Association between Left Atrial Late Gadolinium Enhancement and Atrial Fibrillation: The Multi-Ethnic Study of Atherosclerosis (MESA)

Purpose

To determine the prevalence and correlates of left atrial (LA) late gadolinium enhancement (LGE) at cardiac MRI and its association with atrial fibrillation (AF) in a population-based sample from the Multi-Ethnic Study of Atherosclerosis (MESA).

Materials and Methods

In this secondary post hoc analysis of the MESA cohort (ClinicalTrials.gov no. NCT00005487), participants without AF underwent LGE cardiac MRI at the fifth examination (2010-2012). LA LGE burden was quantified using the image intensity ratio technique on biplane long-axis two-dimensional (2D) LGE images without fat saturation. Survival analysis was performed with log-rank testing and Cox regression.

Results

Of 1697 participants (mean age, 67 years ± 9 [SD]; 872 men), 1035 (61%) had LA LGE, and 75 (4.4%) developed AF during follow-up (median, 3.95 years). At univariable analysis, LA LGE was associated with age (β = .010 [95% CI: .005, .015], P < .001), diastolic blood pressure (β = .005 [95% CI: .001, .009], P = .02), HbA1c level (β = .06 [95% CI: .02, .11], P = .009), heart failure (β = .60 [95% CI: .11, 1.08], P = .02), LA volume (β = .008 [95% CI: .004, .012], P < .001), and LA function (emptying fraction, LA global longitudinal strain, LA early diastolic peak longitudinal strain rate, and LA late diastolic peak strain rate; all P < .05). After adjusting for the variables in the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) AF score, LA LGE independently helped predict incident AF (hazard ratio = 1.46 [95% CI: 1.13, 1.88], P = .003). The highest tertile (LGE > 2%) was twice as likely to develop AF.

Conclusion

Although limited by the 2D LGE technique employed, LA LGE was associated with adverse atrial remodeling and helped predict AF in a multiethnic population-based sample.Clinical trial registration no. NCT00005487Keywords: MR Imaging, Cardiac, Epidemiology Supplemental material is available for this article. © RSNA, 2023.

Energetic Electron Precipitation Driven by Electromagnetic Ion Cyclotron Waves from ELFIN's Low Altitude Perspective

We review comprehensive observations of electromagnetic ion cyclotron (EMIC) wave-driven energetic electron precipitation using data collected by the energetic electron detector on the Electron Losses and Fields InvestigatioN (ELFIN) mission, two polar-orbiting low-altitude spinning CubeSats, measuring 50-5000 keV electrons with good pitch-angle and energy resolution. EMIC wave-driven precipitation exhibits a distinct signature in energy-spectrograms of the precipitating-to-trapped flux ratio: peaks at >0.5 MeV which are abrupt (bursty) (lasting ∼17 s, or Δ L ∼ 0.56 ) with significant substructure (occasionally down to sub-second timescale). We attribute the bursty nature of the precipitation to the spatial extent and structuredness of the wave field at the equator. Multiple ELFIN passes over the same MLT sector allow us to study the spatial and temporal evolution of the EMIC wave - electron interaction region. Case studies employing conjugate ground-based or equatorial observations of the EMIC waves reveal that the energy of moderate and strong precipitation at ELFIN approximately agrees with theoretical expectations for cyclotron resonant interactions in a cold plasma. Using multiple years of ELFIN data uniformly distributed in local time, we assemble a statistical database of ∼50 events of strong EMIC wave-driven precipitation. Most reside at L ∼ 5 - 7 at dusk, while a smaller subset exists at L ∼ 8 - 12 at post-midnight. The energies of the peak-precipitation ratio and of the half-peak precipitation ratio (our proxy for the minimum resonance energy) exhibit an L -shell dependence in good agreement with theoretical estimates based on prior statistical observations of EMIC wave power spectra. The precipitation ratio's spectral shape for the most intense events has an exponential falloff away from the peak (i.e., on either side of ∼ 1.45 MeV). It too agrees well with quasi-linear diffusion theory based on prior statistics of wave spectra. It should be noted though that this diffusive treatment likely includes effects from nonlinear resonant interactions (especially at high energies) and nonresonant effects from sharp wave packet edges (at low energies). Sub-MeV electron precipitation observed concurrently with strong EMIC wave-driven >1 MeV precipitation has a spectral shape that is consistent with efficient pitch-angle scattering down to ∼ 200-300 keV by much less intense higher frequency EMIC waves at dusk (where such waves are most frequent). At ∼100 keV, whistler-mode chorus may be implicated in concurrent precipitation. These results confirm the critical role of EMIC waves in driving relativistic electron losses. Nonlinear effects may abound and require further investigation.

The influence of substance use on traumatic brain injury recovery and rehabilitation outcomes: The Outcome-ABI Study

OBJECTIVE

This study characterised substance-use (alcohol, illicit drugs, amphetamine) in traumatic brain injury (TBI) patients receiving rehabilitation to determine potential benefit of rehabilitation and whether substance-use influenced outcomes in moderate-severe TBI.

DESIGN

Prospective, longitudinal study of adults with moderate or severe TBI receiving inpatient rehabilitation.

SETTING

Specialist acquired brain injury rehabilitation centre in Melbourne, Australia.

PARTICIPANTS

153 consecutive TBI inpatients admitted between January 2016-December 2017 (24-months).

INTERVENTIONS

All TBI inpatients (n=153) received specialist brain injury rehabilitation in accordance with evidence-based guideline care at one, 42-bed rehabilitation centre.

MAIN OUTCOME MEASURES

Data were collected at time of TBI, upon rehabilitation admission and discharge and 12-months post-TBI. Recovery was measured by post-traumatic amnesia (PTA) length-days and change in Glasgow coma scale (admission-discharge). Functional independence was measured on the Functional Independence Measure, Functional Assessment Measure and Mayo Portland Adaptability Index (MPAI). Quality of life (QOL) was measured on the EuroQOL-5D-5L (EQ-5D-5L) and quality of life after brain injury (QOLIBRI) instruments.

