, Brasil, N. 2014/26066-0). Dr. Almeida was funded by Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq, Brazil, N. 200251/2012-0) and Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (Capes, Brazil).

Background: Cortical entrainment to speech correlates with speech intelligibility and attention to a speech stream in noisy environments. However, there is a lack of data on whether cortical entrainment can help in evaluating hearing aid fittings for subjects with mild to moderate hearing loss. One particular problem that may arise is that hearing aids may alter the speech stimulus during (pre-)processing steps, which might alter cortical entrainment to the speech. Here, the effect of hearing aid processing on cortical entrainment to running speech in hearing impaired subjects was investigated.Methodology: Seventeen native English-speaking subjects with mild-to-moderate hearing loss participated in the study. Hearing function and hearing aid fitting were evaluated using standard clinical procedures. Participants then listened to a 25-min audiobook under aided and unaided conditions at 70 dBA sound pressure level (SPL) in quiet conditions. EEG data were collected using a 32-channel system. Cortical entrainment to speech was evaluated using decoders reconstructing the speech envelope from the EEG data. Null decoders, obtained from EEG and the time-reversed speech envelope, were used to assess the chance level reconstructions. Entrainment in the delta- (1–4 Hz) and theta- (4–8 Hz) band, as well as wideband (1–20 Hz) EEG data was investigated.Results: Significant cortical responses could be detected for all but one subject in all three frequency bands under both aided and unaided conditions. However, no significant differences could be found between the two conditions in the number of responses detected, nor in the strength of cortical entrainment. The results show that the relatively small change in speech input provided by the hearing aid was not sufficient to elicit a detectable change in cortical entrainment.Conclusion: For subjects with mild to moderate hearing loss, cortical entrainment to speech in quiet at an audible level is not affected by hearing aids. These results clear the pathway for exploring the potential to use cortical entrainment to running speech for evaluating hearing aid fitting at lower speech intensities (which could be inaudible when unaided), or using speech in noise conditions.

Although the concepts of Western-Eastern integration to optimise management strategies are well-established, investigations on the applicability of these concepts in real-life situations are lacking. This study investigates how integration of (Eastern) Yin-Yang principles of seeking balance into Western concepts benefitted Koreans in combatting financial crises repercussions. Through analysis of 519 South Korean economic magazine covers taken over the period 2007-2012, the study shows the mindset of Korean society during the 2008 financial crisis. The covers provide a balanced interpretation of crisis events as both disastrous and opportunistic. Traditional Yin-Yang values therefore appear to be preserved in Korean management philosophy, even though contemporary Korean business strategies are strongly influenced by Western principles. By comparing these findings with social attitudes during previous crises in Korea, the study provides a real-life example of possible benefits of integrating Eastern and Western philosophy in management strategies.

Background: To assess hearing in response to speech, the envelope frequency following response (FFR) can be observed at the fundamental frequency of a vowel stimulus, and its harmonics. FFRs are complex non-linear phenomena, which require better understanding for allowing robust inferences on the assessment of hearing and hearing aid fitting.\ud \ud Objectives: To evaluate the effect of stimulus bandwidth on FFR detection rates using filtered vowel stimuli with equal sound levels. \ud \ud Design: FFRs were collected whilst presenting repeated vowels (in consonant-vowel-consonant format) filtered into different bandwidths. Eighty stimuli per word were presented at 70 dB SPL LAeq through insert earphones with an inter-stimulus interval of 1s. Responses were detected using frequency-domain Hotelling’s T2 (HT2) tests for individual multiples of the fundamental frequency (F0) and for combinations of F0 multiples. \ud \ud Study Sample: Eleven native English-speaking subjects with normal hearing thresholds.\ud \ud Results: Average detection rates are highest (69%) with stimuli high-pass filtered >1000 Hz, and significantly lower for low-pass filtered stimuli (40%). \ud \ud Conclusion: High-pass filtered vowels elicit stronger FFRs than low-pass filtered vowels at the same dB SPL LAeq. For testing hearing using band-limited speech, filtering effects (due to hearing loss, hearing aid setting or stimulus choice) on responses must be considered.

