Changes in Heart Rate Variability Parameters Following Radiofrequency Ablation in Patients with Atrial Fibrillation: A Systematic Review and Meta-Analysis.

PURPOSE: Radiofrequency (RF) ablation is a prevalent treatment for atrial fibrillation (AF), targeting triggers within the pulmonary vein (PV) for elimination. This study evaluated heart rate variability (HRV) parameter changes at three intervals post-RF ablation: short-term (immediately to 1 month), medium-term (1 to 6 months), and long-term (6 months to 1 year). We compared two ablation techniques: circumferential PV isolation (CPVI) and segmental PV isolation (SPVI). METHODS: A thorough search of databases, including PubMed, Embase, Scopus, Web of Science, and Cochrane, in 2022 yielded 835 pertinent studies. After inclusion criteria were applied, 22 studies were analyzed. RESULTS: Results showed a marked decline in HRV parameters post-AF ablation, with LF/HF as an exception. These reductions persisted in short- and long-term evaluations up to a year post-procedure. Subgroup analysis revealed significant HRV declines, with distinct LF/HF values post-SPVI. CONCLUSION: This meta-analysis suggests the potential of decreased HRV as an indicator of autonomic denervation, necessitating further exploration to optimize therapeutic strategies and enhance patient outcomes.

The investigation of Pulse-Modulated GSM-900 MHz electromagnetic field effects on the electrochemotherapy mechanisms in vivo.

Electrochemotherapy (ECT) as a tumor treatment modality is approved for cutaneous and subcutaneous tumors. The purpose of the present study was to examine the effect of 900 MHz radiofrequency (RF) pulse-modulated by 217 Hz EMFs similar to those emitted by mobile phones on the mechanisms of ECT in vivo including: tumor hypoxia and immune system response, and on tumor volume.4 T1 cells were injected subcutaneously into the right flank of Balb/c mice. The mice were exposed to RF fields at specific absorption rate (SAR) 2 W/kg for 10 min/day and then treated with ECT. Two protocols of ECT were used: ((70 V/cm-5 kHz) and 70 V/cm-4 kHz)). Tumor hypoxia was analyzed through HIF-1α immuonohistochemistry assay. Interleukin 4 (IL-4) and IFN-γ levels were estimated by enzyme-linked immunosorbent assay (ELISA) technique to evaluate immune system response. Also, tumors volume changes were measured for 24 days following the treatment. The results showed that pulse-modulated RF fields could increase hypoxia induced by ECT, significantly (about 13% in ECT (70 V/cm-5 kHz) and 11% in ECT (70 V/cm-4 kHz)). However, these fields did not have significant effect on immune system response (the levels of IL-4 and IFN-γ) and tumor volume changes induced by ECT. Our results indicated that pulse-modulated RF fields could not affect tumor volume changes in ECT with the frequency of 5 kHz and voltage of 70 V/cm efficacy in vivo. However, investigating the role of other environmental intervening factors on this protocol of ECT is recommended in further studies.

The effect of 900 MHz electromagnetic fields on biological pathways induced by electrochemotherapy.

Electrochemotherapy (ECT) is a new and promising treatment strategy for cancer treatment. The aim of this work is to investigate the effect of 900 MHz radiofrequency electromagnetic fields (RF-EMFs) on the mechanisms of ECT (low voltage, high frequency) including cell permeability in vitro, and tumor hypoxia, immune system response in vivo, and on volume of tumors treated with ECT (70 V/cm, 5 kHz). The 4T1 cells were exposed to RF-EMFs at 17, 162, or 349 µW/cm2 power densities, using GSM900 simulator, 10 min. The cells were then put in individual groups, comprising of no treatment, chemotherapy, electric pulses (EPs), or ECT. The cell viability was evaluated. The mice with 4T1 tumor cells were exposed to RF field 10 min/day until the tumor volume reached about 8 mm. Then, the mice tumors were treated with ECT. Tumor hypoxia and immune system response was analyzed through immunohistochemistry (IHC) assay and ELISA technique, respectively. The volume of tumors was also calculated for 24 days following the treatment. The results showed that RF fields at 349 µW/cm2 could increase tumor hypoxia induced by ECT and cause a significant increase of Interferon-gamma (IFN-γ) in comparison with group ECT alone. However, 900 MHz radiations did not affect the volume of tumors treated to ECT (70 V/cm, 5 kHz) significantly. In this study, 900 MHz EMF could improve some biological pathways induced by ECT. Such a positive effect could utilize in some other treatments to increase efficacy, which should be investigated in further research.

The role of 217-Hz ELF magnetic fields emitted from GSM mobile phones on electrochemotherapy mechanisms.

