ABSTRACT
Introducción y objetivoEl exceso de peso puede inducir modificaciones en la estructura y función del miocardio. La presencia de hipertrofia ventricular izquierda es un predictor independiente de morbimortalidad cardiovascular.El objetivo principal del estudio ha sido conocer la prevalencia de alteraciones morfofuncionales cardiacas en pacientes con obesidad y su modificación tras la pérdida de peso después de una cirugía bariátrica (CB).Pacientes y métodosEstudio de cohortes prospectivo de 75 pacientes con obesidad y sin cardiopatía conocida a los que se les realizó un bypass gástrico. Se midieron parámetros antropométricos, analíticos y ecocardiográficos antes, a los 6 y 12 meses de la intervención.ResultadosSe incluyeron 75 pacientes (66,6% mujeres, edad media 39,3 [9,7] años e índice de masa corporal [IMC] 47,8 [7,1] kg/m2). A los 6 y 12 meses de la CB se produjo una reducción significativa del peso corporal, una mejora en los parámetros metabólicos, inflamatorios y protrombóticos, así como en los factores de riesgo cardiovascular asociados a la obesidad (hipertensión arterial [HTA], diabetes mellitus tipo 2 [DM2], dislipemia [DLP] y síndrome de apnea-hipopnea del sueño [SAHOS]).Antes de la intervención, el 62,7% de los pacientes presentaba alteración en la geometría del ventrículo izquierdo, siendo el remodelado concéntrico la más frecuente (38,7%). Además, el 50,7% presentaba disfunción diastólica. Al año de la CB, el patrón ventricular fue normal en el 92% de los casos y la función diastólica mejoró significativamente.ConclusionesNuestros resultados corroboran el efecto negativo de la obesidad sobre el miocardio, así como la potencial reversibilidad de estas alteraciones tras una pérdida significativa de peso después de una CB. (AU)
Introduction and objectiveExcess weight can cause structural and functional cardiac disorders. The presence of left ventricular hypertrophy in the obese patient is an independent predictor of cardiovascular morbidity and mortality.The major aim of the present study is to know the prevalence of cardiac morphofunctional disorders in obese patients, before and after weight loss due to bariatric surgery (BS).Patients and methodsProspective cohort study of 75 patients with obesity without known heart disease referred to gastric bypass. Anthropometric, analytical and echocardiographic parameters were measured before and after 6 and 12 months after BS.ResultsThe study included 75 patients (66.6% women, mean age 39.3 [9.7] years and BMI 47.8 [7.1] kg/m2). At 6 and 12 months after BS there was a significant reduction in body weight and an improvement in metabolic, inflammatory and prothrombotic parameters and in cardiovascular risk factors associated with obesity (hypertension, type 2 diabetes, dyslipidemia and obstructive sleep apnea−hypopnea syndrome).Before surgery, cardiac remodeling was present in 62.7%, most frequently in the form of concentric remodeling (38.7%). Diastolic dysfunction occurred in 50.7% of the patients.One year after surgery, the ventricular pattern was normal in 92% of cases and the diastolic function improved significantly.ConclusionsOur results support the negative effect of obesity on cardiac geometry and function and the potential reversibility of these cardiac alterations after marked weight loss due to BS. (AU)
Subject(s)
Humans , Bariatric Surgery/adverse effects , Diabetes Mellitus, Type 2/complications , Heart Diseases/complications , Obesity, Morbid/complications , Sleep Apnea, Obstructive/complications , Obesity/complications , Obesity/surgery , Prospective Studies , Weight LossABSTRACT
INTRODUCTION AND OBJECTIVE: Excess weight can cause structural and functional cardiac disorders. The presence of left ventricular hypertrophy in the obese patient is an independent predictor of cardiovascular morbidity and mortality. The major aim of the present study is to know the prevalence of cardiac morphofunctional disorders in obese patients, before and after weight loss due to bariatric surgery (BS). PATIENTS AND METHODS: Prospective cohort study of 75 patients with obesity without known heart disease referred to gastric bypass. Anthropometric, analytical and echocardiographic parameters were measured before and after 6 and 12 months after BS. RESULTS: The study included 75 patients (66.6% women, mean age 39.3 [9.7] years and BMI 47.8 [7.1] kg/m2). At 6 and 12 months after BS there was a significant reduction in body weight and an improvement in metabolic, inflammatory and prothrombotic parameters and in cardiovascular risk factors associated with obesity (hypertension, type 2 diabetes, dyslipidemia and obstructive sleep apnea-hypopnea syndrome). Before surgery, cardiac remodeling was present in 62.7%, most frequently in the form of concentric remodeling (38.7%). Diastolic dysfunction occurred in 50.7% of the patients. One year after surgery, the ventricular pattern was normal in 92% of cases and the diastolic function improved significantly. CONCLUSIONS: Our results support the negative effect of obesity on cardiac geometry and function and the potential reversibility of these cardiac alterations after marked weight loss due to BS.