Objectives: Objective detection of brainstem responses to natural speech stimuli is an important tool for the evaluation of hearing aid fitting, especially in people who may not be able to respond reliably in behavioral tests. Of particular interest is the envelope Frequency Following Response (eFFR), which refers to the EEG response at the stimulus' fundamental frequency (and its harmonics), and here in particular to the response to natural spoken vowel sounds. This paper introduces the frequency-domain Hotelling's T2 (HT2) method for eFFR detection. This method was compared, in terms of sensitivity in detecting eFFRs at the fundamental frequency (HT2_F0), to two different single channel frequency domain methods (F-test on Fourier Analyzer amplitude spectra - FA-F-Test and Magnitude Squared Coherence - MSC) in detecting envelope following responses to natural vowel stimuli in simulated data and EEG data from normal hearing subjects. Sensitivity was assessed based on the number of detections and the time needed to detect a response for a false-positive rate of 5%. The study also explored the whether a single-channel, multi-frequency HT2 (HT2_3F) and a multichannel, multi-frequency HT2 (HT2_MC) could further improve response detection.\ud \ud Design: Four repeated words were presented sequentially at 70dB SPL LAeq through ER-2 insert earphones. The stimuli consisted of a prolonged vowel in a /hVd/ structure (where V represents different vowel sounds). Each stimulus was presented over 440 sweeps (220 condensation, 220 rarefaction). EEG data were collected from 12 normal hearing adult participants. After pre-processing and artefact removal, eFFR detection was compared between the algorithms. For the simulation study, simulated EEG signals were generated by adding random noise at multiple signal-to-noise ratios (SNR - 0dB to -60dB) to the auditory stimuli as well as to a single sinusoid at the fluctuating and flattened fundamental frequency (f0). For each SNR, 1,000 sets of 440 simulated epochs were generated. Performance of the algorithms was assessed based on the number of sets for which a response could be detected at each SNR.\ud \ud Results: In simulation studies, HT2_3F significantly outperformed the other algorithms when detecting a vowel stimulus in noise. For simulations containing responses only at a single frequency, HT2_3F performs worse compared to other approaches applied in this study as the additional frequencies included do not contain additional information. For recorded EEG data, HT2_MC showed a significantly higher response detection rate compared to MSC and FA-F-Test. Both HT2_MC and HT2_F0 also showed a significant reduction in detection time compared to the FA-F-Test algorithm. Comparisons between different electrode locations confirmed a higher number of detections for electrodes close to Cz compared to more peripheral locations. \ud \ud Conclusion: The HT2 method is more sensitive than FA-F-Test and MSC in detecting responses to complex stimuli, as it allows detection of multiple frequencies (HT2_F3) and multiple EEG channels (HT2_MC) simultaneously. This effect was shown in simulation studies for HT2_3F and in EEG data for the HT2_MC algorithm. The spread in detection time across subjects is also lower for the HT2 algorithm, with decision on the presence of an eFFR possible within 5 minutes.

Background and Objective: Optimal targets for persistent atrial fibrillation (persAF) ablation are still debated. Atrial regions hosting high dominant frequency (HDF) are believed to participate in the initiation and maintenance of persAF and hence are potential targets for ablation, while rotor ablation has shown promising initial results. Currently, no commercially available system offers the capability to automatically identify both these phenomena. This paper describes an integrated 3D software platform combining the mapping of both frequency spectrum and phase from atrial electrograms (AEGs) to help guide persAF ablation in clinical cardiac electrophysiological studies.Methods: 30 s of 2048 non-contact AEGs (EnSite Array, St. Jude Medical) were collected and analyzed per patient. After QRST removal, the AEGs were divided into 4 s windows with a 50% overlap. Fast Fourier transform was used for DF identification. HDF areas were identified as the maximum DF to 0.25 Hz below that, and their centers of gravity (CGs) were used to track their spatiotemporal movement. Spectral organization measurements were estimated. Hilbert transform was used to calculate instantaneous phase.Results: The system was successfully used to guide catheter ablation for 10 persAF patients. The mean processing time was 10.4?±?1.5 min, which is adequate comparing to the normal electrophysiological (EP) procedure time (120?180 min).Conclusions: A customized software platform capable of measuring different forms of spatiotemporal AEG analysis was implemented and used in clinical environment to guide persAF ablation. The modular nature of the platform will help electrophysiological studies in understanding of the underlying AF mechanisms.

