Heart Rate Activity Research Articles

ANALYZING THE RELATIONSHIP BETWEEN BRAIN AND HEART ACTIVITY ACROSS VARIOUS COLLABORATIVE TASKS

Understanding the correlation between the brain’s activity and the physiological responses of other organs under varying conditions is a crucial area of research that holds significant potential for advancing our knowledge of human physiology. In this study, we focused on investigating the interaction between the heart and brain by employing advanced complexity analysis techniques, specifically examining the fractal dimension and approximate entropy of electroencephalogram (EEG) and R-R interval time series. The analysis was conducted on data collected from 12 subjects who were observed under three distinct conditions: baseline (normal resting state) and two collaborative activities performed both with and without the presence of noise. Our findings revealed that the complexity patterns of EEG and R-R signals showed similar trends in alterations across all conditions, suggesting a strong coupling between the brain’s and heart’s responses. This observed coupling highlights the potential for a coordinated physiological interaction between these two critical systems. Furthermore, our approach, which successfully decoded the heart–brain correlation, offers a promising framework for extending this analysis to explore correlations between the brain and other organs, thereby contributing to a deeper understanding of the complex networks that underlie human health and adaptive physiological responses.

Application of Ear-EEG and Other Wearable Systems in Sleep Assessment

Nowadays, about one-third of adults have the symptoms of insomnia. To assess these issues, one of the traditional methods used is polysomnography (PSG). However, it is expensive and not widely accessible, highlighting the urgent need for advancements in wearable technology to provide a more practical alternative for continuous sleep monitoring at home. This paper aims to explore various sleep assessment methods, including electrocardiography (ECG), photoplethysmography (PPG), and actigraphy, which measure heart activity, pulse wave, and muscle movement, respectively. By evaluating these methods, the paper analyses their advantages and challenges, particularly focusing on their accuracy in sleep stage classification and comfort levels. At the same time, this study compares Ear-EEG systems with other methods to assess their effectiveness in sleep monitoring. The future development directions for Ear-EEG in sleep monitoring are also discussed, encompassing aspects such as age variability, design improvements, and integrating advanced algorithms. Future advancements in at-home sleep assessments are expected to treat sleep disorders more efficiently and conveniently through early detection of disorders and improved user-friendliness compared to PSG.

The effect of power-based control on the haemodynamics and valve function of the biventricular assist circulation system.

Biventricular assist devices (BiVAD) are capable of providing mechanical support to the left and right ventricles to improve blood supply in heart failure, thereby maintaining patients' lives and improving their quality of life. But there is evidence that the incidence of aortic valve incompetence and other valvular pathologies is related to BiVAD support. Such as constant speed (CS) control may cause the valve to close completely and lose its normal valve function. The valve function is related to the percentage of valve opening which is approximately 30% of the cardiac cycle. This study developed a power-based control model for BiVAD that could regulate motors' speed by altering the power to satisfy objectives of keeping valve function and restoring physiologic perfusion. The effects of the power-based controller on the hemodynamics and valve function were investigated by simulating BiVAD under constant power and variable power controls. Different heart failure and activity levels were also mimicked under variable power control to obtain the BiVAD's critical parameters and the assist ratios. The results show that the power-based control can help the BiVAD to assist a patient with heart failure, and the power settings should comprehensively consider objectives of valve function and physiologic perfusion.

Magnetic signature of thermoelectric cardiac dynamics

Developing methods to predict electromagnetic instabilities in cardiac dynamics is crucial. However, a comprehensive view of the heart's magnetic activity at a tissue scale is still needed. To address such a challenging problem, we present a theoretical framework to investigate thermoelectric cardiac dynamics from the magnetic field perspective. Our framework demonstrates that periodic stimulations of cardiac cell strands create an external magnetic field, revealing predictable features of nonlinear spatiotemporal cardiac dynamics. Magnetic restitution curves better discriminate instabilities and bifurcations through a thermo-electro-magnetic map analysis. This new approach lays the foundation for innovative, noninvasive diagnostic tools for cardiac arrhythmias. Published by the American Physical Society 2025

Risk factors associated with the failure of local methotrexate combined with minimally invasive surgery for late cesarean scar pregnancy

