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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.

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Introducción: El desarrollo de herramientas para investigar la actividad electrofisiológica cardiaca ha permitido profundizar en el conocimiento sobre los mecanismos subyacentes a las arritmias cardiacas. Los sistemas de mapeo óptico constituyen una tecnología que responde a la necesidad de superar varios obstáculos en la experimentación. Objetivo: Proporcionar una visión general de la importancia del mapeo óptico en cultivos celulares HL-1, en las investigaciones en electrofisiología cardiaca. Métodos: Se realizó una revisión sobre los estudios electrofisiológicos que involucran la línea celular HL-1 utilizando la técnica de mapeo óptico. Conclusiones: Los trabajos se caracterizan por la implementación de la técnica respecto a la tecnología de los equipos de mapeo, a la utilización de diferentes colorantes y al objetivo de la investigación. Están enfocados en el estudio de mecanismos arritmogénicos, procesos de estiramiento mecánico o remodelación del tejido y en el análisis de nuevos biomateriales. Lo anterior, sustenta la relevancia del mapeo óptico en la investigación cardiaca(AU)

Introduction: The development of tools to study cardiac electrophysiological activity has made it possible to broaden knowledge about the mechanisms underlying cardiac arrhythmias. Optical mapping systems constitute a technology that responds to the need to overcome several hurdles in experimentation. Objective: Provide an overview of the importance of optical mapping in HL-1 cell cultures in cardiac electrophysiology research. Methods: A review was conducted of electrophysiological studies involving the HL-1 cell line using the optical mapping technique. Conclusions: The studies are characterized by implementation of the technique with respect to the technology of mapping equipment, the use of different colorants and the purpose of the research. They focus on the study of arrhythmogenic mechanisms, mechanical stretch processes or tissue remodeling as well as the analysis of new biomaterials. The above substantiates the relevance of optical mapping in cardiac research(AU)

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Introducción: En la actualidad se hace imprescindible el estudio de la diabetes mellitus tipo 2 a partir de técnicas poco costosas en función de la carga sanitaria que representa, es entonces donde la prueba del peso sostenido gana valor como ejercicio isométrico estático cubano en el estudio de la variabilidad de la frecuencia cardíaca. Objetivo: Determinar las respuestas electrofisiológicas autonómicas y hemodinámicas en estado basal y durante la prueba del peso sostenido en pacientes sanos y con diabetes tipo 2. Métodos: Se realizó un estudio en la Universidad de Ciencias Médicas de Santiago de Cuba, no observacional, cuasi-experimental, de tipo antes-después con grupo control de 60 pacientes (30 sanos y 60 con diabetes mellitus tipo 2). Resultados: Los diabéticos presentaron mayor IMC (p = 0,004). En estado basal se experimentaron diferencias significativas entre pacientes sanos y diabéticos. En la mayoría, los parámetros de la variabilidad de la frecuencia cardíaca analizados y durante la prueba del peso sostenido, solo se observaron diferencias significativas en las variables TAS (p = 0,022), BF (p = 0,001) y AF (p = 0,015). Al realizar la prueba del peso sostenido se encontraron variaciones muy significativas (p < 0,001) de los parámetros hemodinámicos, y variaciones significativas de AF (p = 0,023) y BF/AF (p = 0,046) en pacientes sanos; y en diabéticos, diferencias significativas de las variables hemodinámicas. Conclusiones: Se determinó una menor respuesta en pacientes diabéticos con respecto a los sanos del sistema nervioso autónomo, lo que expresa un deterioro de este y una disminución de la actividad simpática y parasimpática(AU)

Introduction: At present it is indispensable to study type 2 diabetes mellitus with low-cost techniques due to the health load it represents. In this context the sustained weight test acquires great value as a Cuban static isometric exercise for the study of heart rate variability. Objective: Determine autonomic and hemodynamic electrophysiological responses at baseline state and during the sustained weight test in healthy subjects and type 2 diabetic patients. Methods: A non-observational quasi-experimental before-after study was conducted at the University of Medical Sciences of Santiago de Cuba based on a control group of 60 patients (30 healthy and 30 with type 2 diabetes mellitus). Results: Diabetics had a higher BMI (p = 0.004). At baseline state significant differences were found between healthy subjects and diabetic patients. In most of the heart rate variability parameters analyzed and during the sustained weight tests, the only variables that showed significant differences were SBP (p = 0.022), FB (p = 0.001) and FA (p = 0.015). The results obtained from the sustained weight test were the following: very significant variations of hemodynamic parameters (p < 0.001), significant FA (p = 0.023) and FB/FA (p = 0.046) variations in healthy subjects, and significant differences in hemodynamic variables in diabetic patients. Conclusions: A lower response by the autonomic nervous system was determined in diabetic patients versus healthy subjects, signaling deterioration of that system and reduced sympathetic and parasympathetic activity(AU)

