Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 13.933
Filtrar
1.
Methodist Debakey Cardiovasc J ; 15(2): 105-110, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31384373

RESUMO

Patients with a functionally univentricular heart who have had an atriopulmonary Fontan are at risk for atrial dilatation, atrial arrhythmias, and progressive circulatory failure. Between 1994 and 2018, we performed 149 Fontan conversions with arrhythmia surgery and epicardial pacemaker placement at Ann & Robert H. Lurie Children's Hospital of Chicago. This operation converts the atriopulmonary Fontan to an extracardiac Fontan that improves hemodynamics and controls the atrial arrhythmias. Operative mortality during that time was 2%, and freedom from death or heart transplant at 10 years is 84%. For properly selected patients, Fontan conversion improves both survival and quality of life. Patients with an atriopulmonary Fontan constitute an eroding population, as they face many comorbidities and have a decreased life expectancy without treatment; therefore, all patients with an atriopulmonary Fontan should be evaluated for this procedure.


Assuntos
Arritmias Cardíacas/cirurgia , Cardiomegalia/cirurgia , Técnica de Fontan , Cardiopatias Congênitas/cirurgia , Adolescente , Adulto , Arritmias Cardíacas/etiologia , Arritmias Cardíacas/mortalidade , Arritmias Cardíacas/fisiopatologia , Cardiomegalia/etiologia , Cardiomegalia/mortalidade , Cardiomegalia/fisiopatologia , Criança , Pré-Escolar , Tomada de Decisão Clínica , Feminino , Técnica de Fontan/efeitos adversos , Técnica de Fontan/mortalidade , Cardiopatias Congênitas/complicações , Cardiopatias Congênitas/mortalidade , Cardiopatias Congênitas/fisiopatologia , Humanos , Masculino , Pessoa de Meia-Idade , Seleção de Pacientes , Intervalo Livre de Progressão , Reoperação , Medição de Risco , Fatores de Risco , Fatores de Tempo , Adulto Jovem
2.
Med Clin North Am ; 103(5): 821-834, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31378328

RESUMO

The narrow therapeutic window of antiarrhythmic drugs makes their use clinically challenging. A solid understanding of the mechanisms of arrhythmias and how antiarrhythmics affect these mechanisms is only a preliminary step in their appropriate selection. Clinical factors, side-effect profiles, and proarrhythmic risks are more important than the cellular mechanisms of actions in drug selection and monitoring. This article provides a simplified approach to understanding cellular mechanisms and provides a practical approach to the selection and use of this important class of medications.


Assuntos
Antiarrítmicos/administração & dosagem , Arritmias Cardíacas/tratamento farmacológico , Potenciais de Ação , Antiarrítmicos/efeitos adversos , Arritmias Cardíacas/fisiopatologia , Humanos , Ablação por Radiofrequência , Medição de Risco
3.
Braz J Cardiovasc Surg ; 34(3): 311-317, 2019 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-31310470

RESUMO

OBJECTIVE: To investigate the effects of preoperative anxiety relieving on electrophysiological changes in patients undergoing off-pump coronary artery bypass surgery. METHODS: A total of 61 patients at ASA III risk group in the age range of 18-65 years were enrolled in the present study. Patients were randomly divided into two groups. Group S (Sedation group) was administered 0.04 mg/kg lorazepam per os (PO) twice before the operation. Group C (control group) was not administered with any anxiolytic premedication. State Trait Anxiety Inventory (STAI-I) and Beck Anxiety Inventory (BAI) were used to evaluate the level of anxiety. Electrocardiography (ECG), pulse oximeter and standard monitoring were performed for each patient. QT and P dispersions in each derivation of all ECGs were calculated. RESULTS: Preoperative STAI-I scores were significantly lower in sedation group compared to the controls. Mean values of QT dispersion measured before induction, at the 1st minute of induction, 30th second of intubation and 4th minute of intubation in sedation group were significantly reduced compared to controls (P=0.024; P=0.027; P=0.001; P=0.033, respectively). The mean values of P dispersion measured before induction, at the 3rd minute of induction, 30th second of intubation and 4th minute of intubation in sedation group were significantly reduced compared to controls (P=0.001; P=0.020; P=0.023; P=0.005, respectively). CONCLUSION: Elevated anxiety levels in patients undergoing coronary bypass surgery have a negative effect through prolonged QT and P-wave dispersion times. Anxiolytic treatment before surgery may be useful to prevent ventricular and atrial arrhythmias and associated complications through decreasing the QT and P-wave dispersion duration.


