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1.
Medicine (Baltimore) ; 100(8): e24896, 2021 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-33663121

RESUMO

INTRODUCTION: Hemodynamically-instable ventricular arrhythmias (VAs) are rare in patients with pulmonary hypertension (PH). To the best of our knowledge, only 1 case has been reported so far. Moreover, the pathogenesis of this kind of arrhythmia remains obscured and its treatment is challenging. Here we report another case and presented the substrate for VAs initiation and therapeutic effect of radiofrequency ablation. PATIENT CONCERNS: This is a 57-year-old man who presented paroxysmal palpitation associated with presyncope at rest. Surface electrocardiogram (ECG) revealed frequent ventricular premature contractions and non-sustained ventricular tachycardia when symptoms occurred. He also had a history of severe PH which was secondary to atrial septal defect and partial anomalous pulmonary venous drainage and suffered from obvious dyspnea when climbing stairs World Health Organization Class III (WHO Class III). DIAGNOSIS: Hemodynamically-instable VAs associated with severe PH. INTERVENTION: Echocardiography revealed enlargement of right ventricle (right ventricle [RV]: 43 mm). Electrophysiological examination showed the origin of VAs is next to a small low-voltage zone of RV. Radiofrequency delivery at the origin successfully terminated VAs without occurrence of complication. OUTCOME: The patient was free from arrhythmias and got an improvement of exercise tolerance, just with mild dyspnea when climbing stairs World Health Organization Class II (WHO class II), during six-month follow up. LESSONS: This case suggests the low-voltage zone of remodeled RV, which may be secondary to increased pulmonary artery pressure, serves as the substrate for VAs initiation in patient with PH. Radiofrequency ablation can successfully terminate VAs and the termination of VAs can significantly improve the patient's impaired exercise tolerance.


Assuntos
Hipertensão Pulmonar/complicações , Ablação por Radiofrequência/métodos , Complexos Ventriculares Prematuros/complicações , Ecocardiografia , Técnicas Eletrofisiológicas Cardíacas/métodos , Ventrículos do Coração/diagnóstico por imagem , Ventrículos do Coração/fisiopatologia , Humanos , Hipertensão Pulmonar/fisiopatologia , Masculino , Pessoa de Meia-Idade , Complexos Ventriculares Prematuros/fisiopatologia , Complexos Ventriculares Prematuros/terapia , Remodelação Ventricular
3.
Circ Arrhythm Electrophysiol ; 14(3): e009458, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33554620
4.
Life Sci ; 267: 118976, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33387579

RESUMO

Cardiac impairment contributes significantly to the mortality associated with several neurodegenerative diseases, such as Alzheimer's disease (AD), Parkinson's disease (PD), and Huntington's disease (HD), primarily recognized as brain pathologies. These diseases may be caused by aggregation of a misfolded protein, most often, in the brain, although new evidence also reveals peripheral abnormalities. After characterization of the cardiac involvement in neurodegenerative diseases, several studies concentrated on elucidating the cause of the impaired cardiac function. However, most of the current knowledge is focused on the mechanical aspects of the heart rather than the electrical disturbances. The main objective of this review is to summarize the most recent advances in the elucidation of cardiac electrical remodeling in the neurodegenerative environment. We aimed to determine a crosstalk between the heart and the brain in three neurodegenerative conditions: AD, PD, and HD. We found that the most studies demonstrated important alterations in the electrocardiogram (ECG) of patients with neurodegeneration and in animal models of the conditions. We also showed that little is described when considering excitability disruptions in cardiomyocytes, for example, action potential impairments. It is a matter of contention whether central nervous system abnormalities or the peripheral ones increase the risk of heart diseases in patients with neurodegenerative conditions. To determine this notion, there is a need for new heart studies focusing specifically on the cardiac electrophysiology (e.g., ECG and cardiomyocyte excitability). This review could serve as an important guide in designing novel accurate approaches targeting the heart in neuronal conditions.


