Cardiac Activity Research Articles

Remote ischemic peri-conditioning suppressed cardiac sympathetic nerve activity especially in the non-culprit lesion in patients with acute myocardial infarction

Abstract Background Remote ischemic periconditioning (RIPC) has demonstrated cardioprotective effects and improved clinical outcomes as an adjunct to emergent percutaneous coronary intervention (PCI) in patients with acute myocardial infarction (AMI). However, it remains to be elucidated whether RIPC affects the cardiac sympathetic nerve activity in patients with AMI. Purpose The purpose of this study is to investigate the effect of RIPC on cardiac sympathetic nerve activity (CSNA) in the culprit and non-culprit lesion respectively in patients with AMI. Methods We randomly assigned 157 patients with suspected AMI undergoing emergent PCI to receive transient limb ischemia (by inflating a cuff at 200 mmHg for 4×5 minutes: RIPC group, n=77) or no procedure (control group, n=80). After excluding inappropriate patients such as those with other diagnosis than AMI, we analyzed 122 patients (62 patients in RIPC and 60 in control group). CSNA was assessed in the culprit and non-culprit lesion respectively by the cardiac MIBG SPECT imaging. Results Patients in RIPC and control group had similar demographic and clinical characteristics at baseline. Patients in RIPC group tended to show higher late uptake only in the non-culprit lesion at discharge. At 1 year after discharge, patients in RIPC group demonstrated significantly higher late uptake (p=0.021) and lower washout rate (p=0.013) than those in control group in the non-culprit lesion. Regarding the culprit lesion, only washout rate tended to be lower in RIPC group at 1 year after discharge. Conclusion(s): Remote ischemic peri-conditioning showed suppressive effect on cardiac sympathetic nerve activity especially in the non-culprit lesion in patients with acute myocardial infarction.SPECT parameters in RIPC and control

Unravelling cardiomyopathies: a comprehensive analysis of phenotypic diversity, endomyocardial biopsy patterns, and the impact of Gremlin-1 on clinical prognosis

Abstract Background Cardiomyopathies are the main cause of progressive heart failure (HF) and despite outstanding advances of diagnostics and therapies, mortality remains high.1,2 The current phenotype-based classification of non-ischemic cardiomyopathies (NICM) is based on a clinical workflow including endomyocardial biopsy (EMB).3-5 Inflammation and fibrosis are essentially involved in progression of HF and lead to development of adverse cardiovascular (CV) events.6,7 The diagnostic algorithm facilitates risk stratification of HF patients but nonetheless risk factors often remain inapparent prior to disease incidence. Objective In this study we investigate EMB patters in patients with NICM and elucidate alterations associated with phenotypic diversity and progression of HF. Methods We prospectively enrolled patients with HF due to NICM in a large-scale all-comers cohort (n=703). All patients underwent guideline-based phenotypic classification including EMB, and RNA data were acquired alongside histological analyses within the myocardium. We then performed a ten-year follow-up to screen for disease progression. Results A guideline-based classification of patients with NICM resulted in a phenotyping of aetiological risk groups (Figure 1A). We found that characteristic expression of fibroinflammatory mediators within the myocardium occurred in patients with symptomatic NICM (Figure 1B). We found that elevated expression of Gremlin-1 (Grem), a potent downstream profibrotic mediator of TGFß pathway, was associated with pro-fibrotic cardiac remodelling (Figure 1C). Further, Gremlin-1 was associated with a significant decrease of left ventricular functional capacity and inversely correlated with late gadolinium enhancement (LGE) (Figure 1D&E). Moreover, the expression of Gremlin-1 was enriched with pro-fibrotic and inflammatory RNA signalling pathways hinting at underlying pathophysiological cascades (Figure 2A&B). Most strikingly, the expression of Gremlin-1 was independently associated with an increased CV risk during the ten-year follow-up (Figure 2C). Thus, patients with Gremlin-1+ EMB were at elevated risk to suffer from all-cause mortality and number of patients eligible for ICD implantation was critically enhanced in patients with Gremlin-1+ EMB (Figure 2D-F). In addition, the estimation of an elevated CV risk by machine learning including Gremlin-1 improved the ten-year risk stratification among all patients with NICM (Figure 2G). Thus, Gremlin-1 was associated with cardiac remodelling and disease activity in HF patients (Figure 2H). Conclusion Our results unveiled that Gremlin-1 is associated with inflammation and cardiac remodelling in patients with symptomatic cardiomyopathy and patients with Gremlin-1+ EMB are at elevated risk to develop adverse CV events. Thus, the histological evaluation of Gremlin-1 may help to identify pathophysiological cascades and improve early risk discrimination and management of HF patients.Figure 1Figure 2