Assuntos
Ansiolíticos/uso terapêutico , Ansiedade/tratamento farmacológico , Ansiedade/fisiopatologia , Ponte de Artéria Coronária sem Circulação Extracorpórea/psicologia , Eletrocardiografia/psicologia , Lorazepam/uso terapêutico , Cuidados Pré-Operatórios/métodos , Adolescente , Adulto , Idoso , Arritmias Cardíacas/fisiopatologia , Arritmias Cardíacas/psicologia , Ponte de Artéria Coronária sem Circulação Extracorpórea/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Valores de Referência , Reprodutibilidade dos Testes , Fatores de Risco , Estatísticas não Paramétricas , Fatores de Tempo , Resultado do Tratamento , Adulto Jovem
4.
Life Sci ; 232: 116526, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31170418

RESUMO

Tumors and heart disease are two of the leading causes of human death. With the development of anti-cancer therapy, the survival rate of cancer patients has been significantly improved. But at the same time, the incidence of cardiovascular adverse events caused by cancer treatment has also been considerably increased, such as arrhythmia, left ventricular (LV) systolic and diastolic dysfunction, and even heart failure (HF), etc., which seriously affects the quality of life of cancer patients. More importantly, the occurrence of adverse events may lead to the adjustment or the cessation of anti-cancer treatment, which affects the survival rate of patients. Understanding the mechanism of cardiotoxicity (CTX) induced by antineoplastic drugs is the basis of adequate protection of the heart without impairing the efficacy of antineoplastic therapy. Based on current research, a large amount of evidence has shown that oxidative stress (OS) plays an essential role in CTX induced by antineoplastic drugs and participates in its toxic reaction directly and indirectly. Here, we will review the mechanism of action of OS in cardiac toxicity of antineoplastic drugs, to provide new ideas for researchers, and provide further guidance for clinical prevention and treatment of cardiac toxicity of anti-tumor drugs in the future.


Assuntos
Antineoplásicos/metabolismo , Cardiotoxicidade/prevenção & controle , Estresse Oxidativo/fisiologia , Antineoplásicos/efeitos adversos , Arritmias Cardíacas/complicações , Arritmias Cardíacas/fisiopatologia , Cardiotoxicidade/metabolismo , Coração/fisiopatologia , Cardiopatias/tratamento farmacológico , Insuficiência Cardíaca/complicações , Insuficiência Cardíaca/fisiopatologia , Humanos , Neoplasias/tratamento farmacológico , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/genética , Qualidade de Vida
5.
Postgrad Med ; 131(4): 261-267, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31002266

RESUMO

Despite the advances in the management of thalassemia major, heart disease remains the leading cause of mortality in patients afflicted with this disorder. Cardiac involvement in thalassemia encompasses a spectrum of disorders including myocardial dysfunction, arrhythmias, pulmonary hypertension, and peripheral vascular disease. Although cardiac siderosis (accumulation of iron in cardiac myocytes) as a consequence of repeated blood transfusions is deemed to be the main etiologic factor for myocardial dysfunction in transfusion-dependent patients, the significance of other pathophysiologic mechanisms is being increasingly recognized especially in non-transfusion dependent patients. Management of cardiac complications in thalassemia major hinges on the treatment of the underlying pathophysiology, which often is unmitigated iron overload. The prevalence and predictors of cardiac complications in 'ex-thalassaemics' [thalassaemic patients undergoing allogeneic hematopoietic stem cell transplantation (HSCT) is unknown at present. In this review, we look at the pathogenesis of cardiac involvement in patients with beta-thalassemia major, the advances in the management of these patients and the future prospects.


