Rhythmic Changes Research Articles

Abstract Su507: Occurrence of Fibrillation in Out-of-hospital Cardiac Arrest Patients Presenting in a Non-shockable Rhythm when Treated with an Automated External Defibrillator

Background: Most out-of-hospital cardiac arrest (OHCA) patients who are initially treated with an automated external defibrillator (AED) and present in a non-shockable rhythm never receive a shock. This analysis reports on patients who presented in a non-shockable rhythm when the AED was initially applied and later transitioned into a shockable rhythm. Methods: Data from a convenience group of OHCA patients treated with a Philips HeartStart Home, Onsite or FRx AED were included. The AEDs were the first defibrillator on scene either in home, in public access or by a BLS team. Application of any medication during AED use was unlikely. Each patient’s heart rhythms were reviewed by an expert. All patients whose initial rhythm was non-shockable but later received at least one shock were identified and the rhythms were analyzed. Results: Out of 876 patients, 322 (36.8%) received at least one shock, of which five patients (1.6%) presented in a non-shockable rhythm and were later shocked. Three patients presented in an organized rhythm. The first patient degraded into Torsade de Pointe as shown in Figure 1; the post-shock rhythm was organized. The second patient received no CPR and A-V pacing was observed in the ECG recording. The pacing stopped when the rhythm transitioned into VF and restarted post shock. The third patient transitioned into VF during chest compressions and the post-shock rhythm was asystole. The remaining two patients presented in asystole and the rhythm evolved to fine VF after receiving chest compressions. After defibrillation, their rhythms returned to asystole. Conclusions: For OHCA patients treated with an AED, presenting in a non-shockable rhythm and later transitioning into a shockable rhythm is rare but possible. Lay-responder CPR may play a role in rhythm evolvement. The impact of rhythm changes on survivability of these patients is unknown.

Cell-type specific contributions to theta-gamma coupled rhythms in the hippocampus

Abstract Distinct inhibitory cell types participate in cognitively relevant nested brain rhythms, and particular changes in such rhythms are known to occur in disease states. Specifically, the co-expression of theta and gamma rhythms in the hippocampus is believed to represent a general coding scheme, but cellular-based generation mechanisms for these coupled rhythms are currently unclear. We develop a population rate model of the CA1 hippocampus that encompasses circuits of three inhibitory cell types (bistratified cells, parvalbumin (PV)-expressing and cholecystokinin (CCK)-expressing basket cells) and pyramidal cells to examine this. We constrain parameters and perform numerical and theoretical analyses. The theory, in combination with the numerical explorations, predicts circuit motifs and specific cell-type mechanisms that are essential for the co-existence of theta and gamma oscillations. We find that CCK-expressing basket cells initiate the coupled rhythms and regularize theta, and PV-expressing basket cells enhance both theta and gamma rhythms. Pyramidal and bistratified cells govern the generation of theta rhythms, and PV-expressing basket and pyramidal cells play dominant roles in controlling theta frequencies. Our circuit motifs for theta-gamma coupled rhythm generation could be applicable to other brain regions.

From oxygen shortage to neurocognitive challenges: behavioral patterns and imaging insights

Environmental hypoxia, resulting from reduced oxygen supply, poses a significant risk of dysfunctioning and damaging the neurocognitive system, particularly in relation to anxiety and stress. Inadequate oxygenation can lead to acute and chronic brain damage. Scholars used behavioral, hemodynamic, and electromagnetic neurofunctional techniques to investigate the effects of normobaric and hypobaric hypoxia on neurocognitive systems. They found a correlation between hypoxia, altered psychomotor responses, and changes in EEG alpha, theta, beta, and gamma rhythms, which affect spatial attention and memory. Hypoxia affects event related potential (ERP) components differently depending on latency. Perceptual responses N1 and P2 remain largely unaffected, while the amplitudes of preattentive MMN, vMMN, and P3a are significantly altered. Late latency components related to attention, particularly P3b, are also altered. These changes illustrate the spectrum from sensory detection to more complex cognitive processing, highlighting the brain's efficiency in managing information. Interestingly, the amplitudes of P3b, ADAN and CNV can increase with increased cognitive demands in hypoxia. This suggests a compensatory response. Prolonged exposure exacerbates these effects, resulting in compensatory delayed behavioral responses and alterations in behavioral monitoring and conflict inhibitory control, as reflected by reduced amplitudes in some attention related ERP components, including N2, N2pc, and ERN. Thus, neurocognitive function and integrity are under stress. ERP sources and hemodynamic images reveal that vulnerable brain regions include the frontal prefrontal cortices, hippocampus, basal ganglia, and parietal and visual cortices, which are essential for attention related processes like decision making and spatial memory. The auditory system appears less affected.

