Intrinsic Duration Research Articles

Developmental Aspects of Greek Vowel Reduction in Different Prosodic Positions

This study investigates the development of Greek vowel reduction across different prosodic positions (stressed, pre-stressed, post-stressed), examining normative data from 72 participants aged 3 years to adulthood and balanced for gender. Participants performed a delayed repetition task, producing real trisyllabic words with the vowels [i, ε, ɐ, o, u] examined in the second syllable. Measurements included relative vowel duration, normalized acoustic vowel space areas, and Euclidean distances of vowels from the centroid of the acoustic space. Our findings show that changes in speech motor control, system stiffness, and stress marking with age, along with children’s prosody sensitivity, contributed to several developmental milestones: the completion of the developmental trajectory of relative vowel duration and temporal vowel reduction at early adolescence; the attainment of adult-like spatial vowel characteristics and their reduction at preschool age; and the early acquisition of the prosodic strength of the stress conditions, leading to vowel reduction from the stressed to pre-stressed to post-stressed conditions. The correlation strength between temporal and spatial vowel reduction across ages revealed age-related differences in spatiotemporal speech organization, with significant gender-related differences observed only in vowel space areas, where females exhibited larger areas possibly related to sociophonetic factors. Intrinsic vowel duration appeared from age 3.

Septal late enhancement by cardiac CT is associated with repeat ablation in nonischemic cardiomyopathy patients.

Scar substrate in nonischemic cardiomyopathy (NICM) patients is often difficult to identify. Advances in cardiac imaging, especially using late iodine-enhanced computed tomography (LIE-CT), allow better characterization of scars giving rise to ventricular tachycardia (VT). Currently, there are limited data on clinical correlates of CT-derived scar substrates in NICM. We sought assess the relationship between scar location on LIE-CT and outcomes after radiofrequency catheter ablation (RFCA) in NICM patients with VT. From 2020 to 2022, consecutive patients with NICM undergoing VT RFCA with integration of cardiac CT scar modeling (inHeart, Pessac, France) were included at two US tertiary care centers. The CT protocol included both arterial-enhanced imaging for anatomical modeling and LIE-CT for scar assessment. The distribution of substrate on CT was analyzed in relation to patient outcomes, with primary endpoints being VT recurrence and the need for repeat ablation procedure. Sixty patients were included (age 64 ± 12 years, 90% men). Over a median follow-up of 120 days (interquartile range [IQR]: 41-365), repeat ablation procedures were required in 32 (53%). VT recurrence occurred in 46 (77%), with a median time to recurrence of 40 days (IQR: 8-65). CT-derived total scar volume positively correlated with intrinsic QRS duration (r = .34, p = 0.008). Septal scar was found on CT in 34 (57%), and lateral scar in 40 (7%). On univariate logistic regression, septal scar was associated with increased odds of repeat ablation (odds ratio [OR]: 2.9 [1.0-8.4]; p = 0.046), while lateral scar was not (OR: 0.9 [0.3-2.7]; p = 0.855). Septal scar better predicted VT recurrence when compared to lateral scar, but neither were statistically significant (septal scar OR: 3.0 [0.9-10.7]; p = 0.078; lateral scar OR: 1.7 [0.5-5.9]; p = 0.391). In this tertiary care referral population, patients with NICM undergoing VT catheter ablation with septal LIE-CT have nearly threefold increased risk of need for repeat ablation.

The Impact of Intravenous Ferric Carboxymaltose on Reverse Electrical Remodeling Following Cardiac Resynchronization Therapy.

The influence of intravenous ferric carboxymaltose (FCM) on reverse electrical remodeling (RER) in patients with heart failure with reduced ejection fraction (HFrEF) post-cardiac resynchronization therapy (CRT) is unknown. This study examines the effect of iron replacement using intravenous FCM on RER in CRT-implanted HFrEF patients with iron deficiency anemia. We retrospectively analyzed 65 patients with successful CRT-defibrillator between March 2017 and January 2020, all with iron deficiency anemia at implantation. The cohort comprised 35 patients in the FCM group and 30 in the non-FCM group. Follow-up data were obtained from visits 6 months post-CRT implantation including baseline characteristics, echocardiographic left ventricular measurements, and electrocardiograms. Changes in intrinsic QRS duration (iQRS) and left ventricular ejection fraction (LVEF) from baseline to 6 months were assessed. The FCM group showed a greater reduction in iQRS duration compared to the non-FCM group (-10.4 ± 2.2 ms vs. -3 ± 2.9 ms, p < 0.0001). Additionally, at the 6-month follow-up, the increase in LVEF was higher in the FCM group than in the non-FCM group (+3.6 ± 1.6% vs. -0.1 ± 1.7%, p < 0.0001). Correlations were found between changes in ferritin levels and iQRS duration (r = -0.725, p < 0.0001) and LVEF (r = 0.712, p < 0.0001). Multivariate regression analysis revealed that elevated ferritin independently influenced the increase in LVEF (p = 0.006, β = 0.554) and the decrease in iQRS (p < 0.001, β = -0.685). Intravenous iron treatment with FCM may reduce iQRS duration and improve LVEF and functional status in HFrEF patients with iron deficiency anemia following CRT.

