Relapse after electric barrier-induced voluntary abstinence: A review

Relapse to drug use during abstinence is a defining feature of addiction. To date, however, results from studies using rat relapse/reinstatement models have yet to result in FDA-approved medications for relapse prevention. To address this translational gap, we and others have developed rat models of relapse after voluntary abstinence from drug self-administration. One of these models is the electric barrier conflict model. Here, we introduce the model, and then review studies on behavioral and neuropharmacological mechanisms of cue-induced relapse and incubation of drug seeking (time-dependent increase in drug seeking during abstinence) after electric barrier-induced abstinence. We also briefly discuss future directions and potential clinical implications. One major conclusion of our review is that the brain mechanisms controlling drug relapse after electrical barrier-induced voluntary abstinence are likely distinct from those controlling relapse after homecage forced abstinence.

Withdrawal from repeated nicotine vapor exposure increases somatic signs of physical dependence, anxiety-like behavior, and brain reward thresholds in adult male rats

Nicotine vapor consumption via electronic nicotine delivery systems has increased over the last decade. While prior work has shed light on the health effects of nicotine vapor inhalation, its unique effects on the brain and behavior have not been thoroughly explored. In this study we assessed markers of withdrawal following 14 days of nicotine vapor exposure. For Experiment 1, 21 adult male rats were exposed to ambient air or 6, 12, or 24 mg/mL nicotine vapor for 14 consecutive days. Following exposure on day 14, rats were injected with the nicotinic receptor antagonist mecamylamine (3.0 mg/mL) and assessed for somatic withdrawal signs and anxiety-like behavior in the elevated plus maze. For Experiment 2, 12 adult male rats were tested for intracranial self-stimulation (ICSS) immediately following exposure to vehicle vapor (50%/50%, vegetable glycerin/propylene glycol) or 24 mg/mL nicotine vapor, for 14 consecutive days. ICSS behavior was assessed for an additional 14 days, following cessation of repeated vapor exposure. Results reveal that rats with repeated nicotine vapor exposure display an increase in behavioral indicators of withdrawal following injection of mecamylamine (precipitated withdrawal). Additionally, increases in ICSS stimulation thresholds, indicative of reduced brain reward sensitivity, persist following cessation of repeated nicotine vapor exposure (spontaneous withdrawal). These data suggest that repeated e-cigarette use leads to nicotine dependence and withdrawal that affects behavior and brain reward function. Further characterization of the health effects of nicotine vapor is necessary to improve treatment strategies for nicotine use disorder and public health policies related to novel nicotine delivery systems.

Cardiac magnetic resonance relaxometry compared to left ventricular ejection fraction in the identification of anthracycline related cardiac changes: a systematic review and meta-analysis

Background

Anthracyclines are associated with cancer therapeutics related cardiac dysfunction (CTRCD). The identification of CTRCD currently uses a change in left ventricular ejection fraction (LVEF). Myocardial damage associated with anthracyclines include myocardial inflammation and oedema. This can be assessed using cardiac magnetic resonance (CMR) relaxometry techniques; T1 and T2 mapping and extracellular volume (ECV) fraction.

Purpose

In this meta-analysis, we compared the magnitude of the changes in LVEF and CMR relaxometry techniques wihtin a month of anthracycline therapy completion.

Methods

We performed a structured literature review as per the PRISMA guidelines across three databases (EMBASE, MEDLINE, and SCOPUS) for studies evaluating CMR relaxometry parameter at baseline and soon after completion of anthracycline therapy (3–5 months post baseline). CMR parameters pre and post anthracycline-based chemotherapy were abstracted. A random effects model was used to pool mean difference (MD) in LVEF and ECV given standardisation in imaging acquisition techniques. A random effects model was used to pool standardized mean difference (SMD) in LVEF, T1, T2 and ECV after anthracycline to adjust for variations in imaging techniques and comparison between techniques.

Results

A total of 174 patients were included from seven studies. 91% were female with a mean age of 55.6 years. The pooled MD in LVEF and ECV was −3.15% [95% CI −4.99, −1.31] and 1.61% [0.90, 2.32], respectively. The pooled SMD in LVEF, T1, T2 and ECV was −0.61 [−0.96, −0.25] 0.34 [0.04, 0.63], 0.67 [0.12,1.21], 0.6 [0.31, 0.89], respectively (Table 1).

Conclusions

T2 mapping, ECV and LVEF can identify early myocardial changes better than T1 mapping. These changes suggest there is marked oedema in the myocardial injury from anthracycline therapy. Whilst these findings support the role of CMR relaxometry in identifying CTRCD, further studies are required.