Evidence for a role of human blood-borne factors in mediating age-associated changes in molecular circadian rhythms.

Aging is associated with a number of physiologic changes including perturbed circadian rhythms; however, mechanisms by which rhythms are altered remain unknown. To test the idea that circulating factors mediate age-dependent changes in peripheral rhythms, we compared the ability of human serum from young and old individuals to synchronize circadian rhythms in culture. We collected blood from apparently healthy young (age 25-30) and old (age 70-76) individuals at 14:00 and used the serum to synchronize cultured fibroblasts. We found that young and old sera are equally competent at initiating robust ~24 hr oscillations of a luciferase reporter driven by clock gene promoter. However, cyclic gene expression is affected, such that young and old sera promote cycling of different sets of genes. Genes that lose rhythmicity with old serum entrainment are associated with oxidative phosphorylation and Alzheimer's Disease as identified by STRING and IPA analyses. Conversely, the expression of cycling genes associated with cholesterol biosynthesis increased in the cells entrained with old serum. Genes involved in the cell cycle and transcription/translation remain rhythmic in both conditions. We did not observe a global difference in the distribution of phase between groups, but found that peak expression of several clock-controlled genes (PER3, NR1D1, NR1D2, CRY1, CRY2, and TEF) lagged in the cells synchronized ex vivo with old serum. Taken together, these findings demonstrate that age-dependent blood-borne factors affect circadian rhythms in peripheral cells and have the potential to impact health and disease via maintaining or disrupting rhythms respectively.

Evidence for a role of human blood-borne factors in mediating age-associated changes in molecular circadian rhythms

Evidence for a role of human blood-borne factors in mediating age-associated changes in molecular circadian rhythms

Changes in Rest-Activity Rhythms in Adolescents as They Age: Associations With Brain and Behavioral Changes in the ABCD Study.

Adolescents with disrupted rest-activity rhythms (RAR) including shorter sleep duration, later sleep timing and low physical activity levels are at a greater risk for mental and behavioral problems. However, it remains unclear whether the same associations can be observed for within-subject changes in RAR. Our longitudinal investigation on RAR used Fitbit data from the Adolescent Brain Cognitive Development (ABCD) Study at the 2-year (FL2: aged 10-13 years) and 4-year follow-up (FL4: aged 13-16 years). 963 youths had good-quality Fitbit data at both time points. In this study we examined changes in RAR from FL2 to FL4, their environmental and demographic contributors as well as brain and behavioral correlates. From FL2 to FL4, adolescents showed decreases in sleep duration and physical activity as well as delayed sleep timing (Cohen's d .44-.75). The contributions of environmental and demographic factors to RAR changes were greatest for sleep timing (explained 10% variance) and least for sleep duration (explained 1% variance). Delays in sleep timing had stronger correlations with behavioral problems including impulsivity and poor academic performance than reductions in sleep duration or physical activity. Additionally, the various brain measures differed in their sensitivity to RAR changes. Reductions in sleep duration were associated with decreased functional connectivity between subcortical regions and sensorimotor and cingulo-opercular networks and with enhanced functional connectivity between sensorimotor, visual and auditory networks. Delays in sleep timing were mainly associated with grey matter changes in subcortical regions. The current findings corroborate the importance of sleep and physical activity in adolescents' brain neurodevelopment and behavioral problems. RAR might serve as biomarkers for monitoring behavioral problems and be potential therapeutic targets for mental disorders in adolescents.

