Análisis tiempo-frecuencia de la fibrilación ventricular. Estudio experimental

Introduction and objectives. The analysis of frequency variability during ventricular fibrillation has yielded inconsistent results. We used an experimental model of ventricular fibrillation, with a short timescale, to analyze variations in frequency and their associated spatial distribution. Methods. Epicardial recordings of ventricular fibrillation were made in 10 perfused isolated rabbit heart preparations using a multiple electrode system (i.e., 240 unipolar electrodes). Both spectral and time-frequency analysis were used to derive the dominant frequency in the anterolateral wall of the left ventricle. Results. Linear regression analysis showed that there was a good correlation between …

Evaluation of the Complexity of Myocardial Activation During Ventricular Fibrillation. An Experimental Study

A B S T R A C T Introduction and objectives: An experimental model is used to analyze the characteristics of ventricular fibrillation in situations of variable complexity, establishing relationships among the data produced by different methods for analyzing the arrhythmia. Methods: In 27 isolated rabbit heart preparations studied under the action of drugs (propranolol and KB-R7943) or physical procedures (stretching) that produce different degrees of change in the complexity of myocardial activation during ventricular fibrillation, use was made of spectral, morphological, and mapping techniques to process the recordings obtained with epicardial multielectrodes. Results: The complexity of ve…

Modifications in Ventricular Fibrillation and Capture Capacity Induced by a Linear Radiofrequency Lesion

[EN] Introduction and objectives: An analysis was made of the effects of a radiofrequency-induced linear lesion during ventricular fibrillation and the capacity to capture myocardium through high-frequency pacing. Methods: Using multiple epicardial electrodes, ventricular fibrillation was recorded in 22 isolated perfused rabbit hearts, analyzing the activation maps upon applying trains of stimuli at 3 different frequencies close to that of the arrhythmia: a) at baseline; b) after radio-frequency ablation to induce a lesion of the left ventricular free wall (length=10 [1] mm), and c) after lengthening the lesion (length=23 [2] mm). Results: Following lesion induction, the regularity of the r…

Changes in the Spectral Characteristics of Ventricular Fibrillation in Lesions Produced by Radiofrequency Ablation. An Experimental Study

INTRODUCTION AND OBJECTIVES Although electro- physiological databases contain information about changes in the time domain in lesions produced by radiofrequency ablation, very few data on changes in the frequency domain are available. The aim of this study was to investigate changes in the spectral characteristics of ventricular fibrillation in zones with radiofrequency lesions. METHODS Recordings of ventricular fibrillation were obtained in 11 isolated perfused rabbit heart preparations using a multiple epicardial electrode located on the left ventricular free wall. Spectral parameters derived by Fourier analysis before and after the creation of transmural radiofrequency lesions were compa…

Ranolazine induced modifications of ventricular fibrillation activation complexity under mechanical stretch

Programmed death-1 (PD-1): A novel mechanism for understanding the acute immune deregulation in ST-segment elevation myocardial infarction

Lipid Profile Results after Cardiovascular Prevention Programme: Euroaction Model in Spain

Background: Cardiovascular prevention and rehabilitation programmes (CVPRP) are an established model of care designed to improve risk factor management. They have been successfully implemented in a variety of settings, in patients with coronary heart disease (CHD). Objective: To assess the long term impact of a nurse-coordinated, multidisciplinary, CVPRP in patients with CHD in the reduction of lipid profile and medication prescription in clinical practice. Methods: The study used an analytical, experimental, population based, prospective and longitudinal design. In Spain, the study was conducted in the Valencian Community, including two randomized hospitals. Coronary patients were prospec…

The Sum of ST-Segment Elevation Is the Best Predictor of Microvascular Obstruction in Patients Treated Successfully by Primary Percutaneous Coronary Intervention. Cardiovascular Magnetic Resonance Study

Introduction and objectives The usefulness of ST-segment elevation resolution (STR) for predicting epicardial reperfusion is well established. However, it is still not clear how ST-segment changes are related to microvascular obstruction (MVO) observed by cardiovascular magnetic resonance (CMR) after primary percutaneous coronary intervention (pPCI) for ST-segment elevation myocardial infarction (STEMI). Methods The study involved 85 consecutive patients admitted for a first STEMI and treated by pPCI who had a patent infarct-related artery. An ECG was recorded on admission and 90 min and 6, 24, 48 and 96 h after pPCI. Thereafter, STR and the sum of ST-segment elevation (sumSTE) in all leads…