Sex- and age-dependent susceptibility to ventricular arrhythmias in the rat heart ex vivo

The incidence of life-threatening ventricular arrhythmias, the most common cause of sudden cardiac death (SCD), depends largely on the arrhythmic substrate that develops in the myocardium during the aging process. There is a large deficit of comparative studies on the development of this substrate in both sexes, with a particular paucity of studies in females. To identify the substrates of arrhythmia, fibrosis, cardiomyocyte hypertrophy, mitochondrial density, oxidative stress, antioxidant defense and intracellular Ca2+ signaling in isolated cardiomyocytes were measured in the hearts of 3- and 24-month-old female and male rats. Arrhythmia susceptibility was assessed in ex vivo perfused hearts after exposure to isoproterenol (ISO) and hydrogen peroxide (H2O2). The number of ventricular premature beats (PVBs), ventricular tachycardia (VT) and ventricular fibrillation (VF) episodes, as well as intrinsic heart rate, QRS and QT duration, were measured in ECG signals recorded from the surfaces of the beating hearts. After ISO administration, VT/VFs were formed only in the hearts of males, mainly older ones. In contrast, H2O2 led to VT/VF formation in the hearts of rats of both sexes but much more frequently in older males. We identified several components of the arrhythmia substrate that develop in the myocardium during the aging process, including high spontaneous ryanodine receptor activity in cardiomyocytes, fibrosis of varying severity in different layers of the myocardium (nonheterogenic fibrosis), and high levels of oxidative stress as measured by nitrated tyrosine levels. All of these elements appeared at a much greater intensity in male individuals during the aging process. On the other hand, in aging females, antioxidant defense at the level of H2O2 detoxification, measured as glutathione peroxidase expression, was weaker than that in males of the same age. We showed that sex has a significant effect on the development of an arrhythmic substrate during aging. This substrate determines the incidence of life-threatening ventricular arrhythmias in the presence of additional stimuli with proarrhythmic potential, such as catecholamine stimulation or oxidative stress, which are constant elements in the pathomechanism of most cardiovascular diseases.

Long-Term Outcomes of Resynchronization–Defibrillation for Heart Failure

BackgroundThe Resynchronization–Defibrillation for Ambulatory Heart Failure Trial (RAFT) showed a greater benefit with respect to mortality at 5 years among patients who received cardiac-resynchronization therapy (CRT) than among those who received implantable cardioverter–defibrillators (ICDs). However, the effect of CRT on long-term survival is not known.MethodsWe randomly assigned patients with New York Heart Association (NYHA) class II or III heart failure, a left ventricular ejection fraction of 30% or less, and an intrinsic QRS duration of 120 msec or more (or a paced QRS duration of 200 msec or more) to receive either an ICD alone or a CRT defibrillator (CRT-D). We assessed long-term outcomes among patients at the eight highest-enrolling participating sites. The primary outcome was death from any cause; the secondary outcome was a composite of death from any cause, heart transplantation, or implantation of a ventricular assist device.ResultsThe trial enrolled 1798 patients, of whom 1050 were included in the long-term survival trial; the median duration of follow-up for the 1050 patients was 7.7 years (interquartile range, 3.9 to 12.8), and the median duration of follow-up for those who survived was 13.9 years (interquartile range, 12.8 to 15.7). Death occurred in 405 of 530 patients (76.4%) assigned to the ICD group and in 370 of 520 patients (71.2%) assigned to the CRT-D group. The time until death appeared to be longer for those assigned to receive a CRT-D than for those assigned to receive an ICD (acceleration factor, 0.80; 95% confidence interval, 0.69 to 0.92; P=0.002). A secondary-outcome event occurred in 412 patients (77.7%) in the ICD group and in 392 (75.4%) in the CRT-D group.ConclusionsAmong patients with a reduced ejection fraction, a widened QRS complex, and NYHA class II or III heart failure, the survival benefit associated with receipt of a CRT-D as compared with ICD appeared to be sustained during a median of nearly 14 years of follow-up. (RAFT ClinicalTrials.gov number, NCT00251251.)