Assuntos
Remodelamento Atrial/fisiologia , Doenças Neurodegenerativas/fisiopatologia , Remodelação Ventricular/fisiologia , Animais , Encéfalo/metabolismo , Técnicas Eletrofisiológicas Cardíacas/métodos , Coração/fisiologia , Humanos , Modelos Animais , Miocárdio/metabolismo , Doenças Neurodegenerativas/metabolismo
5.
Methods Mol Biol ; 2191: 287-307, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-32865751

RESUMO

Optogenetic approaches have evolved as potent means to investigate cardiac electrophysiology, with research ranging from the study of arrhythmia mechanisms to effects of cardiac innervation and heterocellular structural and functional interactions, both in healthy and diseased myocardium. Most commonly, these studies use channelrhodopsin-2 (ChR2)-expressing murine models that enable light-activated depolarization of the target cell population. However, each newly generated mouse line requires thorough characterization, as cell-type specific ChR2 expression cannot be taken for granted, and the electrophysiological response of its activation in the target cell should be evaluated. In this chapter, we describe detailed protocols for assessing ChR2 specificity using immunohistochemistry, isolation of specific cell populations to analyze electrophysiological effects of ChR2 activation with the patch-clamp technique, and whole-heart experiments to assess in situ effects of optical stimulation.


Assuntos
Channelrhodopsins/genética , Técnicas Eletrofisiológicas Cardíacas/métodos , Fenômenos Eletrofisiológicos/genética , Optogenética/métodos , Potenciais de Ação/genética , Animais , Arritmias Cardíacas/genética , Arritmias Cardíacas/metabolismo , Arritmias Cardíacas/patologia , Humanos , Luz , Camundongos , Miocárdio/metabolismo , Miocárdio/patologia , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/patologia , Técnicas de Patch-Clamp/métodos
6.
Am J Physiol Heart Circ Physiol ; 320(2): H713-H724, 2021 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-33337966

RESUMO

The complex pathophysiology of atrial fibrillation (AF) is governed by multiple risk factors in ways that are still elusive. Basic electrophysiological properties, including atrial effective refractory period (AERP) and conduction velocity, are major factors determining the susceptibility of the atrial myocardium to AF. Although there is a great need for affordable animal models in this field of research, in vivo rodent studies are limited by technical challenges. Recently, we introduced an implantable system for long-term assessment of AF susceptibility in ambulatory rats. However, technical considerations did not allow us to perform concomitant supraventricular electrophysiology measurements. Here, we designed a novel quadripolar electrode specifically adapted for comprehensive atrial studies in ambulatory rats. Electrodes were fabricated from medical-grade silicone, four platinum-iridium poles, and stainless-steel fixating pins. Initial quality validation was performed ex vivo, followed by implantation in adult rats and repeated electrophysiological studies 1, 4, and 8 wk postimplantation. Capture threshold was stable. Baseline AERP values (38.1 ± 2.3 and 39.5 ± 2.0 using 70-ms and 120-ms S1-S1 cycle lengths, respectively) confirmed the expected absence of rate adaptation in the unanesthetized state and validated our prediction that markedly higher values reported under anesthesia are nonphysiological. Evaluation of AF substrate in parallel with electrophysiological parameters validated our recent finding of a gradual increase in AF susceptibility over time and demonstrated that this phenomenon is associated with an electrical remodeling process characterized by AERP shortening. Our findings indicate that the miniature quadripolar electrode is a potent new tool, which opens a window of opportunities for better utilization of rats in AF research.NEW & NOTEWORTHY Rodents are increasingly used in AF research. However, technical challenges restrict long-term supraventricular electrophysiology studies in these species. Here, we developed an implantable electrode adapted for such studies in the rat. Our findings indicate that this new tool is effective for long-term follow-up of critical parameters such as atrial refractoriness. Obtained data shed light on the normal electrophysiology and on the increased AF susceptibility that develops in rats with implanted atrial electrodes over time.