Comments on “New epicardial mapping electrode with warming/cooling function for experimental electrophysiology studies” [33 (5) (2011) 653–659]

Evaluation of the Effectiveness of Breastfeeding as a Factor in the Prevention of Breast Cancer

Background: As cancer is one of the main causes of fatal illnesses in the world, and breast cancer is responsible for an elevated number of deaths in women, it is important to implement measures to prevent this disease. Method: In order to assess the influence of breastfeeding in preventing breast cancer in women, forteen prospective cohort articles are included in this study, and their methodological quality has been assessed through the Newcastle Ottawa quality assessment scale cohort studies. After determining the risk of bias for each case study, those with fewer systematic errors and therefore greater validity, have been selected to demonstrate the relationship they propose exists bet…

Decrease of CD4+ T Lymphocytes after myocardial infarction is related with extensive myocardial fibrosis

Purpose: Myocardial fibrosis plays a potential role in left ventricular remodeling and patients' outcome. After myocardial infarction innate immune cells infiltrate infarcted area and replace necrotic tissue by fibrotic tissue. However the role of adaptive immunity, especially T cells, has not yet been investigated in this scenario. Methods: We studied 94 patients with a first STEMI treated with percutaneous revascularization. Leucocyte subsets and a wide variety of lymphocyte subtypes were determined in peripheral blood 24 h after reperfusion by means of flow cytometry. Infarct size and cardiac fibrosis were measured by late enhancement Cardiac Magnetic Resonance (CRM) 1 week and 6 months …

Analyzing the electrophysiological effects of local epicardial temperature in experimental studies with isolated hearts

As a result of their modulating effects upon myocardial electrophysiology, both hypo- and hyperthermia can be used to study the mechanisms that generate or sustain cardiac arrhythmias. The present study describes an original electrode developed with thick-film technology and capable of controlling regional temperature variations in the epicardium while simultaneously registering its electrical activity. In this way, it is possible to measure electrophysiological parameters of the heart at different temperatures. The results obtained with this device in a study with isolated and perfused rabbit hearts are reported. An exploration has been made of the effects of local temperature changes upon…

Influencia del tipo de registro (unipolar o bipolar) en las características espectrales de los registros epicárdicos de la fibrilación ventricular. Estudio experimental

Introduction and objectives. The aim of this study was to examine the hypothesis that the recording mode (ie, unipolar or bipolar) affects the information obtained using spectral analysis techniques during ventricular fibrillation by carrying out an experiment using epicardial electrodes. Methods. Recordings of ventricular fibrillation were obtained in 29 isolated rabbit hearts using a multipleelectrode probe located on the left ventricular free wall. The parameter values obtained in the frequency domain (by Fourier analysis) using unipolar or bipolar electrodes, different interelectrode distances, and different orientations (ie, horizontal, vertical, or diagonal) were compared. Results. Ch…

Modificaciones de las características espectrales de la fibrilación ventricular en las lesiones producidas con radiofrecuencia. Estudio experimental

Introduccion y objetivos Aunque se dispone de informacion sobre las modificaciones en el dominio del tiempo de los registros electrofisiologicos en zonas lesionadas con radiofrecuencia, los datos disponibles en el dominio de la frecuencia son muy escasos. Se analizan las modificaciones de las caracteristicas espectrales de la fibrilacion ventricular en zonas lesionadas con radiofrecuencia. Metodos En 11 preparaciones de corazon aislado y perfundido de conejo, se registra la fibrilacion ventricular con un electrodo multiple epicardico situado en la pared libre ventricular izquierda. Se comparan los parametros espectrales obtenidos mediante analisis de Fourier antes y despues de practicar les…

Estudio experimental de los efectos de EIPA, losartán y BQ-123 sobre las modificaciones electrofisiológicas inducidas por el estiramiento miocárdico

Resumen Introduccion y objetivos Se han implicado diversos mecanismos en la respuesta mecanica al estiramiento miocardico, que incluyen la activacion del intercambiador Na+/H+ por acciones autocrinas y paracrinas. Se estudia la participacion de estos mecanismos en las respuestas electrofisiologicas al estiramiento agudo miocardico mediante el analisis de los cambios inducidos con farmacos. Metodos Se analizan las modificaciones de la fibrilacion ventricular inducidas por el estiramiento agudo miocardico en corazones de conejo aislados y perfundidos utilizando electrodos multiples epicardicos y tecnicas cartograficas. Se estudian 4 series: control (n = 9); durante la perfusion del antagonist…

Psycho-Social Factors in Patients with Cardiovascular Disease Attending a Family-Centred Prevention and Rehabilitation Programme: EUROACTION Model in Spain.

