Impact of natriuresis on worsening renal function during episodes of acute heart failure.

INTRODUCTION AND OBJECTIVES: Worsening renal function (WRF) is a frequent complication in acute heart failure (AHF) with a controversial prognostic value. We aimed to study the usefulness of natriuresis to evaluate WRF. METHODS: We conducted an observational, prospective, multicenter study of patients with AHF who underwent a furosemide stress test. The patients were classified according to whether WRF was present or absent and according to the median natriuretic response. The main endpoint was the combination of mortality, rehospitalization due to HF, and heart transplant at 6 months of follow-up. RESULTS: One hundred and fifty-six patients were enrolled, and WRF occurred in 60 (38.5%). The patients were divided into 4 groups: a) 47 (30.1%) no WRF/low UNa (UNa ≤ 109 mEq/L); b) 49 (31.4%) no WRF/high UNa (UNa > 109 mEq/L); c) 31 (19.9%) WRF/low UNa and d) 29 (18.6%) WRF/high UNa. The parameters of the WRF/low UNa group showed higher clinical severity and worse diuretic and decongestive response. The development of WRF was associated with a higher risk of the combined event (HR, 1.88; 95%CI, 1.01-3.50; P = .046). When stratified by natriuretic response, WRF was associated with an increased risk of adverse events in patients with low natriuresis (HR, 2.28; 95%CI, 1.15-4.53; P = .019), but not in those with high natriuresis (HR, 1.18; 95%CI, 0.26-5.29; P = .826). CONCLUSIONS: Natriuresis could be a useful biomarker for interpreting and prognosticating WRF in AHF. WRF is associated with a higher risk of adverse events only in the context of low natriuresis.

INFLUENCE OF PROXIMAL FIXATION ON ANEURYSM NECK EVOLUTION AFTER ENDOVASCULAR TREATMENT OF INFRARENAL ANEURYSMS.

OBJECTIVE: We analyzed the long-term influence of fixation systems on proximal aortic neck (PAN) evolution by comparing two late-generation endoprostheses, Endurant (Medtronic Vascular, Minneapolis, Minn) with suprarenal fixation (SRF) and Excluder (W.L Gore & Associates, Flagstaff, Ariz) with infrarenal fixation (IRF). METHODS: Our retrospective observational study included consecutive patients undergoing EVAR for aorto-iliac aneurysms (2011-2020). Primary end points: neck enlargement and freedom from significative PAN enlargement (5 mm). Secondary end points: neck-related reintervention, endoleaks and graft migration. Results were reported following the Society of Vascular Surgery reporting standards. RESULTS: 139 patients were included (97 in SRF group and 42 in IRF group). A difference in growth at 10 mm caudal to lowest renal artery at 2 years follow-up was found (mean growth of 1.92 ± 3.38 mm in SRF and 0.16 ± 6.86 mm in IRF; p <.001). A tendency to a major growth in SRF at 4 years follow-up at the lowest renal artery (1.27 ± 3.36 mm vs 0.63 ± 2.2 mm; p = .06), 5 mm distal to lowest renal artery (2.17 ± 3.52 mm vs 0.94 ± 2.76 mm; p =.001) and 10 mm distal to lowest renal artery (2.65 ± 3.86 mm vs 1.12 ± 1.5 mm; p <.001) was shown. Freedom from PAN enlargement was 96.65% and 88.20% in SRF and 100% and 94.4% in IRF at 2 and 4 years follow up respectively (log rank .041). A greater incidence of type II endoleaks in IRF was observed (40.48% vs 15.46%;p =.001). Oversizing > 15% showed to be a risk factor of PAN enlargement (OR 6.85; 95% IC 1.67 - 28.4; p =.007). CONCLUSIONS: A small but significative percentage of patients after EVAR show a progressive PAN enlargement, being significatively greater in SRF, without increasing neck related complications four years after graft deployment.

Use of social media in radiation oncology: multicenter data from the GOCO Group.