Assuntos
Doenças Cardiovasculares/etiologia , Doenças Cardiovasculares/fisiopatologia , Talassemia beta/complicações , Talassemia beta/fisiopatologia , Arritmias Cardíacas/etiologia , Arritmias Cardíacas/fisiopatologia , Transfusão de Sangue/métodos , Cardiomiopatias/etiologia , Cardiomiopatias/fisiopatologia , Insuficiência Cardíaca/etiologia , Insuficiência Cardíaca/fisiopatologia , Testes de Função Cardíaca , Hemoglobinas/metabolismo , Humanos , Sobrecarga de Ferro/fisiopatologia , Talassemia beta/terapia
6.
Sensors (Basel) ; 19(7)2019 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-30974854

RESUMO

The electrocardiogram (ECG) is an important diagnostic tool for cardiovascular diseases. However, ECG signals are susceptible to noise, which may degenerate waveform and cause misdiagnosis. In this paper, the ECG noise reduction techniques based on sparse recovery are investigated. A novel sparse ECG denoising framework combining low-pass filtering and sparsity recovery is proposed. Two sparsity recovery algorithms are developed based on the traditional ℓ 1 -norm penalty and the novel generalized minimax concave (GMC) penalty, respectively. Compared with the ℓ 1 -norm penalty, the non-differentiable non-convex GMC penalty has the potential to strongly promote sparsity while maintaining the convexity of the cost function. Moreover, the GMC punishes large values less severely than ℓ 1 -norm, which is utilized to overcome the drawback of underestimating the high-amplitude components for the ℓ 1 -norm penalty. The proposed methods are evaluated on ECG signals from the MIT-BIH Arrhythmia database. The results show that underestimating problem is overcome by the proposed GMC-based method. The GMC-based method shows significant improvement with respect to the average of output signal-to-noise ratio improvement ( S N R i m p ), the average of root mean square error (RMSE) and the percent root mean square difference (PRD) over almost any given SNR compared with the classical methods, thus providing promising approaches for ECG denoising.


Assuntos
Arritmias Cardíacas/diagnóstico , Doenças Cardiovasculares/diagnóstico , Eletrocardiografia/métodos , Algoritmos , Arritmias Cardíacas/fisiopatologia , Doenças Cardiovasculares/fisiopatologia , Bases de Dados Factuais , Eletrocardiografia/estatística & dados numéricos , Humanos , Processamento de Sinais Assistido por Computador , Razão Sinal-Ruído
7.
Int J Mol Sci ; 20(8)2019 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-31018519

RESUMO

Epilepsy is a common neurological disorder associated with increased morbidity and mortality. Sudden unexpected death in epilepsy, also known as SUDEP, is the main cause of death in patients with epilepsy. SUDEP has an incidence of 1.2 per 1000 person-years in adults and 0.2 per 1000 person-years in children. SUDEP accounts for 8-17% of deaths in patients with epilepsy. It is commonly associated with a history of generalized tonic-clonic seizures, and its risk may be increased by other factors such as postictal electroencephalographic suppression, prone sleeping position, altered heart rate variability, conduction abnormalities, gender, or antiepileptic medications. Recently, electrocardiograms, electroencephalograms, and imaging markers have helped clinicians stratify SUDEP risk and identify patients in need of close monitoring. However, the pathophysiology of SUDEP is likely multifactorial and still unknown. Improving the knowledge of SUDEP incidence, risk factors, and biomarkers can help design and implement effective prevention strategies.