Funding Acknowledgement

Type of funding sources: None.

Cardioprotection against cardiac dysfunction from breast cancer chemotherapy: a bayesian and frequentist network meta-analysis of randomised controlled trials

Background

Anthracyclines (ANT) are the cornerstone of multiple chemotherapy regimens but at the risk of potential cardiotoxicity. Previous RCTs have tested the prophylactic effects of multiple cardioprotective agents to prevent ANT-related cardiotoxicity. Unfortunately, attempts to combine RCT findings in previous meta-analyses have been heterogeneous, creating further uncertainty. There remains an unmet need to determine the role of cardio-protective agents in breast cancer.

Purpose

To assess the comparative efficacy of cardioprotective drugs in patients with breast cancer using both Bayesian and frequentist analyses of randomised controlled trials

Methods

We performed a systematic review using four databases (CENTRAL, Cochrane Reviews, MEDLINE, SCOPUS), to find RCTs evaluating cardio protective drugs in breast cancer patients without prior ANT exposure. The population included was anthracycline naïve, and trials were excluded if cardio-protective agents were commenced post anthracycline treatment. The primary outcome was a mean change in LVEF pre and post ANT dosing. Results were pooled with both Bayesian and frequentist approaches using random effects models in R statistical software.

Results

We identified 12 RCTs from 2807 search results (n=1126, Age 51 years, ANT dose 412m/m2, baseline LVEF 62.6%) with comparisons including beta-blockers (BB) (n=9), Angiotensin Converting Enzyme inhibitors (ACEi)/Angiotensin Receptor Blockers (ARB) (n=3), combination BB + AA (n=2), spironolactone (n=1) and statins (n=1). All included trials had either intermediate or high risk of bias, with marked heterogeneity in ANT dosing and LVEF monitoring. Overall, our Bayesian network meta-analysis showed no statistically significant difference in mean LVEF preservation between AA (1.3%, 95% credible interval [−0.20, 2.9]), BB (0.77, [−0.21, 1.8]), AABB (0.84 [−1.1, 2.8]), SPR (0.72, [−2.3, 3.7]) or statin (0.60, [−2.4, 3.6]) when compared against placebo. After ranking for efficacy, ACEi/ARBs achieved the most protection against LVEF decline of 1.3% [95% CI: −0.2, 2.9] although still not significant. Conversely, frequentist analysis showed benefit in using AA (Standardised Mean Difference (SMD) 1.32% [0.32, 2.33]) and BB (SMD 0.76% [0.12, 1.4]).

Conclusion

Bayesian analysis demonstrated no difference in LVEF with cardio-protective agents. In contrast, frequentist analysis showed that AA and BB may provide significant cardio-protection. The quality of RCT data to date is limited by a high risk of bias and significant heterogeneity between RCA reporting. Larger trials with clear population definition are required to determine whether any drug class provides benefit in this setting.

Funding Acknowledgement

Type of funding sources: None.

Scintillation light detection in the 6-m drift-length ProtoDUNE Dual Phase liquid argon TPC

DUNE is a dual-site experiment for long-baseline neutrino oscillation studies, neutrino astrophysics and nucleon decay searches. ProtoDUNE Dual Phase (DP) is a 6  ×  6  ×  6 m 3 liquid argon time-projection-chamber (LArTPC) that recorded cosmic-muon data at the CERN Neutrino Platform in 2019-2020 as a prototype of the DUNE Far Detector. Charged particles propagating through the LArTPC produce ionization and scintillation light. The scintillation light signal in these detectors can provide the trigger for non-beam events. In addition, it adds precise timing capabilities and improves the calorimetry measurements. In ProtoDUNE-DP, scintillation and electroluminescence light produced by cosmic muons in the LArTPC is collected by photomultiplier tubes placed up to 7 m away from the ionizing track. In this paper, the ProtoDUNE-DP photon detection system performance is evaluated with a particular focus on the different wavelength shifters, such as PEN and TPB, and the use of Xe-doped LAr, considering its future use in giant LArTPCs. The scintillation light production and propagation processes are analyzed and a comparison of simulation to data is performed, improving understanding of the liquid argon properties.

