Fluids and Electrolytes under Confinement in Single-Digit Nanopores

Confined fluids and electrolyte solutions in nanopores exhibit rich and surprising physics and chemistry that impact the mass transport and energy efficiency in many important natural systems and industrial applications. Existing theories often fail to predict the exotic effects observed in the narrowest of such pores, called single-digit nanopores (SDNs), which have diameters or conduit widths of less than 10 nm, and have only recently become accessible for experimental measurements. What SDNs reveal has been surprising, including a rapidly increasing number of examples such as extraordinarily fast water transport, distorted fluid-phase boundaries, strong ion-correlation and quantum effects, and dielectric anomalies that are not observed in larger pores. Exploiting these effects presents myriad opportunities in both basic and applied research that stand to impact a host of new technologies at the water-energy nexus, from new membranes for precise separations and water purification to new gas permeable materials for water electrolyzers and energy-storage devices. SDNs also present unique opportunities to achieve ultrasensitive and selective chemical sensing at the single-ion and single-molecule limit. In this review article, we summarize the progress on nanofluidics of SDNs, with a focus on the confinement effects that arise in these extremely narrow nanopores. The recent development of precision model systems, transformative experimental tools, and multiscale theories that have played enabling roles in advancing this frontier are reviewed. We also identify new knowledge gaps in our understanding of nanofluidic transport and provide an outlook for the future challenges and opportunities at this rapidly advancing frontier.

Observation and Isochoric Thermodynamic Analysis of Partially Water-Filled 1.32 and 1.45 nm Diameter Carbon Nanotubes

Recent measurements of fluids under extreme confinement, including water within narrow carbon nanotubes, exhibit marked deviations from continuum theoretical descriptions. In this work, we generate precise carbon nanotube replicates that are filled with water, closed from external mass transfer, and studied over a wide temperature range by Raman spectroscopy. We study segments that are empty, partially filled, and completely filled with condensed water from -80 to 120 °C. Partially filled, nanodroplet states contain submicron vapor-like and liquid-like domains and are analyzed using a Clausius-Clapeyron-type model, yielding heats of condensation of water inside closed 1.32 nm diameter carbon nanotubes (3.32 ± 0.10 kJ/mol and 3.72 ± 0.11 kJ/mol) and 1.45 nm diameter carbon nanotubes (3.50 ± 0.07 kJ/mol) that are lower than the bulk enthalpy of vaporization and closer to the bulk enthalpy of fusion. Favored partial filling fractions are calculated, highlighting the effect of subnanometer changes in confining diameter on fluid properties and suggesting the promise of molecular engineering of nanoconfined liquid/vapor interfaces for water treatment or membrane distillation.

Discretized hexagonal boron nitride quantum emitters and their chemical interconversion

Quantum emitters in two-dimensional hexagonal boron nitride (hBN) are of significant interest because of their unique photophysical properties, such as single-photon emission at room temperature, and promising applications in quantum computing and communications. The photoemission from hBN defects covers a wide range of emission energies but identifying and modulating the properties of specific emitters remain challenging due to uncontrolled formation of hBN defects. In this study, more than 2000 spectra are collected consisting of single, isolated zero-phonon lines (ZPLs) between 1.59 and 2.25 eV from diverse sample types. Most of ZPLs are organized into seven discretized emission energies. All emitters exhibit a range of lifetimes from 1 to 6 ns, and phonon sidebands offset by the dominant lattice phonon in hBN near 1370 cm^-1. Two chemical processing schemes are developed based on water and boric acid etching that generate or preferentially interconvert specific emitters, respectively. The identification and chemical interconversion of these discretized emitters should significantly advance the understanding of solid-state chemistry and photophysics of hBN quantum emission.

Clinical validation of an artificial intelligence algorithm offering cross-platform detection of atrial fibrillation using smart device electrocardiograms

Introduction

Multiple smart devices capable of “screening” for atrial fibrillation (AF) based on single-lead electrocardiogram (SL ECG) are presently available. Manufacturers' algorithm capabilities and accuracy for the automated detection of AF vary. Reliable artificial intelligence (AI) algorithms would be valuable to assist physicians with managing the large amount of data. We aimed to assess the clinical value of applying a smart device agnostic AI-based algorithm for the detection of AF from five different smart devices (four smartwatches, one handheld device) and compared the results to the cardiologist-interpreted 12-lead ECG in a real world cohort of patients.

Methods

This is a prospective, observational study enrolling patients presenting to a cardiology service at a tertiary referral center. Patients were prescribed a 12-lead ECG, followed by five consecutive smart device recordings from five different manufacturers. SL ECGs were exported as PDF files from the devices and analyzed by a deep neural network (DNN) based platform which allows automated AI assisted cardiac rhythm interpretation.

Results

We prospectively enrolled 157 patients (32% female, median age 66 years). AF was present in 48 patients (31%) at time of recording, as documented by the 12-lead ECG. Accuracy for the detection of AF by the DNN-based algorithm was 96.6% for the Apple Watch 6, 95.2% for the AliveCor Kardia Mobile, 96.0% for the Fitbit Sense, 95.7% for the Samsung Galaxy Watch 3 and 93.8% for the Withings Scanwatch, respectively (Figure 1, left). While diagnostic accuracy of the DNN-based algorithm was similar compared to each manufacturer's individual algorithm, the proportion of SL ECGs with a conclusive diagnosis was significantly higher for all smart devices when using the DNN-based algorithm, p<0.001 (Figure 1, right). As complementary analysis, we assessed sensitivity and specificity detection capabilities in both algorithms (Figure 2).

Conclusion

In this clinical validation, a DNN-based algorithm reported significantly more conclusive diagnoses for each smart device compared to the manufacturers' algorithms, whilst showing similarly high accuracy in the detection of AF compared to the cardiologist-interpreted standard 12-lead ECG. Given further validation, SL ECG assisted rhythm interpretation through a cross-platform AI-algorithm presents a promising clinical value for AF detection and offers a possible solution for managing the data surge for smart device-acquired ECGs.

Funding Acknowledgement

Type of funding sources: None.

Echocardiographic pattern of left ventricular function recovery in tachycardia-induced cardiomyopathy patients

Background

Tachycardia-induced Cardiomyopathy (TIC) represents a reversible type of cardiomyopathy (CM) that is underdiagnosed. Prior pilot studies suggested a specific left ventricular (LV) function recovery pattern in TIC patients. Cardiac chamber remodeling in TIC, however, remains incompletely understood.

Purpose

We aimed to explore differences in LV dimensions and functional recovery in TIC patients when compared to a control group of patients with other forms of CM and functional recovery.

Methods

We identified patients with reduced left ventricular ejection fraction (≤50%) and/or atrial fibrillation or flutter treated between 2015 and 2022. Patients had at least two serial transthoracic echocardiographies (TTE). The minimal interval between the TTEs had to be at least 3 months, and the left ventricular ejection fraction (LVEF) had to either improve (≥15% in absolute value) or normalize (LVEF at follow-up ≥50%). Patients were then divided into two groups: A) patients with atrial fibrillation or atrial flutter at baseline and sinus rhythm at follow-up. These patients were assumed to have TIC. B) Patients with sinus rhythm at both baseline and follow-up, consisting of patients with other forms of CM. The change in ventricular dimensions and function (indexed left ventricular end-systolic – LVESDI, end-diastolic diameters – LVEDDI – and volumes – LVEDVI, LVEF, and fractional shortening – FS) were compared within and across group A and B at baseline and at follow-up. The groups were compared using Kruskal (for independent data) and Wilcoxon (for paired data) tests. A p<0.05 was considered significant.

Results

A total of 261 patients were included (34% female, median age 68 years). The median time between TTEs was 25 months. 104 (39.8%) patients were considered to suffer from TIC and 157 (60.2%) patients were considered to suffer from other forms of CM. The changes in ventricular dimensions and function in both groups are shown in Figure 1 and Table 1. The TIC group showed no improvement in LVEDVI from baseline to the follow-up examination, while the control group showed significant improvement in LVEDVI (1.7% [−24.7, 22.8] vs. 12.4% [−7.1, 29.3], p=0.008). There was no difference in LVEDDI recovery between TIC and control patients (1.7% [−7.3, 10.3] versus 3.1% [−5.4, 10.2], p=0.578).

Conclusions

TIC patients have a specific pattern of functional recovery with similar improvements in systolic function and diameters compared with patients with other CMs, while diastolic parameters remained impaired.

Funding Acknowledgement

Type of funding sources: None.

Risk factors for the development of premature ventricular complex-induced cardiomyopathy: a systematic review and meta-analysis

Background

Premature ventricular complexes (PVCs) can be a reversible cause of heart failure. To date, it is unclear which risk factors contribute to the development of impaired left ventricular function.

Objective

Systematically assessing risk factors for the development of PVC-induced cardiomyopathy (PVC-CM).

Methods

We performed a structured database search of the scientific literature for studies investigating risk factors for the development of PVC-induced Cardiomyopathy. We investigated the reporting of PVC-induced Cardiomyopathy risk factors (RF) and assessed the comparative association of the different RF using random-effect meta-analysis.

Results

A total of 26 studies (9 prospective and 17 retrospective studies) involving 16.764.641 patients were analyzed (mean age 55 y, 58% women, mean PVC burden 17%). Suitable for quantitative analysis were 25 studies examining 6738 (0.04%) patients and 11 RF (≥3 occurrences in multivariable model assessing a binary change in left ventricular - LV- function). Among these risk factors, age (OR 1.02 per increase in the year of age, 95%-CI [1.01, 1.02]), the presence of symptoms (OR 0.18, 95%-CI [0.05, 0.64]), non-sustained VTs (OR 3.01, 95%-CI [1.39, 6.50]), LV origin (OR 2.20, 95%-CI [1.14, 4.23]), epicardial origin (OR 4.72, 95%-CI [1.81, 12.34]), the presence of interpolation - PVCs that do not reset the RR interval (OR 4.93, 95%-CI [1.66, 14.69]) and overall PVC burden (OR 1.06, 95%-CI [1.04, 1.08]) were all significantly associated with PVC-induced Cardiomyopathy. (Figures 1,2)

Conclusion

In this meta-analysis, the most consistent risk factors for PVC-CM were age, non-sustained VTs, LV and epicardial origin, interpolation, and PVC burden, while the presence of symptoms significantly reduced the risk. These findings help tailor stringent follow-up to patients presenting with frequent PVCs and normal LV function.