The activation of cardiac sympathetic nervous system in the non-culprit lesion is a strong prognostic predictor in patients with acute myocardial infarction

Abstract Background The activation of cardiac sympathetic nervous system is associated with poor prognosis in patients with acute myocardial infarction (AMI). However, it remains to be determined whether regional assessment of cardiac sympathetic nerve activity (CSNA) in the culprit and non-culprit lesion of the cardiac MIBG SPECT imaging could have prognostic value in patients with AMI. Purpose The purpose of this study is to investigate the prognostic impact of regional CSNA in patients with AMI. Methods We prospectively enrolled 122 patients with AMI who visited our emergency department and underwent primary percutaneous coronary intervention. The late heart-to-mediastinum ratio (HMR) and washout rate (WR) was calculated to assess CSNA in the whole heart from planar images of in the cardiac MIBG imaging. The MIBG SPECT image parameters were calculated for each coronary artery, and the average WR in the culprit and non-culprit lesion were evaluated to assess the regional status of CSNA in patients with AMI. Abnormal WR in planar image was defined as 34% or more, as previously reported. The cut-off value of late HMR in planar image, WR in the culprit and non-culprit lesions were determined by ROC analysis. The primary endpoint was major adverse cardiac event (MACE) including all cause death, myocardial infarction, hospitalization for heart failure and target lesion revascularization. Results During a mean follow-up period of 3.1±1.8 years, 25 of 122 patients underwent MACE. The late HMR (p=0.004), WR in planar image (p=0.002), WR in the culprit lesion (p=0.023), and WR in the non-culprit lesion (p<0.001) were significantly associated with MACE at univariate Cox proportional hazard analysis. The increased WR in the non-culprit lesion (defined as 28.3% or more: AUC 0.697 [0.576-0.817]) was significantly independently associated with MACE (hazard ratio: 4.36 [1.45-13.11], p=0.009) even adjusted by late HMR, WR in planar image or WR in the culprit lesion, while decreased HMR, abnormal WR in planar image and increased WR in the culprit lesion showed no significant association with MACE in the multivariate model with WR in the non-culprit lesion. Kaplan-Meier analysis revealed that patients with increased WR in the non-culprit lesion had significantly higher risk for MACE than those without increased WR (45% vs 11% p<0.001). Conclusion(s) The activation of cardiac sympathetic nervous system in the non-culprit lesion is particularly associated with poor prognosis in patients with acute myocardial infarction.MACE risk by WR in non-culprit lesion

Characteristics associated with prevalent atrial fibrillation and risk profile for future atrial fibrillation among those in sinus rhythm in an elderly population in the ELSA Brasil Study

Abstract Background Atrial fibrillation (AF) is an arrhythmia that can lead to limiting symptoms and increases the risk of stroke and heart failure (HF). Purpose To evaluate the association of clinical, electrocardiographic, and echocardiographic parameters with prevalent AF or flutter (AFF), and the risk profile for future AFF according to Charge-AF and EHR scores in an elderly population. Methods The ELSA-Brasil is a prospective cohort study designed to investigate cardiovascular disease and diabetes in 15,105 men and women, civil servants from universities or research institutions in six cities of Brazil. We included all participants in ELSA-Brasil aged 60 and over whose diagnosis of AFF could be assessed and had echocardiography performed at the study's baseline. From the initial sample with participants ≥ 60 years (n = 3,263), 400 participants were excluded due to missing data about AFF, and 775 who did not have echocardiographic studies. Results There were 88 (4.2%) participants with AFF at baseline among the 2,088 (65 ± 4.1 years; 53% women) included in this analysis. Those with AFF were older (66.8 ± 4.4 vs 65 ± 4.0 y-o) and had a higher prevalence of HF (16% vs 3.1%), previous myocardial infarction (14.8% vs 3.8%), left bundle branch block (LBBB: 4.6% vs 0,9%), prolonged QT interval (7.9% vs 2.0%), supraventricular extrasystoles (4.6% vs 1.2%), and sinus bradycardia (11.3% vs 2.9%). AFF individuals also presented larger left atrial volume index - LA (33.3 mL/m2 versus 27 mL/m2), left ventricular end-diastolic diameter (4,63 ± 0,6 cm versus 4,47 ± 0,4 cm) and lower left ventricular ejection fraction (LVEF: 63.6 ± 9.1% vs 67.4 ± 6.4%) that non-AFF (all p-values <0.05). In multivariable analysis, prevalent HF, LBBB, larger LA, and lower LVEF were independently associated with the presence of AFF. Among those in sinus rhythm at study baseline, both risk models showed that most individuals in our sample were at low risk. In the Charge-AF, 63% of individuals were identified as presenting low risk (<2.5%), and 12% of the sample was categorized as high risk, with a risk of five-year AFF greater than 5%. Similarly, in the EHR, 67% of participants were classified as low risk, and 13% were considered high risk. Conclusion We found that AFF was present in 4.2% of the subset of older participants in a cohort composed of free-living individuals in Brazil. The presence of AFF was associated with HF history, altered cardiac electrical activity, LA dilation, and worse LV systolic function. Among those with sinus rhythm, 12-13% were considered at high risk of developing AFF (> 5% in five years) based on two clinical scores. Clinical surveillance and monitoring of electrocardiography and echocardiography parameters may help the early identification of risk factors for AFF.