RESULTS

Inpatients with history of illicit drug-use (n=54) reported lower QOL and adjustment at 12-months post-TBI compared to those with no-history (QOLIBRI social relationships: Ratio of Means (RoM)=0.808, p=0.028; MPAI-adjustment: IRR=1.273, p=0.032). Amphetamine-use at time of injury (n=10) was associated with quicker recovery (PTA length-days: IRR=0.173, p<0.01), however lower QOL at 12-months post-TBI was noted in those with a history of amphetamine-use (n=34) compared to those without (QOLIBRI bothered feelings: RoM=0.489, p=0.036).

CONCLUSION

All participants made improvements with rehabilitation post-TBI, however a history of substance-use was associated with lower reported 12-month QOL. Findings add insight to the associations between substance-use and acute recovery, potentially suggestive of a short-term recovery-promoting effect of amphetamine but highlighting the importance of rehabilitation to address long-term sequalae.

Neoadjuvant Chemotherapy With CAPOX Versus Chemoradiation for Locally Advanced Rectal Cancer With Uninvolved Mesorectal Fascia (CONVERT): Initial Results of a Phase III Trial

OBJECTIVE

To compare neoadjuvant chemotherapy (nCT) with CAPOX alone versus neoadjuvant chemoradiotherapy (nCRT) with capecitabine in locally advanced rectal cancer (LARC) with uninvolved mesorectal fascia (MRF).

BACKGROUND DATA

nCRT is associated with higher surgical complications, worse long-term functional outcomes, and questionable survival benefits. Comparatively, nCT alone seems a promising alternative treatment in lower-risk LARC patients with uninvolved MRF.

METHODS

Patients between June 2014 and October 2020 with LARC within 12 cm from the anal verge and uninvolved MRF were randomly assigned to nCT group with 4 cycles of CAPOX (Oxaliplatin 130 mg/m2 IV day 1 and Capecitabine 1000 mg/m2 twice daily for 14 d. Repeat every 3 wk) or nCRT group with Capecitabine 825 mg/m² twice daily administered orally and concurrently with radiation therapy (50 Gy/25 fractions) for 5 days per week. The primary end point is local-regional recurrence-free survival. Here we reported the results of secondary end points: histopathologic response, surgical events, and toxicity.

RESULTS

Of the 663 initially enrolled patients, 589 received the allocated treatment (nCT, n=300; nCRT, n=289). Pathologic complete response rate was 11.0% (95% CI, 7.8-15.3%) in the nCT arm and 13.8% (95% CI, 10.1-18.5%) in the nCRT arm ( P =0.33). The downstaging (ypStage 0 to 1) rate was 40.8% (95% CI, 35.1-46.7%) in the nCT arm and 45.6% (95% CI, 39.7-51.7%) in the nCRT arm ( P =0.27). nCT was associated with lower perioperative distant metastases rate (0.7% vs. 3.1%, P =0.03) and preventive ileostomy rate (52.2% vs. 63.6%, P =0.008) compared with nCRT. Four patients in the nCT arm received salvage nCRT because of local disease progression after nCT. Two patients in the nCT arm and 5 in the nCRT arm achieved complete clinical response and were treated with a nonsurgical approach. Similar results were observed in subgroup analysis.

CONCLUSIONS

nCT achieved similar pCR and downstaging rates with lower incidence of perioperative distant metastasis and preventive ileostomy compared with nCRT. CAPOX could be an effective alternative to neoadjuvant therapy in LARC with uninvolved MRF. Long-term follow-up is needed to confirm these results.

Right ventricular longitudinal strain on CMR predicts ventricular arrhythmias and mortality in cardiac sarcoidosis

Background

Right ventricular (RV) dysfunction and late gadolinium enhancement (LGE) on cardiac magnetic resonance imaging (CMR) are associated with ventricular arrhythmias (VA) and mortality in cardiac sarcoidosis (CS). However, image resolution limits the detection of RV LGE. Global longitudinal RV strain (RVS) correlates to RV scar on electroanatomical mapping and RV function.

Objective

We evaluated the association between RVS on CMR and VA/death (combined-primary-endpoint (CPE)) in patients with CS.

Methods

RVS and RV LGE on MRI were retrospectively compared to variables known to predict outcomes in 66 patients with CS. Outcomes were obtained from electronic medical records and implantable cardioverter defibrillator (ICD) interrogations over median [IQR] 3.7[1.7, 6.3] years. Cox proportional hazard models were used to evaluate survival. Harrell's C-statistic was used to compare variables in risk prediction models.

Results

62.1 % of patients were male, with a mean age [SD] of 52.3 [9.6] years and left ventricular ejection fraction (LVEF) of 51.1[17.5]%. 9 patients with the primary endpoint were more likely to be Caucasian (p = 0.01) with prior VAs (p = 0.002), be on anti-arrhythmic drugs (p = 0.001) with an ICD (p = 0.002). In multivariable analyses adjusted for age, race, and history of VA, RVS (1.18 [1.05-1.31], p = 0.004), RV EDVI (1.08[1.01, 1.14], p = 0.02), and LV LGE (1.07[1.00, 1.13], p = 0.04) predicted the CPE. Risk prediction models including RVS (Cstatistic 0.94), outperformed those including RV and LV LGE (0.89-0.92).

Conclusion

RVS on CMR was the best predictor of VA and mortality in CS.

Advanced imaging for risk stratification for ventricular arrhythmias and sudden cardiac death

Sudden cardiac death (SCD) is a leading cause of mortality, comprising approximately half of all deaths from cardiovascular disease. In the US, the majority of SCD (85%) occurs in patients with ischemic cardiomyopathy (ICM) and a subset in patients with non-ischemic cardiomyopathy (NICM), who tend to be younger and whose risk of mortality is less clearly delineated than in ischemic cardiomyopathies. The conventional means of SCD risk stratification has been the determination of the ejection fraction (EF), typically via echocardiography, which is currently a means of determining candidacy for primary prevention in the form of implantable cardiac defibrillators (ICDs). Advanced cardiac imaging methods such as cardiac magnetic resonance imaging (CMR), single-photon emission computerized tomography (SPECT) and positron emission tomography (PET), and computed tomography (CT) have emerged as promising and non-invasive means of risk stratification for sudden death through their characterization of the underlying myocardial substrate that predisposes to SCD. Late gadolinium enhancement (LGE) on CMR detects myocardial scar, which can inform ICD decision-making. Overall scar burden, region-specific scar burden, and scar heterogeneity have all been studied in risk stratification. PET and SPECT are nuclear methods that determine myocardial viability and innervation, as well as inflammation. CT can be used for assessment of myocardial fat and its association with reentrant circuits. Emerging methodologies include the development of "virtual hearts" using complex electrophysiologic modeling derived from CMR to attempt to predict arrhythmic susceptibility. Recent developments have paired novel machine learning (ML) algorithms with established imaging techniques to improve predictive performance. The use of advanced imaging to augment risk stratification for sudden death is increasingly well-established and may soon have an expanded role in clinical decision-making. ML could help shift this paradigm further by advancing variable discovery and data analysis.

