Novel algorithm for arrhythmogenic focus localization in patients with right ventricular outflow tract arrhythmias

Background: Previously presented new electrocardiography (ECG) algorithm for localization of arrhythmogenic focus (AFo) in right ventricular outflow tract (RVOT) was based on spontaneous arrhythmia QRS morphology analysis. The aim of this study was to estimate the clinical value of our RVOT algorithm in a prospective study.Methods and results: Algorithm validation was made on 62 patients with RVOT arrhythmias (45 women), mean age 41.6 ± 14.3 years, scheduled for transcatheter ablation. Results of preablation ECG analysis with RVOT algorithm were matched with successful ablation sites and statistical indices: sensitivity (sens), specificity (spec), and positive and negative predictive values (PPV, NPV) were calculated for algorithm and for each of 9 RVOT zones (septal and free wall). An algorithm precisely localized AFo in 57 out of 62 patients (sens 91.3%, spec 99%, PPV 91%, NPV 98.8%). Sensitivity values for superior RVOT aspect (71% patients) varied from 88% to 100%, specificity from 95.9% to 100%; PPV values from 85.7% to 100%, NPV from 92.5% to 100%. Although the total number of patients was relatively small in the 2 remaining RVOT aspects (29% patients) high values (sens, spec, PPV, NPV) were gained for intermediate and inferior zones.Conclusions: On the basis of spontaneous arrhythmia QRS analysis, a novel algorithm was built for preablation localization of RVOT arrhythmia in 1 of the 9 RVOT zones. Prospective analysis of our ECG algorithm confirmed that it is a valuable tool to predict the site of successful ablation in patients with RVOT arrhythmias.

Clinical, echocardiographic, and pacing parameters affecting atrial fibrillation burden in patients with tachycardia-bradycardia syndrome

Background: The influence of various factors on atrial fibrillation (AF) development in the population of tachycardia-bradycardia syndrome (TBS) patients remains unclear. There are no data on the impact of different right ventricular pacing percentage (RVp%) profiles. Aim: The purpose of the study was to evaluate the relationship between the AF burden (AFB) and various clinical, echocardiographic, and pacing parameters in TBS patients. Methods: We performed a prospective, one-year registry of TBS patients with documented AF referred for dual-chamber pacemaker (DDD) implantation. Results: The data of 65 patients were analysed. The median 12-month RVp% and AFB was 9.4% and 1.0%, respectively. During the follow-up 14% of patients had no AF (p = 0.003), and the withdrawal of AF symptoms was observed in 49% of patients (p < 0.0001). The AFB was related to the left atrium diameter (r = 0.31, p = 0.02), especially in the subjects with left ventricular ejection fraction < 60% (r = 0.44, p = 0.04). Based on the relative change of RVp%, three groups of various RVp% profile were established: stable, decreasing, and increasing RVp%. In the stable RVp% group (n = 21) there was a quadratic correlation between the 12-month RVp% and AFB (r = 0.71, p = 0.0003). In the stable RVp% > 20% subgroup there was a significant increase of AFB in comparison to the RVp% ≤ 20% subgroup (ΔAFB 1.8% vs. 0.0%, p = 0.03, respectively). In the increasing RVp% group (n = 28) the AFB increased whereas in the decreasing RVp% (n = 16) it remained stable (ΔAFB 0.67% vs. 0.0%, p = 0.034, respectively). Conclusions: DDD implantation in TBS patients is related to a significant reduction in AF symptoms, and left atrial diameter correlates with cumulative AFB in the mid-term observation. Stable RVp% > 20% is associated with AF progression whereas lower stable RVp% may stabilise AF development. Increasing RVp% may be associated with the AFB increase in comparison to the decreasing RVp% subgroup in which AFB remains stable.Background: The influence of various factors on atrial fibrillation (AF) development in the population of tachycardia-bradycardia syndrome (TBS) patients remains unclear. There are no data on the impact of different right ventricular pacing percentage (RVp%) profiles. Aim: The purpose of the study was to evaluate the relationship between the AF burden (AFB) and various clinical, echocardiographic, and pacing parameters in TBS patients. Methods: We performed a prospective, one-year registry of TBS patients with documented AF referred for dual-chamber pacemaker (DDD) implantation. Results: The data of 65 patients were analysed. The median 12-month RVp% and AFB was 9.4% and 1.0%, respectively. During the follow-up 14% of patients had no AF (p = 0.003), and the withdrawal of AF symptoms was observed in 49% of patients (p < 0.0001). The AFB was related to the left atrium diameter (r = 0.31, p = 0.02), especially in the subjects with left ventricular ejection fraction < 60% (r = 0.44, p = 0.04). Based on the relative change of RVp%, three groups of various RVp% profile were established: stable, decreasing, and increasing RVp%. In the stable RVp% group (n = 21) there was a quadratic correlation between the 12-month RVp% and AFB (r = 0.71, p = 0.0003). In the stable RVp% > 20% subgroup there was a significant increase of AFB in comparison to the RVp% ≤ 20% subgroup (ΔAFB 1.8% vs. 0.0%, p = 0.03, respectively). In the increasing RVp% group (n = 28) the AFB increased whereas in the decreasing RVp% (n = 16) it remained stable (ΔAFB 0.67% vs. 0.0%, p = 0.034, respectively). Conclusions: DDD implantation in TBS patients is related to a significant reduction in AF symptoms, and left atrial diameter correlates with cumulative AFB in the mid-term observation. Stable RVp% > 20% is associated with AF progression whereas lower stable RVp% may stabilise AF development. Increasing RVp% may be associated with the AFB increase in comparison to the decreasing RVp% subgroup in which AFB remains stable