Heart Rate and Rhythm Changes in Dogs Treated in a Hyperbaric Oxygen Chamber

In veterinary medicine, hyperbaric oxygen chamber treatment (HBOT) is gaining popularity. Therefore, an increasing number of patients referred for this therapy are being recorded, mainly due to ischemic events, wound healing support, and a high risk of reperfusion damage. During the HBOT procedure, several changes occur in the body’s micro- and macroenvironments. This study involved 34 dogs of various ages and health statuses. The atmospheric conditions in the test hyperbaric chamber included a pressure of 1.5 atmosphere absolute (ATA) at 100% oxygenation. The individuals were divided into three groups: (1) individuals with degenerative mitral valve disease (DMVD), (2) individuals with diseases other than cardiac issues, and (3) healthy individuals who qualified for the HBOT procedure. The period of measurement using the Holter apparatus was divided into four stages: 30 min before the subject’s placement in the hyperbaric chamber; a 4-min compression period (setting chamber conditions); a 90 min HBOT period; and a 1 min decompression period of the hyperbaric chamber. During the HBOT, there was a statistically significant decrease in heart rate in groups 2 and 3 compared to group 1. The heart rate in group 1 remained unchanged through every period of the study. In addition, some of the dogs developed respiratory arrhythmia; in two dogs, premature ventricle beats occurred. The changes observed during the ventricular period indicate that the HBOT procedure causes a significant change in heart rate in dogs without cardiac diseases.

Changes of the Heart Rhythm in Imbalance of Thyroid Gland Hormones and its Morphology in Outbred Rats

To analyze the relationship between the occurrence of atrial fibrillation (AF) and thyroid dysfunction caused by low concentrations of free triiodothyronine (FT3), free triiodothyronine and free thyroxine (FT3 and FT4), and high concentrations of free thyroxine (FT4) with normal values of thyroid-stimulating hormone (TSH) in experiments on outbred rats. The pathogenesis of AF with low concentrations of FT3, FT3 and FT4, and a high concentration of FT4 was studied in an experiment on 146 outbred rats. In the experiment, hypothyroidism, euthyroidism, and thyrotoxicosis were modeled by changing the concentrations of thyroid hormones, and the effect of these conditions on ECG and the incidence of AF was evaluated. The types of the hypothalamic-pituitary-thyroid system response to the L-thyroxine administration in experimental hypothyroidism were identified. A relationship was determined between AF paroxysms and threshold values of thyroid hormones at low concentrations of FT3, FT3 and FT4, and a high concentration of FT4 with normal TSH values. It was shown that achieving the euthyroid status did not reduce the incidence of AF paroxysms by more than 70.0%. In AF with low FT3, low FT3 and FT4, and high FT4, the dose of L-thyroxine must be adjusted.

Psoriasis and Seasonality: Exploring the Genetic and Epigenetic Interactions.

Psoriasis is a multifactorial, chronic, and inflammatory disease that severely impacts patients' quality of life. The disease is caused by genetic irregularities affected by epigenetic and environmental factors. Some of these factors may include seasonal changes, such as solar radiation, air pollution, and humidity, and changes in circadian rhythm, especially in the temporal and polar zones. Thus, some psoriasis patients report seasonal variability of symptoms. Through a comprehensive review, we aim to delve deeper into the intricate interplay between seasonality, environmental factors, and the genetic and epigenetic landscape of psoriasis. By elucidating these complex relationships, we strive to provide insights that may inform targeted interventions and personalized management strategies for individuals living with psoriasis.

An in-silico comparison of anatomical and substrate based AF ablation using electro and optical flow mapping