BackgroundThis study aimed to investigate the risk factors related to the failure of initial combined local methotrexate (MTX) treatment and minimally invasive surgery for late cesarean scar pregnancy (CSP).MethodsThis retrospective case-control study was conducted between January 2016 and December 2023, involving patients with late CSP (≥ 8 weeks) who received local MTX injection combined with either hysteroscopic or laparoscopic surgery. Cesarean scar pregnancy was classified as type I, II, or III based on the direction of growth of the gestational sac and the residual myometrial thickness as assessed by ultrasound. Binary logistic regression analysis was utilized to identify the risk factors associated with the failure of the initial combined treatment.ResultsOverall, 574 patients with late CSP were included in our study. Among them, 29 patients (5.1%) experienced treatment failure with the initial local MTX combined with minimally invasive surgery, while 545 patients (94.9%) achieved successful treatment outcomes. In the univariate analysis, several potential risk factors associated with the initial combined treatment failure were identified, including baseline serum β-human chorionic gonadotropin (β-hCG) levels, type of CSP, time interval between MTX and surgery, and positive fetal heart activity before surgery. Subsequent binary logistic regression analysis revealed the following independent risk factors linked to the failure of the initial combined treatment: baseline serum β-hCG levels exceeding 94,000 IU/L [odds ratio (OR) 3.060, 95% confidence interval (CI) 1.387–6.749, P = 0.006], type III CSP (OR 3.574, 95% CI 1.147–11.135, P = 0.028), a time interval greater than seven days between MTX and surgery (OR 3.847, 95% CI 1.725–8.581, P = 0.001), and the presence of a fetal heartbeat before surgery (OR 4.405, 95% CI 1.014–19.128, P = 0.048).ConclusionThe findings indicate that higher baseline serum β-hCG levels, an extended time interval between MTX and surgery, type III CSP and a positive preoperative fetal heartbeat are significant risk factors for the failure of initial local MTX combined with minimally invasive surgery in patients with late CSP. Individualized treatment strategies are recommended for these high-risk patients with late CSP.

Circadian rhythm of heart rate and activity: A cross-sectional study

ABSTRACT Circadian rhythms are governed by a biological clock, and are known to occur in a variety of physiological processes. We report results on the circadian rhythm of heart rate observed using a wrist-worn wearable device (Fitbit), consisting of over 17,000 individuals over the course of 30 days. We obtain an underlying heart rate circadian rhythm from the time series heart rate by modeling the circadian rhythm as a sum over the first two Fourier harmonics. The first Fourier harmonic accounts for the approximate 24-hour rhythmicity of the body clock, while the second harmonic accounts for non-sinusoidal perturbations. From the diurnal modulation of heart rate, we obtain the following circadian parameters: (i) amplitude of modulation, (ii) bathyphase, and (iii) acrophase. We also consider the circadian rhythm of activity and show that in most individuals, the circadian rhythm of heart rate lags the circadian rhythm of activity. The widespread availability of smartwatches and trackers may enable individuals who are interested in observing their circadian rhythms of numerous physiological parameters, and to measure longitudinal changes in circadian parameters in response to various changes in health-related variables such as diet, sleep, exercise, or illness.

The effectiveness of prolonged hypothermic preservation of isolated rat hearts using oxygen, medical nitrous oxide and carbon monoxide gas mixtures.

The possibility of using an oxygen-nitrous oxide mixture for prolonged hypothermic preservation of rat heart for 24h was investigated. A comparative analysis of restoration of functional activity of hearts in the groups of 24-h preservation at +4°C with different gases (O2, N2) and gas mixtures (CO+O2, N2O+O2, N2+O2, N2O+N2) was carried out. It was shown that the presence of oxygen in the gas mixture was the key factor for heart preservation. No stable heart preservation was observed in oxygen-free mixtures. At the same time, preservation in pure oxygen showed a significantly lower level of cardiac recovery compared to preservation in gas mixtures O2+CO (6.5 atm.) and O2+N2O (6.5 atm.). LVDP (left ventricular developed pressure) values were 30±19mmHg and 46±9mmHg, respectively, with no significant differences found. The decrease in LDVP after 24h of storage was 26-40% of the intact control. The results obtained indicate the presence of pronounced synergistic effects of both gases during 24-h heart preservation, which is confirmed by data of marker genes Nfe2l2, Nox1, Prdx1, Hif1a, Nos2, Slc2a4, Ucp-1, Jun, Casp3 expression analysis and myocardial infarction damage level data. The more frequent occurrence of arrhythmias was observed in the oxygen-nitrous oxide group compared with the CO group, and the mechanism of this phenomenon is unclear. Nevertheless, the already medically approved N2O+O2 gas mixture could serve as a balanced choice for future improvements, offering a shorter duration of cardiac preservation compared to the CO+O2 mixture, while ensuring safety in its use.

