Parental sensitivity, family alliance and infants' vagal tone: Influences of early family interactions on physiological emotion regulation.

In this study, we investigated the influence of parental sensitivity and family alliance on infants' vagal tone, considered as a physiological indicator of emotion regulation. Studies on mother-infant interactions have shown that vagal tone can be influenced by the quality of the interaction, such as interacting with a sensitive mother. To date, no study has investigated the influence of paternal sensitivity or family alliance on infants' vagal tone. We hypothesized that maternal sensitivity, paternal sensitivity, and family alliance would be associated with infants' vagal tone during dyadic and triadic interactions. We also explored if family alliance would act as a moderator on the association between parental sensitivity and vagal tone and if the sensitivity of both parents would act as a moderator on the association between family alliance and vagal tone. This study took place in Switzerland and included 82 families with their 3-4-month-old infants. Results showed that maternal sensitivity and family alliance were associated with infants' vagal tone, but paternal sensitivity was not. We found no significant moderation effect. However, result tendencies suggested that the contribution of paternal sensitivity to infants' emotion regulation could be influenced by family alliance, whereas maternal sensitivity and family alliance have a unique contribution.

En este estudio, investigamos la influencia de la sensibilidad del progenitor y la alianza de familia sobre el tono vagal del infante, considerado como un indicador fisiológico de regulación de la emoción. Los estudios acerca de las interacciones madre-infante han demostrado que el tono vagal puede ser influido por la calidad de la interacción, tal como el interactuar con una mamá sensible. Hasta hoy, ningún estudio ha investigado la influencia de la sensibilidad paterna o la alianza de familia sobre el tono vagal del infante. Nuestra hipótesis es que la sensibilidad materna, la sensibilidad paterna y la alianza de familia estaban asociadas con el tono vagal del infante durante las interacciones diádicas y triádicas. También exploramos si la alianza de familia actuaba como moderadora en la asociación entre la sensibilidad paterna y el tono vagal y si la sensibilidad de ambos progenitores actuaba como moderadora en la asociación entre la alianza de familia y el tono vagal. Este estudio se llevó a cabo en Suiza e incluyó a 82 familias con sus infantes de 3-4 meses de edad. Los resultados muestran que la sensibilidad materna y la alianza de familia estaban asociadas con el tono vagal del infante, pero que la sensibilidad paterna no lo estaba. No encontramos ningún efecto de moderación significativo. Sin embargo, las tendencias del resultado sugieren que la contribución de la sensibilidad paterna a la regulación de la emoción puede ser influida por la alianza de familia, mientras que la sensibilidad materna y la alianza de familia tienen una contribución particularmente única.

Dans cette étude nous nous sommes penchés sur l'influence de la sensibilité paternelle et de l'alliance de la famille sur le tonus vagal des nourrissons, considéré comme étant un indicateur physiologique de la régulation de l'émotion. Les études sur les interactions mère-nourrisson ont montré que le tonus vagal peut être influencé par la qualité de l'interaction, comme l'interaction avec une mère sensible. Jusqu'à présent aucune étude n'a porté sur l'influence de la sensibilité paternelle ou l'alliance familiale sur le tonus vagal des nourrissons. Nous avons fait l'hypothèse que la sensibilité maternelle, la sensibilité paternelle, et l'alliance familiale peuvent être liées au tonus vagal des nourrissons durant les interactions dyadiques et triadiques. Nous avons également exploré si l'alliance familiale pourrait agir comme modératrice sur le lien entre la sensibilité parentale et le tonus vagal et si la sensibilité des deux parents pourrait agir comme modérateur du lien entre l'alliance familiale et le tonus vagal. Cette étude s'est faite en Suisse et a inclus 82 familles avec des bébés de 3-4 mois. Les résultats ont montré que la sensibilité maternelle et l'alliance familiale étaient liées au tonus vagal des bébés mais la sensibilité de l'était pas. Nous n'avons trouvé aucun effet de modération important. Cependant les tendances des résultats ont suggéré que la contribution de la sensibilité paternelle à la régulation de l'émotion des nourrissons pourrait être influencée par l'alliance familiale alors que la sensibilité maternelle et l'alliance familiale a une contribution unique.

A Systematic Review of Respiratory Sinus Arrhythmia in Romantic Relationships.

Respiratory sinus arrhythmia (RSA), an index of the parasympathetic nervous system, has recently gained attention as a physiological component of regulatory processes, social connectedness, and health. Within the context of romantic relationships, studies have operationalized and conceptualized RSA in disparate ways, obscuring a clear pattern of findings. This systematic review synthesizes the rapidly developing literature and clarifies the role of RSA in romantic relationships. We evaluate support for three conceptual hypotheses: (1) resting baseline RSA is associated with better quality relationships; (2) phasic RSA is reflective of changes in threat and connection during couple interactions; and (3) physiological linkage in RSA between romantic partners relates to positive or negative relationship functioning depending on the nature of the linkage (e.g., in-phase vs. antiphase). We identified 26 empirical studies that tested associations between RSA and an index of romantic relationships (i.e., relationship satisfaction). Our findings show that higher RSA is not uniformly "good" for relationships. Higher resting baseline RSA was contemporaneously associated with better quality relationships, yet higher baseline RSA was also unexpectedly associated with relationship violence. Short-term decreases in RSA were found during relationship conflict, though the opposite-phasic increases in RSA during positive romantic partner interactions-was not found due to mixed empirical support. As expected, evidence for RSA linkage was found, though the connection between linkage and relationship functioning depends on the context in which it was measured. We discuss methodological limitations and directions for future research.

La arritmia sinusal respiratoria (ASR), un índice del sistema nervioso parasimpático, ha sido objeto de atención recientemente como componente fisiológico de los procesos reguladores, la conexión social y la salud. Dentro del contexto de las relaciones amorosas, los estudios han operacionalizado y conceptualizado la ASR de diversas maneras, ocultando un patrón claro de signos. Este análisis sistemático sintetiza la bibliografía que se está desarrollando rápidamente y aclara el papel que desempeña la ASR en las relaciones amorosas. Evaluamos el respaldo de tres hipótesis conceptuales: (1) una ASR de reposo en el momento basal está asociada con relaciones de mejor calidad; (2) la ASR refleja cambios en la amenaza y la conexión durante las interacciones de la pareja; y (3) la asociación fisiológica en la ASR entre los integrantes de la pareja se relaciona con el funcionamiento positivo o negativo de la relación según la índole de la asociación (p. ej.: en fase frente a contrafase). Identificamos 26 estudios empíricos que evaluaron las asociaciones entre la ASR y un índice de las relaciones amorosas (p. ej.: la satisfacción con la relación). Nuestros resultados indican que una ASR más alta no es uniformemente "buena" para las relaciones. Una ASR de reposo más alta en el momento basal estuvo asociada contemporáneamente con relaciones de mejor calidad, sin embargo, una ASR más alta en el momento basal también estuvo asociada inesperadamente con la violencia de pareja. Se encontraron disminuciones de la ASR a corto plazo durante el conflicto en las relaciones, aunque no se encontró lo opuesto -aumentos fásicos en la ASR durante las interacciones positivas de los integrantes de la pareja- debido a un respaldo empírico ambivalente. Como se esperaba, se encontraron indicios de una asociación de la ASR, aunque la conexión entre la asociación y el funcionamiento de la relación depende del contexto en el cual se midió. Comentamos las limitaciones metodológicas y damos indicaciones para investigaciones futuras.