Funding Acknowledgement

Type of funding sources: None.

Bone morphogenetic protein 10 as predictor for adverse outcomes in patients with atrial fibrillation

Background

Patients with atrial fibrillation (AF) face an increased risk of death and major adverse cardiovascular events (MACE). Bone morphogenetic protein 10 (BMP10) is a novel atrial-specific biomarker, but data about its prognostic value in AF patients are lacking.

Purpose

We aimed to assess the predictive value of BMP10 for death and MACE in AF patients in comparison to N-terminal prohormone of B-type natriuretic peptide (NT-proBNP).

Methods

Baseline concentrations of BMP10 and NT-proBNP were measured in stable patients with AF enrolled in Swiss-AF, a prospective multicenter observational cohort study. Primary outcomes were all-cause death and MACE (composite of heart failure hospitalization, cardiovascular death, stroke, systemic embolism, myocardial infarction). Measures of discriminative power were used to compare multivariable Cox proportional hazard models using the different biomarkers.

Results

A total of 2219 AF patients were included with a median follow-up of 4.3 years (IQR 3.9, 5.1). Mean age was 73±9 years and 27% were women. Incidence rate per 100 patient-years of all-cause death and MACE increased across BMP10 quartiles (Figure 1). In the multivariable adjusted Cox proportional hazard model, the hazard ratio (HR) and 95% confidence interval (CI) of BMP10 was 1.60 (1.37; 1.87) to predict all-cause death, and 1.54 (1.35; 1.76) to predict MACE. For all-cause death, the C-index (95% CI) was 0.783 (0.763; 0.809) for BMP10, 0.784 (0.765; 0.810) for NT-proBNP, and 0.789 (0.771; 0.815) for both biomarkers combined. For MACE, the C-index (95% CI) was 0.732 (0.715; 0.754) for BMP10, 0.747 (0.731; 0.768) for NT-proBNP, and 0.750 (0.734; 0.771) for both biomarkers combined. When grouping patients according to clinical used NT-proBNP categories (<300, 300–900, >900 ng/l), higher incidence rates and adjusted HRs were observed for the primary outcomes in patients with high BMP10 in the categories of low NT-proBNP (all-cause death aHR 2.28 [1.15; 4.52], MACE aHR 1.88 [1.07; 3.28]) and high NT-proBNP (all-cause death aHR 1.61 [1.14; 2.26], MACE aHR 1.38 [1.07; 1.80]) (Figure 2).

Conclusion

The novel atrial-specific biomarker BMP10 strongly predicts all-cause death and MACE in patients with AF. BMP10 provides additional prognostic information in low- and high-risk patients according to NT-proBNP stratification.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Swiss National Science Foundation, Swiss Heart Foundation

Trimethylamine N-oxide is associated with impaired cognitive function in patients with atrial fibrillation

Introduction

Since patients with atrial fibrillation (AF) are predisposed to suffer from major adverse cerebrovascular events (MACE), they are more likely to suffer MACE linked sequelae, such as cognitive impairment. We hypothesised that the gut microbiome derivate trimethylamine N-oxide (TMAO) may amplify this pathomechanism given its hypercoagulative, proinflammatory and proatherogenic effects.

Methods

Patients of the Swiss-AF cohort with determined TMAO plasma levels, cognitive scores (n=2'379) and cerebral magnetic resonance imaging (cMRI) (n=1'722) collected at baseline were included. TMAO levels were measured by liquid chromatography-mass spectrometry (HPLC). Overall cognitive performance was evaluated using the Cognitive Construct (CoCo) score reflecting different cognitive functions measured by four validated neuropsychological assessments, namely the Montreal Cognitive Assessment (MoCA), Trail Making Test (TMT parts A and B), Semantic Fluency Test (SFT) and Digital Symbol Substitution Test (DSST). The scores were compared with the quartiles of patients' TMAO plasma levels (Q1: 0.6–4, Q2: 4–5.8, Q3: 5.8–9.1, Q4: 9.1–164μmol/l) in linear effect models. All models were adjusted for multiple covariates correlating with this association: For TMAO (overall meat consumption >3 times per week, physical activity, glomerular filtration rate, presence of diabetes mellitus), cognitive function (EQ-5D-5L score, geriatric depression scale, education level) and cerebral affects (white matter lesions volume and total brain volume in cMRI). The relevance of high TMAO plasma levels in different stroke groups in cMRI (i.e., clinically overt, silent, or no stroke) were analysed in a subgroup analysis. The subgroups were additionally adjusted for total brain volume to eliminate the effect of simultaneous decrease of cerebral white matter.

Results

After multivariable adjustment, AF patients in the highest quartile of TMAO levels performed significantly poorer in the global cognitive score (CoCo: estimate −0.11, 95% CI [−0.17, −0.05], p=0.002) compared to patients in the lowest quartile. This was observed also in the MoCA, SFT, DSST, TMT-A and TMT-B.

In the subgroup analysis, an association between the highest TMAO quartile (compared with the lowest quartile) and lower CoCo score was found in the group of patients with overt strokes (−0.18, 95% CI [−0.33, −0.04], p=0.012). Weak evidence of the same association was found in the group of patients with silent strokes (−0.13, 95% CI [−0.25, 0.002], p=0.053) and patients with no strokes (−0.08, 95% CI [−0.16, 0.01], p=0.07).

After adjustment for decreased brain volume, the association remained for silent strokes (−0.14, 95% CI [−0.28, −0.01], p=0.036) indicating the impact of TMAO in this subgroup.

Conclusion

TMAO plasma levels were associated with cognitive impairment in patients with AF. Longitudinal data will clarify dynamics and likely causality between TMAO and cognitive impairment.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Swiss National Science Foundation

An automatic single beat algorithm to discriminate farfield from nearfield bipolar voltage electrograms from the pulmonary veins

Funding Acknowledgements

Type of funding sources: Public hospital(s). Main funding source(s): “Stiftung für Herzschrittmacher und Elektrophysiologie” Basel, Switzerland

Background

Confirmation of pulmonary vein (PV) isolation (PVI) during ablation of atrial fibrillation can be challenging due to superimposition of nearfield (NF) PV and farfield (FF) atrial bipolar voltage electrograms (BVE).

Purpose

To develop an automatic algorithm allowing to discriminate PV nearfield (PV-NF) from atrial farfield (atrial-FF) BVE from a circular mapping catheter during cryoballoon (CB) PVI based on a single-heartbeat analysis.

Methods

BVEs from a decapolar inner-lumen diagnostic catheter (Achieve, Medtronic) during CB PVI were manually classified as PV-NF, atrial-FF and combined FF-NF signal based on the characteristics and disappearance of the PV signal during isolation (Figure, upper row). BVE power spectra were computed using the fast Fourier transform (FFT) and the automatic classification of PV-NF, atrial-FF and combined FF-NF signals was performed using the power in different frequency bands (Figure, lower row). Support vector machine classifier was used to identify PV-NF BVE due to its highest predictive accuracy for the two classes PV-NF+ (PV-NF only and combined FF-NF) and PV-NF- (atrial-FF only). Validation of the approach was performed by comparison of a subset of 80 random samples, which were classified in addition by five experienced electrophysiologists.

Results

We analysed a dataset of 355 BVEs from 57 patients. The examples were balanced between the two classes PV-NF+ and PV-NF-. The mean duration (95% CI) of the BVE was 58 ms (26 to 86), 70 ms (50 to 100) and 94 ms (71 to 139) for PV NF, atrial-FF and combined FF-NF, respectively. The overall balanced accuracy including BVE from all PVs was 82.7% (95% CI: 80.3% to 85.1%). The analysis on individual PVs showed an accuracy of 96.6%, 85.2%, 80.8%, and 76.9% for the right inferior, right superior, left inferior and left superior PV, respectively. Validation of the algorithm in the subset of 80 patients showed a comparable accuracy, sensitivity and specificity in PV-NF detection between the automatic algorithm and the experienced electrophysiologists (82.8%, 89.2%, and 76.3%, compared to 85.2%, 91.9%, and 78.5%, respectively).

Conclusion

A reliable automatic based classification algorithm to identify PV-NF BVE could be developed based on a single-beat analysis. Real-time applications as well as using other electrode configurations may improve local signal interpretation.

Management of conduction disorders after transcatheter aortic valve implantation: results of an EHRA survey

Funding Acknowledgements

Type of funding sources: None.

Background

Left bundle branch block (LBBB) is common after transcatheter aortic valve implantation (TAVI) and is an indicator of subsequent high-grade atrioventricular block. Consensus regarding a reasonable strategy to manage cardiac conduction disturbances after TAVI has been elusive

Methods

The European Heart Rhythm Association (EHRA) conducted a survey to capture contemporary clinical practice for conduction disorders after TAVI. A 25-item online questionnaire was developed and distributed among the EHRA electrophysiology research network centres.

Results

Of 117 respondents, 44% were affiliated with university hospitals. This survey has revealed that a standardized management protocol for advanced conduction disorders such as LBBB or AVB after TAVR is available in 63% of participating centres. Telemetry was chosen by most participants as the most frequent management strategy for patients with new or preexisting LBBB after TAVI (79%, 70%, respectively, Figure 1). Duration of telemetry in patients with new LBBB varied: 18% chose 24 hours, 35% 48 hours, 27% 72 hours and 20% ≥ 72 hours. Similarly, in patients with new LBBB after TAVI undergoing EP study, the cut-off for a prolonged HV interval for PM implantation was heterogenous among European centers (7.4% ≥ 55ms and 44% ≥ 75ms). Conduction system pacing was chosen as preferred device therapy in patients with LBBB and normal LVEF in 3.7% and in patients with LBBB and reduced LVEF in 5.6%.