Cardiac sympathetic innervation, assessed with 123I-MIBG SPECT, predicts left ventricular function improvement in patients with newly diagnosed dilated cardiomyopathy

Abstract Introduction Beta-blockers (BB) are commonly prescribed medications for heart failure (HF) due to their ability to counteract the increased sympathetic nervous system (SNS) activity seen in HF, resulting in downregulation and desensitization of β-receptors. In patients with dilated cardiomyopathy (DCM), the introduction of BB therapy can lead to left ventricular ejection fraction (LVEF) improvement in 30-50% of cases. Single-photon emission computed tomography (SPECT) with 123I-meta-iodobenzylguanidine (MIBG) is a useful tool for assessing cardiac SNS activity. Healthy individuals typically exhibit high SPECT-MIBG uptake and low washout rate (WR) due to normal β-receptor levels and low norepinephrine (NE) levels, respectively (Fig 1A). While better SPECT-MIBG results have been associated with LVEF improvement in the general HF population, less data is available for DCM patients. Purpose This study aimed to evaluate the predictive value of MIBG-SPECT for LVEF improvement in newly diagnosed DCM patients. Methods Twenty-one DCM patients (mean age 47 ± 10 years, 90% male, baseline LVEF 29.5 ± 8.7%, left ventricular end-diastolic volume (LVEDV) 114 ± 36 ml/m2) with stable HF symptoms (NYHA class 1.8 ± 0.6) and newly diagnosed DCM underwent baseline MIBG-SPECT and echocardiography. HF therapy was initiated and up-titrated, and echocardiography was repeated at 6 months. Semi-quantitative parameters from MIBG-SPECT, including the MIBG uptake ratio from the heart and mediastinum (H/M) at 15 minutes (-15) and 4 hours (-4), as well as the WR [WR = (H/M-15 - H/M-4) / H/M-15], were evaluated. Patients were stratified based on median WR - 8.79 (IQR 5.17-12.90). Results After 6-months of HF therapy up-titration, 18 patients improved LVEF, and the mean LVEF increase was 7.7 ± 10.4%. Although, patients with WR > median did not differ in terms of baseline LVEF (30.2 ± 7.0 vs. 27.7 ± 9.6, p=0.52), they had worse LVEF at 6 months (32.0 ± 11.0 vs. 40.6 ± 9.2%, p=0.04). Moreover, WR at baseline strongly correlated with 6-month LVEF (R=-0.51, p=0.01) and was a significant predictor of 6-month LVEF (β=-0.55 ± 0.19, p=0.009). Moreover, WR could successfully predict LVEF improvement ≥ 10% (OR 1.27 [95%CI 1.01-1.61], p=0.03; AUC 0.82 [95%CI 0.63-0.99], p<0.001) with a cut-off point of 8.0 (sensitivity 88%, specificity 77%) (Fig 1B). Conclusion Most DCM patients demonstrated LVEF improvement during 6 months of HF therapy up-titration. Baseline WR from MIBG-SPECT was found to be a reliable predictor of significant LVEF improvement in this patient population.Fig1.A-SPECT-MIBG results. B-ROC curve.