RESULTS OF A DOUBLE-BLIND RCT OF THE FUNCTIONAL EFFECT OF KETONE ESTERS IN OLDER ADULTS

Abstract Background Ketone bodies are metabolites produced during fasting or on a ketogenic diet that have pleiotropic effects on the inflammatory and metabolic aging pathways underpinning frailty in in vivo models. Ketone esters (KEs) are compounds that induce hyperketonemia without dietary changes and may impact physical and cognitive function in young adults. The functional effects of KEs have not been studied in older adults. Objectives Our long-term goal is to examine if KEs modulate aging biology mechanisms and clinical outcomes relevant to frailty in older adults. Here, we report the exploratory functional and quality-of-life outcome measures collected during a 12-week safety and tolerability study of KE (NCT05585762). Design: Randomized, placebo-controlled, double-blinded, parallel-group, pilot trial of 12-weeks of daily KE ingestion. Setting: The Buck Institute for Research on Aging, California. Participants: Community-dwelling older adults (≥ 65 years), independent in activities of daily living, with no unstable medical conditions (n = 30). Intervention: Subjects were randomly allocated (1:1) to consume 25 g daily of either KE (bis-octanoyl (R)-1,3-butanediol) or a taste, appearance, and calorie-matched canola oil placebo (PLA). Measurements: Longitudinal change in physical function, cognitive function and quality of life were analyzed as exploratory outcomes in completers (n = 11 PLA, n = 12 KE). A composite vigor-frailty functional outcome was calculated. Heart rate and activity were followed using digital wearables. Results There were no statistically significant longitudinal differences between groups in exploratory functional, activity-based or quality of life outcomes in this pilot study.

High volume-rate echocardiography for simultaneous imaging of electromechanical activation and cardiac strain of the whole heart in a single heartbeat in humans.

Imaging both electrical and mechanical cardiac function can better characterize cardiac disease and improve patient care. Currently, there is no noninvasive technique that can simultaneously image both electrical and mechanical function of the whole heart at the point of care. Here, our aim is to demonstrate that high volume-rate echocardiography can simultaneously map cardiac electromechanical activation and end-systolic cardiac strain of the whole heart in a single heartbeat. A 32x32 ultrasound matrix array connected to four synchronized ultrasound scanners were used for transthoracic high volume-rate imaging (840 volumes/s) in sixteen young volunteers (28.1±4.2 y.o.). An electromechanical activation map of the whole heart and volumetric end-systolic atrial and ventricular strain images were obtained. The whole heart activation sequence was found to be consistent across volunteers and in agreement with previously reported normal electrical activation sequences. The mean electromechanical activation time was 72.6±15.2 ms in the atria, 132.4±19.7 ms in the ventricles and 154.5±19.6 ms in the whole heart. Volumetric right and left atrial as well as right and left ventricular strains were also consistent across all volunteers, with a mean end-systolic global longitudinal strain of 26.8±6.5% in the atria and -16.6±3.4% in the ventricles. This initial feasibility study demonstrates that noninvasive high-volume rate imaging of the heart in a single heartbeat is feasible and can provide electromechanical activation and systolic strains simultaneously in all four cardiac chambers. This technique can be further developed and used at the point of care to assist for screening, diagnosis, therapy guidance and follow-up of heart disease patients.

Actions Taken by Bystanders During Sudden Cardiac Arrest: Analysis of Emergency Medical Service Documentation in Poland.

Background/Objectives: Sudden cardiac arrest (SCA) is a severe medical condition involving the cessation of the heart's mechanical activity. Following the chain of survival, which includes early recognition and calling for help, early initiation of cardiopulmonary resuscitation (CPR), early defibrillation, and post-resuscitation care, offers the greatest chances of saving a person who has experienced SCA. The aim of this study was to analyze cases of out-of-hospital cardiac arrest (OHCA) and assess the actions taken by bystanders. Methods: The input for analysis consisted of 49,649 dispatch records from the emergency medical team (EMT) at the Voivodeship Emergency Medical Station in Bialystok in 2018-2019. Results: Among the patients where bystanders performed CPR, the return of spontaneous circulation (ROSC) occurred in 30.53% of cases, whereas in the cases where the bystander did not perform CPR, ROSC occurred in 2.35% of cases. When cardiac arrest rhythm was ventricular fibrillation (VF) or pulseless ventricular tachycardia (pVT), ROSC occurred in 58.62% of cases, while there was asystole or pulseless electrical activity (PEA) present, ROSC occurred in 26.56% of cases. In patients who experienced OHCA in a VF/pVT rhythm and who underwent intubation, ROSC occurred in 58.73% of cases, whereas in patients who underwent alternative procedures for airway management, ROSC occurred in 83.33% of cases. Conclusions: The most significant factor influencing the occurrence of ROSC in patients is CPR initiation by bystanders. The presence of a rhythm that requires defibrillation increases the likelihood of achieving ROSC in the patient. Alternative methods for airway management appear to be more beneficial in VF/pVT rhythms.