Conclusions

The management of conduction disorders after TAVI is very heterogeneous across European centres. Risk stratification strategies vary substantially. The role of conduction system pacing in patients with LBBB after TAVI needs to be defined. There is a considerable room for better uniformity in clinical practice.

Healthy lifestyle and atrial fibrillation recurrence after pulmonary vein isolation

Funding Acknowledgements

Type of funding sources: None.

Background/Introduction: Data on the relationship of a healthy lifestyle at the time of atrial fibrillation (AF) ablation with AF recurrence is limited.

Purpose

We investigated the association of healthy lifestyle markers with AF recurrence after ablation.

Methods

In 1439 patients undergoing AF ablation at a tertiary university hospital, a lifestyle score was built. The score included categories of BMI, smoking, blood pressure, fish intake, fruits/vegetable intake, alcohol consumption and physical activity. A higher score indicated a healthier lifestyle and patients were grouped into tertiles. Follow-up included 24h-Holter ECGs at 3 and 6 months and 7d-Holter ECGs at 12 months. Survival analyses and Cox-regression models were used to assess associations of individual factors and score-tertiles with AF recurrence.

Results

Mean age was 61.5 years, 25.9% were female and 59.1% had paroxysmal AF. In 941 patients all lifestyle score variables were available: 129, 675 and 137 patients were in the low, intermediate and high lifestyle group, respectively. Over increasing lifestyle groups, patients were more often female (9.3, 23.3, 38.7%; p<0.0001), had less hypertension (70.5, 53.3, 32.9%; p<0.0001), diabetes (15.5, 6.2, 3.7%; p=0.0002), a smaller left atrial diameter (44.1, 41.0, 37.6mm; p<0.0001) and numerically more paroxysmal AF (56.6, 62.4, 69.4%; p=0.32) with no differences in anti-arrhythmic drugs. In survival analyses (Figure), we saw a trend of more recurrences in the healthiest group compared to the unhealthiest group (logrank p=0.06 for low vs high group). Individually, higher fish intake (logrank p=0.04) and lower blood pressure (logrank p=0.02) were associated with AF recurrence. In Cox-regression models the HR (95% CI) for increasing lifestyle groups was 1.21 (0.98; 1.50, p=0.07). In individual models only higher fish intake (1.25 [1.01; 1.55], p=0.045) was associated with AF recurrence.

Conclusion(s): AF recurrence was numerically more frequent in patients with a healthier lifestyle, despite less comorbidities and smaller LA diameters. This paradoxical relationship might be due to lifestyle changes after PVI, differences in PVI efficacy or residual confounding. Further studies are needed to better understand this association.

Clinical validation of a novel smartwatch for automated detection of atrial fibrillation

Funding Acknowledgements

Type of funding sources: None.

Introduction

The Withings Scanwatch is a novel smartwatch able to record an intelligent (i)ECG with automated detection of AF. While the iECG function from three major manufacturers have been extensively investigated, there is a paucity of data regarding the performance of the iECG function of the Withings Scanwatch.

Methods

We performed a prospective, observational study enrolling consecutive patients presenting to a cardiology service at a tertiary referral center. The aim was to assess the diagnostic performance of the iECG function of the Withings Scanwatch to detect AF compared to a simultaneously acquired cardiologist-interpreted 12-lead ECG. All iECG rhythm strips and 12-lead ECGs were anonymized and distributed to two blinded cardiologists who independently interpreted each tracing and assigned a diagnosis of sinus rhythm, AF or unclassified.

Results

iECGs and 12-lead ECGs were simultaneously recorded in 319 patients (67 yo (IQR 54-76), 48% female, Figure 1). Using the automated algorithm, rhythm was deemed inconclusive in 44 patients (14%). Overall, AF was present in 34 patients (11%). Among the tracings where the algorithm provided a diagnosis, it correctly identified AF with 76% (95%CI 55-91%) sensitivity, 99% (95%CI 97-100%) specificity, and a Kappa (K) coefficient of 0.72 when compared with cardiologist-interpreted 12-lead ECGs. Among patients in sinus rhythm, 3 were labeled AF (false-positive). From the 44 unclassified recordings, blinded cardiologists were able to correctly diagnose AF with 100% (95%CI 59-100%) sensitivity, 93% (95%CI 77-99%) specificity, and a K coefficient of 0.49. A total of 13 iECG recordings (4.1%) were determined to be noninterpretable by the cardiologists. Of the remaining 306 patients with simultaneous recordings, cardiologist interpretation of the iECG tracings demonstrated 97% (95%CI 84-100%) sensitivity, 99% (95%CI 96-100%) specificity and a K coefficient of 0.75.

Conclusion

Automatic rhythm classification was inferior to manual interpretation of iECGs. We found a lower sensitivity for the detection of AF using the Withings iECG function compared to data published on other devices. Cardiologist-iECG interpretation, however, was highly reliable with a diagnostic accuracy of 98% (95%CI 96-100%). Clinical interpretation of iECG readings by a cardiologist is therefore strongly encouraged

Magnetic field interactions of smartwatches and portable electronic devices with cardiovascular implantable electronic devices

Funding Acknowledgements

Type of funding sources: None.

Introduction

Magnetic interference of portable electronic devices (PEDs), such as state-of-the-art mobile phones, with cardiovascular implantable electronic devices (CIEDs) has been reported.

Purpose

The aim of the study was to quantify the magnetic fields of latest generation Smartwatches and other PEDs and to evaluate and predict their risk of CIED interactions.

Method

High resolution magnetic field characterization of five smartwatches able to record an ECG Apple Watch, Series 6 and 7, Fitbit Sense, Samsung Galaxy Watch 3, and Withings Move ECG Watch was performed using a magnetic field camera consisting of 1024 calibrated three axis Hall sensors. Maximal distance of 1 mT (10 Gauss) field strength and 1 mT volume was calculated. Ex vivo measurements of the minimal safety distance (MSD) at which no mode switch can be observed between six representative CIEDs and the PEDs was performed. Results were compared to other PEDs, such as digital pens, headsets and their cases, and a Smartphone.

Result

Maximal 1 mT distances ranged between 10 mm and 19 mm, and 1 mT volumes between 6 cm3 and 19 cm3. The smartwatches and PEDs with measured 1 mT distance 15 mm (B: Microsoft surface pen, C: Airpods Pro case) showed device interaction up to > 15 mm (Figure). Linear regression analysis showed an inverse linear relationship of the MSD with 1 mT distance (B coefficient: 0.459; 95% CI: 0.246-0.672; p<0.001) but not with the volume (p=0.842)

Conclusions

Standardized measurements of the 1 mT field distance and volume is feasible and has the potential to assess the risk of CIED interaction. Smartwatches seem to be safe in contrast to other PEDs such as the Microsoft surface pen or Airpods Pro case with high 1mT volumes and maximal distances with regards to CIED interaction.

Size Selective Corona Interactions from Self-Assembled Rosette and Single-Walled Carbon Nanotubes

Nanoparticle corona phases, especially those surrounding anisotropic particles, are central to determining their catalytic, molecular recognition, and interfacial properties. It remains a longstanding challenge to chemically synthesize and control such phases at the nanoparticle surface. In this work, the supramolecular chemistry of rosette nanotubes (RNTs), well-defined hierarchically self-assembled nanostructures formed from heteroaromatic bicyclic bases, is used to create molecularly precise and continuous corona phases on single-walled carbon nanotubes (SWCNTs). These RNT-SWCNT (RS) complexes exhibit the lowest solvent-exposed surface area (147.8 ± 60 m^-1 ) measured to date due to its regular structure. Through Raman spectroscopy, molecular-scale control of the free volume is also observed between the two annular structures and the effects of confined water. SWCNT photoluminescence (PL) within the RNT is also modulated considerably as a function of their diameter and chirality, especially for the (11, 1) species, where a PL increase compared to other species can be attributed to their chiral angle and the RNT's inward facing electron densities. In summary, RNT chemistry is extended to the problem of chemically defining both the exterior and interior corona interfaces of an encapsulated particle, thereby opening the door to precision control of core-shell nanoparticle interfaces.

Irreversible synthesis of an ultrastrong two-dimensional polymeric material

Polymers that extend covalently in two dimensions have attracted recent attention^1,2 as a means of combining the mechanical strength and in-plane energy conduction of conventional two-dimensional (2D) materials^3,4 with the low densities, synthetic processability and organic composition of their one-dimensional counterparts. Efforts so far have proven successful in forms that do not allow full realization of these properties, such as polymerization at flat interfaces^5,6 or fixation of monomers in immobilized lattices^7-9. Another frequently employed synthetic approach is to introduce microscopic reversibility, at the cost of bond stability, to achieve 2D crystals after extensive error correction^10,11. Here we demonstrate a homogenous 2D irreversible polycondensation that results in a covalently bonded 2D polymeric material that is chemically stable and highly processable. Further processing yields highly oriented, free-standing films that have a 2D elastic modulus and yield strength of 12.7 ± 3.8 gigapascals and 488 ± 57 megapascals, respectively. This synthetic route provides opportunities for 2D materials in applications ranging from composite structures to barrier coating materials.