Assuntos
Fibrilação Atrial/etiologia , Estimulação Cardíaca Artificial , Eletrodos Implantados , Técnicas Eletrofisiológicas Cardíacas/instrumentação , Sistema de Condução Cardíaco/fisiopatologia , Frequência Cardíaca , Monitorização Ambulatorial/instrumentação , Marca-Passo Artificial , Potenciais de Ação , Animais , Fibrilação Atrial/diagnóstico , Fibrilação Atrial/fisiopatologia , Modelos Animais de Doenças , Desenho de Equipamento , Masculino , Valor Preditivo dos Testes , Ratos Sprague-Dawley , Período Refratário Eletrofisiológico , Fatores de Tempo
8.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 406-409, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018014

RESUMO

Catheter ablation is increasingly used to treat atrial fibrillation (AF), the most common sustained cardiac arrhythmia encountered in clinical practice. A recent breakthrough finding in AF ablation consists in identifying ablation sites based on their spatiotemporal dispersion (STD). STD stands for a delay of the cardiac activation observed in intracardiac electrograms (EGMs) across contiguous leads. In practice, interventional cardiologists localize STD sites visually using the PentaRay multipolar mapping catheter. This work aims at automatically characterizing STD by classifying EGM data into STD vs. non STD groups using machine learning (ML) techniques. A dataset of 23082 multichannel EGM recordings acquired by the PentaRay coming from 16 persistent AF patients is included in this study. A major problem hampering the classification performance lies in the highly imbalanced dataset ratio. We suggest to tackle data imbalance using adapted data augmentation techniques including 1) undersampling 2) oversampling 3) lead shift 4) time reversing and 5) time shift. These tools are designed to preserve the integrity of the cardiac data and are validated by a partner cardiologist. They provide enhancement in classification performance in terms of sensitivity, which increases from 50% to 80% while maintaining accuracy and AUC around 90% with oversampling. Bootstrapping is applied to check the variability of the trained classifiers.Clinical relevance-The machine learning techniques developed in this contribution are expected to aid cardiologists in performing patient-tailored catheter ablation procedures for treating persistent AF.


Assuntos
Fibrilação Atrial , Ablação por Cateter , Fibrilação Atrial/cirurgia , Doença do Sistema de Condução Cardíaco , Técnicas Eletrofisiológicas Cardíacas , Humanos , Aprendizado de Máquina
9.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 414-417, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018016

RESUMO

Atrial Fibrillation (AF) is most common sustained cardiac arrhythmia and a precursor to many fatal cardiac conditions. Catheter ablation, which is a minimally invasive treatment, is associated with limited success rates in patients with persistent AF. Rotors are believed to maintain AF and core of rotors are considered to be robust targets for ablation. Recently, multiscale entropy (MSE) was proposed to identify the core of rotors in ex-vivo rabbit hearts. However, MSE technique is sensitive to intrinsic parameters, such as scale factor and template dimension, that may lead to an imprecise estimation of entropy measures. The purpose of this research is optimize MSE approach to improve its accuracy and sensitivity in rotor core identification using simulated EGMs from human atrial model. Specifically, we have identified the optimal time scale factor (τopt) and optimal template dimension (Τopt) that are needed for efficient rotor core identification. The τopt was identified to be 10, using a convergence graph, and the Τopt (~20 ms) remained the same at different sampling rates, indicating that optimized MSE will be efficient in identifying core of the rotor irrespective of the signal acquisition system.