Cited4a limits cardiomyocyte dedifferentiation and proliferation during zebrafish heart regeneration.

Cardiac regeneration involves the interplay of complex interactions between many different cell types, including cardiomyocytes. The exact mechanism that enables cardiomyocytes to undergo dedifferentiation and proliferation to replace lost cells has been intensely studied. Here we report a single nuclear RNA sequencing profile of the injured zebrafish heart and identify distinct cardiomyocyte populations in the injured heart. These cardiomyocyte populations have diverse functions, including stress response, myofibril assembly, proliferation and contraction. The contracting cardiomyocyte population also involves the activation of maturation pathways as an early response to injury. This intriguing finding suggests that constant maintenance of a distinctive terminally differentiated cardiomyocyte population is important for cardiac function during regeneration. To test this hypothesis, we determined that cited4a, a p300/CBP transcriptional coactivator, is induced after injury in the mature cardiomyocyte population. Moreover, loss-of- cited4a mutants presented increased dedifferentiation, proliferation and accelerated heart regeneration. Thus, suppressing cardiomyocyte maturation pathway activity in injured hearts could be an approach to promote heart regeneration.

Cerebral Death: Unraveling the Mystery of the Silent Mind

The permanent loss of all brain stem functions, such as breathing, awareness, and cranial nerve reflexes, is known as brain stem death (BSD), and it presents a significant medical and ethical issue. While other bodily functions, such as heart activity and circulation, can be maintained with medical intervention, BSD is defined by the cessation of brain stem activity. The key characteristic that distinguishes BSD from other conditions, such as coma or a persistent vegetative state, is the complete and irreversible loss of brain stem function—a critical control centre for basic physiological processes. Diagnosing BSD requires strict clinical criteria and diagnostic testing to confirm the full and permanent nature of the condition. This typically involves a comprehensive neurological examination, assessment of cranial nerve reflexes, and confirmation through additional tests, such as cerebral blood flow studies or electroencephalography (EEG). A diagnosis of BSD carries significant ethical and legal implications, particularly in relation to organ donation, as it often plays a role in identifying potential donors. The ethical considerations surrounding BSD include its impact on families, the distinction between death and end-of-life care, and the challenges posed by varying legal and cultural perspectives. It highlights the importance of a clear diagnosis, obtaining informed consent, and adhering to established medical protocols to uphold human dignity and ethical standards. As medical technology advances and societal views evolve, the discussion around brain stem death continues to be a critical issue in both bioethics and modern medical practice.

Obstructive sleep apnea detection based on electrocardiogram signal using one-dimensional convolutional neural network

Obstructive sleep apnea (OSA) is a respiratory obstruction that occurs during sleep and is often known as snoring. OSA is often ignored even though it can cause cardiovascular problems. Early diagnosis is needed for prevention towards worse complications. OSA clinical diagnosis can use polysomnography (PSG) while the patient is sleeping. The PSG examination includes calculating total apnea plus hypopnea every hour during sleep. However, PSG examination tends to be high cost, takes a long time, and is impractical. Since OSA is related to breathing and heart activity, the electrocardiogram (ECG) examination is an alternative tool in OSA analysis. Therefore, this study proposes OSA detection on single lead ECG using one dimensional (1D)-convolutional neural network (CNN). The proposed CNN architecture consists of 4 convolutional layers, 4 pooling layers, 1 dropout layer, 1 flatten layers, 2 dropout layers, 1 dense layer with rectified linear unit (ReLU) activation function, and 1 dense layer with SoftMax activation function. The proposed method was then tested on the ECG sleep apnea dataset from PhysioNet. The proposed model produces an accuracy of 92.69% with the average pooling scenario. The proposed method is expected to help clinicians in diagnosing OSA based on ECG signals.

The Effects of Osteopathic Manipulative Treatment on Arrhythmias: A Double-blind Randomized Controlled Trial in Patients with Cardiac Implantable Electronic Devices.