Prospects for beyond the Standard Model physics searches at the Deep Underground Neutrino Experiment: DUNE Collaboration

The Deep Underground Neutrino Experiment (DUNE) will be a powerful tool for a variety of physics topics. The high-intensity proton beams provide a large neutrino flux, sampled by a near detector system consisting of a combination of capable precision detectors, and by the massive far detector system located deep underground. This configuration sets up DUNE as a machine for discovery, as it enables opportunities not only to perform precision neutrino measurements that may uncover deviations from the present three-flavor mixing paradigm, but also to discover new particles and unveil new interactions and symmetries beyond those predicted in the Standard Model (SM). Of the many potential beyond the Standard Model (BSM) topics DUNE will probe, this paper presents a selection of studies quantifying DUNE's sensitivities to sterile neutrino mixing, heavy neutral leptons, non-standard interactions, CPT symmetry violation, Lorentz invariance violation, neutrino trident production, dark matter from both beam induced and cosmogenic sources, baryon number violation, and other new physics topics that complement those at high-energy colliders and significantly extend the present reach.

Adverse effects of exposure to ambient air pollution on coronary calcification

Background

The association of air pollution with cardiovascular morbidity and mortality has been attributed to acute events (atherothrombosis). It is unclear whether air pollution may influence the subclinical stage of coronary artery disease (CAD). This study investigated the relationship between particulate matter <2.5μm (PM2.5) and nitrogen dioxide (NO2) with coronary calcium score (CCS).

Methods

This study included 606 asymptomatic adults (49% men, aged 56±7 years) recruited from the community in two States of Australia (Victoria and Tasmania). Annual PM2.5 and NO2 concentrations were matched with residential address. CCS was measured using coronary CT scan. Medical history, physical measurements, biochemistry, and socioeconomic status were recorded for assessment of confounders.

Results

Average exposure to PM2.5 and NO2 were 6.7±1.5 (ppm) and 3.6±2.1 (μg/m3), respectively. Of the 606 participants, 17% had high CCS (≥100) and 4% had very high CCS (≥400). Exposure to higher annual PM2.5 was associated with greater odds of high CCS (OR=1.20 [95% CI: 1.02, 1.42]) and very high CCS (OR=1.47 [95% CI: 1.03, 2.11]). Similar adverse associations were also present for NO2 and high CCS (OR=1.13 [95% CI: 1.02, 1.25]) and very high CCS (OR=1.25 [95% CI: 1.06, 1.47]). These findings were independent of age, sex, body size, smoking, comorbidities and socio-economic status.

Conclusions

Ambient air pollution was associated with degree of coronary calcification, independent of standard risk factors. The link between air pollution and CAD is not limited to acute events but appears to include atherogenesis.

Funding Acknowledgement

Type of funding source: None

Cardioprotection using strain-guided management of potentially cardiotoxic cancer therapy: 1 year results of the SUCCOUR trial

Background

Conventional criteria for diagnosis of chemotherapy-related cardiac dysfunction (CTRCD) are dependent on the recognition of heart failure (HF) symptoms and/or changes in LVEF. However, the low sensitivity of EF for minor changes in LV function may delay initiation of cardio-protective therapy (CPT). Global longitudinal strain (GLS) is a robust and sensitive marker of LV dysfunction (LVD), but existing observational data are insufficient to justify changing the diagnostic criteria for CTRCD.

Purpose

To identify whether GLS guidance of CPT would improve cardiac function of at risk patients undergoing potentially cardiotoxic chemotherapy, compared with usual care.

Methods

In this international multicenter prospective randomized controlled trial, 331 pts from 23 international sites taking anthracyclines with another risk factor for HF were randomly allocated into 166 undergoing GLS-guided (CPT for >12% relative reduction in GLS using Echopac software) and 165 EF-guided (CPT for >10% absolute reduction of EF). Pts were followed over 1 year for the primary end-point (ΔEF) with 3D echo (3DE); 2D echo (2DE) was used when 3D images were unsuitable for measurement. Development of CTRCD (EF reduction of 10% to <55%) was a secondary endpoint.

Results

Of 331 randomized patients, 24 withdrew before follow-up imaging was performed (2 died, and rest withdrew or were lost to follow-up). Among 307 patients (age 54±12 years, 94% women) with follow-up 1.0±0.2 years, 277 had breast cancer, 30 had lymphoma/leukemia. HF risk factors were prevalent: 89 (29%) had hypertension and 39 (13%) had diabetes mellitus. The most common chemotherapy regimen during this study was the combination of anthracycline and trastuzumab. The baseline 3D LVEF was 61±5%, and GLS was −20.8±3.2%. At 1 year follow-up, 31 (10%) met CTRCD and was reduced in the GLS-guided arm (Table 1), although new LV dysfunction (EF<55%) and change of EF were not different.