Cardiovascular Reactivity During Marital Conflict in Laboratory and Naturalistic Settings: Differential Associations with Relationship and Individual Functioning Across Contexts.

Cardiovascular reactivity during spousal conflict is considered to be one of the main pathways for relationship distress to impact physical, mental, and relationship health. However, the magnitude of association between cardiovascular reactivity during laboratory marital conflict and relationship functioning is small and inconsistent given the scope of its importance in theoretical models of intimate relationships. This study tests the possibility that cardiovascular data collected in laboratory settings downwardly bias the magnitude of these associations when compared to measures obtained in naturalistic settings. Ambulatory cardiovascular reactivity data were collected from 20 couples during two relationship conflicts in a research laboratory, two planned relationship conflicts at couples' homes, and two spontaneous relationship conflicts during couples' daily lives. Associations between self-report measures of relationship functioning, individual functioning, and cardiovascular reactivity across settings are tested using multilevel models. Cardiovascular reactivity was significantly larger during planned and spontaneous relationship conflicts in naturalistic settings than during planned relationship conflicts in the laboratory. Similarly, associations with relationship and individual functioning variables were statistically significantly larger for cardiovascular data collected in naturalistic settings than the same data collected in the laboratory. Our findings suggest that cardiovascular reactivity during spousal conflict in naturalistic settings is statistically significantly different from that elicited in laboratory settings both in magnitude and in the pattern of associations with a wide range of inter- and intrapersonal variables. These differences in findings across laboratory and naturalistic physiological responses highlight the value of testing physiological phenomena across interaction contexts in romantic relationships.

Prognostic value of low heart rates in patients admitted with acute myocardial infarction.

INTRODUCTION AND OBJECTIVES: The risk prediction scores adopted in acute coronary syndromes (ACS) use incremental models to estimate mortality for heart rate (HR) above 60 bpm. Nonetheless, previous studies reported a nonlinear relationship between HR and events, suggesting that low HR may have an unrecognized prognostic role. We aimed to assess the prognostic impact of low HR in ACS, defined as admission HR <50 bpm. METHODS: This study analyzed data from the AMIS Plus registry, a cohort of hospitalized patients with ACS between 1999 and 2021. The primary endpoint was in-hospital all-cause mortality, while a composite of all-cause mortality, major cardiac/cerebrovascular events was set as the secondary endpoint. A multilevel statistical method was used to assess the prognostic role of low HR in ACS. RESULTS: The study included 51 001 patients. Crude estimates showed a bimodal distribution of primary and secondary endpoints with peaks at low and high HR. A nonlinear relationship between HR and in-hospital mortality was observed on restricted cubic spline analysis. An HR of 50 to 75 bpm showed lower mortality than HR <50 bpm (OR, 0.67; 95%CI, 0.47-0.99) only after primary multivariable analysis, which was not confirmed after multiple sensitivity analyses. After propensity score matching, progressive fading of the prognostic role of HR <50 bpm was evident. CONCLUSIONS: Low admission HR in ACS is associated with a higher crude rate of adverse events. Nonetheless, after correction for baseline differences, the prognostic role of low HR was not confirmed. Therefore, low HR probably represents a marker of underlying morbidity. These results may be clinically relevant in improving the accuracy of risk scores in ACS.

The long-term impact of early adverse experience on adaptive functioning: a pilot study integrating measures of mental status, nonverbal communication, and heart rate variability.

Background: Childhood maltreatment (CM) can disrupt the development of behavioural and physiological systems, increasing the risk of physical and psychological adverse outcomes across the lifespan. CM may cause interpersonal dysfunctions that impair social communication and lead to dysfunctional activation of the autonomic nervous system. The present exploratory study analyzed the long-term impact of CM from an integrated perspective through the simultaneous assessment of psychological symptoms, social and behavioural communication, and physiological regulation.Methods: Participants were 55 healthy university students (9 males and 46 females; mean age ± SD = 25.26 ± 2.83 years), who filled out a battery of questionnaires to assess the presence of CM (Childhood Trauma Questionnaire) and psychopathological symptoms (Symptom Check-List-90 Item Revised). Participants were then subjected to a videotaped interview for the assessment of non-verbal behaviour (Ethological Coding System for Interviews) and measurement of tonic heart rate variability (HRV), a measure of physiological adaptability to the environment. We performed Pearson's correlation analysis to evaluate the associations between non-verbal behaviour, HRV, and CM variables. Multiple regression analysis was used to evaluate the independent associations between CM variables on HRV and nonverbal behaviour.Results: We found an association between more severe CM, increased symptoms-related distress (ps < .001), less submissive behaviour (ps < .018), and decreased tonic HRV (ps < .028). As a result of multiple regression analysis, participants with a history of emotional abuse (R² = .18, p = .002) and neglect (R² = .10, p = .03) were more likely to display decreased submissive behaviour during the dyadic interview. Moreover, early experience of emotional (R² = .21, p = .005) and sexual abuse (R² = .14, p = .04) was associated with decreased tonic HRV.Conclusion: Our preliminary findings show the utility of analyzing the long-term effects of adverse early experiences at different levels of 'adaptive functioning' (the capabilities needed to respond effectively to environmental demands).

Substantial traumatic experiences during childhood, such as emotional abuse, emotional neglect, and sexual abuse were associated with lower heart rate variability levels in a sample of young adults.Young adults with a history of emotional abuse and neglect were more likely to display decreased submissive behaviour (ethological behaviour) during the dyadic interview.Severe childhood maltreatment was associated with increased symptoms-related distress, less submissive behaviour (ethological behaviour), and decreased tonic heart rate variability in young adults.

The RITHMI study: diagnostic ability of a heart rhythm monitor for automatic detection of atrial fibrillation.

INTRODUCTION AND OBJECTIVES: Early detection of atrial fibrillation (AF) is a priority to reduce embolic events by initiating oral anticoagulation therapy. The aim of this study was to evaluate the diagnostic ability of a wrist device designed for automatic AF detection. METHODS: RITHMI is a prospective, comparative, observational study that included 167 patients referred to a cardiology outpatient clinic for a general consultation or for electrical cardioversion. The study evaluated the ability of a wrist monitor that uses a photoplethysmography (PPG) signal and an electrocardiographic lead to automatically detect AF compared with diagnosis established by 2 cardiologists using the 12-lead electrocardiogram. RESULTS: The AF detection algorithm based on the PPG signal had a sensitivity of 91% and a specificity of 96% (diagnostic accuracy: 93%). The automatic algorithm based on the electrocardiographic signal had a sensitivity of 94% and a specificity of 96% (diagnostic accuracy: 95%). The 2 algorithms concurred in the diagnosis in 96% of the cases. Overall, the monitor had a sensitivity and specificity of 95% (diagnostic accuracy: 95% and Kappa index: 0.98). CONCLUSIONS: This study shows that automatic AF detection through the use of a heart rhythm monitor incorporating sensors and algorithms that analyze the PPG signal and the electrocardiographic signal corresponding to lead I is feasible and has high diagnostic accuracy.