Assuntos
Fibrilação Atrial , Ablação por Cateter , Animais , Fibrilação Atrial/cirurgia , Técnicas Eletrofisiológicas Cardíacas , Entropia , Átrios do Coração , Humanos , Coelhos
10.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 2606-2609, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018540

RESUMO

Over the last few years, the use of cardiac mapping for effective diagnosis and treatment of arrhythmias has increased significantly. In the clinical environment, electroanatomical mapping (EAM) is performed during the electrophysiological procedures using proprietary systems such as CARTO, EnSite Precision, RHYTHMIA, etc. These systems generate the 3D model of patient-specific atria with the electrical activity (i.e., intracardiac electrograms (iEGMs)) displayed on it, for further identification of the sources of arrhythmia and for guiding cardiac ablation therapy. Recently, several novel techniques were developed to perform iEGMs analysis to more accurately identify the arrhythmogenic sites. However, there is a difficulty in incorporating the results of iEGMs analysis back to EAM systems due to their proprietary constraints. This created a hurdle in the further development of novel techniques to help navigate patient-specific clinical ablation therapy. Thus, we developed an open source software, VIEgram1, that allows researchers to visualize the results of the various iEGMs analysis on a patient-specific 3D atria model. It eliminates the dependency of the academic environment on the proprietary EAM systems, thereby making the process of retrospective mapping extremely convenient and time efficient. Here, we demonstrate the features of VIEgram such as visual inspection of iEGMs, flexibility in implementing custom iEGMs analysis techniques and interpolation schemes, and spatial analysis.


Assuntos
Ablação por Cateter , Técnicas Eletrofisiológicas Cardíacas , Arritmias Cardíacas/diagnóstico , Átrios do Coração , Humanos , Estudos Retrospectivos
11.
Int Heart J ; 61(5): 922-926, 2020 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-32921670

RESUMO

The incidence of ventricular arrhythmia in patients with an implanted pacemaker is not yet known. The aim of this study was to analyze non-sustained ventricular tachycardia (NSVT) episodes based on stored electrograms (EGM) and determine the occurrence rate and risk factors for NSVT in a pacemaker population.This study included 302 consecutive patients with a dual-chamber pacemaker. A total of 1024 EGMs stored in pacemakers as ventricular high-rate episodes were analyzed. The definition of NSVT was ≥ 5 consecutive ventricular beats at ≥ 150 bpm lasting < 30 seconds.In baseline, most patients (94.8%) had ≥ 60% left ventricular ejection fraction. Of 1024 EGMs, 420 (41.0%) showed appropriate NSVT episodes, as well as premature atrial contractions, atrial tachyarrhythmia, or atrial fibrillation with a rapid ventricular response, whereas other EGMs did not show an actual ventricular arrhythmia. On EGM analysis, during a mean follow-up period of 46.1 months, NSVT occurred one or more times in 82 patients (33.1%). On multivariate analysis, ≥ 50% right ventricular pacing was an independent risk factor for NSVT (odds ratios, 4.519; P < 0.001), but NSVT was not associated with increased all-cause mortality.Moreover, in the pacemaker population, ≥ 50% right ventricular pacing is an independent risk factor for NSVT; however, NSVT was not associated with increased all-cause mortality because of the preserved left ventricular function.


Assuntos
Estimulação Cardíaca Artificial/métodos , Técnicas Eletrofisiológicas Cardíacas , Mortalidade , Marca-Passo Artificial , Taquicardia Ventricular/epidemiologia , Idoso , Idoso de 80 Anos ou mais , Fibrilação Atrial , Complexos Atriais Prematuros , Feminino , Ventrículos do Coração , Humanos , Armazenamento e Recuperação da Informação , Masculino , Pessoa de Meia-Idade , Fatores de Risco , Fatores Sexuais , Taquicardia Supraventricular
12.
PLoS One ; 15(9): e0239074, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32941513