Background: The purpose of this study was to explore the usage patterns and profiles of social media (SM) platforms among Radiation Oncologists (RO) and Physicists in the scope of the Catalan-Occitan Oncology Group (GOCO). Materials and methods: From November 2022 to March 2023, a comprehensive survey was sent to Radiation Oncology professionals within the GOCO group, comprising 31 questions that covered demographics (4) and general inquiries (9), user behavior on social media (7), profile of SM activity (7), and participants' opinions (4) regarding professional use of SM. The survey reached professionals from 12 centers, encompassing 10 in Catalonia and 2 in French Occitania. Results: The survey achieved a 61.37% response rate (178/290 professionals) with an average age of 41.9 years. 120 (67%) were ROs, and 58 (33%) were Physicists. Instagram led in usage (n = 116), followed by Facebook (n = 107) and Twitter (n = 77). Age correlated inversely with the number of platforms used (Spearman's rank correlation coefficient -0.238, p = 0.001). 28% (n = 42) changed clinical practices based on SM information. A 78.5% (n = 117) didn't counter inappropriate content. Most (71.7%, n = 109) spent < 1 hour daily on professional SM use, however more Physicians exceeded 2 hours compared to Physicists (Cohen's kappa 2 = 0.07). 41.8% (n = 64) weren't emotionally concerned while 22.9% (n = 35) felt overwhelmed by SM overload. Conclusions: The study offers valuable insights into the usage patterns, preferences, and attitudes of Radiation Oncology professionals towards SM platforms. This understanding is crucial for optimizing content quality and delivering relevant information, thereby enabling more effective marketing strategies and enhancing emotional management among these professionals.

Epidemiological changes of invasive fungal disease in children with cancer: Prospective study of the National Child Program of Antineoplastic Drugs network, Chile.

BACKGROUND: Invasive fungal diseases (IFD) are high morbidity and mortality infections in children with cancer suffering episodes of high-risk febrile neutropenia (HRFN). IFD epidemiology has changed in the last two decades, with an increasing incidence in recent years due to the growing number of immunocompromised children at risk for IFD. The aim of this study was to evaluate the incidence of IFD in children with cancer in the period 2016-2020 compared to 2004-2006 in six hospitals in Chile. METHODS: Prospective, multicentre study, carried out between 2016 and 2020 in six hospitals in Chile. The defined cohort corresponds to a dynamic group of HRFN episodes in patients <18 years old with cancer, who at the fourth day of evolution still presented fever and neutropenia (persistent HRFN). Each episode was followed until resolution of FN. The incidence of IFD was calculated between 2016 and 2020 and compared with data obtained in the period 2004-2006. The incidence rate was estimated. RESULTS: A total of 777 episodes of HRFN were analysed; 257 (33.1%) were considered as persistent-HRFN occurring in 174 patients. The median age was 7 years (IQR: 3-12 years) and 52.3% (N = 91) were male. Fifty-three episodes of IFD were detected: 21 proven, 14 probable and 18 possible. Possible IFD were excluded, leaving 239 episodes of persistent-HRFN with an IFD incidence of 14.6% (95% CI 10.5-19.9) and an incidence rate of 13.6 IFD cases per 1000 days of neutropenia (95% CI 9.5-20.0). Compared to 2004-2006 cohort (incidence: 8.5% (95% CI 5.2-13.5)), a significant increase in incidence of 6.1% (95% CI 0.2-12.1, p = .047) was detected in cohorts between 2016 and 2020. CONCLUSION: We observed a significant increase in IFD in 2016-2020, compared to 2004-2006 period.

Revealing biases in insect observations: A comparative analysis between academic and citizen science data.

Citizen Science is a powerful tool for biodiversity research, as it facilitates data recording at large scales that would otherwise be impossible to cover by standard academic research. Despite its benefits, the accuracy of citizen science data remains a subject of concern among scientists, with varying results reported so far. Neither citizen science data nor academic records are immune to biases, which can significantly impact the quality and reliability of observations. Here, using insects in the Iberian Peninsula as a case study, we compare data collected by participatory platforms to those obtained through academic research projects, and assess their taxonomic, spatial, temporal, and environmental biases. Results show a prominent taxonomic bias in both academic and citizen science data, with certain insect orders receiving more attention than others. These taxonomic biases are conserved between different participatory platforms, as well as between groups of users with different levels of contribution performance. The biases captured by leading contributors in participatory platforms mirrored those of sporadic users and academic data. Citizen science data had higher spatial coverage and less spatial clustering than academic data, showing also clearer trends in temporal seasonality. Environmental coverage over time was more stable in citizen science than in academic records. User behaviour, preference, taxonomical expertise, data collection methodologies and external factors may contribute to these biases. This study shows the multifaceted nature of biases present in academic records and citizen science platforms. The insights gained from this analysis emphasize the need for careful consideration of these biases when making use of biodiversity data from different sources. Combining academic and citizen science data enhances our understanding of biodiversity, as their integration offers a more comprehensive perspective than relying solely on either dataset alone, especially since biases in these two types of data are not always the same.