A novel device for electrocardiographic imaging

Abstract Background Electrocardiographic imaging (ECGi) is a non-invasive imaging tool that allows 3D visualization and characterization of the electrical activity of the heart from measurements on the body surface by solving the so called "inverse problem of electrocardiography". This method helps overcome the limitations of the conventional12-lead ECG in diagnosing and locating heart arrythmias. We developed a textile 34-electrode imageless device (with no need for MRI or CT-scan). Purpose We aim to evaluate the feasibility and safety of the use of a novel textile imageless 34-electrode device for recording ECGi for identification of electrical activity of the heart. Methods and results The performance of a prototype data acquisition system (DAS) was evaluated in 158 individuals. Tests were conducted in three hospitals. The mean age was 43.32 years old (±17.44); mean height 167.31cm (±18.33); mean weight 70kg (±15.68). Almost 88% of the patients were in sinus rhythm. The relative frequencies of the targeted pathologies are listed in Figure 1. The collection of cardiac signals and posterior representation in virtual reality of a stereoscopic, holographic 3D-360º map, was achieved in 100% of the patients. Figure 2 shows the textile hardware with the silver dry electrodes and a screenshot of the software with an example of a voltage map in a patient in sinus rhythm. There were no adverse effects reported. The DAS is composed of 34 electrodes, being their distribution representative of the electrical activity on the torso. Several studies have discussed the minimum number of electrodes on the torso of the patient required to characterize the heart potentials from the electrical potentials on the torso surface through the inverse problem (1,2). We highlight that the representativeness condition of the electrical activity on the torso is crucial to appropriately estimate cardiac activity with the minimum number of leads on the DAS. Conclusion The use of a novel textile imageless 34-electrode device for recording ECGi for identification of electrical activity of the heart is feasible and safe.Targeted rhythmHardware and software

Autonomic Modulation in Parkinson’s Disease Using Whole-Body Cryostimulation: A Pilot Study

Background: Parkinson’s disease (PD) is a multifaceted neurodegenerative disorder that progressively affects both the central and peripheral nervous systems. This pilot study aimed to examine the effects of repeated whole-body cryostimulation (WBC) sessions on the sympathovagal balance in PD patients and correlate heart rate variability (HRV) indexes with peripheral biomarkers of the autonomic nervous system (ANS). Methods: Seventeen PD patients with mild to moderate motor severity underwent a 10-session WBC cycle over 5 consecutive days. Thirteen patients (6 males, 7 females; mean age 64.5 ± 9.01 years; mean disease duration 5.4 ± 2.3 years) completed the protocol. Cardiac autonomic activity was assessed through HRV measures including RR interval variability (RR mean, RR min, RR max), power density of high and low frequencies (HF, LF), RMSSD, and the LF/HF ratio. Systemic sympathetic activity was evaluated via circulating blood catecholamine levels. Results: Significant increases were observed in RR mean, RR min, RR max, RMSSD, and HF spectrum, indicating enhanced parasympathetic activity. Blood pressure remained stable, suggesting safety. Conclusions: These findings provide initial support to WBC as a potential “rehabilitation booster” in PD, enhancing sympathovagal balance. Further research is needed to explore the long-term benefits of WBC in PD management.

Cesarean scar pregnancy: should surgery be the preferred treatment approach?

To compare the characteristics and outcomes of non-surgical and surgical treatments for Cesarean scar pregnancy (CSP). A retrospective study conducted at a tertiary university affiliated medical center, including all women diagnosed with Cesarean scar pregnancy between 2019 and 2023. Women treated non-surgically (including: methotrexate, uterine artery embolization and balloon catheter) were compared to women treated surgically (including: hysterectomy, hysteroscopy and excision of the pregnancy with or without uterine niche repair). Demographic information, medical history, obstetric and gynecological characteristics, presenting symptoms, imaging findings, management details, surgical characteristics, and follow-up data were collected from the women's electronic medical records. Primary outcome was defined as the β-hCG levels on follow-up visit at 2weeks following treatment. 42 women were diagnosed with Cesarean scar pregnancy during the study period, of them 9 (21%) were treated non-surgically and 33 (79%) were treated surgically. Median age was 33 (30-36) year old and median BMI was 31 (27-35) kg/m2, with no statistical differences in-between the groups. Most of the women had previous two Cesarean sections (n = 12, 28%). 63% of the women were asymptomatic at the time of diagnosis. On transvaginal ultrasound examination, embryo was demonstrated in 66.7% and cardiac activity was observed in 75%. The median gestational age at diagnosis and β-hCG levels were comparable between the non-surgical and surgical treatment groups (p = 0.22, p = 0.61, respectively). In the surgical arm, the most common surgical procedure was excision of the pregnancy with uterine niche repair, that was performed in 14/42 (33%) of the women. Median hospitalization length was 3 (1-4) and 2 (1-3) days, for the non-surgical and surgical treatment groups, respectively (p = 0.51). The hemoglobin level before discharge was similar between the groups (p = 0.20). Only one woman in each group visited the emergency room before the follow-up visit (p = 0.31). β-hCG levels on follow-up were significantly lower in the surgical group compared to the non-surgical (p = 0.02). Cesarean scar pregnancy can be asymptomatic and should be suspected to enable early diagnosis. Both non-surgical and surgical treatments are viable options, with comparable hospitalization lengths; however, the surgical intervention group is expected to show a significantly faster decrease in β-hCG levels.

