Atrial fibrillation is associated with large beat-to-beat variability in mitral and tricuspid annulus dimensions

Aims Beat-to-beat variability in cycle length is well-known in atrial fibrillation (Afib); whether this also translates to variability in annulus size remains unknown. Defining annulus maximal size in Afib is critical for accurate selection of percutaneous devices given the frequent association with mitral and tricuspid valve diseases. Methods and results Images were obtained from 170 patients undergoing 3D echocardiography [100 (50 sinus rhythm (SR) and 50 Afib) for mitral annulus (MA) and 70 (35 SR and 35 Afib) for tricuspid annulus (TA)]. Images were analysed for differences in annular dynamics with a commercially available software. Number of cardiac cycles analysed was 567 in mitral valve and 346 in tricuspid valve. Median absolute difference in maximal MA area over four to six cycles was 1.8 cm2 (range 0.5–5.2 cm2) in Afib vs. 0.8 cm2 (range 0.1–2.9 cm2) in SR, P < 0.001. Maximal MA area was observed within 30–70% of the R-R interval in 81% of cardiac cycles in SR and in 73% of cycles in Afib. Median absolute difference in maximal TA area over four to six cycles was 1.4 cm2 (range 0.5–3.6 cm2) in Afib vs. 0.7 cm2 (range 0.3–1.7 cm2) in SR, P < 0.001. Maximal TA area was observed within 60–100% of the R-R interval in 81% of cardiac cycles in SR, but only in 49% of cycles in Afib. Conclusion MA and TA reach maximal size within a broad time interval centred around end-systole and end-diastole, respectively, with significant beat-to-beat variability. Afib leads to a larger beat-to-beat variability in both timing of occurrence and values of annulus size than in SR.

Beat-to-beat variability in the tricuspid annulus dimensions and dynamics is markedly increased in atrial fibrillation

Background Atrial fibrillation (Afib) leads to beat-to-beat variability in cycle length; however, whether there is associated beat-to-beat variability in the tricuspid annulus (TA) dimensions or variability in the time in cardiac cycle when TA reaches maximal size is unknown. Purpose We aim to assess the beat-to-beat variability in the TA dimensions in Afib compared with sinus rhythm (SR). Methods Images were obtained from 58 patients (29 in Afib, 29 in SR) undergoing either 3D TTE or TEE examination. We measured TA in 3–6 cardiac cycles per patient using commercially available software (TomTec 4MV). Results Median absolute difference in maximal TA area over 3–6 cardiac cycles was 1.60 cm2 (range 0.35 cm2 to 4.08 cm2) in Afib vs. 1.17 cm2 (range 0.32 cm2 to 2.19 cm2) in SR, p=0.0063. Median absolute difference in the maximal circumference was 0.79 cm (range 0.09 cm to 2.2 cm) in Afib vs 0.54 cm (range 0.12 cm to 1.43 cm) in SR, p=0.0175. A total of 118 cardiac cycles were analyzed in patients in SR and 147 in Afib. Timing of maximal TA area was most commonly recorded at end-diastole (80–100% of the R-R interval) in 62% of cycles in SR; however, it was distributed over a broad range in Afib, p<0.0001, [Figure]. Conclusion Afib leads to significant beat-to-beat variability in the maximal TA area, minimal TA area, maximal TA circumference, and in the time of maximal TA area. These findings suggest that accurate assessment of TA dimensions should be based on continuous tracking of the TA over several cardiac cycles, especially in patients with Afib. These observations have significant implications for device sizing in percutaneous tricuspid valve interventions. Timing of Maximal TA Area Funding Acknowledgement Type of funding source: None

Food authentication from shotgun sequencing reads with an application on high protein powders

Here we propose that using shotgun sequencing to examine food leads to accurate authentication of ingredients and detection of contaminants. To demonstrate this, we developed a bioinformatic pipeline, FASER (Food Authentication from SEquencing Reads), designed to resolve the relative composition of mixtures of eukaryotic species using RNA or DNA sequencing. Our comprehensive database includes >6000 plants and animals that may be present in food. FASER accurately identified eukaryotic species with 0.4% median absolute difference between observed and expected proportions on sequence data from various sources including sausage meat, plants, and fish. FASER was applied to 31 high protein powder raw factory ingredient total RNA samples. The samples mostly contained the expected source ingredient, chicken, while three samples unexpectedly contained pork and beef. Our results demonstrate that DNA/RNA sequencing of food ingredients, combined with a robust analysis, can be used to find contaminants and authenticate food ingredients in a single assay.