Subject(s)
Bariatric Surgery , Diabetes Mellitus, Type 2 , Heart Diseases , Obesity, Morbid , Sleep Apnea, Obstructive , Adult , Bariatric Surgery/adverse effects , Diabetes Mellitus, Type 2/complications , Female , Heart Diseases/complications , Humans , Male , Obesity/complications , Obesity/surgery , Obesity, Morbid/complications , Prospective Studies , Sleep Apnea, Obstructive/complications , Weight LossABSTRACT
Introducción: La adaptación del corazón humano al acondicionamiento físico ha sido un tema de interés médico-científico, pues el remodelado cardíaco que comprende variación en el tamaño, forma, grosor de las paredes, y masa ventricular responde al tipo de actividad física. Objetivo: Determinar las modificaciones anatómicas del ventrículo izquierdo en kayacistas y canoístas femeninos y masculinos de alto rendimiento. Material y Métodos: Se realizó un estudio prospectivo, descriptivo de corte transversal en deportistas de canotaje de alto rendimiento que acudieron al Instituto de Medicina del Deporte durante la preparación especial con vistas a participar en los Juegos Olímpicos de Rio de Janeiro 2016. La muestra se conformó con 20 deportistas que cumplieron los criterios de inclusión establecidos, se recogieron los resultados de los diferentes parámetros ecocardiográficos que fueron estudiados para comprobar si existía modificación anatómica del ventrículo izquierdo (MAVI). Se empleó la estadística descriptiva e inferencial. Resultados: Edad promedio 20,9 ± 1,18 años, predominio del sexo masculino (65 por ciento); kayak (60 por ciento) y velocidad (55 por ciento) fueron las disciplinas deportivas y modalidades competitivas predominantes , fue frecuente la hipertrofia concéntrica en ambos sexos (65 por ciento), la edad deportiva de igual o menos de 10 años (60 por ciento), espesor relativo de la pared aumentado (65 por ciento), el índice AKS mayor se encontró en la hipertrofia excéntrica (1,3 por ciento) y el porciento de grasa predominante fue en la hipertrofia concéntrica para un (7,9 por ciento). Conclusiones: El espesor relativo de la pared ventricular tuvo una relación significativa con la modalidad competitiva(AU)
Introduction: The adaptation of the human heart to physical conditioning has been a medical and scientific topic of interest where cardiac remodeling involving changes in size, form, thickness of the walls and ventricular mass responds to the type of physical activity. Objective: To determine the anatomical modifications of the left ventricle in high performance male and female canoeing and kayaking athletes. Material and methods: A prospective, descriptive, cross-sectional study was conducted in high performance canoeing athletes that attended the Instituto de Medicina del Deporte during the special training in view of the preparation for the Olympic Games in Rio de Janeiro, 2016. The sample was composed of 20 athletes that fulfilled the established inclusion criteria. The results of the different echocardiographic parameters were collected and analyzed in order to check whether there were anatomical modifications of the left ventricle (AMLV). Differential and descriptive statistics were used. Results: The average age was 20, 9 ± 1, 18 years, the male sex predominated in the study (65 percent), kayak (60 percent) and velocity (55 percent) were the predominant sports disciplines and competitive modalities, respectively. Concentric hypertrophy in both sexes (65 percent), sporting age of 10 years or less (60 percent), and increase in relative wall thickness (65 percent) were frequent; the highest AKS index was found in eccentric hypertrophy (1,3 percent) and predominant fat percentage was observed in concentric hypertrophy (7,9 percent). Conclusions: The relative thickness of the ventricular wall had a significant relationship with the competitive modalities(AU)
Subject(s)