Spatial dispersion analysis of LGE-CMR for prediction of ventricular arrhythmias in patients with cardiac sarcoidosis

BACKGROUND

Patients with cardiac sarcoidosis (CS) are at increased risk of life-threatening ventricular arrhythmias (VA). Current approaches to risk stratification have limited predictive value.

OBJECTIVES

To assess the utility of spatial dispersion analysis of late gadolinium enhancement cardiac magnetic resonance (LGE-CMR), as a quantitative measure of myocardial tissue heterogeneity, in risk stratifying patients with CS for VA and death.

METHODS

Sixty two patients with CS underwent LGE-CMR. LGE images were segmented and dispersion maps of the left and right ventricles were generated as follows. Based on signal intensity (SI), each pixel was categorized as abnormal (SI ≥3SD above the mean), intermediate (SI 1-3 SD above the mean) or normal (SI <1SD above the mean); and each pixel was then assigned a value of 0 to 8 based on the number of adjacent pixels of a different category. Average dispersion score was calculated for each patient. The primary endpoint was VA during follow up. The composite of VA or death was assessed as a secondary endpoint.

RESULTS

During 4.7 ± 3.5 years of follow up, six patients had VA, and five without documented VA died. Average dispersion score was significantly higher in patients with VA versus those without (0.87 ± 0.08 vs. 0.71 ± 0.16; p = .002) and in patients with events versus those without (0.83 ± 0.08 vs. 0.70 ± 0.16; p = .003). Patients at higher tertiles of dispersion score had a higher incidence of VA (p = .03) and the composite of VA or death (p = .01).

CONCLUSIONS

Increased substrate heterogeneity, quantified by spatial dispersion analysis of LGE-CMR, may be helpful in risk-stratifying patients with CS for adverse events, including life-threatening arrhythmias.

Left Atrioventricular Coupling Index as a Prognostic Marker of Cardiovascular Events: The MESA Study

[Figure: see text].

Cardiac MRI structural and functional predictors of left ventricular ejection fraction recovery following PVC catheter ablation

Frequent premature ventricular contractions (PVCs) can induce cardiomyopathy (PVC CM). We sought to use cardiac magnetic resonance imaging (CMR) to quantify changes in cardiac structure and function of cardiomyopathy patients following catheter ablation for PVCs. Patients undergoing PVC ablation at the Johns Hopkins Hospital with pre-procedural CMR from 2010 to 2018 were included in this study. CMR Images were analyzed to collect information on cardiac structure and function as well as to quantify scar. Of the total 51 included patients, PVC CM (LVEF < 45%) was observed in 51% (n = 29). Of these, 19 had post-ablation ejection fractions quantified, with 78.9% (n = 15) recovering function. Global longitudinal strain was significantly correlated with LVEF (OR 1.831, p < 0.01) but did not predict recovery of function. RV origin of PVCs was more common in the preserved LVEF group but was also significantly correlated with persistently reduced EF post-ablation in the PVC CM group. Scar burden was not correlated with either cardiac function or post-ablation recovery of function. In this cohort, there were no significant CMR findings to predict subsequent recovery of EF after ablation among those with PVC CM. PVC origin in the RV was associated with persistently reduced LVEF after ablation.

Relationship of circulating immune cells with lifestyle factors and cancer recurrence in early-stage breast cancer

PURPOSE

To evaluate the relationship of circulating immune cells with recurrence and metabolic/lifestyle factors in patients with early-stage breast cancer.

METHODS

Patients with early-stage breast cancer were identified from the electronic record and institutional registry. Lymphocyte and monocyte counts were obtained from blood samples at time of diagnosis prior to any chemotherapy. Correlations between lymphocyte and monocyte and recurrence were assessed in the entire cohort and among obese patients, those reporting alcohol consumption and smoking. Competing risk regression was used to analyze time to recurrence.

RESULTS

A total of 950 patients with ≥ 5 years of follow-up were identified; 433 had complete data and were eligible for analysis. 293 (68%) had hormone receptor-positive breast cancer, 82 (19%) HER2 positive, and 53 (13%) triple negative. Patients in the highest quintile of lymphocytes compared to the lowest quintile had lower risk of recurrence (subhazard ratio (SHR) = 0.17, 95% CI [0.03-0.93], p = 0.041) while patients in the highest quintile of monocytes had lower risk for recurrence (SHR = 0.19, 95% CI [0.04, 0.92], p = 0.039). Higher monocytes were more strongly associated with lower recurrence among those reporting alcohol consumption (HR = 0.10, 95% CI [0.01, 0.91], p = 0.04). In obese patients, higher lymphocytes were associated with lower risk of recurrence (p = 0.046); in non-obese patients, higher monocytes were associated with lower risk of recurrence (p = 0.02). There were no correlations among patients who reported tobacco use.

CONCLUSIONS

High lymphocyte and monocyte counts are associated with lower recurrence rate in early-stage breast cancer, particularly in obese patients and those reporting alcohol consumption.

Circulating immune cell dynamics in patients with triple negative breast cancer treated with neoadjuvant chemotherapy

BACKGROUND

Lymphopenia has been associated with inferior cancer outcomes, but there is limited data in breast cancer. We describe the effects of neoadjuvant chemotherapy on circulating immune cells and its association with pathological complete response (pCR) rates in triple negative breast cancer (TNBC).

METHODS

We constructed a database of patients with early stage TNBC treated with neoadjuvant chemotherapy. Circulating lymphocytes and monocytes were assessed before and after neoadjuvant chemotherapy. These were correlated with pCR rates and disease-free survival (DFS) using Fisher's exact test, logistic regression, and the log-rank test.