Assuntos
Morte Súbita/epidemiologia , Epilepsia/genética , Animais , Arritmias Cardíacas/complicações , Arritmias Cardíacas/genética , Arritmias Cardíacas/patologia , Arritmias Cardíacas/fisiopatologia , Morte Súbita/patologia , Epilepsia/epidemiologia , Epilepsia/patologia , Epilepsia/fisiopatologia , Predisposição Genética para Doença , Humanos , Fatores de Risco
8.
J Zhejiang Univ Sci B ; 20(4): 300-309, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30932375

RESUMO

Inter atrial block (IAB) is a prevailing cardiac conduction abnormality that is under-recognized in clinical practice. IAB has strong association with atrial arrhythmia, left atrial enlargement, and electromechanical discordance, increasing the risk of atrial fibrillation (AF) and myocardial ischemia. IAB was generally believed to be caused by impaired conduction along the Bachmann bundle (BB). However, there are three other conduction pathways, including the fibers posteriorly in the vicinity of the right pulmonary veins (VRPV), transseptal fibers in the fossa ovalis (FO), and muscular bundles on the inferior atrial surface near the coronary sinus (CS). We hypothesized that the importance of BB on IAB might have been overestimated. To test this hypothesis, various combinations of conduction pathway blocks were simulated based on a realistic human atrial model to investigate their effects on the index of clinical diagnosis standard of IAB using a simulated 12-lead electrocardiogram (ECG). Firstly, the results showed that the BB block alone could not generate typical P wave morphology of IAB, and that the combination of BB and VRPV pathway block played important roles in the occurrence of IAB. Secondly, although single FO and CS pathways play subordinate roles in inter atrial conduction, their combination with BB and VRPV block could also produce severe IAB. In summary, this simulation study has demonstrated that the combinations of different inter atrial conduction pathways, rather than BB alone, resulted in ECG morphology of IAB. Attention needs to be paid to this in future pathophysiological and clinical studies of IAB.


Assuntos
Fibrilação Atrial/diagnóstico , Fibrilação Atrial/fisiopatologia , Eletrocardiografia , Modelos Cardiovasculares , Adulto , Arritmias Cardíacas/fisiopatologia , Simulação por Computador , Seio Coronário/fisiopatologia , Coração , Átrios do Coração , Humanos , Masculino , Modelos Anatômicos , Veias Pulmonares/fisiopatologia
9.
Am J Ther ; 26(2): e257-e267, 2019 Mar/Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30839374

RESUMO

BACKGROUND: Electrical storm (ES) is a major life-threatening event, which announces a possible negative outcome and poor prognosis and poses challenging questions concerning etiology and management. DATA SOURCES: A literature search was conducted through MEDLINE and EMBASE (past 30 years until the end of September 2018) using the following search terms: ES, ventricular fibrillation, ventricular tachycardia, ablation, and implantable defibrillator. Clinicaltrials.gov was also consulted for studies that are ongoing or completed. Additional articles were identified through bibliographical citations. AREA OF UNCERTAINTY: There is no homogeneous attitude, and therapeutic strategies vary widely. THERAPEUTIC ADVANCES: The aim of this review is to define the concept of ES, to review the incidence and prognostic implications, and to describe the most common strategies of therapeutic advances and trends. The management strategy should be decided after an accurate risk stratification is done in initial evaluation according to hemodynamic tolerability and presence of triggers and comorbidities. General care should be provided in an intensive cardiovascular care unit. The cornerstone of acute medical therapy used in ES is mainly represented by amiodarone and beta-blockers. Deep sedation and mechanical ventilation should provide comfort for treatment administration. First-choice drugs are benzodiazepines and short-acting analgesics. General care may also include thoracic epidural anesthesia to modulate neuroaxial efferents to the heart and to decrease sympathetic hyperactivity. We include a special focus on ablation as a reliable tool to target the mechanism of arrhythmia, finally building an up-to-date standardization. CONCLUSIONS: ES management needs a complex assessment and interpretation of a critical situation in a life-threatening condition. Optimal implantable cardioverter-defibrillator-reprogramming, antiarrhythmic drug therapy and sedation are in first-line approach. Catheter ablation is the elective therapy and plays a central key role in the treatment of ES if possible in combination with hemodynamic support.