Humans , Male , Female , Adolescent , Adult , Water Sports/injuries , Heart Ventricles/physiopathology , Heart Ventricles/diagnostic imaging , Echocardiography/methods , Epidemiology, Descriptive , Cross-Sectional Studies , Prospective StudiesABSTRACT
AIMS: To explore the impact of obesity on the cardiac lipid profile in rats with diet-induced obesity, as well as to evaluate whether or not the specific changes in lipid species are associated with cardiac fibrosis. METHODS: Male Wistar rats were fed either a high-fat diet (HFD, 35% fat) or standard diet (3.5% fat) for 6 weeks. Cardiac lipids were analyzed using by liquid chromatography-tandem mass spectrometry. RESULTS: HFD rats showed cardiac fibrosis and enhanced levels of cardiac superoxide anion (O2), HOMA index, adiposity, and plasma leptin, as well as a reduction in those of cardiac glucose transporter (GLUT 4), compared with control animals. Cardiac lipid profile analysis showed a significant increase in triglycerides, especially those enriched with palmitic, stearic, and arachidonic acid. An increase in levels of diacylglycerol (DAG) was also observed. No changes in cardiac levels of diacyl phosphatidylcholine, or even a reduction in total levels of diacyl phosphatidylethanolamine, diacyl phosphatidylinositol, and sphingomyelins (SM) was observed in HFD, as compared with control animals. After adjustment for other variables (oxidative stress, HOMA, cardiac hypertrophy), total levels of DAG were independent predictors of cardiac fibrosis while the levels of total SM were independent predictors of the cardiac levels of GLUT 4. CONCLUSIONS: These data suggest that obesity has a significant impact on cardiac lipid composition, although it does not modulate the different species in a similar manner. Nonetheless, these changes are likely to participate in the cardiac damage in the context of obesity, since total DAG levels can facilitate the development of cardiac fibrosis, and SM levels predict GLUT4 levels.
Subject(s)
Glucose Transporter Type 4/metabolism , Heart Diseases/pathology , Lipid Metabolism , Obesity/complications , Animals , Chromatography, Liquid , Diet, High-Fat , Disease Models, Animal , Fibrosis , Heart Diseases/etiology , Leptin/metabolism , Male , Rats , Rats, Wistar , Tandem Mass SpectrometryABSTRACT
INTRODUCTION AND OBJECTIVES: The transcription factor TBX1 plays an important role in the embryonic development of the heart. Nothing is known about its involvement in myocardial remodeling after acute myocardial infarction (AMI) and whether its expression can be modulated by a treatment with proven benefit such as mineralocorticoid receptor blockade. METHODS: Acute myocardial infarction was induced in 60 rats via left coronary artery ligation: 50 animals were randomized to be euthanized after 1, 2, 4, 12, or 24 weeks; 10 animals were treated with eplerenone (100 mg/kg/days) 7 days before the AMI until their euthanasia (4 weeks later); 8 additional animals underwent surgery without ligation (control). We analyzed the cardiac expression of TBX1, fetal genes, and fibrosis markers. RESULTS: The gene and protein expression of TBX1 was increased in the infarcted myocardium, peaking 1 week after AMI (P < .01), without changes in the noninfarcted myocardium. Levels of the fetal genes and fibrosis markers also increased, peaking 4 weeks (P < .001) and 1 week (P < .01) after AMI, respectively. The TBX1 expression was correlated with that of the fibrosis markers (P < .01) but not the fetal genes. Eplerenone reduced the TBX1 increase and fibrosis induced by AMI, with an association improvement in ventricular function and remodeling in echocardiography. CONCLUSIONS: These results show the reactivated expression of TBX1 and indicate its involvement in cardiac fibrosis and remodeling after AMI and its participation in the benefit from mineralocorticoid receptor blockade.