Rare Genetic Variants in Young Adults Requiring Pacemaker Implantation.

BACKGROUND: Genetic disease has recently emerged as a cause of cardiac conduction disorders (CCDs), but the diagnostic yield of genetic testing and the contribution of the different genes to CCD is still unsettled. OBJECTIVES: This study sought to determine the diagnostic yield of genetic testing in young adults with CCD of unknown etiology requiring pacemaker implantation. We also studied the prevalence of rare protein-altering variants across individual genes and functional gene groups. METHODS: We performed whole exome sequencing in 150 patients with CCD of unknown etiology who had permanent pacemaker implanted at age ≤60 years at 14 Spanish hospitals. Prevalence of rare protein-altering variants in patients with CCD was compared with a reference population of 115,522 individuals from gnomAD database (control subjects). RESULTS: Among 39 prioritized genes, patients with CCD had more rare protein-altering variants than control subjects (OR: 2.39; 95% CI: 1.75-3.33). Significant enrichment of rare variants in patients with CCD was observed in all functional gene groups except in the desmosomal genes group. Rare variants in the nuclear envelope genes group exhibited the strongest association with CCD (OR: 6.77; 95% CI: 3.71-13.87). Of note, rare variants in sarcomeric genes were also enriched (OR: 1.73; 95% CI: 1.05-3.10). An actionable genetic variant was detected in 21 patients (14%), with LMNA being the most frequently involved gene (4.6%). CONCLUSIONS: Unrecognized rare genetic variants increase the risk of CCD in young adults with CCD of unknown etiology. Genetic testing should be performed in patients age ≤60 years with CCD of unknown etiology. The role of genetic variants in sarcomeric genes as a cause of CCD should be further investigated.

A randomised trial of short- vs long-term androgen deprivation with salvage radiotherapy for biochemical failure following radical prostatectomy: URONCOR 06-24.

BACKGROUND: Salvage radiotherapy (SRT) and androgen-deprivation therapy (ADT) are widely used in routine clinical practice to treat patients with prostate cancer who develop biochemical recurrence (BCR) after radical prostatectomy (RP). However, there is no standard-of-care consensus on optimal duration ADT. Investigators propose three distinct risk groups in patients with prostate cancer treated with SRT in order to better define the indications and duration of ADT combined with SRT. STUDY DESIGN: The URONCOR 06-24 trial (ClinicalTrials.gov identifier NCT05781217) is a prospective, multicentre, randomised, open-label, phase III, clinical trial. The aim of the trial is to determine the impact of short-term (6 months) vs long-term (24 months) ADT in combination with SRT on distant metastasis-free survival (MFS) in patients with prostate cancer with BCR after RP (intermediate and high risk). ENDPOINTS: The primary endpoint is 5-year MFS rates in patients with prostate cancer treated with long- vs short-term ADT in combination with SRT. Secondary objectives are biochemical-relapse free interval, pelvic progression-free survival, time to start of systemic treatment, time to castration resistance, cancer-specific survival, overall survival, acute and late toxicity, and quality of life. METHODS AND ANALYSIS: Total of 534 patients will be randomised 1:1 to ADT 6 months or ADT 24 months with a luteinizing hormone-releasing hormone analogue in combination with SRT, stratified by risk group and pathological lymph node status. ETHICS AND DISSEMINATION: The study is conducted under the guiding principles of the World Medical Association Declaration of Helsinki. The results will be disseminated at research conferences and in peer-reviewed journals. TRIAL REGISTRATION NUMBER: EudraCT number 2021-006975-41.

Instrument to evaluate the perception of abuse and/or disrespectful treatment during childbirth: A validation study.