Assuntos
Arritmias Cardíacas , Terapia de Ressincronização Cardíaca/métodos , Gerenciamento Clínico , Arritmias Cardíacas/fisiopatologia , Arritmias Cardíacas/terapia , Sistema de Condução Cardíaco/fisiopatologia , Humanos
10.
Med Sci Monit ; 25: 1984-1993, 2019 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-30877783

RESUMO

BACKGROUND Augmented cardiac sympathetic afferent reflex (CSAR) plays a role in enhanced sympathetic activity. Given that a strategy for abolishing augmented CSAR-induced sympathetic activation may be beneficial for protecting against ventricular arrhythmias (VAs) triggered by acute myocardial infarction (AMI), we investigated whether cardiac sympathetic afferent denervation (CSAD) could protect against VAs by modulating cardiac sympathetic nerve activity in an AMI dog model. MATERIAL AND METHODS Twenty-two anesthetized dogs were assigned to the CSAD group (n=9) and the sham group (n=13) randomly. CSAD was produced by epicardial application of resiniferatoxin. Heart rate variability (HRV), ventricular action potential duration (APD), APD dispersion, beat-to-beat variability of repolarization (BVR), effective refractory period (ERP) of ventricles, ERP dispersion, plasma norepinephrine (NE) concentration, and left stellate ganglion (LSG) neural activity were determined at baseline and after CSAD. We designed an AMI model by occluding the left anterior coronary artery, and performed analysis of VAs for 60 minutes using electrocardiography. Then, levels of c-fos and nerve growth factor (NGF) were determined. RESULTS Relative to baseline values, CSAD prolonged ERP and APD of ventricles, increased HRV, decreased APD dispersion, BVR, ERP dispersion and serum NE concentration, and attenuated LSG activity in the CSAD group. AMI triggered a remarkable increase in LSG activity and function but decreased the HRV of the sham group animals relative to the CSAD group. Moreover, the CSAD group had higher levels of VAs relative to the sham group. This was accompanied by a corresponding decrease in proteins quantities of NGF and c-fos in the CSAD group in the LSG after AMI compared to the sham group. CONCLUSIONS CSAD can suppress LSG neural activity, hence enhance the electrophysiological stability and protect the heart from AMI-triggered VAs.


Assuntos
Arritmias Cardíacas/fisiopatologia , Simpatectomia/métodos , Sistema Nervoso Simpático/fisiopatologia , Potenciais de Ação , Animais , Arritmias Cardíacas/prevenção & controle , Ablação por Cateter/métodos , Vasos Coronários/fisiopatologia , Modelos Animais de Doenças , Cães , Eletrocardiografia/métodos , Coração/fisiopatologia , Frequência Cardíaca , Ventrículos do Coração/fisiopatologia , Infarto do Miocárdio/fisiopatologia , Isquemia Miocárdica/fisiopatologia
11.
PLoS Comput Biol ; 15(3): e1006597, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30883540

RESUMO

Cardiac fibrosis occurs in many forms of heart disease and is considered to be one of the main arrhythmogenic factors. Regions with a high density of fibroblasts are likely to cause blocks of wave propagation that give rise to dangerous cardiac arrhythmias. Therefore, studies of the wave propagation through these regions are very important, yet the precise mechanisms leading to arrhythmia formation in fibrotic cardiac tissue remain poorly understood. Particularly, it is not clear how wave propagation is organized at the cellular level, as experiments show that the regions with a high percentage of fibroblasts (65-75%) are still conducting electrical signals, whereas geometric analysis of randomly distributed conducting and non-conducting cells predicts connectivity loss at 40% at the most (percolation threshold). To address this question, we used a joint in vitro-in silico approach, which combined experiments in neonatal rat cardiac monolayers with morphological and electrophysiological computer simulations. We have shown that the main reason for sustainable wave propagation in highly fibrotic samples is the formation of a branching network of cardiomyocytes. We have successfully reproduced the morphology of conductive pathways in computer modelling, assuming that cardiomyocytes align their cytoskeletons to fuse into cardiac syncytium. The electrophysiological properties of the monolayers, such as conduction velocity, conduction blocks and wave fractionation, were reproduced as well. In a virtual cardiac tissue, we have also examined the wave propagation at the subcellular level, detected wavebreaks formation and its relation to the structure of fibrosis and, thus, analysed the processes leading to the onset of arrhythmias.