RESULTS

From 2000 to 2015, we identified 95 eligible patients. Median age was 50; 29 (31%) were treated with platinum-containing chemotherapy; and 66 (69%) with nonplatinum-containing chemotherapy (anthracycline-taxane, or either alone). About 32 (34%) patients achieved a pCR; and 33 (35%) had recurrence events. Median follow-up time was 47 months. No significant associations were found between changes in lymphocytes and pCR or DFS. There was a correlation between lower monocyte levels after neoadjuvant chemotherapy and pCR (mean monocyte 0.56 in those with no-pCR vs 0.46 in those with pCR, P = .049, multivariate P = .078) and DFS (median DFS in highest monocyte quartile was 30 vs 107 months in lowest quartile, P = .022, multivariate P = .023). In patients who received nonplatinum regimens, DFS was better among those who had larger decreases in monocytes.

CONCLUSIONS

Development of lymphopenia from neoadjuvant chemotherapy was not associated with pCR in patients with TNBC. However, lower absolute circulating monocytes after neoadjuvant chemotherapy was associated with improved outcomes.

The ELFIN Mission

The Electron Loss and Fields Investigation with a Spatio-Temporal Ambiguity-Resolving option (ELFIN-STAR, or heretoforth simply: ELFIN) mission comprises two identical 3-Unit (3U) CubeSats on a polar (∼93^∘ inclination), nearly circular, low-Earth (∼450 km altitude) orbit. Launched on September 15, 2018, ELFIN is expected to have a >2.5 year lifetime. Its primary science objective is to resolve the mechanism of storm-time relativistic electron precipitation, for which electromagnetic ion cyclotron (EMIC) waves are a prime candidate. From its ionospheric vantage point, ELFIN uses its unique pitch-angle-resolving capability to determine whether measured relativistic electron pitch-angle and energy spectra within the loss cone bear the characteristic signatures of scattering by EMIC waves or whether such scattering may be due to other processes. Pairing identical ELFIN satellites with slowly-variable along-track separation allows disambiguation of spatial and temporal evolution of the precipitation over minutes-to-tens-of-minutes timescales, faster than the orbit period of a single low-altitude satellite (T_orbit ∼ 90 min). Each satellite carries an energetic particle detector for electrons (EPDE) that measures 50 keV to 5 MeV electrons with Δ E/E < 40% and a fluxgate magnetometer (FGM) on a ∼72 cm boom that measures magnetic field waves (e.g., EMIC waves) in the range from DC to 5 Hz Nyquist (nominally) with <0.3 nT/sqrt(Hz) noise at 1 Hz. The spinning satellites (T_spin ∼ 3 s) are equipped with magnetorquers (air coils) that permit spin-up or -down and reorientation maneuvers. Using those, the spin axis is placed normal to the orbit plane (nominally), allowing full pitch-angle resolution twice per spin. An energetic particle detector for ions (EPDI) measures 250 keV - 5 MeV ions, addressing secondary science. Funded initially by CalSpace and the University Nanosat Program, ELFIN was selected for flight with joint support from NSF and NASA between 2014 and 2018 and launched by the ELaNa XVIII program on a Delta II rocket (with IceSatII as the primary). Mission operations are currently funded by NASA. Working under experienced UCLA mentors, with advice from The Aerospace Corporation and NASA personnel, more than 250 undergraduates have matured the ELFIN implementation strategy; developed the instruments, satellite, and ground systems and operate the two satellites. ELFIN's already high potential for cutting-edge science return is compounded by concurrent equatorial Heliophysics missions (THEMIS, Arase, Van Allen Probes, MMS) and ground stations. ELFIN's integrated data analysis approach, rapid dissemination strategies via the SPace Environment Data Analysis System (SPEDAS), and data coordination with the Heliophysics/Geospace System Observatory (H/GSO) optimize science yield, enabling the widest community benefits. Several storm-time events have already been captured and are presented herein to demonstrate ELFIN's data analysis methods and potential. These form the basis of on-going studies to resolve the primary mission science objective. Broad energy precipitation events, precipitation bands, and microbursts, clearly seen both at dawn and dusk, extend from tens of keV to >1 MeV. This broad energy range of precipitation indicates that multiple waves are providing scattering concurrently. Many observed events show significant backscattered fluxes, which in the past were hard to resolve by equatorial spacecraft or non-pitch-angle-resolving ionospheric missions. These observations suggest that the ionosphere plays a significant role in modifying magnetospheric electron fluxes and wave-particle interactions. Routine data captures starting in February 2020 and lasting for at least another year, approximately the remainder of the mission lifetime, are expected to provide a very rich dataset to address questions even beyond the primary mission science objective.

Comparisons of screening strategies for identifying Lynch syndrome among patients with MLH1-deficient colorectal cancer

BRAF and MLH1 promoter methylation testings have been proven effective prescreens for Lynch Syndrome. We aimed to compare different screening strategies for Lynch Syndrome in patients with MLH1(-) CRC. Patients with MLH1(-) CRC who had been tested for BRAF mutation and germline variants of DNA mismatch repair genes were included. We compared the sensitivities and specificities for identifying Lynch Syndrome and the cost-effectiveness of four screening approaches that used the following tests as prescreens: BRAF testing, MLH1 methylation testing, MLH1 methylation & BRAF testing, and MLH1 methylation testing & Revised Bethesda Criteria. Of 109 patients included, 23 (21.1%) were Lynch Syndrome patients. BRAF mutation and MLH1 methylation occurred in 6 (5.5%) and 40 (36.7%) patients, respectively. The sensitivity for identifying Lynch syndrome of BRAF testing was 100%, but the specificity was only 7%. MLH1 methylation testing had a lower sensitivity than BRAF testing (97.5% vs 100%), but had a markedly higher specificity (45.3% vs 7%). The combination of the two testings had a slightly higher specificity than MLH1 methylation testing alone (47.7% vs 45.3%). The MLH1 methylation testing approach had a 10% lower cost of identifying MLH1(-) Lynch syndrome carriers per case than universal genetic testing, but it missed 4.5% of patients. BRAF and MLH1 promoter methylation testings as prescreens for Lynch syndrome are less effective in Chinese patients with MLH1(-) CRC than in their Western counterparts. Universal genetic testing could be considered an up-front option for this population.

Mechanism of spontaneous initiation of ventricular fibrillation in patients with implantable defibrillators

INTRODUCTION

To improve the mechanistic understanding of spontaneous initiation of ventricular fibrillation (VF), we characterized the patterns of premature ventricular complex (PVC) preceding spontaneous VF in primary and secondary implantable cardioverter-defibrillator (ICD) recipients.

METHODS AND RESULTS

A single-center, cross-sectional analysis of 1209 patients with primary and secondary prevention ICD identified 190 patients who received ICD therapy (firing or antitachycardia pacing) for VF or monomorphic ventricular tachycardia (MMVT). Initiation was quantified by the coupling interval (CI), the cycle length immediately preceding the CI (CL(-1)), the CI corrected by CL(-1) using Fridericia's formula (CIc), and the prematurity index (PI). In both VF (n = 44; 23%) and MMVT (n = 134; 71%), the most common pattern of initiation was late-coupled PVC, followed by the short-long-short pattern. The parameters such as pre-initiation median CL, CL(-1), CI, and PI were not significantly different between VF and MMVT for any patterns. At least some events (45% of VF and 63% of MMVT) had extremely long CIs beyond the QTc cut-off estimated from the CL(-1), suggestive of initiation by a train of multiple PVCs or nonsustained VT instead of a single PVC.

CONCLUSION

Some spontaneous VF events in ICD recipients appear to be initiated by a train of multiple PVC or nonsustained VT rather than a single PVC. This finding indicates that patterns of a single PVC are not an important determinant of VF initiation and thus account for conflicting results in previous studies.

Association of right atrial structure with incident atrial fibrillation: a longitudinal cohort cardiovascular magnetic resonance study from the Multi-Ethnic Study of Atherosclerosis (MESA)

BACKGROUND

While studies of the left atrium (LA) have demonstrated associations between volumes and emptying fraction with atrial fibrillation (AF), the contribution of right atrial (RA) abnormalities to incident AF remains poorly understood.

OBJECTIVES

Assess the association between RA structure and function with incident AF using feature-tracking cardiovascular magnetic resonance (CMR).

METHODS

This is a prospective cohort study of all participants in the Multi-Ethnic Study of Atherosclerosis with baseline CMR, sinus rhythm, and free of clinical cardiovascular disease at study initiation. RA volume, strain, and emptying fraction in participants with incident AF (n = 368) were compared against AF-free (n = 2779). Cox proportional-hazards models assessed association between variables.

RESULTS

Participants were aged 60 ± 10 yrs., 55% female, and followed an average 11.2 years. Individuals developing AF had higher baseline RA maximum volume index (mean ± standard deviation [SD]: 24 ± 9 vs 22 ± 8 mL/m2, p = 0.002) and minimum volume index (13 ± 7 vs 12 ± 6 mL/m2, p < 0.001), and lower baseline RA emptying fraction (45 ± 15% vs 47 ± 15%, p = 0.02), peak global strain (34 ± 17% vs 36 ± 19%, p < 0.001), and peak free-wall strain (40 ± 23% vs 42 ± 26%, p = 0.049) compared with the AF-free population. After adjusting for traditional cardiovascular risk factors and LA volume and function, we found RA maximum volume index (hazards ratio [HR]: 1.13 per SD, p = 0.041) and minimum volume index (HR: 1.12 per SD, p = 0.037) were independently associated with incident AF.

CONCLUSIONS

In a large multiethnic population, higher RA volume indices were independently associated with incident AF after adjustment for conventional cardiovascular risk factors and LA parameters. It is unclear if this predictive value persists when additional adjustment is made for ventricular parameters.

Gigabit per second visible light communication based on AlGaInP red micro-LED micro-transfer printed onto diamond and glass

Full-color smart displays, which act both as a display and as a high-speed visible light communication (VLC) transmitter, can be realized by the integration of red-green-blue micron-sized light emitting diodes (micro-LEDs) onto a common platform. In this work, we report on the integration of aluminum gallium indium phosphide red micro-LEDs onto diamond and glass substrates by micro-transfer printing and their application in VLC. The device on-diamond exhibits high current density and bandwidth operation, enabled by diamond's superior thermal properties. Employing an orthogonal frequency division multiplexing modulation scheme, error-free data rates of 2.6 Gbps and 5 Gbps are demonstrated for a single micro-LED printed on-glass and on-diamond, respectively. In a parallel configuration, a 2x1 micro-LED array achieves error-free data rates of 3 Gbps and 6.6 Gbps, on-glass and on-diamond, respectively.

Direct integration of micro-LEDs and a SPAD detector on a silicon CMOS chip for data communications and time-of-flight ranging

We present integration of singulated micron-sized light emitting diodes (micro-LEDs) directly onto a silicon CMOS drive chip using a transfer printing method. An 8x8 micro-LED device array with individual control over each pixel is demonstrated with modulation bandwidths up to 50 MHz, limited by the large modulation depth of the driver chip. The 2 kHz frame rate CMOS driver also incorporates a Single Photon Avalanche Diode device thus allowing detection and transmission functionality on a single integrated chip. Visible light communications at data rates up to 1 Mbps, and time-of-flight ranging with cm-scale resolution are demonstrated using this hybrid integrated system.

On-chip GaN-based dual-color micro-LED arrays and their application in visible light communication

Integrated multi-color micron-sized light emitting diode (micro-LED) arrays have been demonstrated in recent years for display applications; however, their potential as visible light communication (VLC) transmitters is yet to be fully explored. In this work, we report on the fabrication and characterization of on-chip dual-color micro-LED arrays and their application in VLC. For this purpose, blue-green and blue-violet micro-LED arrays were fabricated by transfer printing blue-emitting micro-LEDs onto the substrate of green and violet micro-LEDs, respectively. The potential of these dual-color micro-LED arrays as VLC transmitters is demonstrated with respective error-free data rates of 1.79 and 3.35 Gbps, achieved by the blue-green and blue-violet devices in a dual wavelength multiplexing scheme.

Regional abnormalities on cardiac magnetic resonance imaging and arrhythmic events in patients with cardiac sarcoidosis

BACKGROUND

Patients with cardiac sarcoidosis (CS) may present with arrhythmic events (AE): atrioventricular block (AVB) and/ or ventricular arrhythmias (VA). We sought to: (a) use regional analysis of cardiac magnetic resonance imaging (CMR) to describe anatomic and functional phenotypes of patients with CS and AE; (b) Assess the association of regional CMR abnormalities with the combined endpoint of death, heart transplantation (HT) and AE; and (c) use machine learning (ML) to predict the combined endpoint based on CMR features.

METHODS

we included 76 patients with CS and CMR. We analyzed cine images to determine regional longitudinal (LS) and radial strain (RS); and late gadolinium enhancement imaging to determine regional scar burden (%scar).

RESULTS

Patients with AVB (n = 7), compared with those without, had higher %scar in the anterior (21.8 ± 27.4 vs 5.1 ± 8.9; P = 0.0005) and anteroseptal (19.3 ± 24.5 vs 3.5 ± 5.5; P < .0001) walls. Patients with VA (n = 12), compared with those without, had higher %scar in the basal inferoseptum (20.4 ± 30.8 vs 8.3 ± 13.4; P = .03). During mean follow-up of 4.4 ± 3.3 years, four patients died or underwent HT; eight had VA; and zero developed AVB. Multiple regional abnormalities were associated with the combined endpoint, including scar in the anteroseptal wall (HR 1.06 [1.02-1.09] per 1%scar increase, P = .002). The ML algorithm predicted the combined endpoint with a C-statistic of 0.91.

CONCLUSION

Regional CMR abnormalities are associated with AE in patients with CS.

Secure quantum remote state preparation of squeezed microwave states

Quantum communication protocols based on nonclassical correlations can be more efficient than known classical methods and offer intrinsic security over direct state transfer. In particular, remote state preparation aims at the creation of a desired and known quantum state at a remote location using classical communication and quantum entanglement. We present an experimental realization of deterministic continuous-variable remote state preparation in the microwave regime over a distance of 35 cm. By employing propagating two-mode squeezed microwave states and feedforward, we achieve the remote preparation of squeezed states with up to 1.6 dB of squeezing below the vacuum level. Finally, security of remote state preparation is investigated by using the concept of the one-time pad and measuring the von Neumann entropies. We find nearly identical values for the entropy of the remotely prepared state and the respective conditional entropy given the classically communicated information and, thus, demonstrate close-to-perfect security.

Continuous-variable remote state preparation in the microwave domain would allow to leverage the superconducting technology for quantum networks applications. Here, the authors show how to deterministically prepare squeezed Gaussian states across 35 cm using previously shared entanglement.

Association Between Radiofrequency Rhizotomy Parameters and Duration of Pain Relief in Trigeminal Neuralgia Patients with Recurrent Pain

BACKGROUND

Radiofrequency rhizotomy (RFR) is a commonly used, effective procedure for trigeminal neuralgia (TN), but a subset of patients experiences pain recurrence and requires subsequent surgeries. Currently, the rhizotomy temperature and duration of application are empirically determined, and there is no consensus on what settings are most beneficial. In this study, we analyzed patients who underwent trigeminal RFR and had subsequent surgeries to identify whether rhizotomy parameters were associated with the duration of pain relief.

METHODS

Single-center, retrospective analysis of patients undergoing RFR for TN from 1995 to 2016. The primary endpoint was subsequent procedure. Associations with rhizotomy parameters and covariates were assessed using Cox regression analysis.

RESULTS

The study included 338 patients, average age 65 years; 61% were women. Temperature was significantly associated with both the degree of immediate postoperative pain relief and the duration of pain relief, and in subgroup analyses by multiple sclerosis status and RFR procedural count. Ablation duration was also independently significant, though not when analyzed alongside age, sex, and race. Duration of pain relief was generally shorter in patients with multiple sclerosis and in repeated RFR.

CONCLUSIONS

Higher temperatures may be necessary to achieve pain relief in some patients, given the progressive nature of the facial pain, but they are not associated with longer duration of pain relief in patients who have recurrent pain. Modulation of the ablation duration does not seem to affect the short-term or long-term outcomes.

Parity-Engineered Light-Matter Interaction

The concept of parity describes the inversion symmetry of a system and is of fundamental relevance in the standard model, quantum information processing, and field theory. In quantum electrodynamics, parity is conserved and large field gradients are required to engineer the parity of the light-matter interaction operator. In this work, we engineer a potassiumlike artificial atom represented by a specifically designed superconducting flux qubit. We control the wave function parity of the artificial atom with an effective orbital momentum provided by a resonator. By irradiating the artificial atom with spatially shaped microwave fields, we select the interaction parity in situ. In this way, we observe dipole and quadrupole selection rules for single state transitions and induce transparency via longitudinal coupling. Our work advances the design of tunable artificial multilevel atoms to a new level, which is particularly promising with respect to quantum chemistry simulations with near-term superconducting circuits.

Photon Statistics of Propagating Thermal Microwaves

In experiments with superconducting quantum circuits, characterizing the photon statistics of propagating microwave fields is a fundamental task. We quantify the n^{2}+n photon number variance of thermal microwave photons emitted from a blackbody radiator for mean photon numbers, 0.05≲n≲1.5. We probe the fields using either correlation measurements or a transmon qubit coupled to a microwave resonator. Our experiments provide a precise quantitative characterization of weak microwave states and information on the noise emitted by a Josephson parametric amplifier.

Laparoscopic common bile duct exploration: a safe and definitive treatment for elderly patients

BACKGROUND

Common bile duct (CBD) stone is one of the most common diseases among elderly people. In recent decades, there are numerous studies regarding the safety and efficacy of laparoscopic common bile duct exploration (LCBDE). Elderly patients are often regarded as high-risk patients because they are more likely to present with age-specific deterioration of organ function and coexisting chronic diseases, which may reduce their tolerance of laparoscopic surgery. Although laparoscopic surgery for choledocholithiasis is now widely accepted as the treatment for CBD stone, its appropriateness for the treatment of elderly patients or those with coexisting high-risk patients has not been well established. Therefore, the objective of this paper is to analyze the safety and efficacy of LCBDE in elderly patients.

METHODS

Between January 2012 and November 2015, 376 patients underwent LCBDE in our center. Based on their ages, they were divided into two groups, and a retrospective study was performed. By making comparisons between younger group who were younger than 70 years (n = 253) and elderly group who were 70 years old or older (n = 123), the demographics, clinical characteristics, laboratory data, operative parameters and outcomes were analyzed.

RESULTS

Before operation, elderly patients had more coexisting chronic diseases and risk factors, such as arterial hypertension, heart diseases, pulmonary diseases and previous abdominal surgery (P < 0.05). In both groups, LCBDE was equally successful with a high clearance rate (100 % in elderly patients vs. 98.8 % in younger group, P = 0.554). Besides, the operating time, intraoperative blood loss, postoperative hospital stay, total costs and overall complication showed no significant difference between two groups (P > 0.05). There was no major bile duct injury or death in either group.

CONCLUSION

Although elderly patients are frequently confronted with coexisting disorders, LCBDE can be considered as a safe and effective technique in choledocholithiasis treatment for elderly patients.

Displacement of Propagating Squeezed Microwave States

Displacement of propagating quantum states of light is a fundamental operation for quantum communication. It enables fundamental studies on macroscopic quantum coherence and plays an important role in quantum teleportation protocols with continuous variables. In our experiments, we have successfully implemented this operation for propagating squeezed microwave states. We demonstrate that, even for strong displacement amplitudes, there is no degradation of the squeezing level in the reconstructed quantum states. Furthermore, we confirm that path entanglement generated by using displaced squeezed states remains constant over a wide range of the displacement power.

The Value of Restaging With Chest and Abdominal CT/MRI Scan After Neoadjuvant Chemoradiotherapy for Locally Advanced Rectal Cancer

Little was known with regard to the value of preoperative systemic restaging for patients with locally advanced rectal cancer (LARC) treated with neoadjuvant chemoradiotherapy (CRT). This study was designed to evaluate the role of chest and abdominal computed tomography (CT) scan or magnetic resonance imaging (MRI) on preoperative restaging in LARC after neoadjuvant CRT and to assess the impact on treatment strategy.Between January 2007 and April 2013, 386 newly diagnosed consecutive patients with LARC who underwent neoadjuvant CRT and received restaging with chest and abdominal CT/MRI scan were included. Imaging results before and after CRT were analyzed.Twelve patients (3.1%) (6 liver lesions, 2 peritoneal lesions, 2 distant lymph node lesions, 1 lung lesions, 1 liver and lung lesions) were diagnosed as suspicious metastases on the restaging scan after radiotherapy. Seven patients (1.8%) were confirmed as metastases by pathology or long-term follow-up. The treatment strategy was changed in 5 of the 12 patients as a result of restaging CT/MRI findings. Another 10 patients (2.6%) who present with normal restaging imaging findings were diagnosed as metastases intra-operatively. The sensitivity, specificity accuracy, negative predictive value, and positive predictive values of restaging CT/MRI was 41.4%, 98.6%, 58.3%, and 97.3%, respectively.The low incidence of metastases and minimal consequences for the treatment plan question the clinical value of routine restaging of chest and abdomen after neoadjuvant CRT. Based on this study, a routine restaging CT/MRI of chest and abdomen in patients with rectal cancer after neoadjuvant CRT is not advocated, carcino-embryonic antigen (CEA) -guided CT/MRI restaging might be an alternative.

[Effect of laparoscopic proctectomy and open proctectomy on plasma levels of vascular endothelial growth factor]

OBJECTIVE

To investigate the effect of laparoscopic and open proctectomy on plasma levels of vascular endothelial growth factor (VEGF).

METHODS

From January 2011 to December 2012, 100 rectal cancer patients in Shantou Central Hospital were enrolled in the study. Patients were divided into laparoscopic (LR) group and open (OR) group based on the decision of the patients. There were 63 patients in the LR group (44 cases undergoing low anterior resection and 19 abdominoperineal resection) and 37 patients in the OR group(26 cases undergoing low anterior resection and 11 abdominoperineal resection). Double antibody sandwich enzyme-linked immunohistochemistry was used to detect the level of VEGF on 1-day before and 1-day, 3-day, 7-day after operation.

RESULTS

In the LR group, the postoperative levels of VEGF increased slowly, and the level of VEGF was significantly higher than that before operation until the 7-day after operation(P<0.05) regardless of the procedure. In the OR group, all the postoperative levels of VEGF were significantly increased(P<0.05). There was no significant difference of the VEGF level on 1-day before and 1-day after operation between the two groups(all P>0.05). The VEGF level in the OR group was significantly higher than that in the LR group on the day 3 and day 7 after operation(P<0.05).

CONCLUSION

Compared with open approach, laparoscopic proctectomy has smaller short-term impact on the plasma level of VEGF in rectal cancer patients.

[Clinical significance of multi-slice spiral CT angiography in radical resection of gastric cancer]

OBJECTIVES

To explore the clinical significance of preoperative abdominal multi-slice spiral CT angiography (MSCTA) in radical resection of gastric cancer.

METHODS

One hundred and three patients with gastric cancer were divided into two groups according to their desires. Group I( included 57 patients who underwent preoperative MSCTA and group II( included 46 patients who underwent surgery without preoperative MSCTA. All these patients were operated by the same surgical team.

RESULTS

Six patients(10.5%) with abnormal gastric artery in group I( were discovered. The diagnostic concordance rate between MSCTA and intraoperative findings was 100% in group I( in the locations and alignments of main perigastric vessels and their relationship with cancer lesions. Operative time in group I( was shorter than that in group II( [(206 ± 23) min vs. (257 ± 32) min, P=0.044]. Operative time [(190 ± 50) min] of patients with abnormal gastric artery of group I( was shorter than that [(255 ± 62) min] of patients with abnormal gastric artery discovered during operation of group II( (P=0.048). However there were no differences in blood loss, extent of lymph node dissection, complication rate, length of hospital stay, and hospitalization cost between the two groups(P>0.05).

CONCLUSION

Preoperative MSCTA is beneficial to the evaluation of vascular structure of the cancer and the adjacent tissues, which may reduce postoperative complications.