RESUMO

BACKGROUND: A vectorcardiography approach to electrocardiology contributes to the non-invasive assessment of electrical heterogeneity in the ventricles of the heart and to risk stratification for cardiac events including sudden cardiac death. The aim of this study was to develop an automatic method that identifies a representative QRST complex (QRSonset to Tend) from a Frank vectorcardiogram (VCG). This method should provide reliable measurements of morphological VCG parameters and signal when such measurements required manual scrutiny. METHODS: Frank VCG was recorded in a population-based sample of 1094 participants (550 women) 50-65 years old as part of the Swedish CArdioPulmonary bioImage Study (SCAPIS) pilot. Standardized supine rest allowing heart rate stabilization and adaptation of ventricular repolarization preceded a recording period lasting ≥5 minutes. In the Frank VCG a recording segment during steady-state conditions and with good signal quality was selected based on QRST variability. In this segment a representative signal-averaged QRST complex from cardiac cycles during 10s was selected. Twenty-eight morphological parameters were calculated including both conventional conduction intervals and VCG-derived parameters. The reliability and reproducibility of these parameters were evaluated when using completely automatic and automatic but manually edited annotation points. RESULTS: In 1080 participants (98.7%) our automatic method reliably selected a representative QRST complex where its instability measure effectively identified signal variability due to both external disturbances ("noise") and physiologic and pathophysiologic variability, such as e.g. sinus arrhythmia and atrial fibrillation. There were significant sex-related differences in 24 of 28 VCG parameters. Some VCG parameters were insensitive to the instability value, while others were moderately sensitive. CONCLUSION: We developed an automatic process for identification of a signal-averaged QRST complex suitable for morphologic measurements which worked reliably in 99% of participants. This process is applicable for all non-invasive analyses of cardiac electrophysiology including risk stratification for cardiac death based on such measurements.


Assuntos
Coração/fisiologia , Idoso , Algoritmos , Técnicas Eletrofisiológicas Cardíacas/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
14.
Herzschrittmacherther Elektrophysiol ; 31(4): 334-340, 2020 Dec.
Artigo em Alemão | MEDLINE | ID: mdl-32965520

RESUMO

Cardiac electrophysiology has developed into a broad, exciting, and challenging subdiscipline of modern cardiology. The professional opportunities available to electrophysiologists are diverse and offer a wide variety of career goals. The aim of this article is to show young cardiologists what different career paths can look like if they opt for electrophysiology today. Personal testimonials from five experienced electrophysiologists on their own career paths show decisions, support, obstacles, and destinations of these paths to practice or university professorship. This article aims to support young cardiologists who are considering specialization in electrophysiology during their career planning.


Assuntos
Cardiologia , Escolha da Profissão , Eletrofisiologia Cardíaca , Técnicas Eletrofisiológicas Cardíacas , Especialização
15.
Herzschrittmacherther Elektrophysiol ; 31(4): 341-344, 2020 Dec.
Artigo em Alemão | MEDLINE | ID: mdl-32875379

RESUMO

BACKGROUND: Cardiac electrophysiology training of young cardiologists forms the foundation of optimal heart rhythm patient care. In particular, cardiac electrophysiology is characterized by continuous innovation and has progressed rapidly over the last few years. This may have led to a gap between clinical training and the new technologies and could significantly change training requirements. OBJECTIVE: The aim of the survey was to obtain the opinion of young cardiologists about the current importance and satisfaction of cardiac electrophysiology training and to identify areas for improvement. METHODS: The survey was conducted in May 2020. Young DGK (Deutschen Gesellschaft für Kardiologie, German Society for Cardiology) members were contacted via e­mail and asked to answer an online-based questionnaire. The questionnaire containing information about the current status, satisfaction, and structures of educational and clinical proficiency of cardiac electrophysiology in Germany. RESULTS: Overall, 131 young DGK members completed the survey. Mean age was 33 ± 3.3 years and 68% of the participants were male. Among the participants, 64% were cardiology fellows, while 36% were qualified. A total of 72 participants (53%) reported overall satisfaction with their clinical training and 50% of the participants held the opinion that cardiac electrophysiology should become a larger part of their education. Training courses and fellowships were rated mostly positive (70% vs. 93%, respectively); however, the later were unknown to 41% of the participants. Areas identified for improvement included the following: establishment of general cardiac electrophysiology rotation; enabling access to procedures to gain invasive skills; increased advertising for training courses and fellowships; increase of online-based training courses. CONCLUSION: The survey underlines the interest of young cardiologists in an intensified cardiac electrophysiology training within their cardiology training.