Subject(s)
Myocardial Infarction/genetics , Myocardium/pathology , RNA, Messenger/metabolism , T-Box Domain Proteins/genetics , Ventricular Remodeling/genetics , Actinin/genetics , Actinin/metabolism , Animals , Atrial Natriuretic Factor/genetics , Atrial Natriuretic Factor/metabolism , Blotting, Western , Eplerenone , Fibrosis , Gene Expression Regulation, Developmental , Heart/drug effects , Mineralocorticoid Receptor Antagonists/pharmacology , Myocardium/metabolism , Myosin Heavy Chains/genetics , Myosin Heavy Chains/metabolism , Natriuretic Peptide, Brain/genetics , Natriuretic Peptide, Brain/metabolism , RNA, Messenger/drug effects , Rats , Real-Time Polymerase Chain Reaction , Spironolactone/analogs & derivatives , Spironolactone/pharmacology , T-Box Domain Proteins/drug effects , T-Box Domain Proteins/metabolism , Ventricular Remodeling/drug effectsABSTRACT
INTRODUCTION AND OBJECTIVES: Animal models are a useful tool for the evaluation of disease mechanisms and also for technologies for diagnosis and treatment. In this study we performed a descriptive analysis of the functional and structural cardiac changes occurred as a result of acute coronary occlusion in pigs and its evolution during 5 weeks. METHODS: 19-Large White pigs, weighing 20kg, randomized into 3-experimental series were used. After sternotomy, anterior descending coronary artery was occluded. Duration of occlusion: Series 1 (n=6) 60min; series 2 (n=8) 90min; series 3 (n=5) 60min followed for 5 weeks. The following parameters where then analyzed: global cardiac function (ECG, left ventricular and atrium pressures, aortic flow and cardiac echocardiography), regional contractility, troponin T and CK-MB levels, macroscopic and histological analyzes. RESULTS: Coronary occlusion transiently altered the global cardiac function and produced increased cell damage markers, impaired regional contractility and produced histological changes. The increment of ischemic time (60 vs. 90min) increased infarct size (13.4±5.4% vs. 22.9±7.8 S1 S2%; P=.04). After 5 weeks, morphological remodelling changes were evident. In 79% of cases ischemia triggered ventricular fibrillation. CONCLUSION: The porcine open chest model of acute myocardial infarction and reperfusion is valid for studying the pathophysiology of coronary ischemia, allows direct analysis of regional myocardial function and is easily retrievable in the event of serious arrhythmias.
Subject(s)
Myocardial Infarction/pathology , Myocardial Infarction/physiopathology , Acute Disease , Animals , Chronic Disease , Disease Models, Animal , Female , SwineABSTRACT
Introducción: En pacientes con hipertensión arterial pulmonar (HAP) Galectina- 3, biomarcador de fibrosis miocárdica, se ha asociado a marcadores ecocardiográficos de remodelado ventricular derecho. La relación entre Galectina- 3, remodelado auricular derecho (AD) y capacidad funcional (CF) en pacientes con HAP no ha sido explorado. El objetivo fue medir niveles de Galectina-3 y su relación con CF y remodelado AD en pacientes con HAP Metodos: Estudio prospectivo observacional en que se incluyeron 14 pacientes con HAP En todos los pacientes se midieron los niveles de Galectina-3, proBNP, se evaluó la CF mediante test de caminata 6 minutos (TC6M) y se evaluó remodelado AD. Se consideraron para el análisis dos grupos según la distancia caminada en TC6M (> 200 m vs. ≤ 200 m). Resultados: La edad promedio fue 43 ± 10 años, el 84% mujeres. Los niveles de Galectina-3 fueron 16,1 ± 7,4 ng/mL y el TC6M fue 371 ± 142 mts. Los pacientes con TC6M< 200 m presentaron mayores niveles de Galectina-3 (27,3 ± 4,6 vs 13,7 ± 3,8; p=0,006) y mayor volumen AD (151 ± 21 vs 94 ± 43; p=0,04). Además, se observó una correlación inversa entre el área AD y TC6M (-0,71; p=0,03). Conclusión: Niveles elevados de Galectina-3 y parámetros de remodelado adverso en AD se relacionan con una menor CF en pacientes con HAP. Estos hallazgos apuntan a una mejor caracterización de pacientes con HAP y eventualmente la búsqueda de nuevos objetivos terapéuticos.
Background: Galectin-3 is a biomarker of myo-cardial fibrosis and has been associated with echocar-diographic markers of right ventricular remodeling in patients with pulmonary artery hypertension (PAH). The association among Galectin-3 level, right atrial (RA) remodeling and functional capacity (FC) has not been explored. The objective was to measure plasma Galectin-3 concentrations and its relation with RA remodeling and FC in PAH patients. Methods: This is a prospective observational study and 14 PAH patients were included. Galectin-3 and proBNP levels were measured in all patients. FC was estimated by the 6-minute walk test (6MWT) and used to define 2 groups of subjects (≤200m or >200m). RA area and volume were measured by echocardiography from a 4 chamber view. Results: The average age was 43±10 years, 84% of patients were female. Galectin-3 levels were 16.1±7.4 ng / mL and 6MWT was 371±142 m. We observed an inverse correlation between RA area and 6MWT (-0.71;p=0.03). Conclusions: Higher Galectin-3 concentrations and RA adverse remodeling are related to a decreased FC in PAH patients. These findings may lead to a better characterization of PAH patients and eventually new therapeutic targets.