Conclusion

In this international multicentre trial, the incidence of CTRCD was reduced by strain-guided cardioprotection. Although the final EF and the number of pts developing EF <55% was not altered by strain-guided therapy, this reduces meaningful reduction of EF to the abnormal range. The results support the use of GLS in surveillance for CTRCD.

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): General Electric Medical Systems

The impact of maternal diabetes on fetal left atrial size and function

Introduction

The developmental impact of maternal diabetes on the fetal left atrium (LA) is unclear.

Purpose

To determine if maternal diabetes mellitus (DM) impacts fetal LA size and function (fetal LA strain (LAS)).

Methods

We evaluated LA area (LAA) and LAS on fetuses of diabetic and control mothers who attended a mandated 24 week fetal morphology scan. Participants were excluded from the study if: there was a history of pre-eclampsia or if the fetus did not have adequate images for LAS analysis

We used fetal cardiac 4-chamber view for analysis. A region of interest was drawn along the LA endocardial border for tracking and was used for assessment of maximum LAA.

Baseline variables were compared using Student t test or Mann-Whitney U test and are presented as Mean ± Standard Deviation or Median (Interquartile range (IQR)). Body mass index (BMI), maternal age, gestational age, fetal heart rate (FHR), smoking status, estimated fetal weight (EFW) and Maternal DM were analysed in univariate and multivariate models with respect to LAA and LAS.

Results

160 pregnant women (50 controls, 110 diabetics) were scanned. 9 were excluded due to poor image quality, resulting in 104 mothers with diabetes (T1DM 9, T2DM 8, and gestational DM 87) and 47 controls without diabetes.

The mothers were well matched for age, blood pressure, smoking prevalence and gestational age. The diabetic mothers had a significantly higher BMI: Median (IQR) ((30.4 kg/m2 (25.1–34.8) vs 20.8 kg/m2 (21.4–27.4), p<0.001) and had higher weight (77 kg (65–93) vs 64 kg (62–68), p<0.001).

FHR was higher in fetuses of diabetic mothers (147±10 vs 144±8, p 0.04). Maternal DM resulted in larger LAA 1.68 cm2±0.39 cm2 vs 1.56 cm2±0.36 cm2; p=0. 08, however the result was not significant. The LAS was significantly lower in fetuses with maternal DM compared to fetuses of controls: 28.8% ± 8.8% vs 32.3% ± 9.2%; p 0.033.

On multivariate analysis (Table 1), the predictors of LAS were Maternal DM and FHR and predictors of LAA were EFW and Maternal DM.

Conclusions

Maternal diabetes modulates both LA size and LA function. The association between LA function and FHR may provide an explanation for fetal tachycardia in Maternal DM.

Fetal left atrial strain

Funding Acknowledgement

Type of funding source: None

The reporting of reproducibility of cardiac imaging biomarkers

Introduction

There is inconsistency in the reporting of reproducibility of imaging biomarkers in published literature.

Purpose

To assess the reporting of reproducibility of imaging biomarkers described in original articles across the top 3 multi-modality cardiovascular imaging journals.

Methods

We reviewed all published articles in 2018 in the 3 leading cardiovascular imaging journals: JACC cardiovascular Imaging (A), Circulation. Cardiovascular Imaging (B), and EHJ Cardiovascular Imaging (C). Articles were excluded if they were not original research or reproducibility reporting was not required: case reports, editorials, research supports, meta- analysis, reviews, miscellaneous.

The remaining articles were assessed for the following reproducibility reporting parameters:

1) Discuss reproducibility; 2) Assess reproducibility in current study; 3) Reproducibility tools used: Intra-class correlation coefficient (ICC), coefficient of variance (COV), Bland Altman analysis (BA), etc and 5) Proportion of total population used in reproducibility analysis

Results

Among 951 articles published (Journal A/B/C 521/ 171/ 259), 692 were excluded due to above reasons. 259 articles were assessed for reproducibility data (Figure 1a). 122 of the 259 (47%) articles discussed reproducibility, including 26/122 (21%) referring to previous reproducibility data. Remaining 96/122 (79%) articles demonstrated reproducibility in the current manuscript- there was no difference in the frequency of articles discussing reproducibility across three journals (A 35/85 (41%); B 25/52 (48%); C 62/122 (51%), p=0.39).