AIM: To design and validate a tool to assess a woman's perception of whether she has experienced a situation of abuse or disrespect during childbirth attendance: "Childbirth Abuse and Respect Evaluation-Maternal Questionnaire" (CARE-MQ). METHODS: Multidisciplinary panel of experts (gynecologists, midwives, mothers) participated in creating CARE-MQ. A cross-sectional study was carried out on 901 Spanish women who had given birth between 1 and 3 months before to determine psychometric characteristics. Finally, an exploratory factor analysis (EFA), confirmatory factor analysis (CFA), and a convergent validity study were carried out with the Quality Questionnaire from the Patient's Perspective-Intrapartum (QPP-I), and a reliability study using internal consistency (Cronbach's α) and coefficient of intraclass correlation (CCI). FINDINGS: The KMO test gave a value of 0.935, and Bartlett's sphericity test was <0.001. The EFA identified four components ("Emotional Abuse", "Inadequate Professionalism", "Physical Abuse" y "Lost contact") that explained 55.16 % of variance. In the CFA, a good fit was observed for most of the evaluated indicators. CARE-MQ correlated negatively with QPP-I (Spearman's rho = -0.641, 95 % CI: -0.679, -0.600; p < 0.001) and was statistically associated with variables related to childbirth experience (p < 0.005) such as the use of a birth plan, use of regional analgesia, type of birth, episiotomy, presence of severe tears, skin-to-skin contact, length of hospital stay and postpartum surgical intervention. Cronbach's α value was 0.903. The ICC of absolute agreement after administering the questionnaire one week after was 0.927 (95 % CI: 0.85-0.97). CONCLUSIONS: CARE-MQ is a valid and reliable instrument to evaluate the perception of a woman regarding the situation of abuse and/or disrespect that she may have experienced during birth in a population of Spanish postpartum women.

Right ventricular dysfunction: pathophysiology, experimental models, evaluation, and treatment.

Interest in the right ventricle has substantially increased due to advances in knowledge of its pathophysiology and prognostic implications across a wide spectrum of diseases. However, we are still far from understanding the multiple mechanisms that influence right ventricular dysfunction, its evaluation continues to be challenging, and there is a shortage of specific treatments in most scenarios. This review article aims to update knowledge about the physiology of the right ventricle, its transition to dysfunction, diagnostic tools, and available treatments from a translational perspective.

Encorafenib and binimetinib followed by radiotherapy for patients with BRAFV600-mutant melanoma and brain metastases (E-BRAIN/GEM1802 phase II study).

BACKGROUND: Encorafenib plus binimetinib (EB) is a standard of care treatment for advanced BRAFV600-mutant melanoma. We assessed efficacy and safety of encorafenib plus binimetinib in patients with BRAFV600-mutant melanoma and brain metastasis (BM) and explored if radiotherapy improves the duration of response. METHODS: E-BRAIN/GEM1802 was a prospective, multicenter, single arm, phase II trial that enrolled patients with melanoma BRAFV600-mutant and BM. Patients received encorafenib 450 mg once daily plus binimetinib 45 mg BID, and those who achieved partial response or stable disease at first tumor assessment were offered radiotherapy. Treatment continued until progression.Primary endpoint was intracranial response rate (icRR) after 2 months of EB, establishing a futility threshold of 60%. RESULTS: The study included 25 patients with no BM symptoms and 23 patients with BM symptoms regardless of using corticosteroids. Among them, 31 patients (64.6%) received sequential radiotherapy. After two months, icRR was 70.8% (95% CI: 55.9-83.1); 10.4% complete response. Median intracranial PFS and OS were 8.5 (95% CI: 6.4-11.8) and 15.9 (95% CI: 10.7-21.4) months, respectively (8.3 months for icPFS and 13.9 months OS for patients receiving RDT). Most common grade 3-4 treatment-related adverse event was alanine aminotransferase (ALT) increased (10.4%). CONCLUSION: Encorafenib plus binimetinib showed promising clinical benefit in terms of icRR, and tolerable safety profile with low frequency of high grade TRAEs, in patients with BRAFV600-mutant melanoma and BM, including those with symptoms and need for steroids. Sequential radiotherapy is feasible but it does not seem to prolong response.

Dispersal history of SARS-CoV-2 in Galicia, Spain.

The dynamics of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission are influenced by a variety of factors, including social restrictions and the emergence of distinct variants. In this study, we delve into the origins and dissemination of the Alpha, Delta, and Omicron-BA.1 variants of concern in Galicia, northwest Spain. For this, we leveraged genomic data collected by the EPICOVIGAL Consortium and from the GISAID database, along with mobility information from other Spanish regions and foreign countries. Our analysis indicates that initial introductions during the Alpha phase were predominantly from other Spanish regions and France. However, as the pandemic progressed, introductions from Portugal and the United States became increasingly significant. The number of detected introductions varied from 96 and 101 for Alpha and Delta to 39 for Omicron-BA.1. Most of these introductions left a low number of descendants (<10), suggesting a limited impact on the evolution of the pandemic in Galicia. Notably, Galicia's major coastal cities emerged as critical hubs for viral transmission, highlighting their role in sustaining and spreading the virus. This research emphasizes the critical role of regional connectivity in the spread of SARS-CoV-2 and offers essential insights for enhancing public health strategies and surveillance measures.