A Task-driven Adversarial Channel Selection Method for Binary Classification Based on Magnetocardiography.

As the number of sensors in magnetocardiography (MCG) arrays increases to capture detailed cardiac activity, some channels contribute minimally to task performance, resulting in data redundancy and resource consumption. Although existing methods can reduce the number of channels required to meet task demands, they often struggle to balance computational time and the accuracy of the selected channels and overlook the scalability of the selected channels. This limitation means that when environmental conditions change, or when sensors malfunction, redesigning channel configurations becomes necessary, which increases experimental uncertainties. This study introduces a task-driven adversarial channel selection method tailored for binary classification of MCG signals. The optimal channel combination is determined through a group-wise search using a heuristic algorithm, whose objective function is designed to maximize the difference between the classification accuracy and cosine similarity of the selected channel. In evaluations using an MCG dataset from Qilu Hospital of Shandong University, the proposed method successfully reduced the number of channels from 36 to 5 without compromising classification performance. Furthermore, it outperforms existing hybrid sequential forward search method by achieving comparable accuracy with fewer channels, while also demonstrating superior scalability compared to both hybrid sequential forward search and pearson-rank methods. This approach strikes a balance between computational consumption and accuracy, while improving the scalability of the selected channel combinations, enhancing the efficiency and practicality of the MCG system.

The sympathetic nervous system in heart failure with preserved ejection fraction.

The sympathetic nervous system (SNS) is a major mediator of cardiovascular physiology during exercise in healthy people. However, its role in heart failure with preserved ejection fraction (HFpEF), where exercise intolerance is a cardinal symptom, has remained relatively unexplored. The present review summarizes and critically explores the currently limited data on SNS changes in HFpEF patients with a particular emphasis on caveats of the data and the implications for its subsequent interpretation. While direct measurements of SNS activity in HFpEF patients is scarce, modest increases in resting levels of muscle sympathetic nerve activity are apparent, although this may be due to the co-morbidities associated with the syndrome rather than HFpEF per se. In addition, despite some evidence for dysfunctional sympathetic signaling in the heart, there is no clear evidence for elevated cardiac sympathetic nerve activity. The lack of a compelling prognostic benefit with use of β-blockers in HFpEF patients also suggests a lack of sympathetic hyperactivity to the heart. Similarly, while renal and splanchnic denervation studies have been performed in HFpEF patients, there is no concrete evidence that the sympathetic nerves innervating these organs exhibit heightened activity. Taken together, the totality of data suggests limited evidence for elevated sympathetic nerve activity in HFpEF and that any SNS perturbations that do occur are not universal to all HFpEF patients. Finally, how the SNS responds during exertion in HFpEF patients remains unknown and requires urgent investigation.

Remote ischemic periconditioning suppresses cardiac sympathetic activation in acute myocardial infarction: a randomized controlled trial.

Remote ischemic periconditioning (RIPC) has demonstrated cardioprotective effects and improved clinical outcomes as an adjunct to emergent percutaneous coronary intervention (PCI) in patients with ST-elevation myocardial infarction (STEMI). However, whether RIPC affects the cardiac sympathetic nerve activity in patients with STEMI remains unclear. This study investigated the effects of RIPC on cardiac sympathetic nerve activity in patients with STEMI. We prospectively assigned patients with STEMI who underwent emergent PCI to receive RIPC or no procedure (control group) upon arrival at the cardiac catheterization laboratory. The primary endpoint was cardiac sympathetic nerve activity assessed through the washout rate (WR) in cardiac 123I-metaiodobenzylguanidine (123I-MIBG) imaging. Patients in the RIPC (n = 62) and control (n = 60) groups had similar demographic and clinical characteristics at baseline. Multivariable linear regression models revealed that the culprit lesion of the left anterior descending artery and hemoglobin level were significantly and independently associated with WR at discharge. WRs of the groups differed insignificantly at discharge. However, the RIPC group (n = 49) showed significantly lower WR than the control group (n = 47) at 1year after discharge (p = 0.027). In the single-photon emission computed tomography analysis at 1year after discharge, the RIPC group demonstrated significantly higher late uptake (p = 0.021) and lower WR (p = 0.013) in the nonculprit lesion, with a non-significant decrease in WR for the culprit lesion. RIPC can suppress augmented cardiac sympathetic nerve activity in patients with STEMI, particularly in nonculprit lesions.