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Relato de caso de uma paciente do sexo feminino, com 16 anos de idade à ocasião de sua admissão no Instituto de Cardiologia. A mesma foi encaminhada por serviço de saúde externo devido a síncopes durante atividade física e foi submetida à investigação, com diagnóstico final de taquicardia ventricular catecolaminérgica. Após a definição diagnóstica, foi realizado tratamento medicamentoso com betabloqueador, sendo necessário o implante de marcapasso definitivo por conta da incompetência cronotrópica secundária ao tratamento farmacológico instituído. Posteriormente, por persistência das arritmias ventriculares mesmo com o uso de terapia otimizada, optou-se por realizar um implante de CDI

Case report of a 16-year-old female patient at the time of her admission to the Institute of Cardiology. She was referred by an external healthcare service due to syncope during physical activity and was submitted to the investigation with a final diagnosis of catecholaminergic ventricular tachycardia. Once the diagnosis was established, the patient was administered a beta-blocker and definitive pacemaker implant was required due to chronotropic incompetence secondary to drug therapy. Subsequently, due to the persistence of ventricular arrhythmias despite the use of optimized therapy, we decided to implant an ICD

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Aims: His bundle pacing has shown to prevent detrimental effects from right ventricular apical pacing (RVA) and proved to resynchronize many conduction disturbances cases. However, the extent of His bundle pacing resynchronization is limited. An optimized stimulation waveform could expand this limit when implemented in His bundle pacing sets. In this work, we temporarily implemented RVA and Non-selective His bundle pacing with a biphasic anodal-first waveform (AF-nHB) and compared their effects against sinus rhythm (SR). Methods and results: Fifteen patients referred for electrophysiologic study with conduction disturbances, cardiomyopathy and ejection fraction below 35% were enrolled for the study. The following acute parameters were measured: QRS duration, left ventricular activation (RLVT), time of isovolumic contraction (IVCT), ejection fraction (EF), and dP/dtmax. QRS duration and RLVT decreased markedly under AF-nHB (SR: 169 ± 34 ms vs. nHB: 116 ± 31 ms, P < 0.0005) while RVA significantly increased QRS duration (SR: 169 ms vs. RVA: 198 ms, P < 0.05) and did not change RLVT (P = NS). Consistently, IVCT moderately decreased under AF-nHB (SR: 238 ms vs. RVA: 184 ms, P < 0.05 vs. SR) and dP/dtmax showed a 93.35 [mmHg] average increase under AF-nHB against SR. Also, T-wave inversions were observed during AF-nHB immediately after SR and RVA pacing suggesting the occurrence of cardiac memory. Conclusions: AF-nHB corrected bundle branch blocks in patients with severe conduction disturbances, even in those with dilated cardiomiopathy, outstanding from RVA. Also, the occurrence of cardiac memory during AF-nHB turned up as an observational finding of this study.

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Paciente do sexo masculino, de 62 anos de idade, com megacólon chagásico sem manifestações cardíacas, apresentou evento sincopal sem pródromos, sendo submetido a Holter de 24 horas, ecocardiografia, teste ergométrico e cineangiocoronariografia, que se mostraram normais. O estudo eletrofisiológico mostrou ausência de distúrbios de condução e de indução de taquiarritmias. Durante a fase basal do teste de inclinação, o paciente apresentou taquicardia ventricular polimórfica. Foi realizado implante de cardioversor-desfibrilador implantável. Na evolução, apresentou deterioração da função ventricular com início de terapêutica específica. Após sete anos de acompanhamento, observaram-se três episódios de taquicardia ventricular polimórfica adequadamente revertidos pelo cardioversor-desfibrilador implantável

A 62 year-old man with Chagasic megacolon without cardiac manifestations developed a syncope without prodrome and was submitted to 24-hour Holter monitoring, echocardiogram, exercise test and coronary angiography. Electrophysiology tests showed there was no conduction and tachyarrhythmia induction disorders. During the baseline phase of the tilt test, the patient presented a polymorphic ventricular tachycardia. An implantable cardioverter defibrillator was implanted. At the follow-up, the patient presented left ventricular deterioration and specific therapy was started. After seven years of follow-up, three episodes of polymorphic ventricular tachycardia were observed and were successfully converted