This double-blind randomized controlled trial investigated the effects of osteopathic manipulative treatment (OMT) on cardiac arrhythmias in patients with cardiac implantable electronic devices (CIEDs). Participants (n = 41) with CIEDs were randomly assigned to either the OMT group or the control group (light touch/sham) and received a one-time intervention. No significant change in arrhythmia burden was found in the 1 month following intervention (P = .14). Discrete heart rate (HR), HR variability (HRV), and activity data were obtained from CIEDs in 17 of 41 subjects 1, 3, 7, 14, and 30 days prior to and after intervention. No significant difference was observed. An additional short-term substudy was performed on 20 subjects at the time of the intervention (5 min prior to and after intervention), and HR, respiratory rate, blood pressure, blood oxygen saturation (SpO2), and 1-min short-term HRV were compared. This study did not demonstrate an effect of OMT on arrhythmias, HR, respiratory rate, blood pressure, and blood SpO2. However, differences in OMT versus sham were observed for short-term HRV (P = .022) and a trend for long-term HRV. Importantly, there were no reported adverse effects with either intervention. OMT appears to be safe in cardiac patients.

Improved Remote Photoplethysmography Using Machine Learning-Based Filter Bank

Remote photoplethysmography (rPPG) is a non-contact technology that monitors heart activity by detecting subtle color changes within the facial blood vessels. It provides an unconstrained and unconscious approach that can be widely applied to health monitoring systems. In recent years, research has been actively conducted to improve rPPG signals and to extract significant information from facial videos. However, rPPG can be vulnerable to degradation due to changes in the illumination and motion of a subject, and overcoming these challenges remains difficult. In this study, we propose a machine learning-based filter bank (MLFB) noise reduction algorithm to improve the quality of rPPG signals. The MLFB algorithm determines the optimal spectral band for extracting information on cardiovascular activity and reconstructing an rPPG signal using a support vector machine. The proposed approach was validated with an open dataset, achieving a 35.5% (i.e., resulting in a mean absolute error of 2.5 beats per minute) higher accuracy than those of conventional methods. The proposed algorithm can be integrated into various rPPG algorithms for the pre-processing of RGB signals. Moreover, its computational efficiency is expected to enable straightforward implementation in system development, making it broadly applicable across the healthcare field.

Advancements in wearable heart sounds devices for the monitoring of cardiovascular diseases

AbstractCardiovascular diseases remain a leading global cause of mortality, underscoring the urgent need for intelligent diagnostic tools to enhance early detection, prediction, diagnosis, prevention, treatment, and recovery. This demand has spurred the advancement of wearable and flexible technologies, revolutionizing continuous, noninvasive, and remote heart sound (HS) monitoring—a vital avenue for assessing heart activity. The conventional stethoscope, used to listen to HSs, has limitations in terms of its physical structure, as it is inflexible and bulky, which restricts its prospective applications. Recently, mechanoacoustic sensors have made remarkable advancements, evolving from primitive forms to soft, flexible, and wearable designs. This article provides an in‐depth review of the latest scientific and technological advancements by addressing various topics, including different types of sensors, sensing materials, design principles, denoising techniques, and clinical applications of flexible and wearable HS sensors. This transformative potential lies in the capacity for ongoing, remote, and personalized monitoring, promising enhanced patient outcomes, amplified remote monitoring capabilities, and timely diagnoses. Last, the article highlights current challenges and prospects for the future, suggesting techniques to advance HS sensing technologies for exciting real‐time applications.

A Review on Assisted Living Using Wearable Devices.

Forecasts about the aging trend of the world population agree on identifying increased life expectancy as a serious risk factor for the financial sustainability of social healthcare systems if not properly supported by innovative care management policies. Such policies should include the integration within traditional healthcare services of assistive technologies as tools for prolonging healthy and independent living at home, but also for introducing innovations in clinical practice such as long-term and remote health monitoring. For their part, solutions for active and assisted living have now reached a high degree of technological maturity, thanks to the considerable amount of research work carried out in recent years to develop highly reliable and energy-efficient wearable sensors capable of enabling the development of systems to monitor activity and physiological parameters over time, and in a minimally invasive manner. This work reviews the role of wearable sensors in the design and development of assisted living solutions, focusing on human activity recognition by joint use of onboard electromyography sensors and inertial measurement units and on the acquisition of parameters related to overall physical and psychological conditions, such as heart activity and skin conductance.

Overcoming Lung Challenges in TA-NRP Assisted Heart Recovery in Donation After the Circulatory Determination of Death.