Neurophysiological approaches to exploring emotional responses to cosmetics: a systematic review of the literature

IntroductionThis systematic review explores the use of neurophysiological measurements to study emotional responses to cosmetic products. The aim is to evaluate existing literature on these measurements in cosmetics, identify the main findings, highlight methodological challenges, and propose new guidelines for future research.MethodA systematic search focusing on neurophysiological measures to determine emotions induced by different cosmetic products was carried out in accordance with PRISMA guidelines.ResultsA total of 33 articles identified with the EBSCO database met the inclusion criteria. In all, 10 different measurement tools were used in these articles to assess the emotional effects of cosmetic products.DiscussionThis review emphasizes the complexity of interactions between cosmetics and emotional responses. It underscores the importance of future research with a more holistic approach that couples several physiological measurements. Among them, electrophysiological brain activity shows potential for enhancing understanding of emotional responses related to cosmetic products. Frontal asymmetry, particularly in the alpha frequency band, was often use and frequently linked to positive emotional states, although conflicting evidence exists. Additionally, cardiac activity, specifically the LF/HF ratio, emerges as a promising marker for differentiating between different cosmetic products. However, methodological heterogeneity, present challenges for replicability, generalizability, and complicate data interpretation.

Estimating the economic impact of restricting reproductive healthcare access in Ohio.

This study analyzes the economic impacts of Ohio's Senate Bill 23, which would ban abortion care after fetal cardiac activity is detected. Leveraging previous research and publicly available datasets, a unique set of calculations were developed to determine abortion outcomes, individual costs, and public costs in three scenarios in which abortion care is banned in Ohio. Scenario 1 assumes that all abortion care is sought out-of-state. Scenario 2 assumes that all pregnancies result in a birth. Scenario 3 assumes that pregnancies either result in receiving out-of-state abortion care or result in a birth. The total additional economic impact of restricted abortion access in Ohio likely ranges between $98.8 million and $118.4 million, but could be up to $551.4 million per year. Regardless of the three scenarios analyzed, restrictions to accessing abortion care result in negative economic impacts for both individuals and the state. Several policy recommendations are proposed for consideration by policymakers and communities.

Cardiac electrical and functional activity following an outdoor cold-water swimming event

AimsParticipation in outdoor cold-water swimming (OCWS) events combines endurance exercise and cold exposure. Concerns have emerged about the potential risk of acute adverse cardiac events during OCWS, particularly during endurance events. We analysed the effect of prolonged OCWS on cardiac function in trained athletes. MethodsThe swimming event consisted of laps over a 1000-m course, for up to 6 h, in water at 15 °C. Twenty participants (11 males, 47.3 ± 8.6 years old) were included. Core temperature (Tcore) was monitored using an ingestible temperature sensor during and up to 1 h after the swim. Body composition, blood pressure, electrocardiogram (ECG), and transthoracic echocardiography were assessed 1 day before the event and within the first hour upon completion of the swim. ResultsMean body mass index was 27.1 ± 5.1 kg/m2 and fat mass was 25.2 ± 9.1 %. Mean duration of swimming was 214 ± 115 min. Minimum Tcore was 35.6 ± 1.3 °C. A significant lengthening of the QT interval corrected (QTc) for heart rate was observed post-exercise (437.7 ± 27.7 vs. 457.2 ± 35.9 ms, p = 0.012), with 5 participants exhibiting post-exercise QTc >500ms. OCWS did not alter the biventricular systolic function and left ventricular relaxation. No correlation was observed between ΔQTc and ΔTcore. ConclusionOCWS seemed to acutely delay post-exercise cardiac repolarization without alteration of cardiac function in a healthy trained population. Additional investigations would be warranted to explore the clinical implications of QT lengthening and its relationship with autonomic nervous system regulation during OCWS.