Zika virus non-coding RNAs antagonize antiviral responses by PKR-mediated translational arrest.

Zika virus (ZIKV) is an emerging mosquito-borne flavivirus that causes severe outbreaks in human populations. ZIKV infection leads to the accumulation of small non-coding viral RNAs (known as sfRNAs) that are crucial for evasion of antiviral responses and for viral pathogenesis. However, the mechanistic understanding of how sfRNAs function remains incomplete. Here, we use recombinant ZIKVs and ribosome profiling of infected human cells to show that sfRNAs block translation of antiviral genes. Mechanistically, we demonstrate that specific RNA structures present in sfRNAs trigger PKR activation, which instead of limiting viral replication, enhances viral particle production. Although ZIKV infection induces mRNA expression of antiviral genes, translation efficiency of type I interferon and interferon stimulated genes were significantly downregulated by PKR activation. Our results reveal a novel viral adaptation mechanism mediated by sfRNAs, where ZIKV increases its fitness by repurposing the antiviral role of PKR into a proviral factor.

Patch Test Results with the Latin American Baseline Series in a Colombian Population. 2016-2021.

Background: Contact dermatitis (CD) is one of the most prevalent skin diseases. It is commonly divided into irritant contact dermatitis (ICD) and allergic contact dermatitis (ACD). Patch testing is a procedure used to support the diagnosis of ACD. This test should be interpreted along with the clinical history and morphology of the skin lesions to determine clinical relevance. Objective: To describe the sensitization patterns of patients undergoing patch testing with the Latin American baseline series. Methods: A single-center retrospective study was performed. For the study, patients older than 18 years with a clinical diagnosis of contact dermatitis, who underwent patch testing using the Latin American baseline series were considered. These tests took place at the Alma Mater Hospital of Antioquia between January 1, 2016, and December 31, 2021. Results: A total of 648 patients were included. Patch tests were positive in 63% of cases, with a mean age of 51.5 years. Around 36.6% had atopy-related diseases. The main occupation was housework (30.7%). The hands were the most affected area in the body (31%). The main allergens were nickel sulfate (34%), sodium tetrachloropalladate (24.2%), and thimerosal (8.0%). Fifteen allergens had a percentage below 1%. Hydrocortisone and budesonide did not yield positive results. Conclusion: Nickel sulfate was the most frequent allergen, and women were the most affected. The information gathered could be useful for adjusting the allergens that should be included in the regional baseline series, taking into account the frequency found.

Geometric morphometry of the Rhodniusprolixus complex (Hemiptera, Triatominae): patterns of intraspecific and interspecific allometry and their taxonomic implications.

In the subfamily Triatominae, the genus Rhodnius is one of the most studied, not only because of its epidemiological importance, but also because of the difficulty in differentiating its species. Currently, one of the strategies to control Chagas disease, besides other initiatives such as the analysis of donated blood, is focused on fighting the vector. Correctly identifying triatomines is essential for the entomoepidemiological surveillance of Chagas disease. The objective of the present work was to compare the species of the R.prolixus complex using geometric morphometry of hemelytra and heads to evaluate the patterns of intraspecific and interspecific allometry and their taxonomic implications. This method can help in the diagnosis of close species, whose morphological characteristics are insufficient for correct identification. Specimens from five different collections were used, covering the species included in the R.prolixus complex (R.barretti, R.dalessandroi, R.domesticus, R.marabaensis, R.milesi, R.montenegrensis, R.nasutus, R.neglectus, R.neivai, R.prolixus and R.robustus). Morphometric analyses indicated that the hemelytra are not structures with good resolution for separating species and, for this reason, the use of the heads proved to be more adequate for this group (thus allowing differentiation of all species of the R.prolixus complex). The results suggest that R.milesi is a variant of R.neglectus and confirms that R.prolixus and R.robustus are distinct species. Furthermore, we propose the creation of the R.neivai complex comprising R.domesticus and R.neivai.

Reference intervals for reticulocyte count and derived reticulocyte parameters in a cohort of healthy adults.

INTRODUCTION: Reticulocyte count and novel derived parameters provide insight into the effectiveness of erythropoiesis and may be useful tools in the classification and diagnosis of anemias. However, there is no standardisation, so we consider it necessary that each laboratory evaluates the parameters according to its own methodology and instrumentation and establishes its own reference ranges. Our aim was to establish the reference intervals (RIs) of reticulocyte profile provided by the Beckman Coulter DxH 900 haematological autoanalyzer in our reference population. METHODS: One hundred and seventy-five healthy adults (18 to 62 years) were included. Subjects were collected from the blood donation centre of the Hospital Clínico San Carlos (Madrid, Spain) upon informed consent. Whole blood was collected and assayed for 14 haematological parameters on the Beckman Coulter DxH 900 analyzer in the haematology laboratory of the Clinical Analysis Department. RIs were established as per Clinical and Laboratory Standards Institute EP28-A3c guidelines using three different statistical approaches. RESULTS: RIs estimated using the non-parametric method and the Harrell-Davis bootstrap method were very similar. RIs estimated by the robust method were narrower. Gender partitioning was required for two haematological parameters (low haemoglobin density (LHD) and microcytic anaemia factor (MAF)). The rest of the parameters did not need to be partitioned according to Lahti's method. CONCLUSION: RIs have been established for 14 hematologic parameters of the reticulocyte profile for the Beckman Coulter DxH 900 haematology analyzer using a healthy cohort of adult subjects.

Use of Knotless Barbed Sutures in Laparoscopic Inguinal Hernioplasty in Horses: 40 Cases.

Inguinal hernias (IHs) and ruptures are a relatively common condition in horses, occurring in foals (congenital) and adult (acquired) animals. A retrospective observational analysis was conducted on 40 cases that underwent laparoscopic surgery to close the VRs using barbed sutures alone or combined with other techniques. Signalment, clinical presentation, surgery, and follow-up data were obtained. In total, fifty-nine VRs were closed using barbed sutures (alone or in combination with other methods), with six cases performed prophylactically and forty-four due to acquired IH. Of the forty-four cases with IH, four were non-strangulated hernias, while thirty presented with strangulated small intestines (twenty-eight acquired and two congenital). The results obtained in this study suggest that laparoscopic hernioplasty with barbed sutures is an effective and safe surgical procedure that could be recommended as a standard practice for managing inguinal hernias in horses, particularly when sparing testicles or preserving reproductive capabilities is a priority.

Serum biomarkers for liver fibrosis assessment.

Liver fibrosis is the result of chronic liver injury of different etiologies produced by an imbalance between the synthesis and degeneration of the extracellular matrix and dysregulation of physiological mechanisms. Liver has a high regenerative capacity in the early stage of chronic diseases so a prompt liver fibrosis detection is important. Consequently, an easy and economic tool that could identify patients with liver fibrosis at the initial stages is needed. To achieve this, many non-invasive serum direct, such as hyaluronic acid or metalloproteases, and indirect biomarkers have been proposed to evaluate liver fibrosis. Also, there have been developed formulas that combine these biomarkers, some of them also introduce clinical and/or demographic parameters, like FIB-4, non-alcoholic fatty liver disease fibrosis score (NFS), enhance liver fibrosis (ELF) or Hepamet fibrosis score (HFS). In this manuscript we critically reviewed different serum biomarkers and formulas for their utility in the diagnosis and progression of liver fibrosis.

Transcutaneous Auricular Vagal Nerve Stimulation in Healthy Non-Sedated Horses: A Feasibility Study.

This study aimed to evaluate the feasibility of transcutaneous auricular vagal nerve stimulation (tAVNS) in healthy horses and its effect on heart rate variability (HRV). The study comprised three phases: the selection of mares, their acclimatization to the tAVNS, and the stimulation phase. Stimulation was performed with two electrodes positioned on the right pinna. The settings were 0.5 mA, 250 µs, and 25 Hz for pulse amplitude, pulse width, and pulse frequency, respectively. HRV was analysed before (B1), during (T), and after (B2) the tAVNS. From the 44 mares initially included, only 7 completed the three phases. In these mares, the heart rate (HR) was significantly lower, and frequency domain parameters showed an increased parasympathetic tone in B2 compared with B1. However, in 3/7 mares, the HR was significantly higher during T compared with B1 and B2, compatible with a decreased parasympathetic tone, while in 4/7 mares, the HR was significantly lower and the parasympathetic nervous system index was significantly higher during T and B2 compared with B1. The tAVNS is an economical and easy procedure to perform and has the potential to stimulate vagal activity; however, it was poorly tolerated in the mares included in this study.