Deriving the dietary approaches to stop hypertension (DASH) score in women from seven pregnancy cohorts from the European alphabet consortium

The ALPHABET consortium aims to examine the interplays between maternal diet quality, epigenetics and offspring health in seven pregnancy/birth cohorts from five European countries. We aimed to use the Dietary Approaches to Stop Hypertension (DASH) score to assess diet quality, but different versions have been published. To derive a single DASH score allowing cross-country, cross-cohort and cross-period comparison and limiting data heterogeneity within the ALPHABET consortium, we harmonised food frequency questionnaire (FFQ) data collected before and during pregnancy in ≥26,500 women. Although FFQs differed strongly in length and content, we derived a consortium DASH score composed of eight food components by combining the prescriptive original DASH and the DASH described by Fung et al. Statistical issues tied to the nature of the FFQs led us to re-classify two food groups (grains and dairy products). Most DASH food components exhibited pronounced between-cohort variability, including non-full-fat dairy products (median intake ranging from 0.1 to 2.2 servings/day), sugar-sweetened beverages/sweets/added sugars (0.3–1.7 servings/day), fruits (1.1–3.1 servings/day), and vegetables (1.5–3.6 servings/day). We successfully developed a harmonized DASH score adapted to all cohorts being part of the ALPHABET consortium. This methodological work may benefit other research teams in adapting the DASH to their study’s specificities

Comparison of bacterial production in the water column between two Arctic fjords, Hornsund and Kongsfjorden (West Spitsbergen)

Bacterial production and the accompanying environmental factors were measured in the water columns of two Arctic fjords during the cruise in July and August 2013. Water samples were collected at six stations located in the central part of Hornsund and Kongsfjorden. In Hornsund, where average water temperatures were 1.25-fold lower than in Kongsfjorden, the bacterial production was twice as high (0.116 ± 0.102 vs 0.05 ± 0.03 mg C m−3 h−1). Statistical analysis indicated that chlorophyll a concentration itself was not a significant factor that affected bacterial production, in contrast to its decomposition product, pheophytin, originating from senescent algal cells or herbivorous activity of zooplankton. Single and multiple regression analysis revealed that water temperature, dissolved organic carbon (DOC), and pheophytin concentration were the main factors affecting bacterial production in both fjords