Determinants of physical performance and physiological responses during an Official cross-country marathon of mountain-biking (Xcm-Mtb) / Determinantes del rendimiento físico y las respuestas fisiológicas durante una maratón oficial de bicicleta de montaña a través del campo (XCM-MTB) / Determinantes do desempenho físico e as respostas fisiológicas durante uma maratona oficial de mountain bike cross-country (Xcm-Mtb)

Abstract: Introduction: The variables determinants of physical performance in cross-country marathon of mountain biking (XCMMTB) are still unknown. Objective: We aimed to verify the training control variables and the physiological responses in an official XCM-MTB race. Material and methods: 13 athletes (11 men and 2 women; 33.3 ± 12.7 years of age) participated in this study. It was conducted during an official XCM-MTB in Brazil (route of 70 km). The heart rate (HR), altimetry, velocity, temperature, pacing, and power were obtained every 10 km travelled by the STRAVA application. Multiple linear regression analysis was performed to verify whether the variables could predict physical performance. Results: The athletes maintained constant HR elevation in the corresponding zone 80% HRmax. They also presented a variation in the pacing (F = 35.82; p < 0.001; d = 0.66) and power (F = 7.20; p < 0.001; d = 0.18) showing higher values in the last 10 km. Only pacing can be considered a predictor of the physical performance (β = 0.958; t = 7.30; p < 0.001), specifically the one at 20 km (F = 10.23; p = 0.004; R2 = 0.82). Conclusion: The study concluded that the analyzed variables are reliable for the performance control in an official XCMMTB race. HR and power are variables that can be used to prescribe and control training, as they change according to the requirements of the race. Power can also be used as a performance predictor as it is directly influenced by terrain.

Resumen: Introducción: Las variables determinantes del rendimiento físico en una maratón de ciclismo de montaña (XCM-MTB) aún son desconocidas. Objetivo: Nuestro objetivo fue verificar las variables fisiológicas y de control del entrenamiento en una carrera oficial de XCM-MTB. Materiales y métodos: 13 atletas (11 hombres y 2 mujeres; 33,3 ± 12,7 años) participaron en este estudio. La investigación se realizó durante un XCM-MTB oficial en Brasil (recorrido de 70 km). La frecuencia cardíaca (FC), la altimetría, la velocidad, la temperatura, el ritmo y la potencia se obtuvieron cada 10 km recorridos por la aplicación STRAVA. Se realizó un análisis múltiple de regresión linear para verificar si las variables podían predecir el rendimiento físico. Resultados: Hubo una elevación constante de la FC correspondiente al 80 % de la FCmax. El ritmo presentó una variación (F = 35,82; p < 0,001; d = 0,66) y potencia (F = 7,20; p < 0,001; d = 0,18) con valores superiores en los últimos 10 km. Solo el ritmo a los 20 km (F = 10,23; p = 0,004; R2 = 0,82) puede considerarse predictor del rendimiento físico (β = 0,958; t = 7,30; p < 0,001). Conclusión: El estudio concluyó que las variables analizadas son fiables para la prescripción y control del entrenamiento en una carrera oficial de XCM-MTB. La FC y la potencia son variables que se pueden utilizar para prescribir el entrenamiento. La potencia también se puede utilizar para predecir el rendimiento, ya que está directamente influenciada por el terreno.

Resumo: Introdução: As variáveis determinantes do desempenho físico na maratona de mountain bike cross-country (XCMMTB) ainda são desconhecidas. Objetivo: Nosso objetivo foi verificar as variáveis de controle de treinamento e as respostas fisiológicas em uma corrida oficial de XCMMTB. Material e métodos: Participaram deste estudo 13 atletas (11 homens e 2 mulheres; 33,3 ± 12,7 anos de idade). O estudo foi realizado durante uma corrida oficial de XCM-MTB no Brasil (percurso de 70 km). A frequência cardíaca (FC), altimetria, velocidade, temperatura, ritmo e potência foram obtidos a cada 10 km percorridos através do aplicativo STRAVA. Foi realizada uma análise de regressão linear múltipla para verificar se as variáveis poderiam prever o desempenho físico. Resultados: Os atletas mantiveram uma elevação constante na FC na zona correspondente a 80% da FC máxima. Apresentaram também variação no ritmo (F = 35,82; p < 0,001; d = 0,66) e na potência (F = 7,20; p < 0,001; d = 0,18), mostrando valores mais altos nos últimos 10 km. Apenas o ritmo pode ser considerado um preditor do desempenho físico (β = 0,958; t = 7,30; p < 0,001), especificamente no ponto dos 20 km (F = 10,23; p = 0,004; R2 = 0,82). Conclusão: O estudo concluiu que as variáveis analisadas são confiáveis para o controle de desempenho em uma corrida oficial de XCMMTB. A FC e a potência são variáveis que podem ser usadas para prescrever e controlar o treinamento, pois mudam de acordo com as exigências da corrida. A potência também pode ser usada como um preditor de desempenho, pois é diretamente influenciada pelo terreno.

Cardio-Physiological and Anthropometric Profile of Elite International Handball Players from Top Ranking Macedonian Teams / Perfil Cardiofisiológico y Antropométrico de Jugadores Internacionales de Balonmano de Élite de Equipos Macedonios de Primer Nivel

SUMMARY: Monitoring of body composition and cardiophysiological parameters are main part of the general health status of handball players and significant indicators of their physical fitness. The assessment of body components, especially skeletal muscle mass and body fat mass are important because of their influence on sport performance. The aim of this study is to determine the body composition and cardiophysiological characteristics of elite handball players from Republic of North Macedonia. 27 male HB players from two top ranking teams from RNM were tested ergometrically with Bruce protocol for determination of maximal oxygen consumption; body analysis was made with bioelectrical impedance analyzer, InBody 720. Anthropometric parameters were as follows: mean height was 190.4±7.8 cm and weight 96.3±15.5 kg, skeletal muscle mass (SMM)=47.11±6.69 kg; BMI=26.38±3.1; BF%=15.04±6.01 and WHR=0.9±1.8. The result of ergometrical test produce mean VO2 max=43.92 ml/kg/min which is 100.46 % of reference value. The body composition of elite international handball players from the top handball teams in Republic of North Macedonia showed similar body components as other European handball players. The obesity diagnose parameters were negatively associated with exercise time and maximal oxygen consumption.

El seguimiento de la composición corporal y los parámetros cardiofisiológicos son una parte principal del estado de salud general de los jugadores de balonmano y son indicadores importantes de su condición física. La evaluación de los componentes corporales, especialmente la masa muscular esquelética y la masa grasa corporal, son importantes debido a su influencia en el rendimiento deportivo. El objetivo de este estudio fue determinar la composición corporal y las características cardiofisiológicas de jugadores de balonmano de élite de la República de Macedonia del Norte. Se evaluaron 27 jugadores masculinos de HB de dos equipos de primer nivel de RNM ergométricamente con el protocolo de Bruce para determinar el consumo máximo de oxígeno; el análisis corporal se realizó con el analizador de impedancia bioeléctrica InBody 720. Los parámetros antropométricos fueron los siguientes: talla media 190,4±7,8 cm y peso 96,3±15,5 kg, masa músculo esquelética (SMM)=47,11±6,69 kg; IMC=26,38±3,1; %GC=15,04±6,01 y RCC=0,9±1,8. El resultado de la prueba ergométrica produce un VO2 máximo medio = 43,92 ml/kg/ min, que es el 100,46 % del valor de referencia. La composición corporal de los jugadores de balonmano internacionales de élite de los mejores equipos de balonmano de la República de Macedonia del Norte mostró componentes corporales similares a los de otros jugadores de balonmano europeos. Los parámetros diagnósticos de obesidad se asociaron negativamente con el tiempo de ejercicio y el consumo máximo de oxígeno.