Abstract Background The pursuit of improved outcomes for persistent AF may necessitate the utilization of innovative technologies and ablation methods. We hypothesize that combining electrophysiologic phase and optical flow mapping could offer a novel approach to identify ablation sites in persistent AF while minimizing ablation area, thereby enhancing the effectiveness of substrate-based ablation compared to a purely empiric strategy. Objective To compare the efficacy of a novel electro-optic flow-based ablation strategy (EOF) with empiric ablation for persistent AF patients using a virtual cohort of bi-atrial models. Methods An exploratory cohort (n=20) from a CT-derived bi-atrial in silico population was utilized to simulate AF. A pipeline was developed to assess ablation targets based on simulated AF and to automatically connect targets to closest inert boundaries. As part of target assessment, phase singularities (PS) and Horn-Schunck average optical flow maps were computed. An intersection of information assessed through PS and curl of average optical flow was utilized to generate EOF maps. 5 x strategies comprising purely anatomical, PS based and EOF guided ablations were simulated (1. PVI; 2. PVI+mitral/roof lines; 3. PVI+mitral/box line; 4. PS+anatomical; 5. EOF+anatomical). Ablation efficacy was determined by first examining change of rhythm via ablation and second by calculating the amount of tissue area ablated. Results Ablating PVI alone (Method 1) did not result in AF termination in any case. Ablating PVI with mitral or roof lines (Method 2) resulted in moderate outcomes (6 AF term. / 3 conv. to AT) whereas ablating PVI with mitral and box lines (Method 3) resulted in improved outcomes (9 AF term. / 4 conv. to AT). Compared to purely anatomical approaches, ablating PS or EOF targets and combining them with roof, mitral lines (Method 4 and Method 5 respectively) saw marked improvement (16 AF term. / 2 conv. to AT). Mapping based on EOF (Method 5) resulted in smaller ablation targets compared to a PS guided strategy (Method 4) with the same outcome. Conclusion AF termination to ablated tissue area ratio was higher for EOF based ablation targets compared to PS based or empiric ablations. Algorithmic generation of ablation lesion masks based on predicted targets can provide novel insights into ablation outcomes. Combining EOF targets with empiric lesions represents a potential ablation strategy of individualized substrate modification for persistent AF.Study Pipeline

EEG sensorimotor rhythms dynamics in children with cerebral palsy during the course of neurorehabilitation, depending in the success of their imagination of movements

An analysis of changes in sensorimotor rhythms of the electroencephalogram (EEG) and features of the restoration of motor functions during a course of neurorehabilitation using a non-invasive brain-computer-hand exoskeleton interface was carried out in 50 children aged 7–15 years of both sexes suffering from cerebral palsy (CP). EEG was recorded in 32 leads under conditions of rest and kinesthetic imagination of hand extension movements. Depending on the success of the classifier program in determining imaginary states based on the EEG pattern, the children were divided into two groups – with high and low success when imagining movements. In children of the studied groups, when undergoing a course of neurorehabilitation, differences were revealed in the nature of changes in EEG amplitude in the sensorimotor mu (8–13 Hz) and beta (15–25 Hz) rhythms frequency ranges. When imagining movements of the right hand, intergroup differences for the mu rhythm reached the level of statistical significance in the medial electrodes of the fronto-central and parietal areas of the neocortex, for the beta rhythm – in the medial lead of the parietal region. Children in the group with high success showed a decrease or slight increase in the amplitude of the mu- and beta rhythm in these brain areas at the last session of the course compared to the first. We hypothesize that children in this group are not only better able to kinesthetically imagine movements throughout the course of neurorehabilitation, but also, based on feedback signals, learn to effectively adjust their strategies for movement imagination. Children in the group with low success showed an increase in the amplitude of sensorimotor rhythms in these brain areas, indicating the development of inhibition in the frontoparietal motor network. Patients, whose conditions were determined more accurately by the classifier, achieved higher rates of motor rehabilitation. The results of the study are important for clarifying the brain mechanisms of motor functions restoration in patients with cerebral palsy under the influence of a course of neurorehabilitation.

Impact of sleep deprivation on aperiodic activity: a resting-state EEG study.

Sleep deprivation (SD) has been shown to have a negative impact on alertness, as evidenced by behavioral and electroencephalographic studies. Nevertheless, conventional fixed-bandwidth spectral analysis confused the aperiodic and periodic components, and ignored some important periodic parameters (i.e., center frequency, bandwidth). Here, based on a large open access dataset of SD, we employed a standardized process for multiple electrode analysis and group inference. We found that, compared to SC, the aperiodic offset shifted overall after SD, primarily in the occipital region. And this shift was associated with a reduction in subjective alertness. For periodic component, we did not found any power change in alpha rhythm, but there is an increase in bandwidth of alpha. And the increased regions distributed in the occipital and temporal lobes. These findings highlight the potential significance and value of aperiodic parameters in behavioral and electrophysiological researches.