Modality differences between reporting of reproducibility were as follows: (Echo 66/122 (54%); CT 14/38 (37%); CMR 27/55 (49%); Nuclear 9/26 (35%) and others 6/18 (33%), p=0.04)

Measures used to demonstrate reproducibility were as follows: (1.) ICC 64/96 (67%); 2.) BA 28/96 (29%); 3.) COV 16/96 (17%); 4.) Agreement 18/96 (19%); 5.) Correlation (Pearson's r) 3/96 (3%) p<0.001) (Figure 1b).

The proportion of the total population used for reproducibility analysis ranged from 0.8% to 100%, median 18.6% IQR (7.8%- 56.3%). Regression revealed proportion of total population used, was inversely related to population size (r=−0.32, p 0.002). Modality differences were as follows: (Echo 12.0% (5.7%- 36.1%); CT 17.1% (7.8%- 100%); CMR 25.0% (16.1%- 97.1%); Nuclear 68.9% (29.6% - 100%) and others 56.1% (32.6%- 62.3%), p=0.03).

Conclusions

Approximately half original research manuscripts published across 3 major multi-modality imaging journals discussed or demonstrated reproducibility. No differences across journals were identified. There are differences between modalities with respect to reporting reproducibility. The most common tool used to report reproducibility was ICC. There is marked heterogeneity in the proportion of the total population used to demonstrate reproducibility, this is partly determined by the size of population being examined.

Figure 1. A Snapshot of reproducibility reporting

Funding Acknowledgement

Type of funding source: None

The role of cardio-protective agents in breast cancer patients to prevent anthracycline induced cardiotoxicity: a systematic review and network meta-analysis

Background

Anthracycline (ANT)-based chemotherapy for breast malignancies have significantly improved cancer outcomes. However, the cardiotoxicity induced by ANTs in the breast cancer population has increased major adverse cardiac events. While randomised controlled trials (RCTs) have explored different primary preventative agents to confer cardio-protection pre chemotherapy, comparisons between agents has been limited. It is unclear which drug is the most efficacious in preserving Left Ventricular Ejection Fraction (LVEF) amongst this population.

Purpose

To perform a network meta-analysis of RCTs comparing the impact on LVEF of various prophylactic cardio-protective agents, when prescribed to breast cancer patients prior to ANT-based chemotherapy.

Methods

Two independent authors performed a literature search as per the PRISMA guidelines using four databases (CENTRAL, Cochrane Reviews, MEDLINE, SCOPUS), to find RCTS evaluating cardio protective agents. The trial population was limited to patients with breast cancer without prior ANT exposure. Trials were only included if the cardio-protective agents were commenced prior to ANT dosing. The assessed outcome was a mean change in LVEF pre and post ANT dosing, compared to placebo prevention. Extracted data included age, ANT dose, and LVEF pre and post chemotherapy. The Cochrane Risk of Bias tool was used to appraise included RCTs.

Results

From 2807 search results, we identified twelve RCTs which evaluated 1126 patients. Seven studies assessed beta-blockers alone and two assessed combination ACE inhibitors and beta blockers. Individual studies assessing ACE inhibitors, spironolactone or rosuvastatin alone were also included. All patients were female with an average age of 50.5 and average ANT dose of 412 mg/m2. Our network meta-analysis showed beta-blockers showed significant protection with higher LVEF than placebo by 2.38% [0.52, 4.25]. ACE inhibitors showed a similar magnitude of LVEF preservation 2.59% [−0.20, 5.38] but not statistically significant due to wider CI because of lower sample size (n=250). Spironolactone showed a statistically significant preservation in LVEF by 12.80% [3.44, 22.16], however this was based on a single study (n=83), with marked measurement bias and deviations from intended intervention. All included trials had an intermediate or high risk of bias, with marked heterogeneity in ANT dosing and LVEF monitoring.

Conclusion

Beta-blockers minimise LVEF decline when administered prior to anthracycline chemotherapy, compared against alternate agents. Data may be underpowered to demonstrate the benefit of ACE inhibitor and combination beta blocker/ACE inhibitor prescription. The quality of RCT data to date is limited by a high risk of bias and significant heterogeneity between RCA reporting. This analysis is likely to inform clinical practice, and allow clinicians to prescribe primary cardio-protection in patients at high risk of cardiotoxicity.