Cardiac arrhythmias in fish induced by natural and anthropogenic changes in environmental conditions.

A regular heartbeat is essential for maintaining the homeostasis of the vertebrate body. However, environmental pollutants, oxygen deficiency and extreme temperatures can impair heart function in fish. In this Review, we provide an integrative view of the molecular origins of cardiac arrhythmias and their functional consequences, from the level of ion channels to cardiac electrical activity in living fish. First, we describe the current knowledge of the cardiac excitation-contraction coupling of fish, as the electrical activity of the heart and intracellular Ca2+ regulation act as a platform for cardiac arrhythmias. Then, we compile findings on cardiac arrhythmias in fish. Although fish can experience several types of cardiac arrhythmia under stressful conditions, the most typical arrhythmia in fish - both under heat stress and in the presence of toxic substances - is atrioventricular block, which is the inability of the action potential to progress from the atrium to the ventricle. Early and delayed afterdepolarizations are less common in fish hearts than in the hearts of endotherms, perhaps owing to the excitation-contraction coupling properties of the fish heart. In fish hearts, Ca2+-induced Ca2+ release from the sarcoplasmic reticulum plays a smaller role than Ca2+ influx through the sarcolemma. Environmental changes and ion channel toxins can induce arrhythmias in fish and weaken their tolerance to environmental stresses. Although different from endotherm hearts in many respects, fish hearts can serve as a translational model for studying human cardiac arrhythmias, especially for human neonates.

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.

Exposure to nicotine and withdrawal in Wistar rats: an electrophysiological study.

Throughout the world, smoking is one of the principal causes of preventable death. Nicotine, the primary active component of tabacco, acts as a psychostimulant and modulates the electrical activity of a number of the areas of the brain involved in addiction. Abstinence from nicotine will also impact the functional state of the brain, which is reflected in symptoms of craving and susceptibility to relapse. In addition, given the increase in the sympathetic tone of the heart and pulse rate promoted by nicotine, its consumption can contribute to tachyarrhythmia. The present study investigated the electroencephalographic (EEG) and electrocardiographic (ECG) patterns of Wistar rats submitted to acute or chronic exposure to nicotine, followed by withdrawal for 24 or 48 hours, and the re-administration (or not) of nicotine, to simulate episodes of relapse. The EEG data revealed an increase in all types of brainwaves, with emphasis on high-frequency (alpha, beta, and gamma) brain oscillations following both acute and chronic exposure to nicotine (14 days), whereas in withdrawal, there was a predominancy of delta waves. When exposure to nicotine was reinstated after withdrawal, the observed EEG profile was similar to that found in chronic exposure. The electrocardiogram reads showed that both acute and chronic exposure to nicotine caused abnormalities in the atrioventricular conduction and that, while these changes improve with substance withdrawal, relapse can worsen these parameters. The results of this study indicate that high-frequency brainwaves are correlated with nicotine dependence, while slow brain oscillations are consistent with drug craving, and episodes of nicotine relapse can reproduce brain activity patterns linked to dependence. Finally, exposure to nicotine predisposes the individual to heart rhythm abnormalities, which are attenuated by withdrawal, but may nevertheless be restored rapidly with re-exposure to the substance. This study demonstrated that nicotine increases high-frequency brain oscillations, which is associated with addiction, whereas withdrawal elevates the delta wave power, suggesting craving. Re-exposure to nicotine following withdrawal restores rapidly the EEG profile of chronic dependence. In addition, nicotine has deleterious impacts on cardiac activity, which are linked to fatal arrhythmias. This implies that stopping smoking is beneficial for the amelioration of the alterations in heart rhythm caused by nicotine addiction. This study elucidates the functional states of the brain and heart during both sporadic and chronic nicotine use, and the electrophysiological explanation for substance dependence and drug relapse after craving episodes.

Effects of unconscious tactile stimuli on autonomic nervous activity and afferent signal processing

Autonomic nervous system (ANS) is a mechanism that regulates our internal environment. In recent years, the interest in how tactile stimuli presented directly to the body affect ANS function and cortical processing in humans has been renewed. However, it is not yet clear how subtle tactile stimuli below the level of consciousness affect human heart rate and cortical processing. To examine this, subthreshold electrical stimuli were presented to the left forearm of 43 participants during an image-viewing task, and electrocardiogram (ECG) and electroencephalogram (EEG) data were collected. The changes in the R-wave interval of the ECG immediately after the subthreshold electrical presentation and heartbeat-evoked potential (HEP), the afferent signal processing of cardiac activity, were measured. The results showed that heart rate decelerated immediately after the presentation of subthreshold electrical stimuli. The HEP during stimulus presentation was amplified for participants with greater heart rate acceleration immediately after this deceleration. The magnitude of these effects depended on the type of the subthreshold tactile stimuli. The results suggest that even with subthreshold stimulation, the changes in autonomic activity associated with orienting response and related afferent signal processing differ depending on the clarity of the tactile stimuli.