Electrochemotherapy (ECT), the combination of electric pulses (EPs) and an anticancer drug, is a type of cancer treatment method. We investigated the effect of 217-Hz magnetic fields (MFs) similar to that generated by GSM900 mobile phones, as intervening factors, on proposed mechanisms of ECT including permeability, tumor hypoxia and immune system response. The 4T1 cells were exposed to extremely low-frequency (ELF)-MFs at 93, 120 or 159 µT intensities, generated by Helmholtz coils 10 min, and then put in individual groups, comprising no treatment, chemotherapy, EPs or ECT. The cell viability was evaluated. Then, two treatment protocols were selected for in vivo experiments. The mice with 4T1 tumor cells were exposed to ELF-MFs 10 min/day until the day their tumors reached 8 mm in diameter. Then, the tumors were treated to ECT. Tumor hypoxia and immune system response were analyzed through immunohistochemistry assay and enzyme-linked immunosorbent assay technique, respectively. The results in vitro indicated a significant decreased ECT efficacy of 60 V/cm, 5 kHz at the flux density of 93 µT. The results in vivo showed that pre-exposure to ELF-MFs could increase tumor hypoxia induced by ECT. In addition, exposure to ELF-MFs before ECT caused a significant increase in interferon-γ/interleukin-4 in comparison with ECT alone. More studies, including studies on the effect of ELF-MFs emitted from mobile phones on tumor volume changes induced by ECT, are needed to elucidate how the process of ECT is influenced by the MFs.

The effects of pulsed magnetic field exposure on the permeability of leukemia cancer cells.

PURPOSE: The newer methods of cancer treatment require new idea of drug delivery in cancer cells. Due to numerous researches electromagnetic field affect on cell function and cell membrane for possible therapeutic and drug delivery. In this article, we determined in vitro uptake of fluorescent dyes into the attached K562 cells due to time-varying magnetic field exposure. METHOD AND MATERIAL: The K562 cells were exposed to magnetic pulses via Magstim stimulator and double 70 mm coil. The strength and duration of pulses in all experiments were the same and three different frequencies of 0.25, 1 and 10 Hz pulses for 56, 112 and 28 numbers of pulses were applied (nine experimental groups) and uptake of Ly and PI was measured in each group. RESULT: Our results show that magnetic field can efficiently increase permeability. Among the treatment groups, the system gives the optimal permeabilization when cells are exposed to a train of 28 pulses with 1 Hz frequency.

Effects of man-made electromagnetic fields on heart rate variability parameters of general public: a systematic review and meta-analysis of experimental studies.

OBJECTIVES: The effects of man-made electromagnetic fields (EMFs) on the cardiovascular system have been investigated in many studies. In this regard, the cardiac autonomic nervous system (ANS) activity due to EMFs exposure, assessed by heart rate variability (HRV), was targeted in some studies. The studies investigating the relationship between EMFs and HRV have yielded conflicting results. We performed a systematic review and meta-analysis to assess the data's consistency and identify the association between EMFs and HRV measures. CONTENT: Published literature from four electronic databases, including Web of Science, PubMed, Scopus, Embase, and Cochrane, were retrieved and screened. Initially, 1601 articles were retrieved. After the screening, 15 original studies were eligible to be included in the meta-analysis. The studies evaluated the association between EMFs and SDNN (standard deviation of NN intervals), SDANN (Standard deviation of the average NN intervals for each 5 min segment of a 24 h HRV recording), and PNN50 (percentage of successive RR intervals that differ by more than 50 ms). SUMMARY: There was a decrease in SDNN (ES=-0.227 [-0.389, -0.065], p=0.006), SDANN (ES=-0.526 [-1.001, -0.05], p=0.03) and PNN50 (ES=-0.287 [-0.549, -0.024]). However, there was no significant difference in LF (ES=0.061 (-0.267, 0.39), p=0.714) and HF (ES=-0.134 (0.581, 0.312), p=0.556). In addition, a significant difference was not observed in LF/HF (ES=0.079 (-0.191, 0.348), p=0.566). OUTLOOK: Our meta-analysis suggests that exposure to the environmental artificial EMFs could significantly correlate with SDNN, SDANN, and PNN50 indices. Therefore, lifestyle modification is essential in using the devices that emit EMs, such as cell phones, to decrease some signs and symptoms due to EMFs' effect on HRV.

Investigating the Relationship between Electroconvulsive Therapy and Heart Rate Variability: A Systematic Review.