Assuntos
Cardiologia , Técnicas Eletrofisiológicas Cardíacas , Adulto , Eletrofisiologia Cardíaca , Alemanha , Humanos , Masculino
16.
JACC Clin Electrophysiol ; 6(8): 1053-1066, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32819525

RESUMO

Coronavirus disease 2019 (COVID-19) has presented substantial challenges to patient care and impacted health care delivery, including cardiac electrophysiology practice throughout the globe. Based upon the undetermined course and regional variability of the pandemic, there is uncertainty as to how and when to resume and deliver electrophysiology services for arrhythmia patients. This joint document from representatives of the Heart Rhythm Society, American Heart Association, and American College of Cardiology seeks to provide guidance for clinicians and institutions reestablishing safe electrophysiological care. To achieve this aim, we address regional and local COVID-19 disease status, the role of viral screening and serologic testing, return-to-work considerations for exposed or infected health care workers, risk stratification and management strategies based on COVID-19 disease burden, institutional preparedness for resumption of elective procedures, patient preparation and communication, prioritization of procedures, and development of outpatient and periprocedural care pathways.


Assuntos
Arritmias Cardíacas/diagnóstico , Arritmias Cardíacas/terapia , Cardiologia , Infecções por Coronavirus/epidemiologia , Assistência à Saúde , Técnicas Eletrofisiológicas Cardíacas , Pneumonia Viral/epidemiologia , Assistência Ambulatorial , American Heart Association , Betacoronavirus , Técnicas de Laboratório Clínico , Infecções por Coronavirus/diagnóstico , Infecções por Coronavirus/prevenção & controle , Tomada de Decisão Compartilhada , Pessoal de Saúde , Humanos , Programas de Rastreamento , Política Organizacional , Pandemias/prevenção & controle , Seleção de Pacientes , Equipamento de Proteção Individual/provisão & distribução , Pneumonia Viral/diagnóstico , Pneumonia Viral/prevenção & controle , Retorno ao Trabalho , Medição de Risco , Telemedicina , Estados Unidos/epidemiologia
17.
Rev Cardiovasc Med ; 21(2): 303-307, 2020 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-32706218

RESUMO

A 36-year-old woman with 12-week gestation visited the emergency department, complaining of palpitations. Her electrocardiography (ECG) demonstrated ventricular pre-excitation combined with atrial fibrillation. The polarity of the delta waves in leads V5, V6, I, and aVL were positive and negative in leads V1, III, and aVF, suggesting that the accessory pathway (AP) was located on the right posterior free wall. She did not want to take any medicine to prevent the tachycardia. Moreover, the shortest pre-excited RR interval during the atrial fibrillation was 200 ms, so we decided to ablate the AP without fluoroscopy. An electrophysiology study was performed with guidance of a 3-dimension (3D) navigation system and intracardiac echocardiography (ICE). We ablated the right free wall AP without fluoroscopy. A follow-up ECG no longer exhibited any delta waves. Even in the early period of pregnancy, catheter ablation might be performed safely using ICE and a 3D navigation system without fluoroscopy. Therefore, it could more often be considered as a therapeutic option in pregnant women without concern for radiation exposure.


Assuntos
Ablação por Cateter , Complicações Cardiovasculares na Gravidez/cirurgia , Exposição à Radiação/prevenção & controle , Síndrome de Wolff-Parkinson-White/cirurgia , Potenciais de Ação , Adulto , Ecocardiografia , Eletrocardiografia , Técnicas Eletrofisiológicas Cardíacas , Feminino , Frequência Cardíaca , Humanos , Gravidez , Complicações Cardiovasculares na Gravidez/diagnóstico , Complicações Cardiovasculares na Gravidez/fisiopatologia , Resultado do Tratamento , Síndrome de Wolff-Parkinson-White/diagnóstico , Síndrome de Wolff-Parkinson-White/fisiopatologia
18.
Circ Arrhythm Electrophysiol ; 13(8): e008160, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32631100