Assuntos
Coração/fisiologia , Animais , Animais Recém-Nascidos , Arritmias Cardíacas/fisiopatologia , Simulação por Computador , Sistema de Condução Cardíaco/fisiologia , Modelos Cardiovasculares , Ratos
12.
Vet Clin North Am Equine Pract ; 35(1): 175-190, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30871825

RESUMO

Horses have a high prevalence of resting arrhythmias, cardiac murmurs, and valvular regurgitation, and training can increase the prevalence. This makes it challenging for equine veterinarians who are asked to evaluate horses for poor performance to determine the clinical relevance of some findings. In addition, cardiac disease has the potential to cause collapse or sudden death, putting both the horse and rider at risk. Further diagnostics, such as echocardiograms and resting and exercising ECGs can help to sort out the impact of an abnormality found on resting physical examination. However uncertainty over the importance of some findings continues to exist.


Assuntos
Tolerância ao Exercício/fisiologia , Doenças dos Cavalos/diagnóstico , Doenças dos Cavalos/fisiopatologia , Animais , Arritmias Cardíacas/fisiopatologia , Arritmias Cardíacas/veterinária , Cavalos , Condicionamento Físico Animal
13.
Vet Clin North Am Equine Pract ; 35(1): 191-204, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30871830

RESUMO

Arrhythmias detected on prepurchase examination should be confirmed with an ECG. Exercising ECG determines if the arrhythmia is overdriven during exercise or is a safety concern. An echocardiogram is needed in all horses with a grade 3/6 or louder mid to late systolic, holosystolic, or pansystolic murmur or any holodiastolic decrescendo murmur to identify the cardiac abnormality and its hemodynamic impact. Most horses with arrhythmias and murmurs have a normal performance career and life expectancy and are insurable. Risks for sudden death and congestive heart failure associated with the common murmurs and arrhythmias are identified, because these horses cannot be insured.


Assuntos
Arritmias Cardíacas/veterinária , Sopros Cardíacos/veterinária , Doenças dos Cavalos/diagnóstico , Exame Físico/veterinária , Animais , Arritmias Cardíacas/diagnóstico , Arritmias Cardíacas/fisiopatologia , Sopros Cardíacos/diagnóstico , Sopros Cardíacos/fisiopatologia , Doenças dos Cavalos/fisiopatologia , Cavalos , Seguro
14.
Int J Mol Sci ; 20(6)2019 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-30884748

RESUMO

The QT interval occupies a pivotal role in drug development as a surface biomarker of ventricular repolarization. The electrophysiologic substrate for QT prolongation coupled with reports of non-cardiac drugs producing lethal arrhythmias captured worldwide attention from government regulators eventuating in a series of guidance documents that require virtually all new chemical compounds to undergo rigorous preclinical and clinical testing to profile their QT liability. While prolongation or shortening of the QT interval may herald the appearance of serious cardiac arrhythmias, the positive predictive value of an abnormal QT measurement for these arrhythmias is modest, especially in the absence of confounding clinical features or a congenital predisposition that increases the risk of syncope and sudden death. Consequently, there has been a paradigm shift to assess a compound's cardiac risk of arrhythmias centered on a mechanistic approach to arrhythmogenesis rather than focusing solely on the QT interval. This entails both robust preclinical and clinical assays along with the emergence of concentration QT modeling as a primary analysis tool to determine whether delayed ventricular repolarization is present. The purpose of this review is to provide a comprehensive understanding of the QT interval and highlight its central role in early drug development.