Physical therapies such as electroconvulsive therapy (ECT) may result in higher response and recovery rates, especially in patients who have treatment-resistant depression. Various studies have reported different changes in heart rate variability (HRV) parameters before and after depression treatment with ECT. Therefore, the present study reviews systematically the evidence describing changes in HRV parameters and the cardiac autonomic nervous system associated with ECT. Scopus, Web of Science, PubMed, and Embase electronic databases were searched for papers published up to September 8, 2022, without any restriction on the year and language of the study. A total of 895 articles were reviewed by two independent groups and nine articles that met the inclusion criteria were selected. Time-domain and frequency-domain HRV parameters were assessed. In conclusion, the results of our systematic review provided limited evidence for the influence of ECT on HRV parameters. Despite studies suggesting depression results in a decrease in parasympathetic activity and ECT results in an increase in cardiac vagal activity, ECT seems to have no consistent effect on HRV parameters.

Evaluation of Pulsed Electromagnetic Field Effects: A Systematic Review and Meta-Analysis on Highlights of Two Decades of Research In Vitro Studies.

Pulsed electromagnetic field (PEMF) therapy is a type of physical stimulation that affects biological systems by producing interfering or coherent fields. Given that cell types are significantly distinct, which represents an important factor in stimulation, and that PEMFs can have different effects in terms of frequency and intensity, time of exposure, and waveform. This study is aimed at investigating if distinct positive and negative responses would correspond to specific characteristics of cells, frequency and flux density, time of exposure, and waveform. Necessary data were abstracted from the experimental observations of cell-based in vitro models. The observations were obtained from 92 publications between the years 1999 and 2019, which are available on PubMed and Web of Science databases. From each of the included studies, type of cells, pulse frequency of exposure, exposure flux density, and assayed cell responses were extracted. According to the obtained data, most of the experiments were carried out on human cells, and out of 2421 human cell experiments, cell changes were observed only in 51.05% of the data. In addition, the results pointed out the potential effects of PEMFs on some human cell types such as MG-63 human osteosarcoma cells (p value < 0.001) and bone marrow mesenchymal stem cells. However, human osteogenic sarcoma SaOS-2 (p < 0.001) and human adipose-derived mesenchymal stem cells (AD-MSCs) showed less sensitivity to PEMFs. Nevertheless, the evidence suggests that frequencies higher than 100 Hz, flux densities between 1 and 10 mT, and chronic exposure more than 10 days would be more effective in establishing a cellular response. This study successfully reported useful information about the role of cell type and signal characteristic parameters, which were of high importance for targeted therapies using PEMFs. Our findings would provide a deeper understanding about the effect of PEMFs in vitro, which could be useful as a reference for many in vivo experiments or preclinical trials.

A Comprehensive Review of Computer-Aided Diagnosis of Major Mental and Neurological Disorders and Suicide: A Biostatistical Perspective on Data Mining.

The World Health Organization (WHO) suggests that mental disorders, neurological disorders, and suicide are growing causes of morbidity. Depressive disorders, schizophrenia, bipolar disorder, Alzheimer's disease, and other dementias account for 1.84%, 0.60%, 0.33%, and 1.00% of total Disability Adjusted Life Years (DALYs). Furthermore, suicide, the 15th leading cause of death worldwide, could be linked to mental disorders. More than 68 computer-aided diagnosis (CAD) methods published in peer-reviewed journals from 2016 to 2021 were analyzed, among which 75% were published in the year 2018 or later. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol was adopted to select the relevant studies. In addition to the gold standard, the sample size, neuroimaging techniques or biomarkers, validation frameworks, the classifiers, and the performance indices were analyzed. We further discussed how various performance indices are essential based on the biostatistical and data mining perspective. Moreover, critical information related to the Transparent reporting of a multivariable prediction model for individual prognosis or diagnosis (TRIPOD) guidelines was analyzed. We discussed how balancing the dataset and not using external validation could hinder the generalization of the CAD methods. We provided the list of the critical issues to consider in such studies.

The effect of extremely low-frequency magnetic field (50-60 Hz) exposure on spontaneous apoptosis: The results of a meta-analysis.

BACKGROUND: This paper is a meta-analysis of the published data from in vitro studies to evaluate whether spontaneous apoptosis might be influenced by extremely low frequency (ELF) magnetic fields (MFs). MATERIALS AND METHODS: A comprehensive scientific literature search in electronic databases was conducted and studies covering the period 2000-2010 were selected. Then, published studies involving the desired topic were retrieved. The inclusion criteria were percentage of apoptosis in the cells exposed to 50-60 Hz ELF-MFs. The statistical analysis was performed by comprehensive meta-analysis version 2. RESULTS: The summary measure of association (95% confidence interval) for all 18 effect estimated from 8 studies was 1.18 (1.15, 1.20). Heterogeneity among studies was found. There was no evidence of publication bias for the association between exposure to MF and apoptosis risk. CONCLUSION: Our meta-analysis provided conclusive data that ELF-MFs can increase apoptosis in cancer and normal cells. Furthermore, there is a possibly individual intensity and time range with maximum created effect according to window effect.