Subject(s)
Humans , Male , Female , Adult , Middle Aged , Pulmonary Artery/physiopathology , Ventricular Remodeling , Galectin 3/blood , Hypertension, Pulmonary/physiopathology , Echocardiography , Biomarkers , Prospective Studies , Observational Study , Hemodynamics , Hypertension, Pulmonary/bloodABSTRACT
Atrial fibrillation (AF) is the most common sustained chronic cardiac arrhythmia in clinical practice, which increases the risk of stroke and thromboembolism and is an independent predictor of mortality. The underlying mechanisms involved in the development of AF have yet to be fully elucidated. However, once initiated, AF tends to self-perpetuate, owing to structural and electrical remodeling in the atria. MicroRNAs (miRNAs) represent a sizable sub-group of small non-coding RNAs, which degrades or inhibits the translation of their target mRNAs, thus regulating gene expression and playing an important role in a wide range of biologic processes. Clinically, there is increasing evidence of the potential diagnostic role of miRNAs as biomarkers, representing a novel therapeutic target in AF. The aim of this review is to provide an exhaustive overview of the role of miRNAs in AF and to discuss the diagnostic and therapeutic potential of miRNAs in this arrhythmia.
La fibrilación auricular (FA) es la arritmia cardíaca sostenida crónica más común en la práctica clínica, lo que aumenta el riesgo de accidente cerebrovascular y tromboembolismo, y es un predictor independiente de mortalidad. Los mecanismos subyacentes implicados en el desarrollo de la FA todavía no se han aclarado completamente. Sin embargo, una vez iniciada, la FA tiende a perpetuarse, debido al remodelado estructural y eléctrico en la aurícula. Los microARN (miARN) representan un subgrupo importante de pequeños ARN no codificantes, que degradan o inhiben la traducción de sus ARN mensajeros diana, regulando así la expresión génica y que desempeñan un papel importante en una amplia gama de procesos biológicos. Clínicamente, se ha observado con creciente interés el posible papel diagnóstico de los miARN como biomarcadores, representando una nueva diana terapéutica en la FA. El objetivo de esta revisión es proporcionar una visión exhaustiva de la función de los miARN en la FA y discutir el posible papel diagnóstico y terapéutico de los miARN en esta arritmia.
Subject(s)
Humans , Atrial Fibrillation/genetics , MicroRNAs/physiology , BiomarkersABSTRACT
Atrial fibrillation (AF) is the most common sustained chronic cardiac arrhythmia in clinical practice, which increases the risk of stroke and thromboembolism and is an independent predictor of mortality. The underlying mechanisms involved in the development of AF have yet to be fully elucidated. However, once initiated, AF tends to self-perpetuate, owing to structural and electrical remodeling in the atria. MicroRNAs (miRNAs) represent a sizable sub-group of small non-coding RNAs, which degrades or inhibits the translation of their target mRNAs, thus regulating gene expression and playing an important role in a wide range of biologic processes. Clinically, there is increasing evidence of the potential diagnostic role of miRNAs as biomarkers, representing a novel therapeutic target in AF. The aim of this review is to provide an exhaustive overview of the role of miRNAs in AF and to discuss the diagnostic and therapeutic potential of miRNAs in this arrhythmia.
Subject(s)
Atrial Fibrillation/genetics , MicroRNAs/physiology , Biomarkers , HumansABSTRACT
FUNDAMENTO: A Contração Pós-Repouso (CPR) do músculo cardíaco fornece informações indiretas sobre a manipulação de cálcio intracelular. OBJETIVO: Nosso objetivo foi estudar o comportamento da CPR e seus mecanismos subjacentes em camundongos com infarto do miocárdio. MÉTODOS: Seis semanas após a oclusão coronariana, a contratilidade dos Músculos Papilares (MP) obtidos a partir de camundongos submetidos à cirurgia sham (C, n = 17), com infarto moderado (MMI, n = 10) e grande infarto (LMI, n = 14), foi avaliada após intervalos de repouso de 10 a 60 segundos antes e depois da incubação com cloreto de lítio (Li+) em substituição ao cloreto de sódio ou rianodina (Ry). A expressão proteica de SR Ca(2+)-ATPase (SERCA2), trocador Na+/Ca2+ (NCX), fosfolambam (PLB) e fosfo-Ser (16)-PLB foi analisada por Western blotting. RESULTADOS: Os camundongos MMI apresentaram potenciação de CPR reduzida em comparação aos camundongos C. Em oposição à potenciação normal para camundongos C, foram observadas degradações de força pós-repouso nos músculos de camundongos LMI. Além disso, a Ry bloqueou a degradação ou potenciação de PRC observada em camundongos LMI e C; o Li+ inibiu o NCX e converteu a degradação em potenciação de CPR em camundongos LMI. Embora os camundongos MMI e LMI tenham apresentado diminuição no SERCA2 (72 ± 7% e 47 ± 9% de camundongos controle, respectivamente) e expressão protéica de fosfo-Ser16-PLB (75 ± 5% e 46 ± 11%, respectivamente), a superexpressão do NCX (175 ± 20%) só foi observada nos músculos de camundongos LMI. CONCLUSÃO: Nossos resultados mostraram, pela primeira vez, que a remodelação miocárdica pós-IAM em camundongos pode mudar a potenciação regular para degradação pós-repouso, afetando as proteínas de manipulação de Ca(2+) em miócitos.