Uso de mascarillas faciales y frecuencia cardiaca en adultos de 18 a 60 años / Use of face masks and heart rate in adults aged 18 to 60 years / Uso de máscara facial e freqüência cardíaca em adultos de 18-60 anos de idade

Objetivo. Evaluar la influencia del uso de mascarillas faciales sobre la frecuencia cardiaca (FC) en reposo y en la actividad física en adultos de 18 a 60 años, en la ciudad de Lima, durante la pandemia por la COVID-19 en el 2020. Métodos. Se realizó un estudio de tipo experimental, analítico, prospectivo y transversal. Para la recopilación de datos se realizó una encuesta virtual vía Google forms, con una serie de preguntas e indicaciones para la correcta medida de la FC en diferentes situaciones: reposo, inmediatamente posterior a la actividad y 5 min posterior a la actividad física con y sin el uso de mascarillas (KN95, tela, quirúrgica y N95). Para el presente estudio se analizaron las posibles causas del aumento de la FC, por lo que fueron elegidos 60 adultos asintomáticos, 40 mujeres y 20 hombres, en el rango de edades entre 18 hasta 60 años. Resultados. Se obtuvo que la diferencia de la FC promedio con y sin uso de mascarilla inmediatamente posterior a la actividad física aumentó signifcativamente dependiendo del tipo de mascarilla. Con respecto a la KN95, se presenció un aumento de hasta en 9,6 latidos/min, mientras las mascarillas en tela, quirúrgica y N95 mostraron un aumento de 5,9, 5,6 y 7,4 latidos/min, respectivamente, bajo las mismas condiciones, calculándose en una media de 112,7 latidos/min por sobre 10,6 latidos/min en reposo, evidenciándose un incremento en hasta 7 % de su valor en reposo. Conclusión. Se comprobó que el uso de la mascarilla ejerce una notable influencia en la FC, inmediatamente y 5 minutos posterior terminada la actividad física, siendo la KN95 la mascarilla facial más utilizada y la de mayor influencia en el pulso cardiaco

Objective. To evaluate the influence of the use of face masks on resting heart rate (HR) and physical activity in adults aged 18 to 60 years, in the city of Lima, during the COVID-19 pandemic in 2020. Methods. An experimental, analytical, prospective and cross-sectional study was carried out. For data collection, a virtual survey was carried out via Google Forms, with a series of questions and indications for the correct measurement of HR in different situations: at rest, immediately after activity and 5 min after physical activity with and without the use of masks (KN95, fabric, surgical and N95). For the present study, the possible causes of increased HR were analyzed, so 60 asymptomatic adults, 40 women and 20 men, in the age range of 18 to 60 years, were selected. Results. It was found that the difference in mean HR with and without mask use immediately after physical activity increased signifcantly depending on the type of mask. With respect to the KN95, an increase of up to 9.6 beats/min was observed, while the fabric, surgical and N95 masks showed an increase of 5.9, 5.6 and 7.4 beats/min, respectively, under the same conditions, calculating an average of 112.7 beats/ min over 10.6 beats/min at rest, showing an increase of up to 7% of its value at rest. Results. It was obtained that the difference in the average HR with and without mask use immediately after physical activity increased signifcantly depending on the type of mask. With respect to KN95, an increase of up to 9,6 beats/min was observed, while cloth, surgical and N95 masks showed an increase of 5,9, 5,6 and 7,4 beats/min, respectively, under the same conditions, calculated at an average of 112.7 beats/min over 10,6 beats/min at rest, evidencing an increase in up to 7 % of their value at rest. Conclusion. It was found that the use of the face mask exerts a notable influence on HR, immediately and 5 minutes after the end of the physical activity, being the KN95 the most used face mask and the one with the greatest influence on the cardiac pulse.

Objetivo. Avaliar o influence do uso de máscaras faciais em repouso de freqüência cardíaca (FC) e atividade física em adultos de 18-60 anos de idade, na cidade de Lima, durante a pandemia da COVID-19 em 2020. Métodos. Foi realizado um estudo experimental, analítico, prospectivo e de corte transversal. Para a coleta de dados, foi realizada uma pesquisa virtual através de formulários Google, com uma série de perguntas e indicações para a medição correta de RH em diferentes situações: em repouso, imediatamente após o repouso, imediatamente após o exercício, e imediatamente após o exercício. situações: em repouso, imediatamente após a atividade e 5 minutos após a atividade física com e sem o uso de máscaras (KN95, tecido, cirúrgico e N95). Para o presente estudo, foram analisadas as possíveis causas do aumento do RH e foram selecionados 60 adultos assintomáticos, 40 mulheres e 20 homens, na faixa etária de 18 a 60 anos. Resultados. Descobriu-se que a diferença em HR com e sem o uso da máscara imediatamente após a atividade física aumentou significativamente, dependendo do tipo de máscara. Com respeito ao KN95, foi testemunhado um aumento de até 9,6 batidas/min, enquanto o tecido, as máscaras cirúrgicas e N95 mostraram um aumento de 5,9, 5,6 e 7,4 batimentos/min, respectivamente, nas mesmas condições, com uma média de 112,7 batimentos/min acima de 10,6 batimentos/min em repouso, mostrando um aumento de até 7% de seu valor de repouso. Conclusão. Verificou-se que o uso da máscara facial exerce uma influência notável na FC, imediatamente e 5 minutos após o final da atividade física, sendo a KN95 a máscara facial mais usada e a que tem maior influência no pulso cardíaco.

Opportunistic screening for atrial fibrillation versus detecting symptomatic patients aged 65 years and older: A cluster-controlled clinical trial. / Cribado oportunista de fibrilación auricular frente a detección de pacientes sintomáticos de 65 años o más: ensayo clínico controlado por clúster.

OBJECTIVE: The goal of this study was to assess the effectiveness of opportunistic screening through pulse palpation in the early detection of atrial fibrillation in subjects aged≥65 years versus detection through an active search for patients with symptoms and/or complications and sequelae associated. MATERIAL AND METHODS: This was a cluster randomized controlled trial performed in 48 primary care centers of the Spanish National Healthcare System. A total of 368 physicians and nurses were randomized. The researchers in the experimental group (EG) performed opportunistic screening for auricular fibrillation, whereas the researchers in the control group (CG) actively searched for symptomatic patients. An ECG was performed on patients found to have an irregular heartbeat to confirm the diagnosis of auricular fibrillation. RESULTS: A total of 5,465 patients with a mean age of 75.61 years were recruited for the EG, and 1,525 patients with a mean age of 74.07 years were recruited for the CG. Of these, 58.6% were female, without significant differences between groups. Pulse was irregular in 4.3 and 15.0% of the patients in the EG and the CG, respectively (P<.001). A total of 164 new cases of atrial fibrillation were detected (2.3%), 1.1% in the EG and 6.7% in the CG (adjusted OR: 0.29; 95% CI 0.18-0.45). CONCLUSIONS: Case finding for atrial fibrillation in patients aged≥65 years with symptoms or signs suggestive of atrial fibrillation is a more effective strategy than opportunistic screening through pulse palpation in asymptomatic patients. TRIAL REGISTRATION: The trial is registered in ClinicalTrials.gov (NCT01291953; February 8, 2011).