Preclinical studies showed a relationship between high dominant frequency areas (HDFA) and wave fractionation, but evidence in patient who atrial fibrillation (AF) persists for long-term periods (persAF) it is not well defined. This study aims to assess the spatio-temporal organization characteristics at HDFAs is persAF and its impact after per standard pulmonary vein isolation (PVI). Eight persAF patients had a non-contact array catheter deployed into the left atrium to collect up to 2048 AF electrograms (AEG) for 15 s. AEGs were band-pass filtered (3–30 Hz) followed by ventricular far-field cancellation. DF between 4–10 Hz and its respective organization index (OI) were calculated (4 s with 50% overlap) to produce 3D DF and OI maps. HDFA defined as the regions within a 0.25 Hz drop from the highest DF were determined and their centre of gravity (CG) calculated. Highest DF sites showed a higher OI at their core when compared to the periphery (0.422±0.101 vs. 0.386±0.126, p=0.02) and increased again organization at sites distant from the HDFAs. Similarly, after PVI, OI remained higher as compared to their periphery (0.372±0.026 vs. 0.332±0.036, p=0.22), but with significant lower values when compared with baseline (p

Ablation of persistent atrial fibrillation (persAF) targeting complex fractionated atrial electrograms (CFAEs) detected by automated algorithms has produced conflicting outcomes in previous electrophysiological studies. We hypothesize that the differences in these algorithms could lead to discordant CFAE classifications by the available mapping systems, giving rise to potential disparities in CFAE-guided ablation. This study reports the results of a head-to-head comparison of CFAE detection performed by NavX (St. Jude Medical) versus CARTO (Biosense Webster) on the same bipolar electrogram data (797 electrograms) from 18 persAF patients. We propose revised thresholds for both primary and complementary indices to minimize the differences in CFAE classification performed by either system. Using the default thresholds [NavX: CFE-Mean ≤ 120 ms; CARTO: ICL ≥ 7], NavX classified 70 % of the electrograms as CFAEs, while CARTO detected 36 % (Cohen’s kappa κ ≈ 0.3, P

There is increasing focus on understanding the substrates that maintain persistent atrial fibrillation (persAF) based on dominant frequency (DF) sources and phase singularity points (PS). In this study we aimed to combine these two parameters and study the relationship between them to depict the complex spatiotemporal patterns of fibrillation. For 9 patients with longstanding persAF (duration: 34 ± 25 months) undergoing left atrial (LA) ablation, noncontact array catheter (EnSite Array, St. Jude Medical) was used to collect virtual unipolar electrograms (EGMs) simultaneously from 2048 nodes on the LA. After QRST subtraction, 3D DF maps were obtained through the fast Fourier Transform applied simultaneously to each individual EGM. DF was defined within the range of 4-10Hz (4s time window; 87.5% overlap; 30s/patient). Highest DF (HDF) regions for each individual window were defined as any LA geometry nodes where the calculated DF was within 0.25 Hz of the maximum DF value registered in the window. In order to correlate these HDF locations with PS, phase maps were constructed using the Hilbert transform approach and the locations of PS and its respective chirality (+ clockwise; - anticlockwise) were identified applying an automatic PS detection algorithm. A statistical majority of PSs (92.5%, p Our analysis suggests an organised behaviour of PS of opposite chirality and HDF regions travelling between them. Once an electrophysiological relationship is established, the spatiotemporal behaviour of PS and HDF could provide alternative ablation strategies for AF.

In the present work, we investigated current methods for complex fractionated atrial electrogram (CFAE) classification during persistent atrial fibrillation (persAF). Potential contributing factors concerning the low reproducibility of CFAE-guided ablation outcomes in persAF therapy have been explored, such as inconsistencies in automated CFAE classification performed by different systems, the co-existence of different types of atrial electrograms (AEGs), and insufficient AEG duration for CFAE detection. First, we show that CFAE classification may vary for the same individual, depending on the system being used and settings being applied. Revised thresholds are suggested for the indices calculated by each system to minimize the differences in CFAE detection performed independently by them. Second, our results show that some AEGs are affected by stepwise persAF ablation, while others remain unaffected by it. Different types of AEGs might correlate with distinct underlying persAF mechanisms. Single descriptors measured from the AEGs, such as sample entropy and dominant frequency, were not able to discriminate the different types of AEGs individually, but multivariate analysis using multiple descriptors measured from the AEGs can effectively discriminate the different types of AEGs. Finally, we show that AEG duration of 2.5 s — as currently used by some systems — might not be sufficient to measure CFAEs consistently.