Circadian rhythms of macrophages are altered by the acidic tumor microenvironment

Tumor-associated macrophages (TAMs) are prime therapeutic targets due to their pro-tumorigenic functions, but varying efficacy of macrophage-targeting therapies highlights our incomplete understanding of how macrophages are regulated within the tumor microenvironment (TME). The circadian clock is a key regulator of macrophage function, but how circadian rhythms of macrophages are influenced by the TME remains unknown. Here, we show that conditions associated with the TME such as polarizing stimuli, acidic pH, and lactate can alter circadian rhythms in macrophages. While cyclic AMP (cAMP) has been reported to play a role in macrophage response to acidic pH, our results indicate pH-driven changes in circadian rhythms are not mediated solely by cAMP signaling. Remarkably, circadian disorder of TAMs was revealed by clock correlation distance analysis. Our data suggest that heterogeneity in circadian rhythms within the TAM population level may underlie this circadian disorder. Finally, we report that circadian regulation of macrophages suppresses tumor growth in a murine model of pancreatic cancer. Our work demonstrates a novel mechanism by which the TME influences macrophage biology through modulation of circadian rhythms.

Research on the Notation of Folk Urtiin Duu

This paper deeply explores the notation of Mongolian folk Urtiin Duu, an intangible cultural heritage, and focuses on how to scientifically and rationally record their unique artistic characteristics. The study points out that the simplified notation has the advantages of being easy to learn and flexible in key changes, and is the preferred choice for notating folk Urtiin Duu. In view of the difficulty in recording the free rhythm of folk Urtiin Duu, a method of grouping a group of sound forms based on the combination of the internal rhythmic rhythm and speed changes is proposed to solve the problem of recording non-equal rhythms. For the notation of the core techniques of the decorative elements of folk Urtiin Duu, such as Tashilaga and Nogula, the concept of the music theory symbol system is changed to accurately express them in order to protect the artistic essence of folk Urtiin Duu. In addition, the importance of the backing words in the singing of folk Urtiin Duu is emphasized, and it is advocated to record the backing words in a comprehensive manner to protect the traditional charm of folk Urtiin Duu. This paper comprehensively considers the selection of musical notation, the processing of rhythm, the application of decorative symbols and the standardized recording of filler words, aiming to provide a more scientific and reasonable musical notation strategy for the educational inheritance of folk Urtiin Duu, and promote the inheritance, protection and development of this precious cultural heritage.

Effects of long-term transcutaneous auricular vagus nerve stimulation on circadian vagal activity in people with Prader-Willi Syndrome: A case-series

BackgroundPrader-Willi Syndrome (PWS) is a genetic neurodevelopmental disorder marked by disruptions in circadian rhythms and autonomic nervous system (ANS) activity, hyperphagia, and episodes of emotional outbursts. Previous trials suggest that both invasive and non-invasive vagus nerve stimulation (VNS) can reduce emotional outbursts in PWS, potentially through its effects on vagal activity. AimThis case series investigated the effects of transcutaneous auricular VNS (taVNS) on cardiac markers of circadian vagal activity, specifically heart rate variability (HRV) and heart rate (HR), and their potential links to improvements in emotional outbursts. MethodsFive individuals with PWS (mean age: 26.9 years; 3 males, 2 females) received four hours of daily taVNS for 12 months, followed by one month of two-hour daily sessions. Outcome measures included daily recording of emotional outbursts and every three months 24-h HRV and HR recordings. Mixed cosinor models were applied to analyze changes in circadian rhythms of HRV and HR. A linear mixed model was used to assess the predictive value of cardiac vagal activity on emotional outbursts. ResultsCircadian amplitudes of HRV and HR were significantly higher at the end of the treatment compared to baseline (all p’s < .01). There was a significant increase in the rhythm-adjusted mean of HRV (p < .01), while the rhythm-adjusted HR mean significantly decreased, both indicating increased cardiac vagal activity. Higher rhythm-adjusted mean HRV predicted a lower number of emotional outbursts. ConclusionThe results suggest that taVNS may be effective by targeting ANS activity in individuals with PWS, contributing to improvements in behavioral regulation.