Jahi McMath, a New Disorder of Consciousness / Jahi McMath, un nuevo trastorno de la conciencia / Jahi McMath, um novo transtorno da consciencia

Abstract: In this paper, I review the case of Jahi McMath, who was diagnosed with brain death (BD). Nonetheless, ancillary tests performed nine months after the initial brain insult showed conservation of intracranial structures, EEG activity, and autonomic reactivity to the "Mother Talks" stimulus. She was clinically in an unarousable and unresponsive state, without evidence of self-awareness or awareness of the environment. However, the total absence of brainstem reflexes and partial responsiveness rejected the possibility of a coma. Jahi did not have UWS because she was not in a wakefulness state and showed partial responsiveness. She could not be classified as a LIS patient either because LIS patients are wakeful and aware, and although quadriplegic, they fully or partially preserve brainstem reflexes, vertical eye movements or blinking, and respire on their own. She was not in an MCS because she did not preserve arousal and preserved awareness only partially. The CRS-R resulted in a very low score, incompatible with MCS patients. MCS patients fully or partially preserve brainstem reflexes and usually breathe on their own. MCS has always been described as a transitional state between a coma and UWS but never reported in a patient with all clinical BD findings. This case does not contradict the concept of BD but brings again the need to use ancillary tests in BD up for discussion. I concluded that Jahi represented a new disorder of consciousness, non-previously described, which I have termed "reponsive unawakefulness syndrome" (RUS).

Resumen: En este artículo, revisó el caso de Jahi McMath, quién fue diagnosticada con muerte encefálica (ME). No obstante, exámenes complementarios realizados nueve meses después de la lesión cerebral inicial mostraron conservación de las estructuras intracraneales, actividad en electroencefalografía EEG, y reactividad autonómica a estímulos llamados "Conversación de Madre". Ella estaba clínicamente en un estado sin respuesta a los estímulos, sin evidencia de autoconciencia o conciencia del ambiente. Sin embargo, la ausencia total de reflejos del tronco encefálico y la capacidad de respuesta parcial rechazaron la posibilidad de un coma. Jahi no tenía síndrome de vigilia sin respuesta SVSR porque no estaba en un estado de vigilia y mostró una capacidad de respuesta parcial. Tampoco pudo ser clasificada como paciente LIS porque los pacientes LIS están despiertos y conscientes, y aunque tetrapléjicos, conservan total o parcialmente los reflejos del tronco encefálico, los movimientos oculares verticales u el parpadeo, y respiran por sí mismos. Ella no estaba en un EMC porque no preservaba la excitación y preservaba la conciencia solo parcialmente. La CRS-R dio una puntuación muy baja, incompatible con pacientes de EMC. Los pacientes de EMC preservan total o parcialmente los reflejos del tronco encefálico y, por lo general, respirar por sí solos. El EMC siempre se ha descrito como un estado de transición entre un coma y SVSR pero nunca se ha reportado en paciente con todos los hallazgos clínicos de ME. Este caso no contradice el concepto de ME pero vuelve a plantear la discusión acerca de la necesidad de utilizar exámenes complementarios en ME. Llegué a la conclusión de que Jahi representaba un nuevo trastorno de la conciencia, no descrito anteriormente, que he denominado "síndrome de no despertar con respuesta" (SNDR).

Resumo: Neste artigo, foi revisado o caso Jahi McMath, que foi diagnosticada com morte encefálica (ME). Contudo, exames complementares realizados nove meses depois da lesão cerebral inicial mostraram conservação das estruturas intracranianas, atividade em eletroencefalografia (EEG) e reatividade autonômica a estímulos chamados "Conversación de Madre". Ela estava clinicamente em um estado sem resposta aos estímulos, sem evidência de autoconsciência ou consciência do ambiente. Contudo, a ausência total de reflexos do tronco encefálico e a capacidade de resposta parcial rejeitaram a possibilidade de um coma. Jahi não tinha síndrome de vigia sem resposta (SVSR), porque não estava em um estado de vigia e mostrou uma capacidade de resposta parcial. Também nao pode ser classificada como paciente LIS, porque estes estão acordados e conscientes, e ainda que tetraplégicos, conservam total ou parcialmente os reflexos do tronco encefálicos, os movimentos oculares verticais ou cintilação, e respiram por si próprios. Ela não estava em um EMC porque não preservava a excitação e preservava a consciencia somente parcialmente. A CRS-R deu uma pontuação muito baixa, incompatível com pacientes de EMC. Os pacientes de EMC preservam total ou parcialmente os reflexos do tronco encefálico e, em geral, respirar por si só. O EMC sempre foi descrito como um estado de transição entre coma e SVSR, mas nunca foi relatado em paciente com todos os achados clínicos de ME. Esse caso não contradiz o conceito de ME, mas volta a colocar a discussão sobre a necessidade de utilizar exames complementares em ME. Cheguei a conclusão de que Jahi representava um novo transtorno da consciencia, nao descrito anteriormente, que denominei "síndrome de resposta sem vigília" (SRSV)

Oxygen saturation and heart rate in children at high altitude: a different response of Aymaras and non-Aymaras with chronic exposure at 3500 m / Saturación de oxígeno y ritmo cardiaco de niños en zonas de gran altitud: una respuesta distinta entre Aymaras y no Aymaras con exposición crónica a 3500 m

This work aims to determine if there is a difference between the cardiorespiratory response of children who chronically live at high altitude (Aymaras and non-Aymaras) compared to children that arrive as tourist at a high altitude of 3500 m (Putre, Chile). The subjects were children (Aymaras and non-Aymaras) who were born and live in Putre and children who came to the same location for a tourist visit. We used Oxygen saturation (%) and heart rate (HR, bpm) were evaluated by pulse oxymetry in children from Putre. The results showed similar levels of oxygen saturation were observed among chronic Aymaras and non-Aymara children. A lower oxygen saturation was found in children with acute exposure when compared with chronic children (p<0.0001). The HR of Aymaras and non-Aymara chronic children was lower than that observed in the non-native children (p<0.05). In contrast acute children had a higher HR than chronic children (p<0.001). Negative relationships were observed with correlation values (p<0.01) between oxygen saturation and HR in all groups. We concluded that chronic Aymara children exhibited a higher slope and correlation between oxygen saturation vs HR compared to chronic children who are non-Aymaras, suggesting that chronic natives are more sensitive to hypoxia. And, chronic non-Aymara children have an early blunting response to hypoxia. Further studies are needed to understand the physiological mechanisms in this population group.