RESUMO

BACKGROUND: Advances in ablation for atrial fibrillation (AF) continue to be hindered by ambiguities in mapping, even between experts. We hypothesized that convolutional neural networks (CNN) may enable objective analysis of intracardiac activation in AF, which could be applied clinically if CNN classifications could also be explained. METHODS: We performed panoramic recording of bi-atrial electrical signals in AF. We used the Hilbert-transform to produce 175 000 image grids in 35 patients, labeled for rotational activation by experts who showed consistency but with variability (kappa [κ]=0.79). In each patient, ablation terminated AF. A CNN was developed and trained on 100 000 AF image grids, validated on 25 000 grids, then tested on a separate 50 000 grids. RESULTS: In the separate test cohort (50 000 grids), CNN reproducibly classified AF image grids into those with/without rotational sites with 95.0% accuracy (CI, 94.8%-95.2%). This accuracy exceeded that of support vector machines, traditional linear discriminant, and k-nearest neighbor statistical analyses. To probe the CNN, we applied gradient-weighted class activation mapping which revealed that the decision logic closely mimicked rules used by experts (C statistic 0.96). CONCLUSIONS: CNNs improved the classification of intracardiac AF maps compared with other analyses and agreed with expert evaluation. Novel explainability analyses revealed that the CNN operated using a decision logic similar to rules used by experts, even though these rules were not provided in training. We thus describe a scaleable platform for robust comparisons of complex AF data from multiple systems, which may provide immediate clinical utility to guide ablation. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02997254. Graphic Abstract: A graphic abstract is available for this article.


Assuntos
Potenciais de Ação , Fibrilação Atrial/diagnóstico , Diagnóstico por Computador , Técnicas Eletrofisiológicas Cardíacas , Frequência Cardíaca , Redes Neurais de Computação , Reconhecimento Automatizado de Padrão , Processamento de Sinais Assistido por Computador , Máquina de Vetores de Suporte , Idoso , Fibrilação Atrial/fisiopatologia , Função do Átrio Esquerdo , Função do Átrio Direito , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Sistema de Registros , Reprodutibilidade dos Testes , Fatores de Tempo
19.
J Vis Exp ; (160)2020 06 16.
Artigo em Inglês | MEDLINE | ID: mdl-32628156

RESUMO

Human cardiac slice preparations have recently been developed as a platform for human physiology studies and therapy testing to bridge the gap between animal and clinical trials. Numerous animal and cell models have been used to examine the effects of drugs, yet these responses often differ in humans. Human cardiac slices offer an advantage for drug testing in that they are directly derived from viable human hearts. In addition to having preserved multicellular structures, cell-cell coupling, and extracellular matrix environments, human cardiac tissue slices can be used to directly test the effect of innumerable drugs on adult human cardiac physiology. What distinguishes this model from other heart preparations, such as whole hearts or wedges, is that slices can be subjected to longer-term culture. As such, cardiac slices allow for studying the acute as well as chronic effects of drugs. Furthermore, the ability to collect several hundred to a thousand slices from a single heart makes this a high-throughput model to test several drugs at varying concentrations and combinations with other drugs at the same time. Slices can be prepared from any given region of the heart. In this protocol, we describe the preparation of left ventricular slices by isolating tissue cubes from the left ventricular free wall and sectioning them into slices using a high precision vibrating microtome. These slices can then either be subjected to acute experiments to measure baseline cardiac electrophysiological function or cultured for chronic drug studies. This protocol also describes dual optical mapping of cardiac slices for simultaneous recordings of transmembrane potentials and intracellular calcium dynamics to determine the effects of the drugs being investigated.


Assuntos
Cálcio/fisiologia , Técnicas Eletrofisiológicas Cardíacas , Função Ventricular , Ventrículos do Coração , Humanos , Técnicas In Vitro , Potenciais da Membrana , Microtomia
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