Funding Acknowledgement

Type of funding source: None

Distributions of hypothalamic neuron populations coexpressing tyrosine hydroxylase and the vesicular GABA transporter in the mouse

The hypothalamus contains catecholaminergic neurons marked by the expression of tyrosine hydroxylase (TH). As multiple chemical messengers coexist in each neuron, we determined if hypothalamic TH-immunoreactive (ir) neurons express vesicular glutamate or GABA transporters. We used Cre/loxP recombination to express enhanced GFP (EGFP) in neurons expressing the vesicular glutamate (vGLUT2) or GABA transporter (vGAT), then determined whether TH-ir neurons colocalized with native EGFP^Vglut2 - or EGFP^Vgat -fluorescence, respectively. EGFP^Vglut2 neurons were not TH-ir. However, discrete TH-ir signals colocalized with EGFP^Vgat neurons, which we validated by in situ hybridization for Vgat mRNA. To contextualize the observed pattern of colocalization between TH-ir and EGFP^Vgat , we first performed Nissl-based parcellation and plane-of-section analysis, and then mapped the distribution of TH-ir EGFP^Vgat neurons onto atlas templates from the Allen Reference Atlas (ARA) for the mouse brain. TH-ir EGFP^Vgat neurons were distributed throughout the rostrocaudal extent of the hypothalamus. Within the ARA ontology of gray matter regions, TH-ir neurons localized primarily to the periventricular hypothalamic zone, periventricular hypothalamic region, and lateral hypothalamic zone. There was a strong presence of EGFP^Vgat fluorescence in TH-ir neurons across all brain regions, but the most striking colocalization was found in a circumscribed portion of the zona incerta (ZI)-a region assigned to the hypothalamus in the ARA-where every TH-ir neuron expressed EGFP^Vgat . Neurochemical characterization of these ZI neurons revealed that they display immunoreactivity for dopamine but not dopamine β-hydroxylase. Collectively, these findings indicate the existence of a novel mouse hypothalamic population that may signal through the release of GABA and/or dopamine.

P695 Is reference value of left atrial strain using 2D echocardiography really reliable?

Funding Acknowledgements

MT received research grant from GE Healthcare.

Background

Left atrial (LA) longitudinal strain (LALS) assessed by two-dimensional echocardiography (2DE) speckle tracking analysis is increasingly popular for the estimation of left ventricular diastolic dysfunction and the prediction of adverse outcome. Since standard apical 4-chamber and 2-chamber views often maximize the long-axis of the left ventricle, and the long axis of the left ventricle and that of the left atrium do not lie on the same 2D cutting plane, these views have a risk for the foreshortening of the left atrium. It may cause overestimation of LALS due to the reduction of initial perimeter of region of interest that is a denominator for the strain calculation.

Purpose

The aim of this study was to compare LALS values between 2DE and 3D echocardiography (3DE) in healthy subjects, and investigate whether 2DE speckle tracking analysis overestimates reference value of LALS.

Methods

LALS and LA longitudinal length were measured by both 2DE and 3DE in 105 healthy subjects (median age, 42 years; 59 men). For 2DE, LA longitudinal length from the mitral annulus to the roof of the left atrium were measured on apical 4-chamber and 2-chamber views at end-diastole and at end-systole, and the values were averaged. Apical 4-chamber and 2-chamber LALS was also measured using 2DE speckle tracking software (EchoPac PC, GE Healthcare) for calculating biplane LALS. 3DE LALS was measured using new 3DE LA strain software (4D Auto LAQ, GE Healthcare). 3DE determined LA longitudinal length at both end-diastole and end-systole was also measured using the same 3DE datasets.

Results

Mean values of biplane LALS was 39.6 ± 11.8%. 2DE LA longitudinal length at both end-diastole (r=-0.43) and end-systole (r=-0.54) was negatively correlated with biplane LALS. Multivariable regression analysis revealed that both end-diastolic and end-systolic LA longitudinal length had a significant negative association for biplane LALS after adjusting anthropometric and echocardiography image quality parameters. 3DE LALS analysis was not possible in 11 subjects due to the erroneous LA border determination (Feasibility: 90%). 3DE LALS (23.7 ± 7.6%) was significantly lower than biplane LALS (39.5 ± 12.0%, p < 0.001) with a weak correlation (r = 0.33) in 94 subjects who were possible in both analyses. Paired comparison of LA longitudinal length between 2DE and 3DE revealed that 2DE determined LA length at end-diastole (3.51 ± 0.72 cm vs. 4.85 ± 0.56 cm, p < 0.001) and at end-systole (4.63 ± 0.69 cm vs. 5.84 ± 0.54 cm, p < 0.001) was significantly shorter than that obtained from 3DE.