Assuntos
Arritmias Cardíacas/tratamento farmacológico , Arritmias Cardíacas/fisiopatologia , Desenvolvimento de Medicamentos/métodos , Eletrocardiografia/métodos , Síndrome do QT Longo/tratamento farmacológico , Síndrome do QT Longo/fisiopatologia , Animais , Arritmias Cardíacas/diagnóstico , Coração/efeitos dos fármacos , Coração/fisiopatologia , Ventrículos do Coração/efeitos dos fármacos , Ventrículos do Coração/fisiopatologia , Humanos , Síndrome do QT Longo/diagnóstico
15.
Biomed Res Int ; 2019: 2608547, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30915349

RESUMO

Methods of the electrocardiography (ECG) signal features extraction are required to detect heart abnormalities and different kinds of diseases. However, different artefacts and measurement noise often hinder providing accurate features extraction. One of the standard techniques developed for ECG signals employs linear prediction. Referring to the fact that prediction is not required for ECG signal processing, smoothing can be more efficient. In this paper, we employ the p-shift unbiased finite impulse response (UFIR) filter, which becomes smooth by p < 0. We develop this filter to have an adaptive averaging horizon: optimal for slow ECG behaviours and minimal for fast excursions. It is shown that the adaptive UFIR algorithm developed in such a way provides better denoising and suboptimal features extraction in terms of the output signal-noise ratio (SNR). The algorithm is developed to detect durations and amplitudes of the P-wave, QRS-complex, and T-wave in the standard ECG signal map. Better performance of the algorithm designed is demonstrated in a comparison with the standard linear predictor, UFIR filter, and UFIR predictive filter based on real ECG data associated with normal heartbeats.


Assuntos
Algoritmos , Arritmias Cardíacas/fisiopatologia , Eletrocardiografia/métodos , Processamento de Sinais Assistido por Computador , Feminino , Humanos , Masculino , Razão Sinal-Ruído
17.
Mitochondrion ; 46: 6-14, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30905865

RESUMO

Cardiovascular disease is the leading cause of diabetes-related morbidity and mortality. It is widely accepted that heart failure risk is increased in diabetic patients even after adjusting for coronary artery disease and hypertension. Mitochondria are the center of fatty acid (FA) and glucose metabolism and thus are likely to be impacted by impaired metabolism associated with diabetes. Although the cause of this increased heart failure risk is multifactorial, increasing evidence points toward a crucial role for cardiomyocyte mitochondria dysfunction. Altered energy metabolism, defects in mitochondrial dynamics, increased oxidative stress, impaired calcium (Ca2+) handling and mitochondria-induced cell death are observed in mitochondria of diabetic myocardium. In addition, mitochondrial dysfunction appears to contribute substantially to the origin of arrhythmias in diabetic hearts. The current review will describe these mitochondrial abnormalities in cardiomyocytes attempting to provide an overview of underlying mechanisms. Finally, we briefly discuss the potential link between mitochondrial malfunction and arrhythmogenesis.


Assuntos
Arritmias Cardíacas/fisiopatologia , Complicações do Diabetes/fisiopatologia , Diabetes Mellitus/patologia , Mitocôndrias/patologia , Miócitos Cardíacos/patologia , Morte Celular , Humanos , Metabolismo
18.
Turk Kardiyol Dern Ars ; 47(2): 122-127, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30874505

RESUMO

OBJECTIVE: A study of the T wave peak-to-end (Tp-e) interval, the Tp-e/QT ratio, and the Tp-e/QTc ratio in pediatric heart transplant recipients (HTRs), a group which has a higher risk of sudden cardiac death than the normal population, has not previously been reported. The aim of this study was to assess alterations in ventricular repolarization using the Tp-e interval, Tp-e/ QT ratio, and Tp-e/QTc ratio in clinically stable pediatric HTRs. METHODS: A total of 13 clinically stable HTRs, 13 patients who had undergone cardiac surgery (CS) under cardiopulmonary bypass, and 16 healthy controls under 18 years of age were retrospectively evaluated. RESULTS: No significant differences were observed between the HTR, CS, and control groups in terms of QTc, JTc interval, and T wave amplitude (p>0.05). The Tp-e interval (p=0.001), Tp-e/QT ratio (p<0.001), and Tp-e/QTc ratio (p=0.001) were significantly higher in the HTR group compared with the CS and normal control participants. CONCLUSION: The Tp-e interval, Tp-e/QT ratio, and Tp-e/QTc ratio were elevated in stable HTRs compared with the normal and CS groups.