Volume-targeted ventilation with a Fabian ventilator: maintenance of tidal volumes and blood CO2

ObjectiveTo analyse the performance of the Fabian +NCPAP evolution ventilator during volume guarantee (VG) ventilation in neonates at maintaining the target tidal volume and what tidal and minute volumes are required to maintain normocapnia.MethodsClinical and ventilator data were collected and analysed from 83 infants receiving VG ventilation during interhospital transfer. Sedation was used in 26 cases. Ventilator data were downloaded with a sampling rate of 0.5 Hz. Data were analysed using the Python computer language and its data analysis packages.Results~107 hours of ventilator data were analysed, consisting of ~194 000 data points. The median absolute difference between the actual expiratory tidal volume (VTe) of the ventilator inflations and the target tidal volume (VTset) was 0.29 mL/kg (IQR: 0.11–0.79 mL/kg). Overall, VTe was within 1 mL/kg of VTset in 80% of inflations. VTe decreased progressively below the target when the endotracheal tube leak exceeded 50%. When leak was below 50%, VTe was below VTset by >1 mL/kg in less than 12% of inflations even in babies weighing less than 1000 g. Both VTe (r=−0.34, p=0.0022) and minute volume (r=−0.22, p=0.0567) showed a weak inverse correlation with capillary partial pressure of carbon dioxide (Pco2) values. Only 50% of normocapnic blood gases were associated with tidal volumes between 4 and 6 mL/kg.ConclusionsThe Fabian ventilator delivers volume-targeted ventilation with high accuracy if endotracheal tube leakage is not excessive and the maximum allowed inflating pressure does not limit inflations. There is only weak inverse correlation between tidal or minute volumes and Pco2.

Using out-of-office blood pressure measurements in established cardiovascular risk scores: a secondary analysis of data from two blood pressure monitoring studies

BackgroundBlood pressure (BP) measurement is increasingly carried out through home or ambulatory monitoring, yet existing cardiovascular risk scores were developed for use with measurements obtained in clinics.AimTo describe differences in cardiovascular risk estimates obtained using ambulatory or home BP measurements instead of clinic readings.Design and settingSecondary analysis of data from adults aged 25–84 years in the UK and the Netherlands without prior history of cardiovascular disease (CVD) in two BP monitoring studies: the Blood Pressure in different Ethnic groups (BP-Eth) study and the Home versus Office blood pressure MEasurements: Reduction of Unnecessary treatment Study (HOMERUS).MethodThe primary comparison was Framingham risk calculated using BP measured as in the Framingham study or daytime ambulatory BP measurements. Statistical significance was determined using non-parametric tests.ResultsIn 442 BP-Eth patients (mean age = 58 years, 50% female [n = 222]) the median absolute difference in 10-year Framingham cardiovascular risk calculated using BP measured as in the Framingham study or daytime ambulatory BP measurements was 1.84% (interquartile range [IQR] 0.65–3.63, P = 0.67). In 165 HOMERUS patients (mean age = 56 years, 46% female) the median absolute difference in 10-year risk for daytime ambulatory BP was 2.76% (IQR 1.19–6.39, P<0.001) and only 8 out of 165 (4.8%) of patients were reclassified.ConclusionEstimates of cardiovascular risk are similar when calculated using BP measurements obtained as in the risk score derivation study or through ambulatory monitoring. Further research is required to determine if differences in estimated risk would meaningfully influence risk score accuracy.

Validation of the CrIS fast physical NH₃ retrieval with ground-based FTIR

Presented here is the validation of the CrIS (Cross-track Infrared Sounder) fast physical NH3 retrieval (CFPR) column and profile measurements using ground-based Fourier transform infrared (FTIR) observations. We use the total columns and profiles from seven FTIR sites in the Network for the Detection of Atmospheric Composition Change (NDACC) to validate the satellite data products. The overall FTIR and CrIS total columns have a positive correlation of r = 0.77 (N = 218) with very little bias (a slope of 1.02). Binning the comparisons by total column amounts, for concentrations larger than 1.0 × 1016 molecules cm−2, i.e. ranging from moderate to polluted conditions, the relative difference is on average ∼ 0–5 % with a standard deviation of 25–50 %, which is comparable to the estimated retrieval uncertainties in both CrIS and the FTIR. For the smallest total column range (< 1.0 × 1016 molecules cm−2) where there are a large number of observations at or near the CrIS noise level (detection limit) the absolute differences between CrIS and the FTIR total columns show a slight positive column bias. The CrIS and FTIR profile comparison differences are mostly within the range of the single-level retrieved profile values from estimated retrieval uncertainties, showing average differences in the range of ∼ 20 to 40 %. The CrIS retrievals typically show good vertical sensitivity down into the boundary layer which typically peaks at ∼ 850 hPa (∼ 1.5 km). At this level the median absolute difference is 0.87 (std = ±0.08) ppb, corresponding to a median relative difference of 39 % (std = ±2 %). Most of the absolute and relative profile comparison differences are in the range of the estimated retrieval uncertainties. At the surface, where CrIS typically has lower sensitivity, it tends to overestimate in low-concentration conditions and underestimate in higher atmospheric concentration conditions.