Thoraco-abdominal normothermic regional perfusion (TA-NRP), utilizing Extra Corporeal Membrane Oxygenation (ECMO) devices, has emerged as an effective strategy for heart recovery in donors declared dead by circulatory criteria (DCDD). After death declaration, TA-NRP restores heart activity by reperfusing the arrested heart with oxygenated blood at normothermia. Mechanical ventilation resumption in the donor enables weaning from ECMO and restores systemic circulation and oxygenation using the donor's heart and lungs. However, if pre-existing conditions prevent the donor's lungs from oxygenating blood post-cardiac activity restoration, weaning from veno-arterial ECMO may lead to systemic hypoxia, jeopardizing the restored cardiac function. Anticipating this scenario may guide planning a split ECMO circuit to facilitate earlier and more effective recovery of donor heart function post-ECMO weaning. This manuscript describes three cases of DCDD donors with hypoxic respiratory failure undergoing TA-NRP for heart recovery. By establishing a bridge in the arterial portion of the circuit, clamped out after weaning from veno-arterial ECMO, donor heart function was assessed exclusively with veno-venous ECMO support, leading to successful heart transplantation.

Trimetazidine restores autophagy via lncRNA H19/AMPK in diabetic heart: Implications for its therapeutic value against diabetic cardiomyopathy.

Previous studies have shown that trimetazidine (TMZ) alleviates diabetes-induced cardiac dysfunction. However, the underlying mechanism for its protective effects on cardiac function remains incompletely understood. Diminished autophagy was found in diabetic hearts, and restoration of autophagy generates cardioprotective effect. This study aims to investigate whether and how TMZ produces protective effect through increasing autophagic activity in the diabetic heart. A high-fat diet and low-dose streptozotocin were applied to induce type 2 diabetes mellitus (T2DM) in male C57BL/6 mice, followed by treatment with TMZ for 14 weeks before cardiac function was evaluated. To mimic the diabetic condition, the neonatal rat cardiomyocytes (NRCMs) were exposed to high glucose/palmitic acid (HP) in the presence or absence of TMZ. We found that TMZ treatment promotes autophagic flux in cardiomyocytes, which is impaired in diabetes. We further found that the AMPK and lncRNA H19 played critical roles in mediating TMZ-induced enhancement of autophagy in cardiomyocyte. We showed that TMZ treatment restored the level of H19 and phosphorylated AMPK (p-AMPK T172) in diabetic heart and NRCMs exposed to HP. Of note, the effect of TMZ on autophagy and p-AMPK was abolished by knockdown of H19. These findings indicated that TMZ is able to recover the cardiac autophagic activity which is impaired by T2DM, and the underlying mechanism accounted for this ability is mostly likely attributed to the restored expression of H19 and AMPK activity.

The Effects of Phenanthrene on Electrical Activity in Ventricular Cardiomyocytes of Atlantic Cod (<i>Gadus morhua</i>)

The production of oil on the Arctic shelf and its transport along the Northern Sea Route increase risks of pollution of the ecosystems in the Arctic seas with oil and oil products. Today, polyaromatic hydrocarbons are known as the most toxic oil components, and phenanthrene is predominant in terms of its concentration in oil and physiological effects. Phenanthrene affects the electrical activity of fish heart, but its effects are species-specific. At the same time, the effects of phenanthrene on cardiac function in Arctic fishes, including economically important commercial species, are studied not enough. This study examines the effects of phenanthrene on electrical activity and ionic currents in ventricular myocardium of Atlantic cod (Gadus morhua). The major ionic currents in cod myocardium were IKr, IK1, INa and ICa. Phenanthrene (1 μM) did not affect the duration of action potentials (APs) recorded in isolated cod ventricular cardiomyocytes using patch clamp method. Meanwhile, phenanthrene suppressed rapid delayed rectifier current IKr by 61.33 ± 3.94%, decreasing the repolarization reserve of the myocardium. Phenanthrene did not affect nor the level of resting membrane potential, not background inward rectifier current IK1. Also, application of phenanthrene decreased AP upstroke velocity in cod myocytes, which was due to the suppression of fast sodium current INa. Finally, phenanthrene slightly reduced the amplitude of calcium current ICa and accelerated its inactivation, which overall led to the decrease in ICa charge transfer. Thus, the effects of phenanthrene on cod myocardium at cellular level can be described as potentially proarrhythmic, which makes the populations of cod in Arctic seas vulnerable to pollution of the aquatic environment by oil components after oil spills due to technological disasters.