El objetivo de este trabajo es determinar si existe alguna diferencia entre la respuesta cardiorespiratoria de niños que han vivido crónicamente a gran altitud (Aymaras y no Aymaras) comparados con niños llegados como turistas en grandes alturas de 3500m (Putre, Chile). Los sujetos fueron niños (Aymaras y no Aymaras) que nacieron y vivieron en Putre y niños que llegaron a la zona por una visita turística. Utilizamos saturación de oxígeno (%) y ritmo cardíaco (HR, bpm). Los niños de Putre fueron evaluados utilizando la pulsioximetría. Los resultados mostraron niveles similares de saturación de oxígeno entre los niños crónicos Aymaras y no Ayamaras. En los niños con exposición aguda se encontró una baja saturación de oxígeno al compararse con los niños crónicos (p<0.0001). El HR de los niños crónicos Aymaras y no Aymaras fue menor que el observado en niños no nativos (p<0.05). En cambio, los niños con síntomas agudos tenían una mayor HR que los niños crónicos (p<0.001). Se observaron relaciones negativas con los valores de correlación (p<0.01) entre la saturación de oxígeno y HR en todos los grupos. Concluimos que los niños crónicos Aymaras mostraban una gran pendiente y correlacion entre la saturación de oxígeno contra el HR comparado con los niños crónicos no Aymaras, sugiriendo que los nativos crónicos son más susceptibles a la hipoxia, y que los niños crónicos no Aymaras tiene una respuesta temprana a la hipoxia. Se necesitan estudios posteriores para entender los mecanismos fisiológicos en este grupo de población.

The effect of an exercise intervention on haemodynamic variables in pregnant women / El efecto de una intervención de ejercicio sobre variables hemodinámicas en mujeres embarazadas / O efeito de uma intervenção de exercício sobre as variáveis hemodinâmicas em mulheres grávidas

ABSTRACT Objective: This study evaluated the effect of exercise on heart rate (HR), systolic pressure (SBP), and diastolic pressure (DBP) at different gestational ages during pregnancy Methods: The exercise intervention and control groups from a previous multi-intervention clinical trial were used. Ninety-two pregnant women were analysed [control group: n = 48; exercise group: n = 44]. The outcome variables were the percentage change in SBP DBP and HR during follow-up intervals (16-20 weeks, 20-24 weeks, 24-28 weeks, and 28-32 weeks). Results: Resting HR showed a lower increase in the exercise group than in the control group during the interval of gestational weeks 16-20 (p=0.0ll) [Median Interquartile range: 8.8 (0 to 27.9) control group; 2.2 (-6.9 to 8.1) exercise group]. During this same interval SBP decreased in both control and exercise groups, with more decrease in the control group (P<0.05) [Median Interquartile range: -4.29 (-11.1 to 1.9) control group; -0.89 (-4.76 to 6.36)]. Conclusion: Aerobic exercise in pregnancy significantly attenuated increase of resting HR at the beginning of the second trimester of pregnancy.

RESUMEN Objetivo: Se evaluó el efecto del ejercicio sobre la frecuencia cardíaca (FC), la presión sistólica (PAS) y diastólica (PAD) durante diferentes edades gestacionales. Métodos: Se utilizaron los grupos de intervención y control de ejercicio de un ensayo clínico previo. Las mujeres embarazadas (n=92) fueron analizadas [controles: n=48; grupo de ejercicio: n=44]. Las variables resultado fueron el cambio porcentual en PAS, PAD y FC durante los intervalos de seguimiento (16-20, 20-24, 24-28 y 28-32 semanas). Resultados: La FC en reposo mostró un aumento menor en el grupo de ejercicio que en el grupo control durante el intervalo de semanas de gestación 16-20 (p = 0.011) [Rango intercuartil mediano: grupo control 8.8 (0 a 27.9); 2.2 (-6.9 a 8.1) grupo de ejercicio]. Durante este intervalo, la PAS disminuyó tanto en el grupo control como en el ejercicio, con mayor disminución los controles(P <0.05) [Rango intercuartil mediano: -4.29 (-11.1 a 1.9) grupo control; -0,89 (-4,76 a 6,36)]. Conclusión: El ejercicio aeróbico atenuó significativamente el aumento de la frecuencia cardíaca en reposo al comienzo del segundo trimestre del embarazo.

RESUMO Objetivo: Foi avaliado o efeito do exercício na pressão da frequência cardíaca (FC), sistólica (PAS) e diastólica (PAD) durante diferentes idades gestacionais. Métodos: Serão utilizados os grupos de intervenção e controle do exercício de um ensaio clínico anterior Gestantes (n = 92) foram analisadas [controles: n = 48; grupo de exercícios: n = 44]. As variáveis de desfecho foram a variação percentual da SAP DAOP e CF durante os intervalos de acompanhamento (16-20, 20-24, 24-28 e 28-32 semanas). Resultados: A FC em repouso selecionou um aumento menor no grupo do exercício do que no grupo controle durante o intervalo gestacional de 16 a 20 semanas (p = 0,011) [Intervalo interquartil mediano: grupo controle 8,8 (0 a 27,9); 2,2 (-6,9 a 8,1) grupo de exercícios]. Durante esse intervalo, a PAS diminuiu tanto no grupo controle quanto no exercício, com uma maior diminuição nos controles (P <0,05) [Intervalo interquartil médio: -4,29 (-11,1 a 1,9) no grupo controle; -0,89 (-4,76 a 6,36)]. Conclusão: O exercício aeróbico atenuará o aumento da frequência cardíaca em repouso no início do segundo trimestre da gravidez.

Disfunción sinusal transitoria secundaria a tratamiento con lacosamida / Transient sinus dysfunction secondary to lacosamide treatment

RESUMEN Se presenta el caso de una paciente de 84 años de edad, con antecedentes de hipertensión arterial, dislipemia, insuficiencia venosa crónica y osteoartrosis, que -debido a una neuralgia del trigémino- había recibido tratamiento con varios fármacos, sin lograr control del dolor neuropático, por lo que se inició tratamiento con lacosamida en monoterapia, con incremento de dosis hasta lograr el objetivo terapéutico; pero la paciente presentó manifestaciones clínicas y alteraciones electrocardiográficas compatibles con disfunción sinusal, que se resolvieron tras la reducción de la dosis del fármaco.

ABSTRACT The case of an 84-year-old female patient is presented, with a history of high blood pressure, dyslipidemia, chronic venous failure and osteoarthritis, which -due to trigeminal neuralgia- had received treatment with several drugs, without achieving neuropathic pain control; that was why the treatment with lacosamide was started in monotherapy, with an increase in dose until the therapeutic objective was achieved; but the patient presented clinical manifestations and electrocardiographic alterations compatible with sinus dysfunction, which were solved after reducing the dose of the drug.