The Intrinsic Statistical Properties and Correlations of Short Gamma-Ray Bursts

The intrinsic statistical properties and correlations of short gamma-ray bursts (SGRBs) have not been fully determined, due to the limitations of observations. In this paper, we compile a more extensive sample of 82 SGRBs with measured redshifts and present a comprehensive study of their intrinsic characteristics. We obtain the median values of the intrinsic duration (T 90,z), peak energy (E p,z), isotropic energy (E iso), and peak luminosity (L iso) as 0.47 s, 466 keV, 8.21 ×1050 erg, and 3.22 × 1051 erg s−1, respectively. We update the spectrum–energy correlations, and report and , which further confirm the previous results that the E p,z–E iso correlations of SGRBs and long gamma-ray bursts (LGRBs) are different and that this correlation can be used to distinguish GRB types. We report for the first time that there is a tighter correlation between the isotropic energy of the prompt emission of SGRBs and the star formation rate of their host galaxies, which reads . Using the measured jet break time (t jet) of 11 SGRBs, we tentatively investigate the E iso–E p,z–t jet,z and L iso–E p,z–t jet,z correlations of SGRBs and find that three-parameter correlations of SGRBs also exist and are different from those of LGRBs. Based on the E iso–E p,z–t jet,z correlation, we estimate the t jet,z values of other SGRBs and calculate the opening angles of SGRBs. We find that the median value of the SGRB opening angle is 7.°5, which is larger than that of LGRBs.

GRB 191019A: A Short Gamma-Ray Burst in Disguise from the Disk of an Active Galactic Nucleus

Long and short gamma-ray bursts (GRBs), canonically separated at around 2 s duration, are associated with different progenitors: the collapse of a massive star and the merger of two compact objects, respectively. GRB 191019A was a long GRB (T 90 ∼ 64 s). Despite the relatively small redshift z = 0.248 and Hubble Space Telescope follow-up observations, an accompanying supernova was not detected. In addition, the host galaxy did not have significant star formation activity. Here we propose that GRB 191019A was produced by a binary compact merger, whose prompt emission was stretched in time by the interaction with a dense external medium. This would be expected if the burst progenitor was located in the disk of an active galactic nucleus, as supported by the burst localization close to the center of its host galaxy. We show that the light curve of GRB 191019A can be well modeled by a burst of intrinsic duration t eng = 1.1 s and of energy E iso = 1051 erg seen moderately off axis, exploding in a medium of density ∼107–108 cm−3. The double-peaked light curve carries the telltale features predicted for GRBs in high-density media, where the first peak is produced by the photosphere and the second by the overlap of reverse shocks that take place before the internal shocks could happen. This would make GRB 191019A the first confirmed stellar explosion from within an accretion disk, with important implications for the formation and evolution of stars in accretion flows and for gravitational-waves source populations.

The impact of intravenous ferric carboxymaltose on reverse electrical remodeling following cardiac resynchronization therapy