Conclusions

Our results highlighted that LA cavity visualizing on the standard apical 4-chamber and 2-chamber views are often longitudinally foreshortened, and this is a potential cause for the overestimation of LALS. 3DE may overcome this limitation.

P1378 Impact of maternal diabetes on fetal left atrial function

Purpose

We sought to evaluate if fetal ER can detect impairment of left atrial function in the fetal heart as a result of maternal diabetes.

Methods

We performed a prospective observational study evaluating patients who were referred to the high risk pregnancy service as a result of maternal diabetes (pre-existing or gestational) and healthy controls.

Patients were excluded if adequate imaging of the fetal myocardium was not possible. Baseline characteristics of the mother and cardio-metabolic risk factors were recorded.

The fetal echocardiogram focused on the 4 chamber view. We used the 4 chamber view with closure of the mitral valve as the zero reference point (R-R) gating. The strain curves from 6 atrial segments were averaged.

Normality of the data was assessed using the Shapiro-Wilk test. The Mann-Whitney U test was used to compare ER between fetuses, whose mothers had diabetes versus those fetuses whose mothers were healthy controls.

Results

A total of 120 fetal scans were performed. 5 were excluded due to poor image quality, which prevented strain analysis. 115 fetal scans were analysed (87 with maternal diabetes and 27 healthy controls). The diabetic subjects and controls did not defer significantly in age Mean ± SD (31± 5 vs 30± 5, p= 0.81). The mothers with diabetes had a higher body mass index than controls (Median [IQR]) (30.5 kg/m2 [25.1, 35.3] vs 24.6 kg/m2 [22.1, 28.6] p < 0.001).

The presence of maternal diabetes resulted in lower fetal ER (28.5% [22.1, 36.2] vs 33.4% [26.6, 41.6] P = 0.01).

Figure 1 illustrates the Box-Whisker plot comparing Fetal ER between fetuses exposed to maternal diabetes and fetuses where mothers were healthy controls.

Conclusion

The presence of maternal diabetes results in impaired fetal left atrial function as measured by fetal left atrial strain (ER).

Abstract P1378 Figure 1

P1482Preclinical diastolic dysfunction assessed by left atrial strain and association with incident heart failure

Background

Left atrial strain in the reservoir phase (LASr) measures passive LA stretch and is a sensitive marker of left ventricular diastolic dysfunction (DD). However, reduced LASr has not been prospectively validated against clinical heart failure (HF) endpoints and its place in diastology evaluation is unclear.

Aim

We sought whether DD grades defined by previously validated ranges of LASr predicted incident HF and whether reclassifying indeterminate diastolic function based on reduced LASr could facilitate assessment of HF risk.

Methods

Community dwelling elderly subjects were recruited and underwent baseline clinical and echocardiographic assessment. Where imaging was suitable, speckle-tracking echocardiography assessed LASr and subjects were assigned DD grades based on published ranges: normal >35%, grade 1 24–35%, grade 2 19–24%, grade 3 <19%. Current ASE/EACVI recommendations were used to identify those with indeterminate function; LASr-defined DD (LASr-DD) was defined as LASr ≤23%. Follow-up was ≤2 years and incident HF adjudicated by Framingham criteria.

Results

Of 610 subjects (age 71±5 yrs., 46% male) LASr analysis was feasible in 590 (97%); average LASr was 39% (IQR 34–43%). Incident HF was associated with LASr-DD grade, occurring in 8 (36%) with grade ≥2, 14 (10%) with grade 1 and 39 (9%) with normal function (p<0.001). Adjusted odds ratio for incident HF for LASr-DD grade ≥2 was 3.12 (95% CI 1.06–9.1, p=0.038) Diastolic function was indeterminate in 147 (24%) subjects; of 144 (98%) with LAS analysis, 6 (75%) of those with LASr-DD vs. 15 (11%) with normal LASr experienced incident HF (p<0.001).

Univariable Multivariable* OR (95% CI) p-value OR (95% CI) p-value LASr-DD grade:   1 1.13 (0.59–2.15) 0.7 0.84 (0.42–1.69) 0.63   ≥2 5.7 (2.26–14.5) <0.001 3.12 (1.06–9.1) 0.038 *Adjusted for age, hypertension, diabetes, BMI, global longitudinal strain, E/e', LA volume index, LV mass index (all p<0.1 on univariable analysis).

Incorporating LA strain in practice

Conclusion

DD defined by LASr is predictive of HF for grades ≥2 independent of other diastolic measures. Indeterminate diastolic function with LASr ≤23% is associated with incident HF. LASr may complement current diastolic function assessment recommendations.