Como paradigma de última data en el Hospital de Especialidades del IESS. Dr. José Carrasco Arteaga, incluimos como actividad médica relevante propia de un Hospital Nivel III. "ELECTROFISIOLOGIA INVASIVA". [Editorial] / As a paradigm of last data in the Hospital de Especialidades del IESS. Dr. Jose Carrasco Arteaga, we include as a relevant medical activity typical of a Level III Hospital. "INVASIVE ELECTROPHYSIOLOGY". [Editorial]

Como paradigma de última data en el Hospital de Especialidades del IESS. Dr. José Carrasco Arteaga, incluimos como actividad médica relevante propia de un Hospital Nivel III. "ELECTROFISIOLOGIA INVASIVA". La Electrofisiología Invasiva es una de las subespecialidades más recientes de la Cardiología Clínica, es la encargada de estudiar y tratar las alteraciones del ritmo cardiaco, las "arritmias cardiacas", siendo el área del conocimiento más extensa, más compleja y de más rápido desarrollo de la cardiología actual, como lo reconoce la American Board of Internal Medicine (ABIM). La Electrofisiología, por medio de la ablación por catéter, es el método terapéutico de elección para un amplio número de arritmias cardiacas, permite la cura definitiva de éstas molestas y muchas veces peligrosas patologías cardiacas

Treinamento de força em sessão com exercícios poliarticulares gera estresse cardiovascular inferior a sessão de treino com exercícios monoarticulares / Strength training session with multi-joint exercises generates less cardiovascular stress than a single-joint strength training session / Sesiones de entrenamiento de fuerza con ejercicios poliarticulares que generen menos estrés cardiovascular que sesiones de entrenamiento de fuerza con ejercicios monoarticulares

Resumo Objetivo: Avaliar respostas da frequência cardíaca (FC), pressão arterial sistólica (PAS) e diastólica (PAD) e duplo produto (DP) em sessões de treino compostas por exercícios poliarticulares (STP) e monoarticulares (STM). Métodos: A amostra foi composta por 12 homens. As intervenções tiveram quatro exercícios de força (EF) distintos, com três séries de oito a dez repetições máximas. Resultados: Na PAS, a STP proporcionou incrementos inferiores à STM (p < 0,001). Observou-se efeito do momento para FC (p < 0,001) e PAD (p < 0,001). A PAD diminui após o aquecimento e teve menor valor no penúltimo EF. No DP, indica-se efeito do treino (p = 0,002), com valores inferiores para STP. Conclusão: STP proporcionou menor estresse cardiovascular e maior resposta hipotensiva quando comparada com a STM.

Abstract Objective: To evaluate responses of heart rate (HR), systolic blood pressure (SBP) and diastolic blood pressure (DBP), as well as the double product (DP) in multi- (MJ) and single-joint (SJ) strength training sessions. Methods: The sample was composed by 12 mans. Interventions had four different exercises in each day, three sets of eight to ten repetitions. Results: About SBP, MJ provided lower increments in relation to the SJ (p < 0.001). There was effect of the moment for HR (p < 0.001) and for DPB (p < 0.001). The PAD decreases after warm up and had smaller value in the penultimate exercise. For DP, was shown lower training effect for the multi-joint sessions (p = 0.002). Conclusions: MJ provided lower stress and greater cardiovascular hypotensive response when compared to SJ.

Resumen Objetivo: Evaluar las respuestas de la frecuencia cardiaca (FC), presión arterial sistólica (PAS) y presión arterial diastólica (PAD), y doble producto (DP) en sesiones de fuerza poliarticular (SEP) y monoarticular (SEM). Métodos: La muestra estuvo compuesta por 12 hombres. Las intervenciones tuvieron cuatro ejercicios separados con tres series de 8 a 10 repeticiones máximas. Resultados: En la PAS, la SEP proporciona incrementos inferiores a la SEM (p < 0,001). Se observó un efecto del momento del análisis para la FC (p < ,001) y para la PAD (p < 0,001). La PAD disminuyó después del calentamiento y tuvo menor valor en el penúltimo ejercicio. En DP se indicó un efecto del entrenamiento con SEP que proporcionó valores inferiores (p = 0,002). Conclusiones: La SEP proporciona menos estrés y mayor respuesta hipotensiva cardiovascular en comparación con la SEM.

El análisis de la variabilidad de frecuencia cardiaca como una herramienta para evaluar los efectos de la meditación chi sobre la regulación cardiovascular / Heart Rate Variability analysis as a tool for assessing the effects of chi meditation on cardiovascular regulation

Approximately 30 indices have been proposed for assessing heart rate variability (HRV). Some are mathematically identical or very closely related to each other, and results can be interpreted from completely different viewpoints. Comparing various indices from a tachogram, and combining statistical significance with physiological plausibility could improve the result's interpretation. Using the KubiosHRV package, we studied the chi-meditation R-R database available at Physionet.org, addressing the following questions: i) Which HRV indices are the most suitable for describing meditation effects? ii) Are the effects of meditation beneficial, harmful or insubstantial? iii) Which are the most likely physiological events associated to meditation? It was concluded that power spectrum low frequency component (LF), LF/HF ratio, and nonlinear indices α 1 and α 2, recurrence rate and Shannon entropy performed the best (p<0.05). Observed changes suggest that they harmonize with changes observed in other health-pursuing circumstances as physical training, stress combating; whereas they are in the opposite tendency of changes associated to aging, heavy smoking, high blood glucose levels, autonomic heart denervation and congestive heart failure. Changes induced by chi meditation seem to be associated to increases in respiratory component around0.04 Hz, lower entropy and reduced long-term correlation with higher cardio vascular complexity(AU)

Alrededor de 30 índices han sido propuestos para evaluar la Variabilidad de la Frecuencia Cardiaca. Algunos de esos índices son matemáticamente idénticos o muy semejantes a otros y los resultados pueden ser interpretados desde puntos de vista completamente distintos. Al comparar varios índices estimados a partir de un tacograma y combinando la significación estadística con la plausibilidad biológica pudiera mejorarse la interpretación de los resultados. Utilizando el paquete de análisis KubiosHRV estudiamos la base de datos de señales R-R Chi meditation, disponible en el portal Physionet.org, centrándonos en las interrogantes siguientes: i) ¿cuáles índices son los más adecuados para describir los efectos de la meditación? ii) ¿son los efectos de la meditación beneficiosos, nocivos o insustanciales? iii) ¿cuáles son los eventos fisiológicos asociados a la meditación? Se concluye que el componente de baja frecuencia del espectro de potencia (LF), la relación LF/HF y los índices no lineales α 1 yα 2, la razón de recurrencia y la entropía de Shannon, fueron los indicadores más apropiados (p < 0.05). Los cambios observados parecen armonizar con cambios observados en otras acciones promotoras de salud como entrenamiento físico, combatir el estrés, mientras que exhiben una tendencia opuesta a los cambios asociados al envejecimiento, hábito de fumar, elevados niveles de glucosa, denervación cardiaca, e insuficiencia cardiaca congestiva. Los cambios inducidos por la meditación chi parecen estar asociados a incrementos en el componente respiratorio próximo a los 0.04 hertzios, a una menor entropía y una menor correlación a largo término combinadas a una mayor complejidad cardiovascular(AU)

O controle do ritmo não é melhor do que o da frequência na fibrilação atrial com insuficiência cardíaca / Rhythm control is no better than the frequency of atrial fibrillation with heart failure

O controle do ritmo não é melhor do que o controle da frequência para os pacientes portadores de fibrilação atrial, mesmo que eles tenham disfunção ventricular esquerda.