Алгоритм количественной оценки кардиореспираторной синхронизации для характеристики функционального состояния и межсистемных взаимодействий у спортсменов

Introduction. The rhythm of the heart (heart rate, HR) is closely related to the rhythm of breathing. The phenomenon of respiratory sinus arrhythmia (an increase in heart rate during inhalation and a decrease during exhalation) is well known. Cardiorespiratory interactions and synchronization of these two signals are evaluated differently in the literature. The purpose of this work was to propose and test an approach to assess cardiorespiratory synchronization – the calculation of the cross-correlation coefficient between heart rate and respiration curve, for a more objective characterization of an athlete’s bodily states. Methods. A photoplethysmogram and respiration were recorded in 45 healthy athletes (18-25 years old) in three situations: rest, paced breathing at 6 times per minute (resonant frequency) and the performance of a sensorimotor task (tapping with the rhythmic metronome sounds and then reproducing a given rhythm from memory). For the HR and respiration curves, filtering and smoothing algorithms using the Savitsky-Goley method were applied sequentially, and then the cross-correlation coefficient between the two curves was calculated. The spectral parameters of heart rate variability (LF and HF) were also obtained, since during spontaneous breathing its contribution to the HR is reflected in HF band, and when breathing at a resonant frequency, a peak occurs at a frequency of 0.1 Hz in the LF band. Results. The cross-correlation coefficient, as well as the peak of HR spectral power at 0.1 Hz, increases significantly when breathing at a resonant frequency. The relationship between these indicators is most accurately described not by a linear, but by a logarithmic dependence. When performing a sensorimotor task, the so-called respiratory waves in the heart rhythm spectrum (HF) do not change from rest to tapping by a metronome and then to holding the rhythm by memory. At the same time, the cross-correlation coefficient demonstrates significant changes between these situations. In addition, a significant correlation was found between the change in the cross-correlation coefficient and the stability of rhythm maintenance (from memory): an increase in the cardiorespiratory synchronization leads to a decrease in motor rhythm stability. Conclusion. Assessment of cardiorespiratory synchronization due to the peculiarities of both signals (changes in heart rate and respiratory phases) requires preliminary preparation of data arrays: filtering and smoothing the stepped curve of heart rate dynamics. The calculation of the cross-correlation coefficient can be used to assess cardiorespiratory synchronization in real time and is likely to be applicable in short time fragments to assess emotional reactions and other short-term fluctuations in psychophysiological conditions, where the classical method of assessing changes in heart rhythm in the frequency or time domains is not applicable.

Senegenin regulates the mechanism of insomnia through the Keap1/Nrf2/PINK1/Parkin pathway mediated by GAD67.

GAD67 impacts insomnia as a key enzyme catalysing the conversion of glutamate (Glu) to gamma-aminobutyric acid (GABA). Senegenin enhances neuroprotection and is used widely to treat insomnia and other neurological diseases. This study aimed to investigate how senegenin regulates insomnia through a GAD67-mediated signalling pathway. We measured GAD67 expression levels in insomnia patients and evaluated the expression levels of GAD67 and Keap1/Nrf2/Parkin/PINK1-related cytokines following GAD67 lentiviral transfection in PC12 cells and in rat models. We also assessed cellular reactive oxygen species (ROS) and mitochondrial membrane potential levels. Additionally, EEG/EMG was used to analyse the sleep phases of rats and to assess memory and exploration functions. Pathological changes and the expression of GAD67 and sleep-related proteins in the hippocampus were examined. The results showed that GAD67 expression was increased in insomnia patients, ROS levels were elevated, and the mitochondrial membrane potential was decreased in the GAD67-KD group. Insomnia rats exhibited changes in sleep rhythm, learning, and exploration dysfunction, pathological changes in the CA1 region of the hippocampus, and differential expression of GAD67 and sleep-related factors. Inhibitory neurofactor expression levels were decreased in insomnia rats, showing a positive correlation in the GAD67-KD group and a negative correlation in the GAD67-OE group. Conversely, excitatory factor expression levels were increased in insomnia rats, showing a positive correlation in the GAD67-KD group and a negative correlation in the GAD67-OE group. Senegenin intervention modulated cytokine expression levels. In conclusion, GAD67 negatively regulates insomnia, and senegenin can regulate insomnia by mediating the expression of cytokines in the GAD67-regulated Keap1/Nrf2/Parkin/PINK1 pathway.