Direct Chemical Vapor Deposition Synthesis of Porous Single-Layer Graphene Membranes with High Gas Permeances and Selectivities

Single-layer graphene containing molecular-sized in-plane pores is regarded as a promising membrane material for high-performance gas separations due to its atomic thickness and low gas transport resistance. However, typical etching-based pore generation methods cannot decouple pore nucleation and pore growth, resulting in a trade-off between high areal pore density and high selectivity. In contrast, intrinsic pores in graphene formed during chemical vapor deposition are not created by etching. Therefore, intrinsically porous graphene can exhibit high pore density while maintaining its gas selectivity. In this work, the density of intrinsic graphene pores is systematically controlled for the first time, while appropriate pore sizes for gas sieving are precisely maintained. As a result, single-layer graphene membranes with the highest H₂ /CH₄ separation performances recorded to date (H₂ permeance > 4000 GPU and H₂ /CH₄ selectivity > 2000) are fabricated by manipulating growth temperature, precursor concentration, and non-covalent decoration of the graphene surface. Moreover, it is identified that nanoscale molecular fouling of the graphene surface during gas separation where graphene pores are partially blocked by hydrocarbon contaminants under experimental conditions, controls both selectivity and temperature dependent permeance. Overall, the direct synthesis of porous single-layer graphene exploits its tremendous potential as high-performance gas-sieving membranes.

Trimethylamine-N-oxide (TMAO) is associated with cardiovascular mortality and vascular brain lesions in patients with atrial fibrillation

Introduction

Trimethylamine-N-oxide (TMAO) is a well characterized pro-atherogenic metabolite derived from the microbial processing of phosphatidylcholine and carnitine (usually present in red meat) and subsequent hepatic oxydation, which promotes endothelial dysfunction, platelet activation and thrombosis initiation. Its role concerning cerebral and cardiovascular adverse events has been assessed in various patient subpopulations but not for long term in patients with atrial fibrillation.

Methods

Baseline TMAO plasma levels were measured by high-performance liquid chromatography/mass spectrometry in plasmas of 2,379 subjects from our multicentric study. Among them, 1,722 participants at time of recruitment underwent brain MRI. Participants were stratified into TMAO tertiles and Cox PH models, linear mixed effect models or logistic mixed effect models were employed adjusting for several risk factors (age, sex, BMI, active and past smoke habit, cystatin c levels, heart failure, diabetes mellitus, hypertension, coronary artery disease and history of TIA/stroke). Subjects were prospectively followed with a median observation time of 4 years.

Results

Subjects in the highest tertile of TMAO were older (75.4 vs. 70.6 years in low tertile p<0.001) and had significantly more often comorbidities, (26.9% of subjects were diabetic vs. 9.1% in low tertile p<0.001), with higher BMI (28.1 vs 27.0, p<0.001) and worse renal function as assessed by serum cystatin C (1.46 vs 1.07, mg/dl; p<0.001). Heart failure was present in 37.9% participants in the upper compared to 15.8% in the lower tertile. (p<0.001). As shown in Figure 1, Kaplan Meier estimates showed increased cardiovascular mortality with increasing TMAO tertiles (p<0.0001). After adjustment for the abovementioned factors the upper tertile (T3) had an increased hazard ratio (HR) compared to the lowest one (HR 2.36 95% CI 1.56–3.58 p<0.01). Similar trends for global and ischemic stroke occurrences were not found although TMAO levels positively weakly correlated with NIHSS severity (Spearman's coefficient 0.31 p=0.02). Concerning brain MRI findings, TMAO tertiles identified individuals with different prevalence of small non-cortical infarcts (30.5%, 18.1% and 17.4% in high, middle and low tertiles respectively; p<0.001) and when present, larger white matter lesions volumes (5061 mm3, 4158 mm3 and 2970 mm3; p<0.001). After adjustment, the association with small non-cortical infarcts with TMAO levels remained significant in the highest tertile (T3) (OR 1.48 95% CI 1.07–2.05; p=0.02) and a trend towards larger white matter lesions volumes was observed (estimate 1307 95% CI −90–2705; p=0.07).

Conclusions

TMAO represents a robust prognostic independent biomarker identifying multimorbid, high risk patients for cardiovascular mortality and brain damage.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Swiss National Science Foundation (SNSF) and Theodor und Ida Herzog-Egli Foundation Figure 1. CV mortality according to TMAOFigure 2. Brain lesions assessment

Augmenting the living plant mesophyll into a photonic capacitor

Living plants provide an opportunity to rethink the design and fabrication of devices ordinarily produced from plastic and circuit boards and ultimately disposed of as waste. The spongy mesophyll is a high -surface area composition of parenchyma cells that supports gas and liquid exchange through stomata pores within the surface of most leaves. Here, we investigate the mesophyll of living plants as biocompatible substrates for the photonic display of thin nanophosphorescent films for photonic applications. Size-sorted, silica-coated 650 ± 290 -nm strontium aluminate nanoparticles are infused into five diverse plant species with conformal display of 2-μm films on the mesophyll enabling photoemission of up to 4.8 × 10¹³ photons/second. Chlorophyll measurements over 9 days and functional testing over 2 weeks at 2016 excitation/emission cycles confirm biocompatibility. This work establishes methods to transform living plants into photonic substrates for applications in plant-based reflectance devices, signaling, and the augmentation of plant-based lighting.

Cellular lensing and near infrared fluorescent nanosensor arrays to enable chemical efflux cytometry

Nanosensors have proven to be powerful tools to monitor single cells, achieving spatiotemporal precision even at molecular level. However, there has not been way of extending this approach to statistically relevant numbers of living cells. Herein, we design and fabricate nanosensor array in microfluidics that addresses this limitation, creating a Nanosensor Chemical Cytometry (NCC). nIR fluorescent carbon nanotube array is integrated along microfluidic channel through which flowing cells is guided. We can utilize the flowing cell itself as highly informative Gaussian lenses projecting nIR profiles and extract rich information. This unique biophotonic waveguide allows for quantified cross-correlation of biomolecular information with various physical properties and creates label-free chemical cytometer for cellular heterogeneity measurement. As an example, the NCC can profile the immune heterogeneities of human monocyte populations at attomolar sensitivity in completely non-destructive and real-time manner with rate of ~600 cells/hr, highest range demonstrated to date for state-of-the-art chemical cytometry.

Cardiac autonomic function and cognitive performance in patients with atrial fibrillation

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): Swiss National Science Foundation

OnBehalf

Swiss-AF Investigators

Background

Atrial fibrillation (AF) is associated with loss of cognition and dementia. Cardiac autonomic dysfunction has been linked to cognitive decline. We aimed to investigate if reduced cardiac autonomic function (CAF) is associated with cognitive impairment in AF patients. 

Methods

Patients with paroxysmal, persistent and permanent AF were enrolled from a multicenter cohort study if they presented in AF ("AF group") or in sinus rhythm ("SR group") on a baseline 5-minute ECG recording. Parameters quantifying CAF (heart rate variability triangular index (HRVI), mean heart rate (MHR), the root mean square of successive differences (RMSSD) and the standard deviation of the normal-to-normal intervals (SDNN)) were calculated. We used the Montreal Cognitive Assessment (MoCA) to assess global cognitive function.

Results

1,685 AF patients with a mean age of 73 ± 8 years, 29% females, were included. The MoCA score was 24.5 ± 3.2 in the AF group (n = 710 patients) and 25.4 ± 3.2 in the SR group (n = 975 patients). After adjusting for multiple confounders, lower HRVI was associated with lower MoCA scores, both in the SR group (β=0.049; 95% confidence interval (CI): 0.016 to 0.081; p = 0.003) and in the AF group (β=0.068; 95% CI: 0.020 to 0.116; p = 0.006). In the AF group, higher MHR was associated with a poorer performance in the MoCA (β=-0.008; 95% CI: -0.014 to -0.002; p = 0.014 ). Other parameters of CAF were not associated with cognition.

Conclusion

Our data suggest that impaired CAF is associated with worse cognitive performance in patients with AF. Elderly AF patients with impaired HRVI might undergo cognitive testing in order to screen for cognitive impairment.

Gender-related differences in patient selection for and outcomes after pace and ablate for refractory atrial fibrillation: insights from a large multicenter cohort

Funding Acknowledgements

Type of funding sources: None.

Background

A pace & ablate strategy may be performed in cases of severe refractory atrial arrhythmias.

Purpose

We aimed to assess gender related differences in patient selection and clinical outcomes after pace & ablate.

Methods

In a retrospective multicenter study, patients undergoing AV-junction-ablation between 2011 and 2019 were studied. Gender-related differences in terms of baseline characteristics, device-related complications, heart failure (HF) hospitalisations and death were assessed.

Results

Overall, 513 patients underwent AV-junction-ablation (median age 75 years, 50% males). At baseline, male patients were younger (72 vs. 78 years, p < 0.001), more frequently had non-paroxysmal AF (82% vs. 72%, p = 0.006), a lower LVEF (35% vs. 55%, p < 0.001) and more often received biventricular stimulation (75% vs. 25%, p < 0.001). Interventional complications were rare in both gender (1.2% vs 1.6%, p = 0.72). Following AV-junction-ablation, improvement of EHRA-class by ≥1 and of LVEF by ≥5% occurred in 44% and 19% of patients respectively, without gender differences (p = 0.66 and p = 0.38). Patients were followed for a median of 42 months in survivors (IQR 22-62). Lead-related complications (11 patients, 2.1%), infections (1 patient, 0.2%) and upgrade to ICD or CRT (18 patients, 3.5%) were rare. In Kaplan Meier analysis, HF hospitalisations during 4 years of follow-up were more common in men (22% vs 11%, p = 0.02), as were death (28% vs 21%, p = 0.02) and the combination of death or HF hospitalisation (37% vs. 26%, p = 0.008, Figure). Gender remained an independent predictor of the combined endpoint of death or HF hospitalisation after adjustment for age, LVEF and type of stimulation.

Conclusion

A Pace & Ablate strategy is safe and results in improvement of EHRA class and LVEF in a substantial number of patients. We found significant gender differences in patient selection for pace & ablate. Female patients had a more favorable clinical course after AV-junction-ablation, which was independent of age, EF and type of stimulation. Abstract Figure. Comb. endpoint of death or heart failure

Non-invasive predictors for infranodal conduction delay in patients with left bundle branch block after transcatheter aortic valve replacement

Funding Acknowledgements

Type of funding sources: None.