Background: Coronary heart disease (CHD) persists as the leading cause of death worldwide. Cardiovascular prevention and rehabilitation (CVPR) has an interdisciplinary focus, and includes not only in physiological components, but it also addresses psycho-social factors. Methods: The study analysed the Spanish psycho-social data collected during the EUROACTION study. In Spain, two hospitals were randomised in the Valencia community. Coronary patients were prospectively and consecutively identified in both hospitals. The intervention hospital carried out a 16-week CVPR programme, which aimed to assess illness perceptions and establish healthy behaviours in patients and their partners. Results…

Resultados de la estrategia farmacoinvasiva y de la angioplastia primaria en la reperfusión del infarto con elevación del segmento ST. Estudio con resonancia magnética cardiaca en la primera semana y en el sexto mes

Introduction and objectives: Pharmacoinvasive strategy represents an attractive alternative to primary angioplasty. Using cardiovascular magnetic resonance imaging we compared the left ventricular outcome of the pharmacoinvasive strategy and primary angioplasty for the reperfusion of ST-segment elevation myocardial infarction. Methods: Cardiovascular magnetic resonance was performed 1 week and 6 months after infarction in two consecutive cohorts of patients included in a prospective university hospital ST-segment elevation myocardial infarction registry. During the period 2004-2006, 151 patients were treated with pharmacoinvasive strategy (thrombolysis followed by routine non-immediate angi…

Effects of chronic exercise on myocardial refractoriness: a study on isolated rabbit heart

Aim:  To determine whether chronic physical training increases atrial and ventricular refractoriness in isolated rabbit heart. Methods:  Trained rabbits were submitted to a protocol of treadmill running. The electrophysiological parameters of refractoriness investigated in an isolated heart preparation were: (1) atrial effective refractory period (AERP) and atrial functional refractory period and ventricular effective and functional refractory periods (VERP and VFRP) using the extrastimulus technique at four different pacing cycle lengths; (2) the dominant frequency (DF) of ventricular fibrillation (VF). A multi-electrode plaque containing 256 electrodes and a spectral method were used to o…

Modificaciones de la fibrilación ventricular y de la capacidad de captura inducidas por una lesión lineal con radiofrecuencia

Resumen Introduccion y objetivos Analizar los efectos, en la fibrilacion ventricular y en la capacidad de capturar al miocardio mediante estimulacion a frecuencias rapidas, de una lesion lineal producida con radiofrecuencia. Metodos En 22 corazones de conejo aislados y perfundidos, se utilizaron electrodos multiples epicardicos para registrar la fibrilacion ventricular. Se analizaron los mapas de activacion al aplicar trenes de estimulos a tres frecuencias distintas, cercanas a las de la arritmia, en tres situaciones: a) basalmente; b) tras producir con radiofrecuencia una lesion en la pared libre del ventriculo izquierdo (longitud, 10 ± 1 mm), y c) tras ampliar su extension (longitud, 23 ±…

A novel multielectrode for epicardial recording with temperature control based in Peltier cells

Electrophysiological parameters of the myocardium are influenced by temperature. Working with experimental models of isolated heart, the analysis of modulating effect exerted by local changes of temperature can provide some information about the mechanisms of certain arrhythmias and their electrophysiological bases, such as ventricular fibrillation. Conventional multiple electrodes do not seem to be appropriate, being necessary the development of specific devices. The design and implementation of a device adapted to these requirements is presented in this paper. This is a multi-electrode able to reproduce located and controlled conditions of hypothermia and hyperthermia, in a determined are…

La suma de la elevación del segmento ST predice mejor la obstrucción microvascular en pacientes tratados con éxito con una intervención coronaria percutánea primaria. Un estudio de resonancia magnética cardiovascular

Introduccion y objetivos La utilidad de la resolucion del segmento ST (RST) para la prediccion de la reperfusion epicardica esta bien establecida. La asociacion de los cambios del segmento ST con la obstruccion microvascular (OMV) observada en la resonancia magnetica cardiovascular (RMC) tras una intervencion coronaria percutanea primaria (ICPp) en el infarto de miocardio con elevacion del ST (IMEST) no se ha aclarado todavia. Metodos Estudiamos a 85 pacientes consecutivos ingresados por un primer IMEST y tratados con una ICPp que tenian una arteria relacionada con el infarto permeable. Se registro un ECG al ingreso, tras 90 min y tras 6, 24, 48 y 96 h de la ICPp. Se calculo la RST y la sum…