Abstract Funding Acknowledgements Type of funding sources: None. Background The effect of intravenous ferric carboxymaltose (FCM) on reverse electrical remodeling (RER) in patients with heart failure with reduced ejection fraction (HFrEF) following cardiac resynchronization therapy (CRT) implantation is unknown. Purpose The current study aims to examine the effect of iron replacement with intravenous FCM on RER in CRT-implanted patients with HFrEF and iron deficiency. Methods The present study retrospectively analyzed 65 patients with successful CRT-D device implantation between March 2017 and January 2020 with iron deficiency (defined as ferritin &amp;lt;100 μg/L) at implantation. Follow-up data were obtained from the 6-month routine follow-up visits of patients following CRT implantation. Demographic characteristics, laboratory results, medical history, medication details, functional status, information on whether intravenous FCM therapy was administered during CRT device implantation, echocardiographic left ventricular (LV) measurements, baseline electrocardiogram (ECG) recorded before CRT device implantation, and follow-up ECG were collected for analysis for each study patient. From baseline to 6-month follow-up, the change in intrinsic QRS duration (without biventricular pacing) was calculated as a primary endpoint, and the change in LV ejection fraction (LVEF) was assessed as a secondary endpoint of the study. Results Thirty-five of 65 patients were in the FCM group, while the remaining 30 study participants were in the non-FCM. The two study groups were similar regarding baseline characteristics, except for ferritin levels, which were minimally significantly lower in the FCM group (10.7±5.0μg/L vs 13.5 ±3.9μg/L, p= 0.012). At the 6-month follow-up, both mean ferritin levels increased significantly in the FCM group compared to baseline (from 10.7±5.0 to 86.5±7.6μg/L, p &amp;lt; 0.0001), while these levels were not significantly increased in the non-FCM group (from 13.5±3.9 to 14.1±4.2μg/L, p = 0.962). There was a significant reduction in intrinsic QRS durations compared to baseline at 6-month follow-up after CRT implantation in both FCM and non-FCM group (from 148.4±5.3 to 138.0±5.1ms, p &amp;lt; 0.0001; from 149.8±5.0 to 146.8±4.6ms, p &amp;lt; 0.0001, respectively). The change in intrinsic QRS duration from baseline to 6-month follow-up was significantly greater in the FCM group than in the non-FCM group (-10.4±2.2ms vs -3±2.9ms, p &amp;lt; 0.0001). At the 6-month follow-up, the change in LVEF from baseline was significantly higher in the FCM group than in the non-FCM group (+3.6±1.6% vs -0.1±1.7%, p &amp;lt; 0.0001). The change in ferritin level was negatively correlated with the change in intrinsic QRS duration (r = -0.725, p &amp;lt; 0.0001), whereas there was a positive correlation between the change in ferritin level and the change in LVEF (r = 0.712, p &amp;lt; 0.0001). Conclusions Treatment with FCM was induced RER and improvement in LVEF in HFrEF patients with iron deficiency following CRT implantation.

Left bundle branch area pacing guided by electroanatomical mapping in patients with structural heart disease and advanced conduction abnormalities

Abstract Funding Acknowledgements Type of funding sources: None. Background Left bundle branch area pacing (LBBAP) can be technically challenging and fluoroscopy-intense, particularly in patients with structural heart disease (SHD) and advanced conduction abnormalities. Three-dimensional electroanatomical mapping (EAM) facilitates high-resolution, real-time, and non-fluoroscopic lead navigation, electrogram and pace mapping. Purpose The purpose of the study was to prospectively evaluate the feasibility, safety, and outcomes of routine EAM-guided LBBAP in patients with SHD and advanced conduction abnormalities. Methods Consecutive patients with SHD and advanced conduction abnormalities (defined as second or third-degree atrioventricular (AV) block and/or complete bundle branch block) who underwent an attempt at EAM-guided LBBAP were included. EAM-guided lead implantation was performed in all patients following a standardized protocol irrespective of the pacing indication and type of conduction disturbance. The feasibility, safety, procedural and mid-term outcomes were evaluated. Electrical, echocardiographic, and clinical parameters were assessed at implantation and last follow-up. Results Thirty-two patients (68±18 years; 19% female) were included. The indication for pacing was cardiac resynchronization therapy in 50%, AV block in 44%, and pace-and-ablate in 6% of patients; 24 patients (75%) had an intrinsic QRS &amp;gt;150 ms, 17 (53%) had LBBB. Primary EAM-guided LBBAP was successful in 29 patients (91%). Procedural duration was 95 (70-110) min, total fluoroscopy time 0.93 (0.40-1.73) min, and total fluoroscopy dose 35.4 (20.5-77.2) cGycm2 (Figure 1A). The paced QRS duration during LBBAP was significantly shorter than the baseline intrinsic QRS duration (121.9±10.7 vs. 159.2±34.4 ms; p&amp;lt;0.001) (Figure 1B) and remained stable (120.3±11.1 ms; p=0.370) during a mean follow-up of 7.0±5.9 (median 5.4 [IQR 2.1-12.6]) months. LBBAP capture threshold was 0.57±0.23V/0.4ms at implantation and remained low during follow-up (0.58±0.18V/0.5±0.2ms; p=0.877). There was no increase in LBBAP capture threshold &amp;gt;1.0V/0.4 ms during follow-up. Overall LVEF improved significantly from 44.2±14.3% at baseline to 49.4±13.1% at last follow-up (p=0.009), NYHA functional class from 2.4±0.6 to 1.8±0.6 (p=0.002), respectively (Figure 1C+D). No complications occurred that required intervention. Conclusion Routine near-zero fluoroscopy EAM-guided LBBAP can safely be performed in patients with SHD and advanced conduction abnormalities with high success rates and favourable mid-term outcomes. Further studies are needed to investigate whether the use of EAM improves overall outcome of conduction system pacing, and to identify specific patient populations who benefit the most from EAM-guided lead implantation.