Assuntos
Arritmias Cardíacas/fisiopatologia , Transplante de Coração , Adolescente , Estudos de Casos e Controles , Criança , Eletrocardiografia , Feminino , Sistema de Condução Cardíaco , Cardiopatias Congênitas/cirurgia , Humanos , Masculino
19.
Sensors (Basel) ; 19(4)2019 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-30781412

RESUMO

In recent years, wearable devices have been popularly applied in the health care field. The electrocardiogram (ECG) is the most used signal. However, the ECG is measured under a body-motion condition, which is easily coupled with some noise, like as power line noise (PLn) and electromyogram (EMG). This paper presents a grey spectral noise cancellation (GSNC) scheme for electrocardiogram (ECG) signals where two-stage discrimination is employed with the empirical mode decomposition (EMD), the ensemble empirical mode decomposition (EEMD) and the grey spectral noise estimation (GSNE). In the first stage of the proposed GSNC scheme, the input ECG signal is decomposed by the EMD to obtain a set of intrinsic mode functions (IMFs). Then, the noise energies of IMFs are estimated by the GSNE. When an IMF is considered as noisy one, it is forwarded to the second stage for further check. In the second stage, the suspicious IMFs are reconstructed and decomposed by the EEMD. Then the IMFs are discriminated with a threshold. If the IMF is considered as noisy, it is discarded in the reconstruction process of the ECG signal. The proposed GSNC scheme is justified by forty-three ECG signal datasets from the MIT-BIH cardiac arrhythmia database where the PLn and EMG noise are under consideration. The results indicate that the proposed GSNC scheme outperforms the traditional EMD and EEMD based noise cancellation schemes in the given datasets.


Assuntos
Arritmias Cardíacas/diagnóstico , Eletrocardiografia/métodos , Processamento de Sinais Assistido por Computador , Dispositivos Eletrônicos Vestíveis , Algoritmos , Arritmias Cardíacas/fisiopatologia , Eletromiografia , Humanos , Razão Sinal-Ruído
20.
Expert Rev Cardiovasc Ther ; 17(3): 225-235, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30715961

RESUMO

INTRODUCTION: The past few years have given rise to extensive research on an interatrial block and its clinical relevance, mainly its association with supraventricular arrhythmias. In 2015, the authors of this article reviewed the Bayes syndrome for the first time and after three years there has been so much evidence accumulated that it seems reasonable to rewrite an update, based fundamentally on the new findings. Focused on its relationship with cardioembolic strokes, today efforts are being targeted at understanding its pathophysiology, its diagnosis, and its prognostic implications, in order to learn if it should be treated. Areas covered: A non-systematic review of the literature was developed using the Pubmed and Cochrane databases, focusing on randomized clinical trials and large observational studies that evaluated new physiopathological and epidemiological aspects, new clinical scenarios in which it has been assessed and its association with dementia. Finally, those studies that proposed new possible treatments were reviewed. Expert commentary: Interatrial block is not only a predictor of supraventricular arrhythmias, is a subclinical disease that might be considered as a marker of risk for adverse outcomes. Although there is some evidence to suggest that early treatment may be beneficial, potential therapies have yet to be investigated.


Assuntos
Arritmias Cardíacas/fisiopatologia , Átrios do Coração/fisiopatologia , Bloqueio Interatrial/fisiopatologia , Humanos , Ensaios Clínicos Controlados Aleatórios como Assunto
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA