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Burn patients often face elevated pain, anxiety, and depression levels. Music therapy adds to integrative care in burn patients, but research including electrophysiological measures is limited. This study reports electrophysiological signals analysis during Music-Assisted Relaxation (MAR) with burn patients in the Intensive Care Unit (ICU). This study is a sub-analysis of an ongoing trial of music therapy with burn patients in the ICU. Electroencephalogram (EEG), electrocardiogram (ECG), and electromyogram (EMG) were recorded during MAR with nine burn patients. Additionally, background pain levels (VAS) and anxiety and depression levels (HADS) were assessed. EEG oscillation power showed statistically significant changes in the delta (p < 0.05), theta (p = 0.01), beta (p < 0.05), and alpha (p = 0.05) bands during music therapy. Heart rate variability tachograms high-frequencies increased (p = 0.014), and low-frequencies decreased (p = 0.046). Facial EMG mean frequency decreased (p = 0.01). VAS and HADS scores decreased - 0.76 (p = 0.4) and - 3.375 points (p = 0.37) respectively. Our results indicate parasympathetic system activity, attention shifts, reduced muscle tone, and a relaxed state of mind during MAR. This hints at potential mechanisms of music therapy but needs to be confirmed in larger studies. Electrophysiological changes during music therapy highlight its clinical relevance as a complementary treatment for ICU burn patients.Trial registration: Clinicaltrials.gov (NCT04571255). Registered September 24th, 2020. https//classic.clinicaltrials.gov/ct2/show/NCT04571255.
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Queimaduras , Eletroencefalografia , Eletromiografia , Unidades de Terapia Intensiva , Musicoterapia , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Ansiedade/terapia , Queimaduras/terapia , Queimaduras/fisiopatologia , Eletrocardiografia , Frequência Cardíaca/fisiologia , Musicoterapia/métodos , Terapia de Relaxamento/métodosRESUMO
Protecting sensitive patient data, such as electrocardiogram (ECG) signals, during RF wireless transmission is essential due to the increasing demand for secure telemedicine communications. This paper presents an innovative chaotic-based encryption system designed to enhance the security and integrity of telemedicine data transmission. The proposed system utilizes a multi-scroll chaotic system for ECG signal encryption based on master-slave synchronization. The ECG signal is encrypted by a master system and securely transmitted to a remote location, where it is decrypted by a slave system using an extended state observer. Synchronization between the master and slave is achieved through the Lyapunov criteria, which ensures system stability. The system also supports Orthogonal Frequency Division Multiplexing (OFDM) and adaptive n-quadrature amplitude modulation (n-QAM) schemes to optimize signal discretization. Experimental validations with a custom transceiver scheme confirmed the system's effectiveness in preventing channel overlap during 2.5 GHz transmissions. Additionally, a commercial RF Power Amplifier (RF-PA) for LTE applications and a development board were integrated to monitor transmission quality. The proposed encryption system ensures robust and efficient RF transmission of ECG data, addressing critical challenges in the wireless communication of sensitive medical information. This approach demonstrates the potential for broader applications in modern telemedicine environments, providing a reliable and efficient solution for the secure transmission of healthcare data.
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This study assessed morphometric traits of the ampulla of the oviducts in prepubertal gilts treated with chorionic gonadotropins. With the day of slaughter as D0, gilts were assigned to four treatments (n = 8 each): control (untreated), eCG (200 IU eCG on D3), eCG+hCG (1200 IU eCG on D6 plus 500 IU hCG on D3), and eCG+hCG+AI (the previous treatment plus artificial insemination on D1). Blood and ampullae samples were collected at slaughter. Serum progesterone concentrations were higher for gilts treated with hCG than for those in the eCG and control treatments (p < 0.001), but estradiol concentrations did not differ (p > 0.05). The epithelium, muscle and lumen areas and the inner and larger ampullae diameters did not differ across treatments (p > 0.05). Therefore, treatment with chorionic gonadotropins did not alter the ampullae morphometry of prepubertal gilts.
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Gonadotropina Coriônica , Estradiol , Inseminação Artificial , Progesterona , Maturidade Sexual , Animais , Feminino , Gonadotropina Coriônica/farmacologia , Gonadotropina Coriônica/administração & dosagem , Progesterona/sangue , Progesterona/farmacologia , Estradiol/sangue , Estradiol/farmacologia , Maturidade Sexual/efeitos dos fármacos , Inseminação Artificial/veterinária , Suínos , Sus scrofaRESUMO
Envenomation by reptile venom, particularly from lizards, poses significant health risks and can lead to physiological and cardiovascular changes. The venom of Heloderma horridum horridum, endemic to Colima, Mexico, was tested on Wistar rats. Electrocardiographic (ECG) data were collected pre-treatment and at 5-min intervals for 1 h post-envenomation. A specially designed computational linear regression algorithm (LRA) was used for the segmentation analysis of the ECG data to improve the detection of fiducial points (P, Q, R, S, and T) in ECG waves. Additionally, heart tissue was analyzed for macroscopic and microscopic changes. The results revealed significant electrocardiographic alterations, including pacemaker migration, junctional extrasystoles, and intraventricular conduction aberrations. By applying a linear regression algorithm, the study compensated for noise and anomalies in the isoelectric line in an ECG signal, improving the detection of P and T waves and the QRS complex with an efficiency of 97.5%. Cardiac enzyme evaluation indicated no statistically significant differences between the control and experimental groups. Macroscopic and microscopic examination revealed no apparent signs of damage or inflammatory responses in heart tissues. This study enhances our understanding of the cardiovascular impact of Heloderma venom, suggesting a greater influence on changes in conduction and arrhythmias than on direct cardiac damage to the myocardium.
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Algoritmos , Eletrocardiografia , Ratos Wistar , Animais , Ratos , Modelos Lineares , Coração/efeitos dos fármacos , Lagartos , Masculino , Peçonhas/toxicidade , México , Animais PeçonhentosRESUMO
Manganese (Mn2+) is an abundant chemical element in the earth's crust and is present in soil, water, and industrial environments, including mining, welding, and battery manufacturing. Manganese (Mn) is an essential metal needed as a cofactor for many enzymes to maintain proper biological functions. Excessive exposure to Mn in high doses can result in a condition known as manganism, which results in disorders of the neurological, cardiac, and pulmonary systems. The aim of this study was to assess cardiac susceptibility to manganese intoxication in Colossoma macropomum subjected to a fixed concentration of 4 mg/mL for a period of up to 96 h. This study used 45 Tambaquis (30.38 ± 3.5 g) divided into five groups of 9 animals/treatment. The treated groups were exposed to the manganese concentration for a period of 24, 48, 72, and 96 h, after which the animals' ECGs were recorded, showing heart rate, R-R interval, P-Q interval, QRS complex duration and S-T interval. The results showed that cardiac activity decreased as the contact time increased, with an increase in the P-Q and S-T intervals. This indicates that the breakdown of circulatory homeostasis in these animals was caused by contact time with manganese.
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Eletrocardiografia , Manganês , Animais , Manganês/toxicidade , Frequência Cardíaca/efeitos dos fármacos , Intoxicação por Manganês , Coração/efeitos dos fármacos , Coração/fisiologiaRESUMO
Introduction: Hyperkalemia is a prevalent electrolyte disorder related to elevated serum potassium levels, resulting in diverse abnormal electrocardiographic findings and associated clinical signs and symptoms, often necessitating specific treatment. However, in some patients, these abnormal findings may not be present on the electrocardiogram even in elevated serum potassium levels. This study aims to identify electrocardiographic abnormalities related to the severity of hyperkalemia and the clinical outcomes in an emergency department in southwestern Colombia. Methodology: This is a retrospective cross-sectional descriptive study. We described the electrocardiographic findings, clinical characteristics, treatment, and outcomes related to the degrees of hyperkalemia. The potential association between the severity of hyperkalemia and electrocardiographic findings was evaluated. Results: A total of 494 patients were included. The median of the potassium level was 6.6 mEq/L. Abnormal electrocardiographic findings were reported in 61.5% of the cases. Mild and severe hyperkalemia groups reported abnormalities in 59.9% and 61.2%, respectively. The most common electrocardiography abnormalities were the peaked T wave 36.2%, followed by wide QRS 83 (16.8%). Only 1.4% of patients had adverse outcomes. The abnormal findings were registered in 61.5%. Mortality was 11.9%. The peaked T wave was the most common finding across different levels of hyperkalemia severity. Conclusion: High serum potassium levels are related with abnormal ECG. However, patients with different degrees of hyperkalemia could not describe abnormal ECG findings. In a high proportion of patients with renal chronic disease and hyperkalemia, the abnormalities in the ECG could be minimal or absent.
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INTRODUCTION AND OBJECTIVE: Cisplatin induces many collateral effects such as gastrointestinal disorders, nephrotoxicity, and dysautonomia. Recently our group showed that cisplatin treatment induces gastric emptying delay and that physical exercise and treatment with pyridostigmine prevent this change. In the current study, we investigated the role of moderate exercise on cardiac activity and autonomic balance in rats treated with cisplatin. METHODS: Male Wistar rats were divided into saline, cisplatin, exercise, and exercise+cisplatin groups. Cardiac and autonomic disorders were induced by (cisplatin - 3 mg/kg, i.p. once a week/per 5 weeks). Exercise consists of swimming (1 hour per day/5× day per week/per 5 weeks without overload). Forty-eight hours after the last session of the training or treatment, we assessed the cardiac activity and HRV via electrocardiogram analysis in DII derivation. RESULTS: Cisplatin increase (p<0.05) R-R' interval and decrease (p<0.05) heart rate vs. saline. Exercise+cisplatin prevented (p<0.05) changes in R-R' interval. Exercise per se induced bradycardia vs. saline group. We observed an increase in LF (nu) and a decrease in HF (nu) in the cisplatin group vs. saline. These changes were not significant. Moreover, cisplatin treatment increased (p<0.05) QT, QTc, and JT intervals compared with the saline group. In the exercise+cisplatin groups these increases were prevented significantly (p<0.05). CONCLUSION: In the current study, chronic use of cisplatin induced electrocardiographic changes without altering autonomic balance. Moderate physical exercise prevented this phenomenon indicating that exercise can be beneficial in patients in chemotherapy.
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This study evaluated the effect of bovine somatotropin (bST) on pregnancy rate (PR) and size of the dominant follicle (DF) on the day of intravaginal progesterone (P4) removal in protocols for fixed-time artificial insemination (FTAI). Bos indicus (Nellore) females (n = 392) were distributed into three groups. The control group (CG; n = 92) received an intravaginal P4 device + estradiol benzoate on day (d)0; prostaglandin F2α on d7 (first application); removal of P4 + estradiol cypionate (EC) + PGF2α (second application) + ultrasound (US) of the DF on d9; the FTAI was performed on d11; and pregnancy diagnosis (PD) was performed on d45. The bST group (bSTG; n = 142) underwent the same protocol as the CG, except that the animals received 125 mg of bST on d7. The equine chorionic gonadotropin (eCG) group (eCGG; n = 158) underwent the same protocol as the CG, except that the animals received 300 IU of eCG on d9. The PRs of the bSTG, eCGG, and CG were 48%, 48%, and 35%, respectively (p < .05); the bSTG and eCGG showed greater PRs, with follicles 6-7.9 mm (p < .05) and 8-8.9 mm in diameter, respectively. The bSTG exhibited a greater dimension of the DF on d9 of the protocol (p < .05). The eCGG had higher PRs with a body condition score (BCS) of 2.5, and the bSTG had a BCS of 3.0 (p < .05). It was concluded that bST increased PR, bST showed better performance in smaller DF and larger follicular diameter on d9 of the protocol, eCG acted better on animals with lower BCSs, and bST can be used in FTAI.
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Hormônio do Crescimento , Inseminação Artificial , Taxa de Gravidez , Progesterona , Animais , Feminino , Inseminação Artificial/veterinária , Inseminação Artificial/métodos , Gravidez , Bovinos , Hormônio do Crescimento/farmacologia , Hormônio do Crescimento/administração & dosagem , Progesterona/administração & dosagem , Progesterona/farmacologia , Estradiol/administração & dosagem , Estradiol/farmacologia , Estradiol/análogos & derivados , Folículo Ovariano/efeitos dos fármacos , Dinoprosta/administração & dosagem , Dinoprosta/farmacologia , Sincronização do Estro/métodos , Administração IntravaginalRESUMO
Reviewing the current state of knowledge on reproductive performance and productive traits in rams has many advantages. First, the compilation of this information will serve as a literature resource for scientists conducting research around the world and will contribute to the understanding of the data collected and interpreted by researchers on the different hormonal strategies used to improve reproductive performance in rams. Second, it will allow scientists to identify current knowledge gaps and set future research priorities in ram reproduction. Rams play an important role in the global flock economy, but their reproductive analysis has been limited in the use of hormonal technologies to increase the productivity of sheep flocks. In this review, we cite the most important works on six hormones that, in one way or another, modify the hypothalamus-pituitary-gonadal axis, at different doses, in and out of the reproductive season, breeds, application methods, among other factors. The overall aim is to increase the reproductive efficiency of rams in different scenarios and, in some cases, of other species due to the lack of limited information on rams.
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INTRODUCTION: The electrocardiogram (ECG) is a valuable tool for interpreting ventricular repolarization. This article aims to broaden the diagnostic scope beyond the conventional ischemia-centric approach, integrating an understanding of pathophisiological influences on ST-T wave changes. METHODS: A review was conducted on the physiological underpinnings of ventricular repolarization and the pathophisiological processes that can change ECG patterns. The research encompassed primary repolarization abnormalities due to uniform variations in ventricular action potential, secondary changes from electrical or mechanical alterations, and non-ischemic conditions influencing ST-T segments. RESULTS: Primary T waves are characterized by symmetrical waves with broad bases and variable QT intervals, indicative of direct myocardial action potential modifications due to ischemia, electrolyte imbalances, and channelopathies. Secondary T waves are asymmetric and often unassociated with significant QT interval changes, suggesting depolarization alterations or changes in cardiac geometry and contractility. CONCLUSION: We advocate for a unified ECG analysis, recognizing primary and secondary ST-T changes, and their clinical implications. Our proposed analytical framework enhances the clinician's ability to discern a wide array of cardiac conditions, extending diagnostic accuracy beyond myocardial ischemia.
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Eletrocardiografia , Humanos , Arritmias Cardíacas/fisiopatologia , Arritmias Cardíacas/diagnóstico , Sistema de Condução Cardíaco/fisiopatologia , Potenciais de AçãoRESUMO
Although healthcare and medical technology have advanced significantly over the past few decades, heart disease continues to be a major cause of mortality globally. Electrocardiography (ECG) is one of the most widely used tools for the detection of heart diseases. This study presents a mathematical model based on transfer functions that allows for the exploration and optimization of heart dynamics in Laplace space using a genetic algorithm (GA). The transfer function parameters were fine-tuned using the GA, with clinical ECG records serving as reference signals. The proposed model, which is based on polynomials and delays, approximates a real ECG with a root-mean-square error of 4.7% and an R2 value of 0.72. The model achieves the periodic nature of an ECG signal by using a single periodic impulse input. Its simplicity makes it possible to adjust waveform parameters with a predetermined understanding of their effects, which can be used to generate both arrhythmic patterns and healthy signals. This is a notable advantage over other models that are burdened by a large number of differential equations and many parameters.
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PURPOSE: Acquired QT prolongation is frequent and leads to a higher mortality rate in critically ill patients. KardiaMobile 1L® (KM1L) is a portable, user-friendly single lead, mobile alternative to conventional 12-lead electrocardiogram (12-L ECG) that could be more readily available, potentially facilitating more frequent QTc assessments in intensive care units (ICU); however, there is currently no evidence to validate this potential use. METHODS: We conducted a prospective diagnostic test study comparing QT interval measurement using KM1L with conventional 12-L ECG ordered for any reason in patients admitted to an ICU. We compared the mean difference using a paired t-test, agreement using Bland-Altman analysis, and Lin's concordance coefficient, numerical precision (proportion of QT measurements with <10 ms difference between KM1L and conventional 12-L ECG), and clinical precision (concordance for adequate discrimination of prolonged QTc). RESULTS: We included 114 patients (61.4% men, 60% cardiovascular etiology of hospitalization) with 131 12-L ECG traces. We found no statistical difference between corrected QT measurements (427 ms vs. 428 ms, p = .308). Lin's concordance coefficient was 0.848 (95% CI 0.801-0.894, p = .001). Clinical precision was excellent in males and substantial in females (Kappa 0.837 and 0.781, respectively). Numerical precision was lower in patients with vasoactive drugs (-13.99 ms), QT-prolonging drugs (13.84 ms), antiarrhythmic drugs (-12.87 ms), and a heart rate (HR) difference of ≥5 beats per minute (bpm) between devices (-11.26 ms). CONCLUSION: Our study validates the clinical viability of KM1L, a single-lead mobile ECG device, for identifying prolonged QT intervals in ICU patients. Caution is warranted in patients with certain medical conditions that may affect numerical precision.
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Eletrocardiografia , Síndrome do QT Longo , Masculino , Feminino , Humanos , Estado Terminal , Estudos Prospectivos , Síndrome do QT Longo/diagnóstico , Frequência Cardíaca/fisiologiaRESUMO
The objective of this study was to evaluate the effect of three doses of equine chorionic gonadotropin (eCG) for ovarian superstimulation on ovarian response, follicular development and cumulus-oocyte complexes (COCs) collection in llamas. For this purpose, eighteen multiparous non-lactating adult (4-7 yo) female llamas with an average body condition of 2.8 (BCS 1-5) were submitted to a follicular ablation (FA) to induce a new follicular wave emergence. Two days after FA (Day 0), synchronized llamas were randomly allocated to three treatment groups (n = 6/group) and given 500, 750 and 1000 IU of eCG (Novormon®, Syntex, Buenos Aires, Argentina) per animal respectively to induce ovarian superstimulation. Transrectal ultrasonography were performed on Days 2, 4, and 6; and ovum pick up (OPU) was performed on Day 6. Data was evaluated by one-way analysis of variance (ANOVA), repeated measures ANOVA, and 2-tailed Chi-square. The average size (mm) of follicles was greater (p≤ 0.05) in the 1000 IU group compared to the other groups. There was a greater (p≤ 0.05) number of follicles ≥ 7 mm in the 1000 IU group compared to the 500 IU group. Number of COCs collected on Day 6 and the COC recovery rate were not different among groups. In conclusion, a single dose of 1000 IU of eCG induced the best ovarian response resulting in larger and greater number of follicles at the time of OPU.
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Numerous papers report the efficiency of the automatic interpretation capabilities of commercial algorithms. Unfortunately, these algorithms are proprietary, and academia has no means of directly contributing to these results. In fact, nothing at the same stage of development exists in academia. Despite the extensive research in ECG signal processing, from signal conditioning to expert systems, a cohesive single application for clinical use is not ready yet. This is due to a serious lack of coordination in the academic efforts, which involve not only algorithms for signal processing, but also the signal acquisition equipment itself. For instance, the different sampling rates and the different noise levels frequently found in the available signal databases can cause severe incompatibility problems when the integration of different algorithms is desired. Therefore, this work aims to solve this incompatibility problem by providing the academic community with a diagnostic-grade electrocardiograph. The intention is to create a new standardized ECG signals database in order to address the automatic interpretation problem and create an electrocardiography system that can fully assist clinical practitioners, as the proprietary systems do. Achieving this objective is expected through an open and coordinated collaboration platform for which a webpage has already been created.
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This work presents an algorithm for the detection and classification of QRS complexes based on the continuous wavelet transform (CWT) with splines. This approach can evaluate the CWT at any integer scale and the analysis is not restricted to powers of two. The QRS detector comprises four stages: implementation of CWT with splines, detection of QRS complexes, searching for undetected QRS complexes, and correction of the R wave peak location in detected QRS complexes. After, the onsets and ends of the QRS complexes are detected. The algorithm was evaluated with synthetic ECG and with the manually annotated databases: MIT-BIH Arrhythmia, European ST-T, QT and PTB Diagnostic ECG. Evaluation results of the QRS detector were: MIT-BIH arrhythmia database (109,447 beats analyzed), sensitivity Se = 99.72% and positive predictivity P+ = 99.87%; European ST-T database (790522 beats analyzed), Se = 99.92% and P+ = 99.55% and QT database (86498 beats analyzed), Se = 99.97% and P+ = 99.99%. To evaluate the delineation algorithm of the QRS onset (Qi) and QRS end (J) with the QT and PTB Diagnostic ECG databases, the mean and standard deviations of the differences between the automatic and manual annotated location of these points were calculated. The standard deviations were close to the accepted tolerances for deviations determined by the CSE experts. The proposed algorithm is robust to noise, artifacts and baseline drifts, classifies QRS complexes, automatically selects the CWT scale according to the sampling frequency of the ECG record used, and adapts to changes in the heart rate, amplitude and morphology of QRS complexes.
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Eletrocardiografia , Análise de Ondaletas , Humanos , Eletrocardiografia/métodos , Algoritmos , Arritmias Cardíacas/diagnóstico , Bases de Dados FactuaisRESUMO
Ventricular septal rupture (VSR) is a rare and devastating complication of acute myocardial infarction. Early detection, assessment of the hemodynamic impact, and illustration of the pathophysiological context are crucial functions of echocardiography in decision-making for intensive management and reparative intervention. To evaluate this entity, echocardiography exhibits two strengths: its bedside nature and its multiple modalities. This document reviews the comprehensive use of echocardiography in the study of post-infarction VSR.
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Infarto do Miocárdio , Ruptura do Septo Ventricular , Humanos , Ruptura do Septo Ventricular/etiologia , Ruptura do Septo Ventricular/complicações , Fatores de Risco , Infarto do Miocárdio/complicações , Infarto do Miocárdio/diagnóstico por imagem , EcocardiografiaRESUMO
Two experiments were conducted in the Northern (UK) and Southern (Brazil) hemispheres to determine the effect of season (month of conception) on the development of supplementary CL (SCL) and the relationship with pregnancy loss. In experiment 1, 199 pregnancies were followed between Day 14 and term, to determine the number of SCL and pregnancy viability (Northern Hemisphere). From the 199 pregnancies, 178 were obtained from inseminations during the breeding season (March-September), while the rest, 21 pregnancies resulted from conceptions in the non-breeding season (October to February). Pregnancies conceived in the breeding season were more likely (P < 0.01) to have at least 1 SCL (75.8 %, 135/178) than pregnancies from the non-breeding season (33 %, 7/21). However, the pregnancy loss between Days 35 and 120 of pregnancy in mares with no SCL was similar (3.5 %, 2/57; P >0.1) than from mares with SCL (1.4 %, 2/142). In Experiment 2 (Southern Hemisphere), three groups of recipients were used based on their ovarian activity at the time of embryo transfer: Anestrus (n = 8), transitional (n = 7) and cyclic (n = 7) recipient mares. While all transitional and cyclic mares developed at least 1 SCL, only 50 % of anestrous recipients (4/8) developed SCL by 120 of gestation. In conclusion, the development of SCL in pregnant mares is influenced by the time of season of conception, therefore it appears to be regulated by the photoperiod and the endogenous seasonal variation in gonadotropin concentrations. Mares with no SCL were not at increased risk of pregnancy loss.
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Anestro , Corpo Lúteo , Gravidez , Feminino , Animais , Estações do Ano , BrasilRESUMO
Heart diseases rank among the most fatal health concerns globally, with the majority being preventable through early diagnosis and effective treatment. Electrocardiogram (ECG) analysis is critical in detecting heart diseases, as it captures the heart's electrical activities. For continuous monitoring, wearable electrocardiographic devices must ensure user comfort over extended periods, typically 24 to 48 h. These devices demand specialized algorithms with low computational complexity to accommodate memory and power consumption constraints. One of the most crucial aspects of ECG signals is accurately detecting heartbeat intervals, specifically the R peaks. In this study, we introduce a novel algorithm designed for wearable devices, offering two primary attributes: robustness against noise and low computational complexity. Our algorithm entails fitting a least-squares parabola to the ECG signal and adaptively shaping it as it sweeps through the signal. Notably, our proposed algorithm eliminates the need for band-pass filters, which can inadvertently smooth the R peaks, making them more challenging to identify. We compared the algorithm's performance using two extensive databases: the meta-database QT database and the BIH-MIT database. Importantly, our method does not necessitate the precise localization of the ECG signal's isoelectric line, contributing to its low computational complexity. In the analysis of the QT database, our algorithm demonstrated a substantial advantage over the classical Pan-Tompkins algorithm and maintained competitiveness with state-of-the-art approaches. In the case of the BIH-MIT database, the performance results were more conservative; they continued to underscore the real-world utility of our algorithm in clinical contexts.
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Cardiopatias , Dispositivos Eletrônicos Vestíveis , Humanos , Processamento de Sinais Assistido por Computador , Eletrocardiografia/métodos , AlgoritmosRESUMO
A low-power long-term ambulatory ECG monitor was developed for the acquisition, storage and processing of three simultaneous leads DI, aVF and V2 with a beat-to-beat heart rate measurement in real time. It provides long-term continuous ECG recordings until 84 h. The monitor uses a QRS complex detection algorithm based on the continuous wavelet transform with splines, which automatically selects the scale for the analysis of ECG records with different sampling frequencies. It includes a lead-off detection to continuously monitor the electrode connections and a real-time system of visual and acoustic alarms to alert users of abnormal conditions in its operation. The monitor presented is based in an ADS1294 analogue front end with four channels, 24-bit analog-to-digital converters and programmable gain amplifiers, a low-power dual-core ESP32 microcontroller, a microSD memory for data storage in a range of 4 GB to 32 GB and a 1.4 in thin-film transistor liquid crystal display (LCD) variant with a resolution of 128 × 128 pixels. It has programmable sampling rates of 250, 500 and 1000 Hz; a bandwidth of 0 Hz to 50% of the selected sampling rate; a CMRR of -105 dB; an input margin of ±2.4 V; a resolution of 286 nV; and a current consumption of 50 mA for an average battery life of 84 h. The ambulatory ECG monitor was evaluated with the commercial data-acquisition system BIOPAC MP36 and its module for ECG LABEL SS2LB, simultaneously comparing the morphologies of two ECG records and obtaining a correlation of 91.78%. For the QRS detection in real time, the implemented algorithm had an error less than 5%. The developed ambulatory ECG monitor can be used for the analysis of the dynamics of the heart rate variability in long-term ECG records and for the development of one's own databases of ECG recordings of normal subjects and patients with cardiovascular and noncardiovascular diseases.
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Eletrocardiografia Ambulatorial , Processamento de Sinais Assistido por Computador , Humanos , Frequência Cardíaca/fisiologia , Coração/fisiologia , Eletrocardiografia , Arritmias Cardíacas/diagnóstico , AlgoritmosRESUMO
Cardiovascular diseases are currently the leading cause of death worldwide. Thus, there is a need for non-invasive ambulatory (Holter) ECG monitors with automatic measurements of ECG intervals to evaluate electrocardiographic abnormalities of patients with cardiac diseases. This work presents the implementation of algorithms in an FPGA for beat-to-beat heart rate and RT interval measurements based on the continuous wavelet transform (CWT) with splines for a prototype of an ambulatory ECG monitor of three leads. The prototype's main elements are an analog-digital converter ADS1294, an FPGA of Xilinx XC7A35T-ICPG236C of the Artix-7 family of low consumption, immersed in a low-scale Cmod-A7 development card integration, an LCD display and a micro-SD memory of 16 Gb. A main state machine initializes and manages the simultaneous acquisition of three leads from the ADS1294 and filters the signals using a FIR filter. The algorithm based on the CWT with splines detects the QRS complex (R or S wave) and then the T-wave end using a search window. Finally, the heart rate (60/RR interval) and the RT interval (from R peak to T-wave end) are calculated for analysis of its dynamics. The micro-SD memory stores the three leads and the RR and RT intervals, and an LCD screen displays the beat-to-beat values of heart rate, RT interval and the electrode connection. The algorithm implemented on the FPGA achieved satisfactory results in detecting different morphologies of QRS complexes and T wave in real time for the analysis of heart rate and RT interval dynamics.