PO-05-005 SEPTAL LATE ENHANCEMENT BY CARDIAC CT IS SIGNIFICANTLY ASSOCIATED WITH VT RECURRENCE AFTER CATHETER ABLATION IN PATIENTS WITH NONISCHEMIC CARDIOMYOPATHY

Scar substrate in patients with nonischemic cardiomyopathy (NICM) is often difficult to identify and characterize. Advances in cardiac imaging, especially using late iodine-enhanced CT (LIE-CT), allow better characterization of scars that give rise to the arrhythmia. Currently, there is limited data on clinical correlates of CT-derived scar substrates in NICM patients and outcomes. To assess relationship between scar location on LIE-CT and outcomes. Consecutive patients from 2018-2020 with non-ischemic cardiomyopathy undergoing index ventricular tachycardia (VT) radiofrequency ablation (RFA) and pre procedural cardiac CT scar modeling (InHeart models, Pessac, France) at Brigham and Women’s Hospital and Medical University of South Carolina were included. 3 patients had VT ablations at an outside facility prior to index ablation at our centers. 5 patients had CT data that could not be interpreted and were excluded. Primary endpoints were need for repeat procedure post index ablation and VT recurrence. 63 patients, mean age 63+/-12y, 90% male, mean EF 39+/-14%. 33 patients (52%) required repeat procedures. 49 patients (78%) had VT recurrence with average time to recurrence of 59 days. CT derived total scar volume was also found to be positively correlated with intrinsic QRS duration (r=0.35, p=0.005) similar to what has been shown in prior studies of cardiac MRI-detected late gadolinium enhancement. 35 patients (56%) had septal scar on cardiac CT and 42 (67%) had lateral scar (figure 1). Univariate logistic regression showed that septal scar on CT was predictive of need for repeat ablation with OR 2.9 (p=0.049; 1.0-8.4). In contrast, lateral scar did not show a statistically significant relationship (p=0.364; OR = 0.6; 0.1-1.8). Septal scar better predicted VT recurrence when compared to lateral scar, but neither were statistically significant (p=0.089; OR 2.9; 0.5-10.6 and p=0.547;OR 1.48; 0.4-5.3, respectively). In this tertiary care referral population, patients with NICM undergoing VT catheter ablation with septal LIE-CT have nearly 3-fold increased risk of VT recurrence.

A novel approach for developing left bundle branch pacing and left bundle branch block in a canine model.

Left bundle branch pacing (LBBP) has shown the benefits in the treatment of dyssynchronous heart failure (HF). The purpose of this study was to develop a novel approach for LBBP and left bundle branch block (LBBB) in a canine model. A "triangle-center" method by tricuspid valve annulus angiography for LBBP implantation was performed in 6 canines. A catheter was then applied for retrograde His potential recording and left bundle branch (LBB) ablation simultaneously. The conduction system was stained to verify the "triangle-center" method for LBBP and assess the locations of the LBB ablation site in relation to the left septal fascicle (LSF). The mean LBB potential to ventricular interval and stimulus-peak left ventricular activation time were 11.8 ± 1.2 and 35.7 ± 3.1 ms, respectively. The average intrinsic QRS duration was 44.7 ± 4.7 ms. LBB ablation significantly prolonged the QRS duration (106.3 ± 8.3 ms, p < .001) while LBBP significantly shortened the LBBB-QRS duration to 62.5 ± 5.3 ms (p < .001). After 6 weeks of follow-up, both paced QRS duration (63.0 ± 5.4 ms; p = .203) and LBBB-QRS duration (107.3 ± 7.4 ms; p = .144) were unchanged when comparing to the acute phase, respectively. Anatomical analysis of 6 canine hearts showed that the LBBP lead-tip was all placed in LSF area. The new approach for LBBP and LBBB canine model was stable and feasible to simulate the clinical dyssynchrony and resynchronization. It provided a useful tool to investigate the basic mechanisms of underlying physiological pacing benefits.