8117 Late-night Salivary Cortisol in the Diagnosis of Cushing's Disease Recurrence

Abstract Disclosure: A.E. Alexandre: None. P.C. Elias: None. M. De Castro: None. L.M. Mermejo: None. D.C. Aragon: None. A.C. Moreira: None. Cushing’s Disease (CD) remission following transsphenoidal surgery (TSS) is most often defined by low morning cortisol levels and the requirement of glucocorticoid (GC) replacement therapy. However, CD recurrence is not a well studied event. There is no standard definition of remission criteria and no accurate cutoff for biochemical tests on CD recurrence. Late-night salivary cortisol (LNSC) has been shown to have higher accuracy in confirming CD recurrence than urinary free cortisol and dexamethasone suppression test (DST). However, few studies addressed LNSC performance following remission after TSS. The study aimed to establish cutoff values of LNSC with higher sensitivity (S) and specificity (E) in CD recurrence diagnosis.In a retrospective cohort study of 65 patients with remitted CD after TSS, remission was defined as improvement of sign and symptoms related to CD and a plasma cortisol &amp;lt;5mcg/dL in 30 days following TSS. Eleven patients progressed to permanent adrenal insufficiency and were excluded from the study. All 54 patients had at least four LNSC sampling and a minimal follow-up of 24 months after TSS. LNSC was determined by RIA. A cutoff value of 270 ng/dl for LNSC is used for the diagnosis of CD. Patients were divided in three different groups: Overt Recurrence (OR): elevated LNSC and worsening of CD`s signs and symptoms. Remission (RM): normal LNSC and no clinical signs of CD recurrence. Biochemical Recurrence (BR): at least 2 elevated biochemical parameters (LNSC or DST) but no worsening of signs and symptoms associated with CD. The mean of the 2 LNSC last values when OR was diagnosed and the mean of 2 LNSC last values of follow up for RM patients were used to estimate the accuracy of LNSC for diagnosing recurrence using a ROC curve (AUC) and its 95% confidence interval. Of the 54 patients included, 46 females; 8 males; mean age at diagnosis: 32 years, (5 – 58 yrs); mean time of follow-up: 12.8 years (4 – 31.7 yrs). Thirteen were classified as OR, 18 as RM and 23 as BR; and mean time of GC use after TSS was: 8.7; 34 and 17 yrs, respectively, significantly lower in OR compared to RM (p:0.046). A LNSC cutoff value of 272 mcg/dL had sensitivity of 85% and specificity of 95% (AUC: 0.97; 95% IC = [0.93; 1,00]) for CD recurrence diagnosis. BR patients presented LSNC fluctuation along follow-up.LNSC is a useful tool for CD recurrence screening. Setting LSNC specific assay cutoff values might be needed. LSNC cutoff values were similar for the initial CD diagnosis, as well as for CD recurrence diagnosis. Shorter time of GC replacement may be an important predictor of CD recurrence. Patients with BR should be followed more carefully as they may be at higher risk of recurrence. Multiple LNSC sampling on successive days can be easily performed and may detect subtle changes in cortisol rhythm. Presentation: 6/1/2024