2D Isochronal Correlation Method to Detect Pacing Capture during Ventricular Fibrillation

During ventricular fibrillation (VF), a portion of myocardial tissue can be captured by pacing at a rate near the fibrillation rate. Interruption of ventricular fibrillation can be favored by achieving stable myocardial capture, lowering the energy required for electrical cardioversion. Existence of myocardial capture during electrical stimulation is determined by visual inspection of electrograms (EGM) by an experienced observer. The objective of this work is the development of a semi-automatic method for the detection of myocardial capture based on the 2D correlation of isochronal maps. In 4 isolated rabbit hearts VF was induced by ventricular pacing with an increasing rate. An array of 1…

Efectos de la estreptomicina en las modificaciones de la activación miocárdica durante la fibrilación ventricular inducidas por el estiramiento

Se ha evaluado si las modificaciones en la activacion miocardica durante la fibrilacion ventricular producidas por el estiramiento agudo pueden ser contrarrestadas por un bloqueador de los receptores sensibles al estiramiento. En 16 corazones aislados de conejo, se ha analizado la refractariedad y la frecuencia de activacion durante la fibrilacion ventricular antes, durante y despues de producir un estiramiento agudo localizado en la pared libre del ventriculo izquierdo, en ausencia (serie A, n = 8) o en presencia (serie B, n = 8) de estreptomicina 200 μmol. Durante la perfusion de estreptomicina (serie B), tanto basalmente como durante y despues del estiramiento, la fibrilacion ventricular…

New epicardial mapping electrode with warming/cooling function for experimental electrophysiology studies

Cardiac electrical activity is influenced by temperature. In experimental models, the induction of hypothermia and/or hyperthermia has been used for the study of mechanisms of cardiac arrhythmia. A system that allows for localized, controlled induction, besides simultaneously recording electrical activity in the same induced area, needs to be developed ad hoc. This article describes the construction and application of a new system capable of locally modifying the epicardial temperature of isolated hearts and of carrying out cardiac mapping with sufficient spatial resolution. The system is based on a thermoelectric refrigerator and an array of 128 stainless steel unipolar electrodes in encap…

Dynamics of serum-induced endothelial cell apoptosis in patients with myocardial infarction

In patients with ST-segment elevation myocardial infarction (STEMI) reperfused with primary coronary intervention (PCI), the dynamics of endothelial cell (EC) viability, apoptosis and necrosis and its relationship with the structural consequences on the left ventricle have not been addressed so far.In 20 STEMI patients, we incubated human umbilical vein endothelial cells (HUVECs) with serum drawn before reperfusion and subsequently afterwards (24, 96 h, 30 days). Viability, apoptosis and necrosis percentages were evaluated by flow cytometry. Values were compared with 12 age- and sex-matched control subjects with normal coronary arteries. Cardiac magnetic resonance (CMR) was performed during…

Effect of Streptomycin on Stretch-Induced Change in Myocardial Activation During Ventricular Fibrillation

The aim of this study was to determine whether the changes in myocardial activation pattern resulting from acute stretching during ventricular fibrillation can be counteracted by administering a compound that blocks receptors sensitive to stretch. The study involved 16 isolated rabbit hearts, in which refractoriness and activation frequency during ventricular fibrillation were measured before, during and after localized acute stretching of the left ventricular free wall, either without (series A, n=8) or with (series B, n=8) the presence of streptomycin, 200 micromol. At baseline and during and after stretching, ventricular fibrillation was slower with streptomycin perfusion in series B tha…

Apoptosis and Mobilization of Lymphocytes to Cardiac Tissue Is Associated with Myocardial Infarction in a Reperfused Porcine Model and Infarct Size in Post-PCI Patients

ST-segment elevation myocardial infarction (STEMI) is the most severe outcome of coronary artery disease. Despite rapid reperfusion of the artery, acute irrigation of the cardiac tissue is associated with increased inflammation. While innate immune response in STEMI is well described, an in-depth characterization of adaptive immune cell dynamics and their potential role remains elusive. We performed a translational study using a controlled porcine reperfusion model of STEMI and the analysis of lymphocyte subsets in 116 STEMI patients undergoing percutaneous coronary intervention (PCI). In the animal model, a sharp drop in circulating T lymphocytes occurred within the first hours after reper…

Prognostic Value of a Comprehensive Cardiac Magnetic Resonance Assessment Soon After a First ST-Segment Elevation Myocardial Infarction