Efeito da dexmedetomidina sobre a arritmia cardíaca induzida pela adrenalina em cães anestesiados pelo sevofluorano / Effect of dexmedetomidine on the heart arrhythmia induced by the adrenaline in dogs anesthetized by sevoflurane

Avaliou-se o efeito da dexmedetomidina sobre o ritmo cardíaco em 20 cães, sem raça definida, de ambos os sexos e considerados sadios, anestesiados pelo sevofluorano e submetidos a doses crescentes de adrenalina. Os animais foram, aleatoriamente, distribuídos em dois grupos (placebo e dexmedetomidina). No grupo placebo, os animais receberam, por via intravenosa, solução de NaCl a 0,9 por cento, na dose de 0,3ml/kg. Foram considerados dois momentos, M0 e M1, imediatamente antes e após a aplicação, respectivamente. Após 10 minutos, realizou-se a indução anestésica com sevofluorano, por meio de máscara facial vedada, até a perda do reflexo laringotraqueal. Em seguida, procedeu-se à intubação orotraqueal e a manutenção da anestesia foi realizada com a administração de sevofluorano na concentração de 1,5CAM, em circuito anestésico com reinalação parcial de gases. Decorridos 20 minutos da indução anestésica, iniciou-se a administração intravenosa contínua de solução de adrenalina a 2 por cento em doses crescentes de 1, 2, 3, 4 e 5mg/kg/min, por meio de bomba de infusão, com aumento da dose em intervalos de 10 minutos. Imediatamente antes desse acréscimo eram feitas as mensurações (M2 a M6). No grupo dexmedetomidina empregou-se a mesma metodologia substituindo-se a solução de NaCl a 0,9 por cento por hidrocloridrato de dexmedetomidina, na dose de 1µg/kg. Foram registradas as pressões arteriais, em M0 e em M2 a M6, e o traçado eletrocardiográfico, na derivação DII (M2 a M6), considerando-se para efeito estatístico o número total de bloqueios atrioventriculares (BAV) de primeiro e segundo graus e de complexos ventriculares prematuros (ESV), coincidentes com cada dose de adrenalina. Os dados foram submetidos à análise de variância seguida pelo teste de Tukey (P<0,05). Verificou-se que a dexmedetomidina interfere significativamente na condução atrioventricular levando a maior ocorrência de BAV e reduz o número de ESV nas doses infundidas de 2 e 3mg/kg/min ...

The effect of dexmedetomidine on the cardiac rhythm in twenty healthy mongrel dogs of both sexes anesthetized with sevofluorane and submitted to increasing doses of adrenaline was evaluated. The animals were randomly allotted to different treatment groups. Animals of placebo group were intravenous injected with 0.9 percent NaCl solution at 0.3ml/kg/IV. Two moments were considered, M0 and M1, the moments immediately before and after application, respectively. Ten minutes later, the dogs were anesthetized using sevofluorane via face mask until lost of their laringotracheal reflex. Then, orotracheal intubation was performed and maintenance of anesthesia was kept with 1,5MAC sevofluorane using an anesthetic circuit with a rebreathing system. Twenty minutes after anesthesia induction, continuous IV administration of 2 percent adrenaline solution was given at increasing doses of 1,2,3,4 and 5mg/kg/min., every ten minutes, respectively. The moments M2 to M6 were measured immediately before the next increase of dose. In dexmedetomidine group, the same technique was used replacing 0.9 percent NaCl by dexmedetomidine hydrochloride at 1mg/kg. Blood pressures were recorded at M0 and M2 to M6. Electrocardiography line in the derivation DII (M2 to M6) was used to observe the number of atrioventricular blocks (AVB) of first and second degrees and ventricular premature complexes (VPC). Statistic evaluation was performed by analysis of variance followed by Tukey's test (P<0.05). Dexmedetomidine significantly altered the atrioventricular conduction resulting in a higher occurrence of AVB. This drug reduced the number of VPC at 2 and 3mg/kg/min of adrenaline. After administration of dexmedetomidine, reduction of arterial blood pressure up to one hour and reduction of cardiac rate were observed

Compact cell image projector: application to study the relationship between stimulus interval and contraction amplitude in isolated rat cardiomyocytes / Projetor compacto de imagem celular: aplicação ao estudo da relação entre intervalo entre estímulos e amplitude de contração em cardiomiócitos isolados de rato

Cardiac inotropy depends, among other factors, on the interval between contractions. In this study, we developed instrumentation for cell shortening recording, which was used to investigate the influence of stimulatory rhythm on contraction amplitude of isolated rat ventricular myocytes. Peak cell shortening amplitude was recorded during electric stimulation at the average rate of 0.5 Hz with different stimulatory patterns: regular and pseudo-random rhythms, as well as double pulse stimulation. Cells were perfused at 23 ºC with modified Tyrode’s solution with or without 10 nM isoproterenol (ISO). The main advantages of the developed microscopy system were its relatively low cost(~US$ 1,000.00), small size (150 × 170 × 300 mm), and absence of detectable optic distortions. We observed that average contraction amplitude was similar for all stimulatory patterns, in the absence and presence of ISO (p > 0.05), although the amplitude of individual contractions was highly dependent on the previous interval, and was significantly increased by ISO (p < 0.05). With the double pulse patterns, the amplitude ratio of contractions following the shorter and the longer intervals was ~0.55. ISO positive inotropic effect was more prominent for contractions after short intervals, which increased the ratio to ~0.80. This might be explained by acceleration of the recovery of sarcoplasmic reticulum Ca2+ release channels from the adapted state, possibly by proteinkinase A-dependent phosphorylation, which would resultin enhanced systolic Ca2+ release.

O inotropismo cardíaco depende de inúmeros fatores, entre eles o intervalo entre contrações. Neste trabalho, desenvolvemos instrumentação para registro de encurtamento celular e investigamos a influência do ritmo estimulatório sobre a atividade contrátil de miócitos ventriculares isolados de rato. A amplitude do encurtamento celular foi registrada durante estimulação elétrica à freqüência média de 0,5 Hz, com ritmo regular, ritmo pseudoaleatório e pulsos duplos. Os miócitos foram perfundidos a 23 ºC com solução de Tyrode modificada contendo ou não 10 nMde isoproterenol (ISO). O sistema de microscopia desenvolvido é de custo relativo baixo (~US$ 1.000,00), dimensões reduzidas(150 × 170 × 300 mm) e apresenta boa qualidade óptica (sem distorções ou paralaxe detectáveis). Observamos que a amplitude média das contrações foi semelhante em todos os ritmos estimulatórios na ausência e presença de ISO (p > 0,05), embora a amplitude de contrações individuais fosse dependente do intervalo precedente, e ISO tenha causado aumento da amplitude média das contrações (p < 0,05). Nos padrões com pulso duplo, a razão de amplitude das contrações que seguem o menor e o maior intervalo foi ~0,55. O efeito inotrópico positivo de ISO foi mais pronunciado para contrações após intervalos curtos, o que levou a razão para ~0,80. Isto poderia ser explicado por aceleração da recuperação dos canais de liberação de Ca2+ do retículo sarcoplasmático do estado adaptado, causada possivelmente por fosforilação pela proteína quinase A, o que aumentaria a quantidade de Ca2+ liberada durante a sístole.