The mechanisms of effects of oil-derived polyaromatic hydrocarbons on cardiac electrical activity in navaga cod (Eleginus nawaga)

The intensive development of oil and gas industries in the Arctic threatens Arctic aquatic ecosystems. The toxic and primarily lethal cardiotoxic effects of oil in living organisms are believed to be associated with polyaromatic hydrocarbons (PAHs), and previous works revealed the electrophysiological mechanisms of action of individual oil-derived PAHs. However, the physiological effects of a complex PAHs mixture in oil water-soluble fraction (WSF) have not been previously studied. This study is focused on the effects of oil WSF on electrical activity and major ionic currents in the working myocardium of navaga (Eleginus nawaga), which is one of the most important commercial fish species in the Arctic. We found that 1% and 10% solutions of oil WSF cause a marked increase in the duration of action potentials (APs) in navaga cardiomyocytes. This effect appears to be due to the suppression of rapid delayed rectifying current IKr (IC50 about 3% in ventricular and atrial myocardium). At higher concentrations, oil WSF also suppressed calcium current ICaL (IC50 = 10.6%), which led to a decrease in the contractile activity in isolated myocardial preparations. Unlike individual tricyclic PAHs, oil WSF did not affect fast sodium current INa and AP upstroke velocity. An assessment of the content of tricyclic PAHs in 10% solution of oil WSF showed that their total concentration is relatively low and does not exceed 100 nM. Thus, oil WSF also has a powerful cardiotoxic effect in fish myocardium, but its effects differ from the previously studied effects of tricyclic PAHs and suggest the presence of yet unexplored oil compounds that have a more powerful toxic potential against ERG channels.

Do extra-pulmonary triggers or autonomic neural activity affect rhythm control by anti-arrhythmic drugs in patients with post-ablation atrial fibrillation recurrence?

The role of anti-arrhythmic drugs (AADs) in recurrent atrial fibrillation (AF) after catheter ablation (CA) is not fully understood. The aim of this study was to explore the effects of AADs in patients who recurred after AFCA depending on extra-pulmonary vein triggers (ExPVTs) and post-ablation heart rate variability (HRV) parameters. We analyzed 2,036 patients who underwent de-novo AFCA and 486 patients with post-AFCA recurrence who underwent rhythm control with AADs. We investigated the effects of ExPVTs and 3rd month HRV parameters on the post-AFCA recurrence and subsequent AAD responsiveness. A total of 486 out of 2,036 patients developed clinical recurrence of AF and subsequently underwent rhythm control with AADs. 486 out of 310 patients (63.8%) remained free of second recurrence at 1-year. Post-AFCA recurrence was significantly higher in patients with ExPVT [Log-rank p < 0.001, HR 1.45 (1.16-1.83), p = 0.001] or higher 3rd month root mean square of the differences between successive RR intervals (rMSSD) [Log-rank p < 0.001, HR 1.36 (1.11-1.65), p = 0.003] than their counterparts. Patients with ExPVTs during the de-novo procedure had significantly higher 3rd month rMSSD (15.0 [11.0-23.0] vs. 17.0 [11.0-28.0], p = 0.022). Patients with high 3rd month rMSSD had higher rate of ExPVTs during the repeat procedure (n = 160, 41.0% vs. 22.2%, p = 0.019). Among patients with recurrent AF after AFCA, post-AAD recurrence did not differ depending on the presence of ExPVT [Log-rank p = 0.455, HR 1.12 (0.78-1.69), p = 0.436] or 3rd month rMSSD [Log-rank p = 0.457, HR 1.16 (0.87-1.55), p = 0.300]. Post-AAD recurrence did not differ between class IC and III AADs (p for interaction = 0.311). ExPVT and post-procedural high rMSSD are independent risk factors for post-AFCA recurrence but not for AAD response in patients with recurrent AF. AADs may suppress ExPVTs and modulate cardiac autonomic activity after post-AFCA recurrence.