Introduction

Left bundle branch block (LBBB) is the most common conduction disorder after transcatheter aortic valve replacement (TAVR) with an increased risk of atrioventricular (AV) block. The aim of the current study was to identify non-invasive predictors for infranodal conduction delay in patients with LBBB.

Methods

We analyzed consecutive patients undergoing TAVR with pre-existing or new-onset LBBB between August 2014 and August 2020. His ventricular (HV) interval measurement was performed on day 1 after TAVR. Baseline, procedural, as well as surface and intracardiac electrocardiographic parameters were included. Infranodal conduction delay was defined as HV interval >55 ms.

Results

Of 825 patients screened after TAVR, 151 patients (82 ± 6 years, 39% male) with LBBB were included. Among these, infranodal conduction delay was observed in 25%. ΔPR (difference in PR interval after and before TAVR), PR and QRS duration after TAVR were significantly longer in the group with HV prolongation. In a multivariate analysis in patients with sinus rhythm (n = 131), ΔPR (OR per 10 ms increase: 1.52; 95% CI: 1.19-2.01; p = 0.002) was the only independent factor associated with infranodal conduction delay. The AUC of the ROC curve was 0.724 (95% CI) for ΔPR. A change in PR interval by 20 ms yielded a sensitivity of 26% and specificity of 83% with a positive predictive value of 45% and a negative predictive value of 84% to predict HV prolongation.

Conclusions

Simple analysis of surface ECG and a calculated ΔPR <20ms can be used as predictor for the absence of infranodal conduction delay in post-TAVR patients with LBBB. Abstract Figure HV

Efficacy and safety of a high power short duration ablation-index guided protocol for pulmonary vein isolation using a single catheter

Funding Acknowledgements

Type of funding sources: None.

Background

Catheter ablation for atrial fibrillation (AF) is the most common performed electrophysiological procedure. The cost of this procedure remains high.

Purpose

To improve health care utilization, we aimed to compare the efficacy and safety of a minimalistic, streamlined single radiofrequency catheter ablation approach using high power short duration ablation-index guided protocol (HPSD) vs. a standard single catheter protocol.

Methods

A circular mapping catheter free PVI with a single transseptal puncture was performed in 91 patients. A CARTO fast anatomical map was performed with the ablation catheter. Pacing maneuvers were used to confirm exit block. Procedural characteristics and success rates were compared using HPSD- vs. a standard ablation-protocol. Freedom from recurrence was defined as a 1-year absence of AF episodes > 30 s, beyond the 3-month-blanking-period.

Results

Using the HPSD-protocol the median procedure, map and RF ablation time were significantly shorter in the HPSD group compared to the standard group, 84 (IQR 76-100) vs. 118 minutes (IQR 104-141), 12 (IQR 10-16) vs. 18 minutes (IQR 15-21) and 1036 (898-1184) vs. 1949 seconds (IQR 1693-2261), respectively, P < .001 for all. First-pass-PVI was achieved using the HPSD-protocol in 23 patients (74%) and the standard-protocol in 30 patients (53%), p = 0.08. Localization of conduction gaps are illustrated for the HPSD-protocol and the standard-protocol in Figure 1. The residual gap was identified using the ablation catheter only in all patients. No procedural complication were observed. At 12 months follow-up, 60 (89.6%) patients remained free from AF with no differences between groups.

Conclusions

A minimalistic, CMC-free HPSD-guided PVI approach is very efficient, safe, likely cost-saving, and associated with excellent clinical outcomes at 1 year. Abstract Figure 1

Diameter Dependence of Water Filling in Lithographically Segmented Isolated Carbon Nanotubes

Although the structure and properties of water under conditions of extreme confinement are fundamentally important for a variety of applications, they remain poorly understood, especially for dimensions less than 2 nm. This problem is confounded by the difficulty in controlling surface roughness and dimensionality in fabricated nanochannels, contributing to a dearth of experimental platforms capable of carrying out the necessary precision measurements. In this work, we utilize an experimental platform based on the interior of lithographically segmented, isolated single-walled carbon nanotubes to study water under extreme nanoscale confinement. This platform generates multiple copies of nanotubes with identical chirality, of diameters from 0.8 to 2.5 nm and lengths spanning 6 to 160 μm, that can be studied individually in real time before and after opening, exposure to water, and subsequent water filling. We demonstrate that, under controlled conditions, the diameter-dependent blue shift of the Raman radial breathing mode (RBM) between 1 and 8 cm^-1 measures an increase in the interior mechanical modulus associated with liquid water filling, with no response from exterior water exposure. The observed RBM shift with filling demonstrates a non-monotonic trend with diameter, supporting the assignment of a minimum of 1.81 ± 0.09 cm^-1 at 0.93 ± 0.08 nm with a nearly linear increase at larger diameters. We find that a simple hard-sphere model of water in the confined nanotube interior describes key features of the diameter-dependent modulus change of the carbon nanotube and supports previous observations in the literature. Longer segments of 160 μm show partial filling from their ends, consistent with pore clogging. These devices provide an opportunity to study fluid behavior under extreme confinement with high precision and repeatability.

Validation of the Canadian syncope risk score in a large prospective international multicenter study

Background

Management and risk stratification of patients with syncope in the emergency department (ED) is often challenging. In an effort to support ED physicians in disposition decisions, the Canadian Syncope Risk Score (CSRS) was developed to predict 30-day serious outcomes.

Methods

The CSRS was developed in a Canadian multicenter study and contains nine predictors: predisposition to vasovagal syncope, heart disease, systolic pressure <90 or >180mmHg in the ED, troponin level >99th percentile, abnormal QRS axis, QRS duration >130ms, QTc interval >480ms and an ED diagnosis of vasovagal or cardiac syncope. Patients can achieve a CSRS score between −3 and +11 points. We validated the CSRS in a large prospective international multicenter study recruiting patients 40 years or older presenting to the ED with a syncopal event within the last 12 hours. Recruitment centers contained smaller provincial hospitals, as well as big University Hospitals in eight countries on three continents. Primary outcome measure were 30-day serious arrhythmic and non-arrhythmic adverse events, as defined by the authors of the original score.

Results

1581 patients were eligible for this analysis. The population in this validation cohort was older (mean age 68 vs 54 years) and had a considerably higher rate of serious outcomes compared to the derivation cohort (n=186 (11.8%) vs n=147 (3.6%)). The area under the receiver operating characteristic curve (AUC) for the CSRS was 0.88 (95% confidence interval (CI) 0.86–0.91) and significantly higher compared to the validated OESIL score (AUC 0.75, 95% CI 0.71–0.78, p<0.001). Calibration curve analysis showed an underestimation of risk in patients with a low CSRS and an overestimation in patients with a high CSRS. The rate of observed serious outcomes within 30d increased from 0.8% in the very low risk group (CSRS equal to or below −2) to 48% in the (very) high risk group (CSRS equal to or above 4, Hazard ratio 79.4, 95% CI 11.1–570.9). A Kaplan-Meier plot was used to visualize rates of serious outcomes in three different risk groups (Figure).

Conclusion

This is the first validation of the Canadian Syncope Risk Score in a large international syncope cohort. The prognostic discrimination of the CSRS for 30-day serious outcomes was very good in our validation cohort and comparable to that of the Canadian derivation study. Despite suboptimal calibration, prognostic analysis showed a high rate of serious outcomes in the CSRS (very) high risk group and a low rate of serious outcomes in the very low risk group. Allowing the clinical judgement of the ED physician in the form of suspected syncope etiology to be a part of the score seems to largely contribute to the high performance of the CSRS. Additional validation studies might be needed to further increase the accuracy of the CSRS in different patient populations with a different incidence of outcomes in settings outside of Canada.

Figure 1

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Swiss National Science Foundation; Swiss Heart Foundation

Development and validation of an ECG-based cardiac syncope risk calculator

Background

The early diagnosis of cardiac syncope is often challenging. We therefore developed an ECG-based risk calculator as an aid for rapid rule-out or rule-in of cardiac syncope and aimed to validate this decision tool.

Methods

In a prospective diagnostic international multicenter study (derivation cohort), 2007 patients, 40 years or older, presenting with syncope to the emergency department were recruited. The primary diagnostic outcome, cardiac syncope, was centrally adjudicated by two independent cardiologists using all clinical information obtained during syncope work-up including 12-month follow up. 12-lead ECG was recorded at presentation and read by residents blinded to clinical information. Significant ECG predictors of cardiac syncope were identified using penalized backward selection. Findings were validated in an independent US multicenter cohort with 2'269 syncope patients.

Results

In the derivation cohort (median age 71 years, 40% women), centrally adjudicated cardiac syncope was present in 267 patients (16%). Seven ECG criteria (rhythm, heart rate, corrected QT-interval, ST-segment depression, atrioventricular-block, bundle-branch-block and ventricular extrasystole/non-sustained ventricular tachycardia) were identified as significant predictors for cardiac syncope and combined into the bAseL Ecg Risk calculaTor for Cardiac Syncope (ALERT-CS). Diagnostic accuracy of ALERT-CS for cardiac syncope, as quantified by the area under the receiver-operating characteristics curve (AUC), was high (0.80, 95%-confidence interval (CI) 0.77–0.83) and significantly higher compared to the EGSYS score (0.73, 95% CI 0.70–0.76, p<0.001). In combination, ALERT-CS significantly increased the AUC of BNP (0.82, 95% CI 0.79–0.85 vs 0.77, 95% CI 0.74–0.81, p=0.003), hs-cTnT (0.84, 95% CI 0.0.81–0.87 vs 0.77, 95% CI 0.74–0.80, p<0.001) and integrated clinical judgment in the ED (0.90, 95% CI 0.89–0.92 vs 0.87, 95% CI 0.84–0.90, p<0.001).