Ablation targeting complex fractionated atrial electrograms (CFAE) for treating persistent atrial fibrillation (persAF) has shown conflicting results. Differences in automated algorithms embedded in NavX (St Jude Medical) and CARTO (Biosense Webster) could influence CF AE target identification for ablation, potentially affecting ablation outcomes. To evaluate this effect, automated CFAE classification performed by NavX and CARTO on the same bipolar electrograms from 18 persAF patients undergoing ablation was compared. Using the default thresholds, NavX classified 69±5% of the electrograms as CFAEs, while CARTO detected 35±5%% (Cohen's kappa κ≈0.3, P

Atrial regions hosting dominant frequency (DF) may represent potential drivers of persistent atrial fibrillation (persAF). Previous work showed that DF can exhibit cyclic behaviour. This study aims to better understand the spatiotemporal behaviours of persAF over longer time periods. 10 patients undergoing persAF ablation targeted at DF were included. Left atrial (LA) non-contact virtual electrograms (VEGMs, Ensite Array, St Jude Medical) were collected for up to 5 min pre-/post- ablation. DF was identified as the peak from 4-10 Hz, in 4 s windows (50 % overlap). High DF (HDF) map was created and automated pattern recognition algorithm was applied to look for recurring HDF spatial patterns within each patient. Recurring HDF patterns were found in all patients. Patients who changed rhythm to atrial flutter after ablation demonstrated single dominant pattern (DP) among the recorded time period, which might consistent with the higher level of regularity during flutter. Ablation regularized AF as demonstrated by increased DP recurrence after ablation. The time interval (median [IQR]) of DP recurrence for the patients still in atrial fibrillation(AF) after ablation (7 patients) decreased from 21.1 s [11.8~49.7 s] to 15.7s [6.5~18.2 s]. The proposed method quantifies the spatiotemporal regularity of HDF DPs over long time periods and may offer a more comprehensive dynamic overview of persAF behaviour and the impact of ablation.

Atrial fibrillation is the most common cardiac arrhythmia, and it is associated with increased risk of stroke, heart failure, and mortality. This work describes spectral analysis techniques that are being used in conjunction with visualization algorithms to help guide catheter ablation procedures that aim at treating patients with arrhythmia.

Introduction: CARTO (Biosense Webster) and NavX (St Jude Medical) provide different algorithms to support Complex Fractionated Atrial Electrograms (CFAE)-guided ablation of atrial fibrillation (AF). CARTO uses the Interval Confidence Level (ICL) as its primary metric, with Average Complex Interval (ACI) and Shortest Complex Interval (SCI) as complementary metrics for CFAE identification. Similarly, NavX uses CFEmean and CFE-StdDev respectively. Differences in commercial CFAE algorithms have never been formally investigated, and furthermore no defined thresholds exist for the complementary metrics to characterize CFAE. This could potentially impact CFAE-targeted AF ablation. Methods: Bipolar electrograms (EGMs, 2.5 s duration) at different left atrial regions were collected from 18 patients undergoing first time persistent AF ablation guided by EnSite NavX: pre- (455 EGMs), and post- (342 EGMs) pulmonary vein isolation and roof line creation. The EGMs and their calculated CFEmean and CFE-StdDev were exported and analysed offline with a validated (100% agreement) MATLAB script that calculates ICL, ACI and SCI. To demonstrate the significance of threshold selection, each EGM was classified as either fractionated or non-fractionated according to both NavX (CFEmean 30-120 ms) and CARTO (using ICL ≥ 4; 5; 6; 7), as well as whether or not there was agreement (i.e. both CFAE or both non-CFAE) between the classifications. Where EGM classifications agreed (CFEmean 30-120 ms and ICL ≥ 4), their respective CFE-StdDev, ACI and SCI were selected to generate ROC curves in an attempt to optimize sensitivity and specificity for CFAE categorization based on the agreement between the two commercial systems. Results: CFEmean increased and ICL decreased post-ablation (Fig. 1A). CFAE categorisation varied according to the use of CFEmean or ICL, and for each ICL threshold (Table [1][1]). Classification agreement between ICL and CFEmean decreased from 79% to 63% as the ICL threshold increased from 4 to 7 (Fig. 1B). For CFAE discrimination, ROC analysis indicated thresholds for: CFE-StdDev at 58 ms (sensitivity: 0.892, specificity: 0.716; area under ROC curve: 0.821, p ≤ 0.0001); ACI at 85 ms (0.869; 0.681; 0.784, ≤0.0001, respectively); and SCI at 62 ms (0.876; 0.738; 0.865; ≤0.0001, respectively). | CFAE metrics & thresholds | % of EGMs categorised as CFAEs | |:------------------------- | ------------------------------ | | ICL > =4 | 58% | | ICL > =5 | 51% | | ICL > =6 | 44% | | ICL > =7 | 36% | | CFEmean (30-120 ms) | 70% | Table 1 Conclusions: Ablation reduces fractionation irrespective of whether ICL or CFEmean are used for CFAE assessment, implying that both CARTO and NavX are sensitive to similar atrial substrate electrical characteristics. However, CFAE categorisation as performed by the two systems does not always agree, which may potentially affect substrate mapping and ablation targeting. The thresholds for CFE-StdDev, ACI and SCI suggested here could be used concurrently with CFEmean and/or ICL to improve CFAE classification and potentially increase CFAE-guided ablation specificity. ![Graphic][2] Figure 1(A) CFEmean and ICL pre-/ vs. post-ablation. (B) % agreement between CFAE categorisation as performed by CFEmean and ICL. (C) ROC curves for CFE-StdDev, ACI and SCI for discriminating CFAEs based on the agreement between both NavX and CARTO. [1]: #T1 [2]: /embed/inline-graphic-1.gif

Introduction: The dominant frequency (DF) of atrial electrograms (EGMs) is believed to reflect atrial substrate with periodic activation responsible for the maintenance of persistent atrial fibrillation (persAF). This study assessed whether ablation for persAF affected DF spatio-temporal behaviour using global simultaneous non-contact mapping. Methods: Five patients with symptomatic longstanding persAF (duration of 34±25 months) undergoing first time ablation were recruited. A non-contact array catheter (EnSite Array, St. Jude Medical) was deployed in the left atrium (LA) both pre- and post-pulmonary vein isolation, but prior to any other substrate modification. Virtual unipolar EGMs were collected simultaneously from 2048 nodes on the LA geometry.After ventricular far-field influence cancellation, fast Fourier transform was used to determine the DF for each EGM. DF was defined within the range of 4Hz to 10 Hz (4 s time window; 50% overlap; up to 38 s per patient). Highest DF (HDF) regions for each individual window were defined as any LA geometry nodes where the calculated DF was within 0.25 Hz of the maximum DF measured for that window. The spatio-temporal behaviour of the HDF areas was studied pre- and post-ablation by assessing the proportion of time for which each node was defined as a HDF region, and compared using the paired-samples t-test. Results: Prior to ablation, considering all patients, an average of 24.5% of the LA was defined as an HDF area for any given time. This decreased significantly to 11.2% post-ablation (p

Regional turboprop passenger aircraft are more fuel efficient than equivalent regional turbofan jets. Aerodynamic interaction between the propeller and the aircraft wing and body cause higher noise and vibration in the turboprop cabin than in jets; to improve the passenger cabin of turboprops, an improve comfort model is required to enable design optimization. Three age-stratified focus groups were conducted with the aim of eliciting passenger priorities for comfort in aircraft cabins. Participants discussed view elicited in response to images of different aircraft, and aircraft interiors. Transcriptions of the focus groups were coded using NVivo and the most common thematic areas identified for each age group. Physical comfort (space and seat design), the physical environment (noise, air quality, vibration, thermal), safety and hygiene were the most commonly coded thematic areas. The oldest group (50–70) rated the thermal environment as more important than younger groups. Turboprop aircraft were considered noisy and to be less comfortable than turbojets. However, noise and vibration were considered to be outside of the passenger’s control and therefore accepted.

Rotors have been related to atrial fibrillation (AF) maintenance. We analyzed the behavior of rotors in persistent AF (persAF) utilizing a novel non-contact methodology and compared this to real time dominant frequency (DF) analysis. 2048 noncontact virtual unipolar atrial electrograms (VEGMs) were collected simultaneously (EnSite Array, St. Jude Medical) from 10 persAF patients (duration: 34 ± 25 months) undergoing left atrial (LA) ablation. After QRST-removal, FFT was used to identify the global DF of the LA (range 4-10 Hz; 1 s time-window; 50 % overlap; highest DF (HDF) (DF -0.25 Hz); up to 20 s/patient). The organization index (OI) was measured and phase was found via Hilbert-transform. Phase singularities (PSs) were tracked and were categorized according to their lifespan into short (lifespan 100 ms). A total of 4578 PSs were tracked. 5.05 % (IQR: 2.75 ~ 30.25 %) of the tracked PSs were long-lived and were observed in 11 % (IQR: 2.75 ~ 17.5 %) of the windows. The windows with rotors showed significantly higher HDF (mean ± SD, 8.0 ± 0.43 Hz vs 7.71 ± 0.50 Hz, p