Radio-bright versus radio-dark gamma-ray bursts – more evidence for distinct progenitors

ABSTRACT We analyse two distinct samples of gamma-ray bursts (GRBs), with and without radio afterglow emission. We use an updated sample of 211 GRBs and find, in agreement with previous results (although with a sample that is almost twice as large), that the intrinsic gamma-ray duration (Tint) and isotropic equivalent energy (Eiso) distributions between these two populations appear to be significantly different. This implies that the radio-bright GRBs are more energetic and last longer than radio-dark GRBs. The two samples’ redshift distributions (z) are not statistically different. We analyse several correlations between variables (Eiso, Tint, jet opening angle, and z), accounting for selection effects and redshift evolution using the Efron–Petrosian method. We find a statistically significant anticorrelation between the jet opening angle and redshift, as well as between Tint and redshift, for both radio-bright and radio-dark GRBs. Finally, in agreement with previous work, we find that very high energy (0.1–100 GeV) extended emission is present only in the radio-bright GRB sample. Our work supports the possibility that the radio-bright and radio-dark GRBs originate from different progenitors.

Effects of Word Stress on Vowel Duration and Vowel Quality in the Speech of Korean Learners of English

Unstressed English vowels are reduced in their durational and spectral aspects. Vowel reduction in relation to word stress in English has been one of the challenges faced by Korean learners of English in learning English vowel system. In this study, we investigated effects of word stress on the vowel duration and vowel quality. This study focused on two unstressed vowels (/ə/ and /ɪ/) and three stressed vowels (/ʌ/, /ɪ/, and /i/). Words with five target vowels in the first syllable of word were collected from sentences produced by two subject groups. Vowel durations and first and second formant values were calculated and analyzed for the effect of stress which interplayed with intrinsic vowel duration and vowel quality. Study results indicated that speech data of Korean learners of English had much less magnitude in vowel shortening and reduction of vowel quality in unstressed vowels than those of English speakers. In addition, the five target vowels tended to be grouped into two in vowel space for Korean learners of English. Pedagogical implications of this study are discussed to improve learning and teaching English vowel system for Korean learners of English.

His bundle combined with deep septal left bundle branch area pacing for atrial fibrillation prior to atrioventricular node ablation.

To mitigate the risk of dyssynchrony-induced cardiomyopathy, international guidelines advocate His bundle pacing (HBP) with a ventricular backup lead prior to atrioventricular node ablation in treatment-refractory atrial fibrillation and normal left ventricular ejection fraction. As a result of concerns with long-term pacing parameters associated with HBP, this case series reports an adopted strategy of HBP combined with deep septal left bundle branch area pacing (dsLBBAP) in this patient cohort, enabling intrapatient comparison of the two pacing methods. Eight patients aged 72 ± 10 years (left ventricular ejection fraction 53 ± 4%) underwent successful combined HBP and dsLBBAP implant prior to AV node ablation. Intrinsic QRS duration was 118 ± 46 ms. When compared to dsLBBAP, HBP had lower sensed ventricular amplitude (2.4± 1.1 vs. 15 ± 5.3V, p= .001) and lower lead impedance (522 ± 57 vs. 814 ± 171ohms, p= .02), but shorter paced QRS duration (101 ± 20 vs. 119 ± 17 ms, p= .02). HBP pacing threshold was 1.0± 0.6V at 1ms pulse width, and dsLBBAP pacing threshold was 0.5± 0.2V at 0.4ms pulse width. Five patients underwent cardiac CT showing adequate dsLBBAP ventricular septal penetration (8.6± 1.3 mm depth, 2.4± 0.5 mm distance from left ventricular septal wall). No complications occurred during a mean follow-up duration of 121 ± 92 days. Combined HBP and dsLBBAP pacing is a feasible approach as a pace and ablate strategy for atrial fibrillation refractory to medical therapy.