ObjectivesTo evaluate the prognostic value of a comprehensive cardiac magnetic resonance (CMR) assessment soon after a first ST-segment elevation myocardial infarction (STEMI).BackgroundCMR allows for a simultaneous assessment of wall motion abnormalities (WMA), WMA with low-dose dobutamine (WMA-dobutamine), microvascular obstruction, and transmural necrosis. This approach has been proven to be useful to predict late systolic recovery soon after STEMI. Its prognostic value and the relative prognostic weight of these indexes are not well-defined.MethodsWe studied 214 consecutive patients with a first STEMI treated with thrombolytic therapy or primary angioplasty discharged from hospital. In …

Experimental Study of the Effects of EIPA, Losartan, and BQ-123 on Electrophysiological Changes Induced by Myocardial Stretch

[ES] Introducción y objetivos Se han implicado diversos mecanismos en la respuesta mecánica al estiramiento miocárdico, que incluyen la activación del intercambiador Na+/H+ por acciones autocrinas y paracrinas. Se estudia la participación de estos mecanismos en las respuestas electrofisiológicas al estiramiento agudo miocárdico mediante el análisis de los cambios inducidos con fármacos. Métodos Se analizan las modificaciones de la fibrilación ventricular inducidas por el estiramiento agudo miocárdico en corazones de conejo aislados y perfundidos utilizando electrodos múltiples epicárdicos y técnicas cartográficas. Se estudian 4 series: control (n = 9); durante la perfusión del antagonista d…

Evaluación de la complejidad de la activación miocárdica durante la fibrilación ventricular. Estudio experimental

Resumen Introduccion y objetivos Analizar en un modelo experimental las caracteristicas de la fibrilacion ventricular en situaciones con distintos grados de complejidad y establecer la relacion existente entre los datos aportados por distintos metodos de analisis de la arritmia. Metodos En 27 preparaciones de corazon aislado de conejo estudiadas bajo la accion de farmacos (propranolol y KB-R7943) o procedimientos fisicos (estiramiento) que causan distintos grados de variacion de la complejidad de la activacion miocardica durante la arritmia, se han utilizado tecnicas espectrales, morfologicas y cartograficas para procesar los registros obtenidos con multielectrodos epicardicos. Resultados L…

The Beneficial Effect of Physical Exercise on Inflammatory Makers in Older Individuals.

Old age is associated with a loss of motor functions and a general progressive decline in cognitive functions. Physical exercise is one of the ways in which inflammatory levels in general can be reduced, and therefore physical exercise can be considered a biological aging decelerator. In this article, we examine the relationships between physical exercise and inflammatory markers reported for the different physical exercise protocols that have been used in studies with older individuals, as well as the effects of these regimens. The different types of exercises programmed, and methods used to implement them were very heterogeneous in the articles we analysed. Both, the aerobic exercise and…

P729PD-1/PD-L1 axis contributes to infarct size in ST elevation myocardial infarction

Programmed death-1 (PD-1) and Programmed death-1 ligand (PD-L1) regulate immune response. Previous studies associate an immune deregulation in ST-elevation myocardial infarction STEMI. We recruited 100 patients with a first STEMI treated with reperfusion. In all patients PD-1 and PD-L1 expression was studied 24 h post-reperfusion in peripheral blood mononuclear cells (PBMCs), by means of flow cytometry and molecular biology. PD-1 and PD-L1 expression was serially analyzed in the first 20 patients before reperfusion and 24h, 96h and 30 days afterwards. Results were compared with 30 age- and sex-matched controls. Cardiac Magnetic Resonance was used to quantify infarct size 1-week after infarc…

Resultados de la estrategia farmacoinvasiva y de la angioplastia primaria en la reperfusión del infarto con elevación del segmento ST. Estudio con resonancia magnética cardiaca en la primera semana y en el sexto mes

[EN] Introduction and objectives: Pharmacoinvasive strategy represents an attractive alternative to primary angioplasty. Using cardiovascular magnetic resonance imaging we compared the left ventricular outcome of the pharmacoinvasive strategy and primary angioplasty for the reperfusion of ST-segment elevation myocardial infarction. Methods: Cardiovascular magnetic resonance was performed 1 week and 6 months after infarction in two consecutive cohorts of patients included in a prospective university hospital ST-segment elevation myocardial infarction registry. During the period 2004-2006, 151 patients were treated with pharmacoinvasive strategy (thrombolysis followed by routine non-immediate…