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BACKGROUND: Electrogram-guided ablation procedures have been proposed as an alternative strategy consisting of either mapping and ablating focal sources or targeting complex fractionated electrograms in atrial fibrillation (AF). However, the incomplete understanding of the mechanism of AF makes difficult the decision of detecting the target sites. To date, feature extraction from electrograms is carried out mostly based on the time-domain morphology analysis and non-linear features. However, their combination has been reported to achieve better performance. Besides, most of the inferring approaches applied for identifying the levels of fractionation are supervised, which lack of an objective description of fractionation. This aspect complicates their application on EGM-guided ablation procedures. METHODS: This work proposes a semi-supervised clustering method of four levels of fractionation. In particular, we make use of the spectral clustering that groups a set of widely used features extracted from atrial electrograms. We also introduce a new atrial-deflection-based feature to quantify the fractionated activity. Further, based on the sequential forward selection, we find the optimal subset that provides the highest performance in terms of the cluster validation. The method is tested on external validation of a labeled database. The generalization ability of the proposed training approach is tested to aid semi-supervised learning on unlabeled dataset associated with anatomical information recorded from three patients. RESULTS: A joint set of four extracted features, based on two time-domain morphology analysis and two non-linear dynamics, are selected. To discriminate between four considered levels of fractionation, validation on a labeled database performs a suitable accuracy (77.6 %). Results show a congruence value of internal validation index among tested patients that is enough to reconstruct the patterns over the atria to located critical sites with the benefit of avoiding previous manual classification of AF types. CONCLUSIONS: To the best knowledge of the authors, this is the first work reporting semi-supervised clustering for distinguishing patterns in fractionated electrograms. The proposed methodology provides high performance for the detection of unknown patterns associated with critical EGM morphologies. Particularly, obtained results of semi-supervised training show the advantage of demanding fewer labeled data and less training time without significantly compromising accuracy. This paper introduces a new method, providing an objective scheme that enables electro-physiologist to recognize the diverse EGM morphologies reliably.

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BACKGROUND: Areas with high frequency activity within the atrium are thought to be 'drivers' of the rhythm in patients with atrial fibrillation (AF) and ablation of these areas seems to be an effective therapy in eliminating DF gradient and restoring sinus rhythm. Clinical groups have applied the traditional FFT-based approach to generate the three-dimensional dominant frequency (3D DF) maps during electrophysiology (EP) procedures but literature is restricted on using alternative spectral estimation techniques that can have a better frequency resolution that FFT-based spectral estimation. METHODS: Autoregressive (AR) model-based spectral estimation techniques, with emphasis on selection of appropriate sampling rate and AR model order, were implemented to generate high-density 3D DF maps of atrial electrograms (AEGs) in persistent atrial fibrillation (persAF). For each patient, 2048 simultaneous AEGs were recorded for 20.478 s-long segments in the left atrium (LA) and exported for analysis, together with their anatomical locations. After the DFs were identified using AR-based spectral estimation, they were colour coded to produce sequential 3D DF maps. These maps were systematically compared with maps found using the Fourier-based approach. RESULTS: 3D DF maps can be obtained using AR-based spectral estimation after AEGs downsampling (DS) and the resulting maps are very similar to those obtained using FFT-based spectral estimation (mean 90.23 %). There were no significant differences between AR techniques (p = 0.62). The processing time for AR-based approach was considerably shorter (from 5.44 to 5.05 s) when lower sampling frequencies and model order values were used. Higher levels of DS presented higher rates of DF agreement (sampling frequency of 37.5 Hz). CONCLUSION: We have demonstrated the feasibility of using AR spectral estimation methods for producing 3D DF maps and characterised their differences to the maps produced using the FFT technique, offering an alternative approach for 3D DF computation in human persAF studies.

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O tratamento da estenose aórtica com implante por cateter de bioprótese valvar aórtica é sabidamente eficaz. Contudo, os distúrbios de condução são complicações frequentes e associam-se a elevada taxa de implante de marcapasso definitivo. Questões referentes ao melhor modo de estimulação, ao papel do cardiodesfibrilador na profilaxia de morte súbita e ao prognóstico ainda não apresentam consenso. Relata-se, portanto, um caso de paciente que, após o implante valvar, evoluiu com bloqueio completo de ramo esquerdo agudo e bradiarritmia, insuficiência cardíaca refratária ao tratamento medicamentoso, com fração de ejeção gravemente comprometida e intolerância ao betabloqueador por bradiarritmia. Optou-se, então, pela terapia de ressincronização ao invésdo marcapasso convencional, com boa resposta clínica. A associação com cardiodesfibrilador foi descartada paraprofilaxia de morte súbita após o estudo eletrofisiológico, o qual não evidenciou instabilidade elétrica ventricular...

Treatment of aortic stenosis with valve of transcatheter implant is known to be effective. However, conduction disorders are common complications and are associated with a high permanent pacemaker implantation rate. Questions regarding the best pacing mode, the role of the defibrillator in sudden death prevention and prognosis, do not have consensus yet. We report, therefore, the case of a patient who developed complete blockage of acute left bundle branch and bradyarrhythmia, heart failure refractory to drug therapy, poor ejection fraction and intolerance to betablocker due bradyarrhythmias after valve implant. Thus, we chose resynchronizationtherapy instead of conventional pacemakers and obtained a good clinical response. The association with adefibrillator was ruled out for sudden death prevention after the electrophysiological study, which did not show ventricular electrical instability...

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