A predicted probability for cardiac syncope below 5.5% by ALERT-CS identified 138 patients (8%) eligible for triage towards rapid rule-out of cardiac syncope with a sensitivity of 99%. A predicted probability above 37.5% identified 181 patients (11%) eligible for triage towards rapid rule-in of cardiac syncope with a specificity of 95%. Prognostic verification for 30-day major adverse cardiac events (MACE) showed a high rate of MACE in the rule-in group and a very low rate of MACE in the rule-out group (Figure).

External validation (median age 72 years, 48% women) showed similar diagnostic accuracy (AUC 0.76, 95% CI 0.73–0.79) and prognostic results.

Conclusion

Combining seven ECG criteria within the simple ALERT-CS may aid ED physicians in the early rule-out or rule-in of cardiac syncope.

Figure 1

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Swiss National Science Foundation, Swiss Heart Foundation

Association of biomarkers of inflammation with hospitalization for heart failure and death in patients with atrial fibrillation

Background

Hospitalization for heart failure and death are among the most common adverse clinical outcomes in patients with atrial fibrillation (AF). The underlying mechanisms are poorly understood.

Purpose

We hypothesised that inflammation, quantified by plasma levels of C-reactive protein (CRP) and interleukin 6 (IL-6), is independently associated with hospitalization for heart failure and death in a large, contemporary cohort of AF patients.

Methods

Patients with established AF and 65 years of age or older were enrolled in two large, prospective, multicentre cohort studies in Switzerland. Plasma levels of high-sensitivity (hs) CRP and IL-6 were measured from frozen EDTA plasma samples obtained at baseline. Using these two biomarkers, we calculated an inflammation score ranging from 0 to 4 (1 point for each biomarker between the 50th and 75th percentile, 2 points for each biomarker above the 75th percentile). We constructed multivariable Cox proportional hazards models to quantify the associations of hs-CRP, IL-6 and the inflammation score with time to first hospitalization for heart failure and time to all-cause mortality, respectively.

Results

A total of 3,784 patients with AF (median age 72 years, 28% women, 24% with a prior history of heart failure and 84% anticoagulation use at baseline) were followed for a median (interquartile range [IQR]) of 4.0 (2.9–5.1) years. The median (IQR) plasma levels of hs-CRP and IL-6 at baseline were 1.64 (0.81–3.69) mg/L and 3.42 (2.14–5.60) pg/mL, respectively. The incidence rates of hospitalization for heart failure and death were 3.04 and 2.80 per 100 person-years, respectively. After multivariable adjustment, both biomarkers were significantly associated with the risk of hospitalization for heart failure (per increase in 1 standard deviation [SD], adjusted hazard ratio [aHR] 1.22, 95% confidence interval [CI] 1.11–1.34 for log-transformed hs-CRP, and aHR 1.48, 95% CI 1.35–1.62 for log-transformed IL-6) and death (per increase in 1 SD, aHR 1.40, 95% CI 1.27–1.54 for log-transformed hs-CRP, and aHR 1.67, 95% CI 1.53–1.81 for log-transformed IL-6). Incidence rates of hospitalization for heart failure increased from 1.34 to 7.31 per 100 person-years across categories of the inflammation score (Figure 1). A strong relationship persisted after multivariable adjustment. Similar findings were observed for all-cause mortality.

Conclusions

Inflammation is a strong predictor of hospitalization for heart failure and death in patients with AF. Targeting inflammation may be a promising treatment strategy to improve outcomes in these patients at high risk for adverse outcomes.

Figure 1

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): Swiss National Science Foundation

The Admit-AF risk score: a clinical risk score for predicting hospital admissions in patients with atrial fibrillation

Background

Patients with atrial fibrillation (AF) have a high risk of hospital admissions, but there is no validated prediction tool to identify those at highest risk.

Purpose

To develop and externally validate a risk score for all-cause hospital admissions in patients with AF.

Methods

We used a prospective cohort of 2387 patients with established AF as derivation cohort. Independent risk factors were selected from a broad range of variables using the least absolute shrinkage and selection operator (LASSO) method fit to a Cox regression model. The developed risk score was externally validated in a separate prospective, multicenter cohort of 1300 AF patients.

Results

In the derivation cohort, 891 patients (37.3%) were admitted to the hospital over a median follow-up 2.0 years. In the validation cohort, hospital admissions occurred in 719 patients (55.3%) during a median follow-up 1.9 years. The most important predictors for admission were age (75–79 years: adjusted hazard ratio [aHR], 1.33; 95% confidence interval [95% CI], 1.00–1.77; 80–84 years: aHR, 1.51; 95% CI, 1.12–2.03; ≥85 years: aHR, 1.88; 95% CI, 1.35–2.61), prior pulmonary vein isolation (aHR, 0.74; 95% CI, 0.60–0.90), hypertension (aHR, 1.16; 95% CI, 0.99–1.36), diabetes (aHR, 1.38; 95% CI, 1.17–1.62), coronary heart disease (aHR, 1.18; 95% CI, 1.02–1.37), prior stroke/TIA (aHR, 1.28; 95% CI, 1.10–1.50), heart failure (aHR, 1.21; 95% CI, 1.04–1.41), peripheral artery disease (aHR, 1.31; 95% CI, 1.06–1.63), cancer (aHR, 1.33; 95% CI, 1.13–1.57), renal failure (aHR, 1.18, 95% CI, 1.01–1.38), and previous falls (aHR, 1.44; 95% CI, 1.16–1.78). A risk score with these variables was well calibrated, and achieved a C-index of 0.64 in the derivation and 0.59 in the validation cohort.

Conclusions

Multiple risk factors were associated with hospital admissions in AF patients. This prediction tool selects high-risk patients who may benefit from preventive interventions.

The Admit-AF risk score

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): The Swiss National Science Foundation (Grant numbers 33CS30_1148474 and 33CS30_177520), the Foundation for Cardiovascular Research Basel and the University of Basel

Validation of the FAINT risk score in a large prospective international multicenter study

Background

Risk stratification of older patients presenting to the Emergency Department (ED) with syncope remains an unmet clinical need. The FAINT Score was derived in a large American cohort in an attempt to predict 30-day serious cardiac outcomes in patients >60y.o. While a FAINT score of 0 showed high sensitivity to exclude death and serious outcomes at 30 days in the derivation cohort, it remains unvalidated.

Methods

We validated the FAINT score (History of heart failure, history of arrhythmia, initial ECG result abnormal, elevate NT-proBNP, elevated hs-troponin T) in a large prospective international multicenter study recruiting patients 40 years presenting to the ED with syncope within the last 12 hours in eight countries on three continents. Main outcome measure was 30-day serious cardiac events or mortality. We assessed the performance and calibration of the FAINT score for validation and compared it to the OESIL score (Age >64y, cardiovascular disease history, syncope without prodromes, abnormal ECG).

Results

1885 patients were eligible for this validation analysis. 169 (8.9%) patients experienced 30-day serious adverse events.

A FAINT score of 0 was present for 378 patients (20% of the cohort) and allowed for a sensitivity of 0.97 to rule out adverse events and death at 30-days. A FAINT score of 0 or 1 was present for 626 patients (33% of the cohort) and allowed for a sensitivity of 0.92.

The area under the receiver operating characteristic curve (AUC) for the FAINT score was 0.75 (95%, Confidence Interval (CI) 0.72–0.79), which was comparable to the performance of N-terminal pro-B-type natriuretic peptide (NT-proBNP) or high-sensitivity Troponin T (hs-cTnT) alone, which are two biomarkers used in the FAINT score. The score did not outperform the OESIL score.

A calibration curve showed that the score was extremely well calibrated for low-risk patients.

Conclusion

This is the first validation of the FAINT score in a large international syncope cohort. The safety of a FAINT score of 0 or 1 was good and comparable to the results obtained in the derivation cohort. While the score is suitable to highlight low-risk patients and calibrates well in an external cohort, its discrimination for higher risk patients is not better than biomarkers alone or an older, less complex risk score.

Figure 1. Area under the Receiver Operating Curve (ROC) for the FAINT score and for NT-proBNP and hs-cTnT as continuous markers as well as for the OESIL score. CI = Confidence Interval.

Funding Acknowledgement

Type of funding source: Public hospital(s). Main funding source(s): University Hospital Basel, Switzerland

A simple method to detect phrenic nerve impairment during cryoballoon ablation of atrial fibrillation using aVF in the standard surface ECG

Background

Phrenic nerve palsy (PNP) is the most common complication in cryoballoon ablation of atrial fibrillation. Monitoring techniques such as compound motor action potential (CMAP) measurements using additional leads, or catheters positioned in the subdiaphragmatic hepatic vein or the esophagus have demonstrated to be effective to prevent PNP.

Purpose

This study investigates the safety and feasibility of a simple monitoring strategy using the lead aVF of the standard surface 12 lead ECG for CMAP monitoring to prevent PNP.

Methods

In 263 continuous patients undergoing cryoballoon ablation, a decapolar catheter was placed in the right subclavian vein to stimulate the phrenic nerve during ablation of the right sided pulmonary veins (12V@2.9 ms at 60 bpm). Capture was continuously monitored using the CMAP potential in the inferior aVF lead of the surface ECG and manually by palpation of the abdominal movement. The freeze was terminated early if the amplitude of the aVF signal decrease by >25% in three consecutive beats or if the diaphragmatic contraction decreased.

Results

Phrenic nerve injury documented by a reduction of the signal in aVF was observed in 13 of the 263 patients (5%) during freezes of the right superior pulmonary vein. Reduced diaphragmatic contraction detected by palpation of the abdomen was never observed without previous reduced amplitude in the surface aVF signal and was therefore never the trigger to stop a freeze. In patients with phrenic nerve injury, the mean initial amplitude was 1mV (SD ±0.3mV) and the mean minimal amplitude was 0.3mV (SD ±0.2mV). Mean time to recovery of the aVF amplitude was 160 seconds. Twelve patients (4.6%) showed complete recovery whereas one patient (0.4%) showed only partial recovery, as demonstrated in a sniff test at the end of the procedure. This patient showed no clinical signs of phrenic nerve palsy the following day, and full recovery was demonstrated in a sniff test 3 months later.

Conclusion

Monitoring of CMAP using the aVF signal from a standard 12-lead ECG during phrenic nerve stimulation to reduce the incidence of phrenic nerve palsy is safe and feasible. This technique is readily available during every standard ablation without placing additional electrodes and more sensitive than manual palpation.

aVF signal before and during ablation

Funding Acknowledgement

Type of funding source: None

Impaired heart rate variability triangular index to identify clinically silent strokes in patients with atrial fibrillation

Introduction

The identification of clinically silent strokes in patients with atrial fibrillation (AF) is of high clinical relevance as they have been linked to cognitive impairment. Overt strokes have been associated with disturbances of the autonomic nervous system.

Purpose

We therefore hypothesize that impaired heart rate variability (HRV) can identify AF patients with clinically silent strokes.

Methods

We enrolled 1358 patients with AF without a history of stroke or transient ischemic attack from the multicenter SWISS-AF cohort study who were in sinus rhythm (SR-group, n=816) or AF (AF-group, n=542) on a 5 minute resting ECG recording. HRV triangular index (HRVI), the standard deviation of normal-to-normal intervals (SDNN) and the mean heart rate (MHR) were calculated. Brain MRI was performed at baseline to assess the presence of large non-cortical or cortical infarcts, which were considered silent strokes without history of stroke or transient ischemic attack. We constructed binary logistic regression models to analyze the association between HRV parameters and silent strokes.

Results

At baseline, silent strokes were detected in 10.5% in the SR group and 19.9% in the AF group. In the SR-group, HRVI <15 was the only parameter independently associated with the presence of silent strokes (odds ratio (OR) 1.69; 95% confidence interval (CI): 1.04–2.72; p=0.033) after adjustment for various clinical covariates (age, sex, systolic blood pressure, history of hypertension, history of diabetes, history of heart failure, prior myocardial infarction, prior major bleeding, intake of oral anticoagulation, antiarrhythmics or betablockers). Similarly, in the AF-group, HRVI<15 was independently associated with the presence of silent strokes (OR 1.65, 95% CI: 1.05–2.57; p=0.028). SDNN<70ms and MHR<80 were not associated with silent strokes, neither in the SR group, nor in the AF group (Figure).

Conclusions

Reduced HRVI is independently associated with the presence of clinically silent strokes in an AF population, both when assessed during SR and during AF. Our data suggest that a short-term measurement of HRV in routine ECG recordings might contribute to identifying AF patients with clinically silent strokes.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): Swiss National Science Foundation

Incidence, characteristics, determinants and prognostic impact of recurrent syncope

Background

The incidence, characteristics, determinants, and prognostic impact of recurrent syncope are largely unknown, causing uncertainty for both patients and physicians.

Methods

We characterized recurrent syncope including sex-specific aspects and its impact on death and major adverse cardiovascular events (MACE) in a large prospective international multicenter study enrolling patients ≥40 years presenting with syncope to the emergency department (ED). Syncope etiology was centrally adjudicated by two independent and blinded cardiologists using all information becoming available during syncope work-up and 12-month follow-up. MACE were defined as a composite of all-cause death, acute myocardial infarction, surgical or percutaneous coronary intervention, life-threatening arrhythmia including cardiac arrest, pacemaker or implantable cardioverter defibrillator implantation, valve intervention, heart-failure, gastrointestinal bleeding or other bleeding requiring transfusion, intracranial hemorrhage, ischemic stroke or transient ischemic attack, sepsis and pulmonary embolism.

Results

Incidence of recurrent syncope among 1790 patients was 20% (95%-confidence interval (CI) 18% to 22%) within 24 months. Patients with an adjudicated final diagnosis of cardiac syncope (hazard ratio (HR) 1.50, 95%-CI 1.11 to 2.01) or syncope of unknown etiology even after central adjudication (HR 2.11, 95%-CI 1.54 to 2.89) had an increased risk for syncope recurrence (Figure). LASSO regression fit on all patient information available early in the ED identified more than three previous episodes of syncope as the only independent predictor for recurrent syncope (HR 2.13, 95%-CI 1.64 to 2.75). Recurrent syncope within the first 12 months after the index event carried an increased risk for all-cause death (HR 1.59, 95%-CI 1.06 to 2.38) and MACE (HR 2.24, 95%-CI 1.67 to 3.01), whereas recurrences after 12 months did not have a significant impact on outcome measures.

Conclusion

Recurrence rates of syncope are substantial and vary depending on syncope etiology. There seem to be no reliable patient characteristics available early on the ED that allow for the prediction of recurrent syncope with only a history of more than three previous syncope being associated with a higher risk for future recurrences. Importantly, recurrent syncope within the first 12 months carries an increased risk for death and MACE.

Figure 1

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Swiss National Science Foundation, Swiss Heart Foundation

P993Incidence of atrial fibrillation early after cavotricuspid isthmus ablation

Background

Atrial fibrillation (AF) is a common finding in patients undergoing cavotricuspid isthmus ablation for isthmus dependent right atrial flutter (RAF). Little is known about the time of its occurrence.

Purpose

We aimed to investigate the incidence of AF early after RAF ablation in a well-defined, prospective cohort.

Methods

A total of 255 participants with RAF ablation from 5 centers and at least one completed follow-up were included. Structured clinical follow-up was performed at 3, 6 and 12 months including a 24 hour Holter-ECG. The endpoint was incidence of AF detected clinically or by Holter-ECG. Risk factors associated with the occurrence of AF were assessed using separate, univariate Cox proportional-hazards models.

Results

Mean age was 67 years, 80% were male and previous episodes of AF were known in 40%. Over a mean follow-up of 7.4 (±4.4) months AF was detected in 35 (13.7%) participants after RAF ablation (Figure A). After 3, 6 and 12 months AF was detected in 18 (7.1%), 30 (11.7%) and 34 (13.3%) patients. No difference in the incidence of AF after RAF ablation was found comparing patients with and without a history of AF (log-rank p value = 0.44) (Figure B). Comparing patients with and without AF during follow-up, there was no difference in age (68 vs 66 years, p = 0.36), sex (69 vs 81% male, p = 0.08), prior heart failure (29 vs 19%, p = 0.20), hypertension (43 vs 38%, p = 0.56) or left atrial volume (46.6 vs 39.6 ml, p = 0.10), but patients with previous AF had a lower left ventricular ejection fraction (LVEF) (45.7 vs 52.3%, p = 0.02). In separate, univariate Cox proportional-hazards models only increasing LVEF (Hazard ratio 0.97, 95% confidence interval (0.95; 0.99, p = 0.02)) was associated with a lower risk of incident AF after RAF ablation, but no other risk factor.

Conclusions

AF occurred in 13.7% of patients early after cavotricuspid isthmus ablation for RAF. There was no difference in the occurrence of AF between patients with and without previously known episodes of AF. Only impaired LVEF was associated with AF occurrence.

Abstract Figure

Highly Ordered Two-Dimensional MoS2 Archimedean Scroll Bragg Reflectors as Chromatically Adaptive Fibers

Nanostructured fibers provide a basis for a unique class of multifunctional textiles, composites, and membrane applications, including those capable of chromatic modulating because of their high aspect ratio, surface area, and processing capability. Here in, we utilize two-dimensional (2D) materials including molybdenum disulfide (MoS₂) and hexagonal boron nitride (hBN) to generate single layer Archimedean scroll fibers, possessing cross sections formed from a single 2D molecular layer. Chemical vapor deposited (CVD) monolayer MoS₂ (0.29-0.33% in volume) and 226-259 nm-thick poly(methyl methacrylate) (PMMA) were used to create Bragg reflector fibers, exploiting the anisotropic function, exhibiting reflection at 630-709 nm, and verifying the highly ordered nanoinclusions. The Bragg reflectors show a memory response to heating and cooling, which switches the reflection wavelength from 629 to 698 nm. We simulate the reflection and transmission spectra of MoS₂/PMMA and MoS₂/polydimethylsiloxane layered composites to provide the design of scroll fiber composites using the transfer matrix methods. Moreover, we demonstrate the incorporation of a few-layer CVD hBN into the scroll fiber composite that emits photons at 576 nm. The highly oriented layered structures extend the capability of the fiber nanocomposites to take advantage of anisotropic optical, electrical, and thermal properties unique to 2D materials.

P5673Combination of high-sensitivity cardiac troponin and B-Type natriuretic peptide (BNP) for diagnosis and risk-stratification of syncope

Background

While high-sensitivity cardiac troponin (hs-cTn) and B-Type natriuretic peptide (BNP) have been assessed separately for the diagnosis and risk-stratification of patients with syncope, their combined accuracy is unknown.

Methods

We assessed the diagnostic and prognostic accuracy of the combination of hs-cTnI and BNP in a prospective international multicenter study enrolling patients 40 years and older presenting with syncope to the emergency department (ED). Hs-cTnI (Architect) and BNP (Architect) concentrations were measured in a blinded fashion. Cardiac syncope, as adjudicated by two independent physicians using all available clinical information including one year follow-up, was the diagnostic endpoint. MACE were defined as death, resuscitation, life-threatening arrhythmia, implantation of a pacemaker or implantable cardioverter defibrillator (ICD), acute myocardial infarction, pulmonary embolism, stroke/transient ischemic attack (TIA), intracranial bleeding or valvular intervention. Patients were classified in three risk groups (low (<10%), medium (10–30%), high (>30%)) for cardiac syncope based on hs-cTnI and BNP levels.

Results

Among 1533 patients, cardiac syncope was the adjudicated final diagnosis in 233 (15.2%). Hs-cTnI and BNP concentrations both remained independent predictors of cardiac syncope in multivariable models. The diagnostic accuracy of the combination hs-cTnI/BNP for cardiac syncope was good with an area under the curve (AUC) of 0.81 (95%-CI 0.78–0.84) and significantly better than each biomarker separately or a set of clinical variables (each p<0.001). The classification of patients in three risk groups, depending on the probability for cardiac syncope based on their hs-cTnI and BNP values, translated well in predictions for MACE (AUC 0.79, 95%-CI 0.77–0.82) and death (AUC 0.78, 95%-CI 0.74–0.82) at 2 years follow-up. Based on these results, we designed a visual tool allowing convenient patient-specific diagnostic and prognostic risk evaluation based solely on hs-cTnI and BNP concentrations (Figure).

Risk stratification based on hs-cTnI/BNP

Conclusion

The combination hs-cTnI/BNP may have clinical utility in patients presenting to the ED with syncope as it allows good diagnostic as well as prognostic discrimination.

Acknowledgement/Funding

Swiss National Science Foundation, Swiss Heart Foundation, Cardiovascular Research Foundation Basel, University Basel

2409ALERT-CS - Development of an ECG-based cardiac syncope risk calculator

Background

Syncope is a common symptom with rising incidence, often leading to emergency department (ED) visits. Early determination of diagnosis is often difficult in patients with syncope and there is an unmet clinical need for tools that can support physicians in their decision making. We hypothesized that an electrocardiogram (ECG)-based cardiac syncope risk calculator might create a simple and attractive clinical decision tool for the diagnosis and risk stratification of patients with syncope.

Methods

Based on a large prospective diagnostic international multicenter study enrolling patients who presented to the ED with syncope, we derived a cardiac syncope risk calculator by penalized stepwise backward-selection and multivariable logistic regression utilizing predefined ECG criteria. Primary diagnostic endpoint was cardiac syncope, as adjudicated by two independent physicians taking into account all available information including cardiac work-up and 12-month follow-up. Major adverse cardiac events (MACE) including life-threatening arrhythmias, myocardial infarction, pulmonary embolism, stroke, transient ischemic attack, valvular surgery, and death within 30 days were the prognostic endpoint.

Results

Median age in our cohort was 71 years and 40% of patients were women. Of all 2007 patients enrolled, 1696 patients were eligible for the prognostic analysis and 1550 patients were eligible for the diagnostic analysis.

We identified seven ECG criteria (rhythm, heart rate, corrected QT-interval, ST-segment depression, atrioventricular-block, bundle-branch-block and ventricular extrasystole/non-sustained ventricular tachycardia) as significant predictors for cardiac syncope and combined them into the bAseL Ecg Risk calculaTor for Cardiac Syncope (ALERT-CS). Diagnostic accuracy for cardiac syncope, as quantified by the area under the receiver operating characteristic curve (AUC), was high (AUC 0.80, 95%-confidence interval (CI) 0.77 to 0.83), and significantly higher compared to that of the EGSYS score (AUC 0.73, 95%-CI 0.70 to 0.76, p<0.001). Prognostic verification of the ALERT-CS to predict 30-day overall MACE showed similar accuracy (AUC 0.75, 95%-CI 0.71 to 0.79).

Comparison of diagnostic discrimination

Conclusion

Combining seven ECG criteria within a simple risk calculator for cardiac syncope may aid physicians in the diagnosis and risk stratification of patients presenting to the ED with syncope.

Acknowledgement/Funding

Swiss National Science Foundation, Swiss Heart Foundation, Cardiovascular Research Foundation Basel, University Basel

P1876Atrial fibrillation related symptoms and cardiovascular outcomes

Background

Comprehensive information on the impact of atrial fibrillation (AF)-related symptoms and quality of life (QoL) on adverse outcomes is sparse.

Purpose

We aimed to investigate whether AF-related symptoms and/or QoL are associated with cardiovascular outcomes in a large cohort of AF patients.

Methods

A total of 3902 participants with documented AF from two nationwide prospective cohort studies in Switzerland were included. Information on AF-related symptoms was assessed yearly by standardized questionnaires, QoL was quantified using a visual analog scale (0–100, with higher scores indicating better QoL). The primary endpoint was a composite of stroke and systemic embolism. The secondary endpoint was a composite of cardiovascular death, hospitalization for heart failure and myocardial infarction. We assessed associations using multivariable, time-updated Cox proportional-hazards models including age, sex, study cohort, history of heart failure, hypertension, diabetes, prior stroke, prior myocardial infarction, vascular disease and prior catheter ablation for AF as covariates.

Results

Mean age was 72 years, and 72% were male. The median QoL score was 75 points, and 2572 (66%) participants had AF-related symptoms. Symptomatic individuals were younger (71 vs 75 years) and had more often paroxysmal AF (29 vs 23%) (p for both <0.001). The most frequent symptoms were palpitations (42%), dyspnea (25%) and fatigue (18%). In multivariable, time-updated models, the hazard ratio (HR) was 1.24 (95% confidence intervals (CI) 0.72; 2.11, p=0.43) for the primary endpoint and HR 0.83 (95% CI 0.65; 1.06, p=0.14) for the secondary endpoint in symptomatic vs non-symptomatic individuals. There was a significant, inverse association for a 5-point increase in the QoL score with both the primary (HR 0.94 (95% CI 0.88; 0.99), p=0.04) and secondary (HR 0.91 (95% CI 0.88; 0.93), p<0.0001) endpoints.

Conclusions

AF-related symptoms are not associated with adverse cardiovascular events in AF patients. In contrast, QoL is inversely associated with to adverse cardiovascular outcomes.

P3782Frailty to predict unplanned hospitalizations, stroke, bleeding and death in atrial fibrillation

Aim

We investigated the prevalence of frailty, and the relationships between frailty and the risk of adverse clinical outcomes in patients with atrial fibrillation (AF).

Methods

Patients with known AF were enrolled in a nation-wide observational cohort study in Switzerland. Information on medical history, medication, lifestyle factors and clinical measurements were obtained. The primary outcome was unplanned hospitalizations, secondary outcomes were all-cause mortality, bleeding and stroke. The frailty index (FI) was measured using a cumulative deficit approach according to previously published criteria. Participants were divided into three groups (non-frail, pre-frail and frail) according to their FI at study entry. The association between frailty and clinical outcomes was assessed using multivariable adjusted Cox proportional hazard models.

Results

We included 2369 patients with a mean age of 73±8 years (27.3% female). The prevalence of frailty and pre-frailty was 10.6% and 60.7%, respectively. Frailty was associated with unplanned hospitalization (adjusted hazard ratio [HR] 3.59; 95% confidence interval [95% CI], 2.78–4.63; p<0.001), all-cause mortality (adjusted HR 16.72; 95% CI 7.75–36.05; p<0.001), bleeding (adjusted HR 2.46; 95% CI 1.61–3.77; p<0.001), and stroke (adjusted HR 3.29; 95% CI 1.29–8.39; p=0.01) (Figure). Similarly, pre-frailty was significantly associated with unplanned hospitalization (adjusted HR 1.82; 95% CI 1.49–2.22; p<0.001), all-cause mortality (adjusted HR 5.07; 95% CI 2.43–10.59; p<0.001) and bleeding (adjusted HR 1.53; 95% CI 1.11–2.13; p=0.01), but not with stroke.

Cumulative incidence of adverse events

Conclusion

In our cohort, more than two thirds of AF patients were either pre-frail or frail. These patients have a high risk of unplanned hospitalizations and other adverse outcomes, indicating that frailty is a powerful tool to predict adverse clinical outcomes in AF patients.

Acknowledgement/Funding

Swiss National Science Foundation; Foundation for Cardiovascular Research Basel; University of Basel

P1258Left atrial dimension and risk of cardiovascular outcomes in patients with and without atrial fibrillation: a systematic review and meta-analysis

Background

The prognostic value of left atrial (LA) dimensions measured by transthoracic echocardiogram among patients with versus without atrial fibrillation (AF) is uncertain. We aimed to investigate the association of LA echocardiographic parameters with the risk of cardiovascular events in AF patients compared to non-AF patients.

Methods

MEDLINE and EMBASE were searched from inception to July 2018. Records were retained if they studied the association between LA echocardiographic parameters and cardiovascular outcomes in AF patients, and in populations with no or less than 10% of AF patients. Left atrial dimensions had to be measured by transthoracic echocardiography, and parameters of interest were the following: LA diameter (LAD), LA diameter indexed to body surface (LADI), LA volume (LAV) and LA volume indexed to body surface (LAVI). Data were independently abstracted by 2 reviewers and pooled using inverse variance random-effects meta-analysis. The primary outcome was incident stroke and thromboembolic events. Secondary outcomes were heart failure, all-cause mortality and major adverse cardiac events (MACE).

Results

Twenty-three studies of AF patients (14'939 patients) and 69 studies of non-AF patients (52'654 patients) were included. Summary of the meta-analyses for the associations of LA parameters with cardiovascular outcomes is presented in the Figure. Increasing LAD was significantly associated with the risk of stroke and thromboembolic events in non-AF patients (P=0.03), but not among AF patients (P=0.27), and the association did not differ between population (P for difference=0.05) (Figure, A). Greater LADI was associated with risk of stroke and thromboembolic events in AF patients (P<0.001) and in non-AF patients (P=0.04), but the association did not differ between populations (P for difference=0.49). For MACE, increasing LADI was significantly associated with the outcome in AF patients (P<0.001) and in non-AF patients (P<0.001), but the association was stronger in non-AF populations (P for difference<0.001). Increasing LAVI was associated with high risk of MACE in AF patients (P=0.03) and in non-AF populations (P<0.001). Again, the correlation was stronger among non-AF patients (P for difference<0.001). Other associations did not differ between populations, and meta-analysis of LAV was not conducted by the limited number of studies.

Summary of meta-analysis

Conclusions

Left atrial echocardiographic parameters are powerful predictors of adverse cardiovascular events, mainly among individuals without AF.