8706 Hypoparathyroidism and Hypercalcemia in Premature Secondary to Excessive Vitamin D: Everything in Excess is Opposed

Abstract Disclosure: D.M. Bastos: None. A. Bastos: None. Introduction: Vitamin D intoxication in children is rare but its incidence is increasing as vitamin D is supplemented more often and in higher doses. Coma, ventricular fibrillation, and acute renal insufficiency are possible life-threatening presentations of vitamin D-induced hypercalcemia. Nephrocalcinosis, renal lithiasis, vascular calcifications, and arterial hypertension are known late complications of severe or longstanding hypercalcemia. The most common causes of vitamin D intoxication in children are manufacturing errors, parental dosing errors, and erroneous medical prescriptions. Case Presentation: A premature girl admitted to the neonatal ICU 3 months ago due to poor weight gain and was taking vitamin D and infant formulas and developed tachycardic heart rhythm with irregular rhythm and kidney changes. The investigation of the condition was re-evaluated, and the patient was seen with hypercalcemia, an increase of more than 100x in the dosage of 25(OH)vitamin D, an increase in the dosage of 1.25(OH)vitamin D, suppressed PTH, an increase in creatinine and urea. In addition, an ultrasound was performed showing the presence of small kidney stones, none of which were obstructive. After discontinuing vitamin D supplementation, the patient progressed satisfactorily with a reduction in cardiac and renal changes. Discussion: Currently, vitamin D supplementation has been carried out more frequently, as, in addition to increasing the absorption of calcium in the body, it reduces the risk of diseases, such as rickets and osteopenia of prematurity. The body is only able to produce vitamin D after exposure to sunlight. In the absence of regular exposure, dietary sources alone are not sufficient to maintain adequate levels. Cases of hypervitamin D generally occur in situations of excessive supplementation. In the present report, the dose used was 40 times higher than recommended. Initial tests revealed elevated calcium and undetectable PTH levels. The diagnosis of vitamin D intoxication is not common in cases of hypercalcemia, as it is infrequent, especially before the advent of vitamin D supplementation. Vitamin D toxicity is usually iatrogenic, or due to accidental overdose. These factors, along with a lack of public education about safe dosing, have likely contributed to the increase in reported cases of vitamin D toxicity. Conclusion: Vitamin D supplementation, especially when using compounded medications, must be adequately monitored due to the potential risk of poisoning. Vitamin D toxicity remains a pressing issue and its incidence will likely continue to grow, primarily because of the widespread availability of over-the-counter formulations and public interest. Presentation: 6/3/2024

A study on serum potassium and serum magnesium levels in acute myocardial infarction with special emphasis on rhythm disturbance

Background and objectives. Myocardial infarction (MI) is a severe cardiac event associated with plaque formation in arteries, leading to reduced blood flow to the heart. Arrhythmias, such as bradyarrhythmia or tachyarrhythmia, commonly accompany MI, contributing to its morbidity and mortality. Electrolyte disturbances, particularly potassium and magnesium imbalances, can exacerbate arrhythmic risks in MI patients. This study aimed to assess the incidence of alterations in serum potassium and magnesium levels during acute MI and their correlation with rhythm disturbances. Material and methods. A prospective analytical study was conducted with 150 patients diagnosed with acute MI based on ECG changes and elevated cardiac markers. Serum potassium and magnesium levels were measured, and rhythm disturbances were assessed using continuous cardiac monitoring and standard ECG. Spearman correlation analysis was performed to evaluate the association between serum potassium, serum magnesium, and rhythm changes. Results. The study investigated the demographic and clinical characteristics of participants and the potential relationship between serum electrolyte levels and arrhythmic changes. The mean age of the participants was 54.3 years, with a male predominance (76% male, 24% female). Among the participants, 50.67% had diabetes, 52% had hypertension, and 28% had both conditions. Serum electrolyte analysis showed elevated magnesium levels in 6.66% and elevated potassium levels in 12.66% of patients. Notably, arrhythmic changes in ECG were present in 62% of patients, with sinus tachycardia being the most prevalent (17%). However, statistical analysis revealed no significant correlation between serum magnesium, serum potassium, and rhythm changes (p &gt;0.05). These findings suggest that while arrhythmic changes are common, they are not directly associated with elevated levels of these electrolytes, indicating the need for further investigation into other potential factors influencing arrhythmias in this population. Conclusion. Despite the prevalence of electrolyte disturbances in acute MI patients, this study found no significant association between serum magnesium, serum potassium levels, and rhythm disturbances. Further research is warranted to elucidate the complex interplay between electrolyte imbalances and arrhythmias in MI.