Linking trait network to growth performance of submerged macrophytes in response to ammonium pulse

Extreme precipitation events caused by climate change leads to large variation of nitrogen input to aquatic ecosystems. Our previous study demonstrated the significant effect of different ammonium pulse patterns (differing in magnitude and frequency) on submersed macrophyte growth based on six plant morphological traits. However, how connectivity among plant traits responds to nitrogen pulse changes, which in turn affects plant performance, has not yet been fully elucidated. The response of three common submersed macrophytes (Myriophyllum spicatum, Vallisneria natans and Potamogeton maackianus) to three ammonium pulse patterns was tested using plant trait network (PTN) analysis based on 18 measured physiological and morphological traits. We found that ammonium pulses enhanced trait connectivity in PTN, which may enable plants to assimilate ammonium and/or mitigate ammonium toxicity. Large input pulses with low frequency had stronger effects on PTNs compared to low input pulses with high frequency. Due to the cumulative and time-lagged effect of the plant response to the ammonium pulse, there was a profound and prolonged effect on plant performance after the release of the pulse. The highly connected traits in PTN were those related to biomass allocation (e.g., plant biomass, stem ratio, leaf ratio and ramet number) rather than physiological traits, while phenotype-related traits (e.g., plant height, root length and AB ratio) and energy storage-related traits (e.g., stem starch) were least connected. V. natans showed clear functional divergence among traits, making it more flexible to cope with unfavorable habitats (i.e., high input pulses with low frequencies). M. spicatum with high RGR revealed strong correlations among traits and thus supported nitrogen accumulation from favourable environments (i.e., low input pulses with high frequencies). Our study highlights the responses of PTN for submerged macrophytes to ammonium pulses depends on their intrinsic metabolic rates, the magnitude, frequency and duration of the pulses, and our results contribute to the understanding of the impact of resource pulses on the population dynamics of submersed macrophytes within the context of global climate change.

Reclassifying Swift Gamma-Ray Bursts with Diverse Duration Distributions

We select the largest sample of Swift gamma-ray bursts (GRBs) so far to reexamine the classification in terms of time duration, hardness ratio, and physical collapse model. To analyze the sample selection effect, we divide the observed Swift GRB sample into four subsamples according to signal-to-noise level, spectral quality, and extended emission. First, we find that only the sample of Swift GRBs with well-measured peak energy can be evidently divided into two types at a boundary of ∼1 s, and other data sets are well described by three Gaussian functions. Using Swift GRBs with known redshift, a Kolmogorov–Smirnov test shows the intrinsic duration distributions of five data sets are equally distributed. Second, we ascertain in the plane of hardness ratio versus duration that the hardness ratio of short GRBs is significantly higher than those of middle classes and long GRBs, while the latter two components are the same in statistics, implying the so-called middle class to be artificial. Third, we apply a collapse model to discriminate the boundaries between collapse and noncollapse Swift bursts. It is interesting to find that a significant fraction, ≥30%, of Swift short GRBs could have originated from the collapsing progenitors, while all long GRBs are produced from the collapsars only. Finally, we point out that short GRBs with extended emission are the main contributors to the noncollapsar population with longer duration.

Iconic Associations Between Vowel Acoustics and Musical Patterns, and the Musical Protolanguage Hypothesis

Vowels are the most musical and sonic elements of speech. Previous studies found non-arbitrary associations between vowel intrinsic pitch and musical pitch in senseless syllables. In songs containing strings of senseless syllables, vowels are connected to melodic direction in close correspondence to their intrinsic pitch or the frequency of the second formant F2. This paper shows that also vowel intrinsic duration is related to musical patterns. It is generally assumed that low vowels like [a ɔ o] have a higher intrinsic duration than high vowels like [i y u] and that there is a positive correlation between the first formant F1 and duration. Analyzing 20 traditional Alpine yodels I found that vowels with longer intrinsic duration tend to align with longer notes, whereas vowels with shorter intrinsic duration with shorter notes. This new result might shed some light on size-sound symbolism in general: Since there is a direct match between vowel intrinsic duration and the “size” of musical notes, there is no need to explain the “size” of musical notes via Ohala's “frequency code” hypothesis. Moreover, I will argue that the iconic associations found between vowel acoustics and musical patterns support the idea of a sound-symbolic musical protolanguage. Such a protolanguage may have started with vowel syllables conveying pitch, timbre, as well as emotional, indexical, and sound-symbolic information.