Acknowledgement/Funding

Baker Heart and Diabetes Institute

1271Short-term effects of exposure to ambient fine particulate matter on out-of-hospital cardiac arrest: a nationwide case-crossover study in Japan

Introduction

The cardiovascular health consequences of ambient air pollution generally equal or exceed those due to pulmonary diseases and cancers. Particulate matter less than 2.5μm in aerodynamic diameter (PM2.5) has become a major focus of research on the short-term exposure to air pollution and cardiovascular disease. However, the evidence regarding the association between several air pollutants and out-of-hospital cardiac arrest (OHCA), has been inconsistent, which could be due to limited sample sizes (∼11,000). Thus, a larger study may assist in characterising possible associations.

Purpose

This study aimed to identify the associations between exposure to ambient air pollution and the incidence of OHCA in Japan.

Methods

A case-crossover design was used to determine the odds ratio (OR) of OHCA across Japan with daily exposure of PM2.5, carbon monoxide (CO), photochemical oxidants (Ox), and sulfur dioxide (SO2) on the day of the arrest or 1–3 days before it (lag 0–3). OHCA cases were identified through the All-Japan Utstein registry of the Fire and Disaster Management Agency from January 1, 2014 to December 31, 2015. All cause OHCAs were investigated by conditional logistic regression adjusted for daily temperature and relative humidity.

Results

A total of 249,372 OHCAs were included during study period. Each 10 μg/m3 increase in daily PM2.5 exposure over 4 days was associated with all cause OHCA risk (lag 0: OR 1.017, 95% confidence interval (CI) 1.010, 1.024; lag 1: OR 1.015, 95% CI 1.008, 1.022; lag 2: OR 1.018, 95% CI 1.011, 1.025; lag 3: OR 1.021, 95% CI 1.014, 1.028; lag 0–1: OR 1.022, 95% CI 1.014, 1.030). CO, Ox and SO2 also showed significant associations with OHCAs. In the multi-pollutant model, the effects of PM2.5 remained independent of CO, Ox and SO2 (Table).

Conclusion

Short-term exposure to PM2.5 was independently associated with an increased risk of OHCA.

2284Sex and age differences in short-term exposure to ambient fine particulate matter and out-of-hospital cardiac arrest: a nationwide case-crossover study in Japan

Introduction

Accumulating evidence has shown the elevated risk for cardiovascular diseases (CVD) with exposure to air pollution, such as fine particles <2.5μm in aerodynamic diameter (PM2.5). A bi-directional relationship exists between air pollution and traditional CV risk factors like obesity, diabetes, and hypertension. However, little is known about the effect of age and sex on association between ambient air pollution and out-of-hospital cardiac arrest (OHCA).

Purpose

This study aimed to identify sex and age differences in the associations between exposure to PM2.5 and OHCA in Japan.

Methods

A case-crossover design was used to determine the odds ratio (OR) of OHCA across Japan with daily PM2.5 exposure on the day of the arrest or 1–3 days before it (lag 0–3). OHCA cases were identified through the All-Japan Utstein registry of the Fire and Disaster Management Agency from January 1, 2014 to December 31, 2015. OHCAs were investigated by conditional logistic regression adjusted for daily temperature and relative humidity with stratification by sex and age.

Results

A total of 249,372 OHCAs were included during study period. Their mean age was 75 years and 57% were male. Each 10 μg/m3 increase in daily PM2.5 exposure over 4 days was associated with all cause OHCA risk for male (lag 0: OR 1.022, 95% confidence interval (CI) 1.013, 1.031; lag 1: OR 1.016, 95% CI 1.007, 1.025; lag 2: OR 1.016, 95% CI 1.007, 1.026; lag 3: OR 1.017, 95% CI 1.008, 1.027; lag 0–1: OR 1.025, 95% CI 1.015, 1.036). Increased risk in OHCA was also found with lag 1 to lag 3 PM2.5 exposure among women. Lag 0 to lag 3 PM2.5 exposures were significantly associated with OHCA among patients older than 65 years. Among 35 to 64 years, only lag 3 PM2.5 exposure was associated with an increased risk in OHCA. No significant association was observed between PM2.5 exposure and OHCA among patients less than 35 years.

Conclusions

Short-term exposure to PM2.5 is associated with an increased risk of OHCA in both sexes. Patients older than 65 years were more susceptible to PM2.5 exposure than younger age group.