[Experimental study on the treatment of smoke inhalation injury with lung lavage and exogenous pulmonary surfactant]

To investigate the prevention and treatment effects of lung lavage and exogenous pulmonary surfactant (PS) on endogenous surfactant system dysfunction and acute respiratory failure caused by severe smoke inhalation, Wistar rats were randomly divided into five groups: Group I, normal control; Group II, smoke inhalation; Group III, smoke + lavage + PS + mechanical ventilation (MV); Group IV, smoke + lavage + MV; Group V, smoke + MV. The lungs were lavaged with 30 ml/kg 0.9% NaCl containing 100 mg/kg PS or same volume of saline via tracheal catheter at 5 min after smoke inhalation, then the animals were placed on a ventilator for 4 h, and observed until 24 h postinjury. The arterial blood gas levels, lung water volume, static lung compliance (Cst), total protein and albumin contents in bronchoalveolar lavage fluid (BALF), surface tension properties of BALF, and fatality rate at 24 h were measured. Smoke inhalation caused a similar acute hypoxia and severe carbon monoxide poisoning immediately in all injuried groups. The animals in group II showed acute respiratory failure, serious high permeability pulmonary edema, and surfactant system dysfunction. The surface tension properties of BALF, Cst, and the oxygenation were significantly improved with lung lavage and exogenous PS treatment. The lung water volume, total protein and albumin contents in BALF were decreased dramatically in this group. The fatality rate at 24 h declined markedly only in group III. It was suggested that lung lavage and exogenous surfactant treatment trestores effectively endogenous surfactant function inhibited by smoke inhalation, improves lung function, prevents high permeability pulmonary edema and respiratory failure, and decreases the mortality in early stage after smoke inhalation injury.

[IR and UV-vis spectra of nitrogen-doped fullerene]

Nitrogen-doped fullerene derivative's IR and UV-vis spectra are reported. Some of the C60 IR silent modes are activated due to nitrogen atom reducing C60 molecular symmetry. UV-vis spectrum indicates nitrogen is donor.

[Determination of placental alkaline phosphatase (PLAP) for detecting the damages of alveolar type I cells caused by smoke inhalation]

The placental alkaline phosphatase (PLAP) is a marker enzyme of alveolar type I cells. To evaluate the damages of alveolar type I cells and its relations with the development of acute lung injury caused by smoke inhalation, the present study was designed to observe the dynamic changes in PLAP contents in plasma and bronchoalveolar lavage fluid (BALF). Following the induction of smoke inhalation injury in rat, the arterial blood gas levels, lung water volume, total protein and albumin contents in BALF, and PLAP contents in plasma and BALF were determined respectively in normal control and injured animals at 2, 6, 12 and 24 h after injury. The pathomorphology of lung tissues was also observed. It was found that after smoke inhalation, animals showed acute respiratory failure and serious pulmonary edema. The total protein and albumin levels in BALF increased markedly. Both PLAP contents in plasma and BALF also increased dramatically, and there was a significant positive correlation between the changes in the PLAP and the total protein contents in BALF. The pathomorphologically serious structural damage of alveolar type I cells were also found. PLAP may be not only a marker of alveolar type I cells injury, but also interrelated with the permeability increase of alveolar-capillary membrane after smoke inhalation.

The human serotonin 5-HT2C receptor: complete cDNA, genomic structure, and alternatively spliced variant

The complete 4775-nt cDNA encoding the human serotonin 5-HT2c receptor (5-HT2cR), a G-protein-coupled receptor, has been isolated. It contains a 1377-nt coding region flanked by a 728-nt 5'-untranslated region and a 2670-nt 3'-untranslated region. By using the cloned 5-HT2cR cDNA probe, the complete human gene for this receptor has been isolated and shown to contain six exons and five introns spanning at least 230 kb of DNA. The coding region of the human 5-HT2CR gene is interrupted by three introns, and the positions of the intron/exon junctions are conserved between the human and the rodent genes. In addition, an alternatively spliced 5-HT2CR RNA that contains a 95-nt deletion in the region coding for the second intracellular loop and the fourth transmembrane domain of the receptor has been identified. This deletion leads to a frameshift and premature termination so that the short isoform RNA encodes a putative protein of 248 amino acids. The ratio for the short isoform over the 5-HT2CR RNA was found to be higher in choroid plexus tumor than in normal brain tissue, suggesting the possibility of differential regulation of the 5-HT2CR gene in different neural tissues or during tumorigenesis. Transcription of the human 5-HT2CR gene was found to be initiated at multiple sites. No classical TATA-box sequence was found at the appropriate location, and the 5'-flanking sequence contains many potential transcription factor-binding sites. A 7.3-kb 5'-flanking 5-HT2CR DNA directed the efficient expression of a luciferase reporter gene in SK-N-SH and IMR32 neuro-blastoma cells, indicating that it contains a functional promoter.

Differential roles of two tandem E2F sites in repression of the human p107 promoter by retinoblastoma and p107 proteins

Although many lines of evidence indicate that the cellular protein p107 is closely related to the retinoblastoma protein, the exact function of the p107 gene and its regulation are presently not known. To investigate the molecular mechanism controlling expression of the human p107 gene, a 5' flanking sequence of this gene was isolated and shown to promote high-level expression of a luciferase reporter gene in cycling human 293 and Saos-2 cells. Sequencing and transcription mapping analyses showed that the human p107 promoter is TATA-less and contains a tandem, direct repeat of E2F-binding sites, with the 3' copy overlapping the major transcription initiation site. Deletion analysis of the p107 promoter showed that a promoter DNA fragment containing only the two E2F sites together with the leader sequence could direct relatively efficient expression in 293 cells. Site-directed mutagenesis of these E2F sites revealed that although both sites were important for p107 promoter activity, mutation on the proximal, initiation site copy of the E2F site showed a stronger effect. The human p107 promoter could be repressed by the retinoblastoma protein and its own gene product. Interestingly, the repression was found to be mediated through the 5' copy of the E2F site. These studies demonstrate for the first time differential roles of two tandem E2F sites in promoter regulation.

The murine erythrocyte protein-4.2-encoding gene: similarities and differences in structure and expression from its human counterpart

We have isolated a complete cDNA encoding for the mouse erythrocyte protein 4.2 (P4.2). The entire P4.2 cDNA consists of 3465 nt with an open reading frame (ORF) of 691 amino acids. Northern blot analysis of mouse reticulocyte or spleen RNA using the P4.2 cDNA as a probe, detected a 3.5-kb message. The size of the mouse P4.2 cDNA or message that we obtained, appears to be different from those reported recently. Despite the similarity to the human P4.2 cDNAs, the mouse cDNA has a longer 3' untranslated region. A genomic clone covering the first exon and flanking sequences of the mouse P4.2 gene was isolated. Sequencing results from the first exon-intron junction region and polymerase chain reaction (PCR) experiments revealed that the mouse reticulocyte P4.2 RNA does not exhibit alternative splicing in the region identified in the human P4.2 RNA.