BACKGROUND: Post-rest contraction (PRC) of cardiac muscle provides indirect information about the intracellular calcium handling. OBJECTIVE: Our aim was to study the behavior of PRC, and its underlying mechanisms, in rats with myocardial infarction. METHODS: Six weeks after coronary occlusion, the contractility of papillary muscles (PM) obtained from sham-operated (C, n=17), moderate infarcted (MMI, n=10) and large infarcted (LMI, n=14) rats was evaluated, following rest intervals of 10 to 60 seconds before and after incubation with lithium chloride (Li+) substituting sodium chloride or ryanodine (Ry). Protein expression of SR Ca(2+)-ATPase (SERCA2), Na+/Ca2+ exchanger (NCX), phospholamban (PLB) and phospho-Ser(16)-PLB were analyzed by Western blotting. RESULTS: MMI exhibited reduced PRC potentiation when compared to C. Opposing the normal potentiation for C, post-rest decays of force were observed in LMI muscles. In addition, Ry blocked PRC decay or potentiation observed in LMI and C; Li+ inhibited NCX and converted PRC decay to potentiation in LMI. Although MMI and LMI presented decreased SERCA2 (72±7% and 47±9% of Control, respectively) and phospho-Ser16-PLB (75±5% and 46±11%, respectively) protein expression, overexpression of NCX (175±20%) was only observed in LMI muscles. CONCLUSION: Our results showed, for the first time ever, that myocardial remodeling after MI in rats may change the regular potentiation to post-rest decay by affecting myocyte Ca(2+) handling proteins.
FUNDAMENTO: La Contracción pos pausa (CPP) del músculo cardíaco provee informaciones indirectas sobre la manejo del calcio intracelular. OBJETIVO: Nuestro objetivo fue estudiar el comportamiento de la CPP y sus mecanismos subyacentes en Ratas con infarto de miocardio. MÉTODOS: Seis semanas después de la oclusión coronaria, la contractilidad de los Músculos Papilares (MP) obtenidos a partir de Ratas sometidos a falsa cirurgia (C, n = 17), con infarto moderado (MMI, n = 10) y gran infarto (LMI, n = 14), fue evaluada después de pausas de estímulos de 10 a 60 segundos antes y después de la incubación con cloruro de litio (Li+) en substitución del cloruro de sodio o rianodina (Ry). La expresión proteica de SR Ca(2+)-ATPasa (SERCA2), intercambiador Na+/Ca2+ (NCX), fosfolamban (PLB) y fosfo-Ser (16)-PLB fue analizada por Western blotting. RESULTADOS: Los Ratas MMI presentaron potenciación de CPP reducida en comparación a los Ratas C. En oposición a la potenciación normal para Ratas C, fueron observadas decaimientos de fuerza post-reposo en los músculos de Ratas LMI. Además de eso, la Ry bloqueó la decaimiento o potenciación de PRC observada en Ratas LMI y C; el Li+ inhibió el NCX y convirtió la decaimiento en potenciación de CPP en Ratas LMI. Aunque los Ratas MMI y LMI hayan presentado disminución en el SERCA2 (72 ± 7% y 47 ± 9% de Ratas control, respectivamente) y expresión proteica de fosfo-Ser16-PLB (75 ± 5% y 46 ± 11%, respectivamente), la superexpresión del NCX (175 ± 20%) sólo fue observada en los músculos de Ratas LMI. CONCLUSIÓN: Nuestros resultados mostraron, por primera vez, que el remodelado miocárdico post-IAM en Ratas puede cambiar la potenciación regular para decaimiento post-reposo, afectando las proteínas de manejo del Ca(2+) en miocitos.