On the relationship between the duration and energy of non-repeating fast radio bursts: census with the CHIME data

ABSTRACT A correlation between the intrinsic energy and the burst duration of non-repeating fast radio bursts (FRBs) has been reported. If it exists, the correlation could be used to estimate the intrinsic energy from the duration, and thus could provide a new distance measure for cosmology. However, the correlation arose from small-number statistics (68 FRBs) and was not free from contamination by latent repeating populations, which might not have such a correlation. Finding a way to separate/exclude the repeating bursts from the mixture of all different types of FRBs is essential for investigating this property. Using a much larger sample from the new FRB catalogue (containing 536 FRBs) recently released by the CHIME (Canadian Hydrogen Intensity Mapping Experiment)/FRB Project, combined with a new classification method developed based on unsupervised machine learning, we carried out further scrutiny of the relationship. We found that there is a weak correlation between the intrinsic energy and duration for non-repeating FRBs at z &amp;lt; 0.3, with a Kendall τ correlation coefficient of 0.239 and a significance of 0.001 (statistically significant), whose slope looks similar to that of gamma-ray bursts. This correlation becomes weaker and insignificant at higher redshifts (z &amp;gt; 0.3), possibly owing to the lack of faint FRBs at high z and/or the redshift evolution of the correlation. The ‘scattering time’ in the CHIME/FRB catalogue shows an intriguing trend: it varies along the line obtained from a linear fit on the energy versus duration plane between these two parameters. A possible cosmological application of the relationship must wait for more observations of faint FRBs at high z.

Heart Rate Variability Reveals Altered Autonomic Regulation in Response to Myocardial Infarction in Experimental Animals.

The analysis of beating rate provides information on the modulatory action of the autonomic nervous system on the heart, which mediates adjustments of cardiac function to meet hemodynamic requirements. In patients with myocardial infarction, alterations of heart rate variability (HRV) have been correlated to the occurrence of arrhythmic events and all-cause mortality. In the current study, we tested whether experimental rodent models of myocardial infarction recapitulate dynamics of heart rate variability observed in humans, and constitute valid platforms for understanding mechanisms linking autonomic function to the development and manifestation of cardiovascular conditions. For this purpose, HRV was evaluated in two engineered mouse lines using electrocardiograms collected in the conscious, restrained state, using a tunnel device. Measurements were obtained in naïve mice and animals at 3–∼28 days following myocardial infarction, induced by permanent coronary artery ligation. Two mouse lines with inbred and hybrid genetic background and, respectively, homozygous (Homo) and heterozygous (Het) for the MerCreMer transgene, were employed. In the naïve state, Het female and male mice presented prolonged RR interval duration (∼9%) and a ∼4-fold increased short- and long-term RR interval variability, with respect to sex-matched Homo mice. These differences were abrogated by pharmacological interventions inhibiting the sympathetic and parasympathetic axes. At 3–∼14 days after myocardial infarction, RR interval duration increased in Homo mice, but was not affected in Het animals. In contrast, Homo mice had minor modifications in HRV parameters, whereas substantial (> 50%) reduction of short- and long-term RR interval variation occurred in Het mice. Interestingly, ex vivo studies in isolated organs documented that intrinsic RR interval duration increased in infarcted vs. non-infarcted Homo and Het hearts, whereas RR interval variation was not affected. In conclusion, our study documents that, as observed in humans, myocardial infarction in rodents is associated with alterations in heart rhythm dynamics consistent with sympathoexcitation and parasympathetic withdrawal. Moreover, we report that mouse strain is an important variable when evaluating autonomic function via the analysis of HRV.

Upgrades from Previous Cardiac Implantable Electronic Devices Compared to De Novo Cardiac Resynchronization Therapy Implantations: Results from CRT Survey-II in the Turkish Population.

Cardiac resynchronization therapy is the guideline-directed treatment option in selected heart failure with reduced left ventricular ejection fraction patients. Data regarding the contemporary clinical practice of cardiac resynchronization therapy in Turkey have been published recently. This sub-study aims to compare clinical and periprocedural characteristics between cardiac resynchronization therapy upgrade and de novo implantations. Turkish arm of the Cardiac Resynchronization Therapy Survey-II was conducted between October 1, 2015, and December 31, 2016, at 16 centers. All consecutive patients who underwent an upgrade to cardiac resynchronization therapy system (n=60) or de novo cardiac resynchronization therapy implantation (n=335) were eligible. Distribution of age, gender, and heart failure etiology were similar in the 2 groups. Atrial fibrillation, valvular heart disease, and chronic kidney disease were more common in cardiac resynchronization therapy upgrade patients. Narrow intrinsic QRS duration and left ventricular ejection fraction being 75% in both groups, and only beta-blockers were prescribed at rates of >90% in both groups. Cardiac resynchronization therapy upgrades are performed with high procedural success rates and without excess periprocedural complication risk. Feared complications of cardiac resynchronization therapy upgrades due to the pre-existing device should not delay the procedure if indicated.