Clinical and Laboratory Data Up on Hospital Admission are Predictors of New-Onset Atrial Fibrillation in Patients Hospitalized Due to COVID-19 Pneumonia. / Variáveis Clínicas e Laboratoriais na Admissão Hospitalar são Preditores de Fibrilação Atrial Nova em Pacientes Internados com Pneumonia por COVID-19.

BACKGROUND: New-onset atrial fibrillation (NOAF) occurs in patients hospitalized due to COVID-19. It is still unknown whether clinical and laboratory data assessed upon hospital admission have predictive value for NOAF. OBJECTIVES: To analyze, upon hospital admission, variables with predictive potential for the occurrence of NOAF in patients with COVID-19 pneumonia. METHODS: Observational, retrospective, case-control study. Electronic medical reports of consecutive patients, 60 years of age or older, hospitalized due to COVID-19 pneumonia between March 1st and July 15th, 2020, were reviewed. Non-paired Student or chi-squared tests compared variables. A Cox proportional hazard model was employed to identify independent predictors of NOAF. P value < 0.05 was considered statistically significant. RESULTS: Among 667 patients hospitalized due to COVID-19, 201 (30.1%) fulfilled the inclusion criteria. NOAF was documented in 29 patients (14.4%), composing group 1. Group 2 was composed of 162 patients without NOAF. Ten patients were excluded due to the AF rhythm upon hospital admission. In groups 1 and 2, there were differences in overall in-hospital survival rate (24.1 % vs. 67.9%; p<0.001), length of stay in ICU (11.1 ± 10.5 days vs. 4.9 ± 7.5 days; p=0.004) and need for mechanical ventilation rate (82.9% vs. 32.7%; p<0.001). In the Cox model, age > 71 y/o (HR=6.8; p<0.001), total leukocyte count ≤ 7,720 cels.µL-¹ (HR=6.6; p<0.001), serum [Na+] ≤ 137 mEq.L-¹ (HR=5.0; p=0.001), SAPS3 score > 55 (HR=5.6; p=0.002), and disorientation (HR=2.5; p=0.04) on admission were independent predictors of NOAF. CONCLUSION: NOAF is a common arrhythmia in elderly hospitalized patients with COVID-19 pneumonia. Clinical and laboratory parameters evaluated on admission have a predictive value for the occurrence of NOAF during hospitalization.

FUNDAMENTO: Fibrilação atrial nova (FAN) ocorre em pacientes internados por COVID-19. Há controvérsias quanto ao valor preditivo de dados clínicos e laboratoriais à admissão hospitalar para ocorrência de FAN. OBJETIVOS: Analisar, à admissão hospitalar, variáveis com potencial preditivo para ocorrência de FAN em pacientes com pneumonia por COVID-19. MÉTODO: Estudo observacional, retrospectivo, caso-controle. Foram avaliados prontuários eletrônicos de pacientes consecutivos ≥ 60 anos, hospitalizados com pneumonia por COVID-19 entre 1º de março e 15 de julho de 2020. Comparações feitas pelos testes `t' de Student ou qui-quadrado. Foi empregado modelo de risco proporcional de Cox para identificação de preditores de FAN. Considerou-se o valor de p < 0,05 como estatisticamente significativo. RESULTADOS: Entre 667 pacientes internados por COVID-19, 201 (30,1%) foram incluídos. FAN foi documentada em 29 pacientes (14,4%) (grupo 1). Grupo 2 foi composto por 162 pacientes que não apresentaram FAN. Dez pacientes excluídos por estarem em FA na admissão hospitalar. Houve diferenças entre os grupos 1 e 2, respectivamente, no tempo de permanência em UTI (11,1±10,5 dias vs. 4,9±7,5 dias; p=0,004), necessidade de ventilação invasiva (82,9% e 32,7%; p<0,001) e mortalidade hospitalar (75,9% vs. 32,1%; p<0,001). No modelo de Cox, idade > 71 anos (hazard ratio [HR]=6,8; p<0,001), leucometria ≤ 7.720 cels.µL-1 (HR=6,6; p<0,001), natremia ≤ 137 mEq.L-1 (HR=5,0; p=0,001), escore SAPS3 > 55 (HR=5,6; p=0,002) e desorientação (HR=2,5; p=0,04) foram preditores independentes de FAN. CONCLUSÕES: FAN é uma arritmia comum em idosos hospitalizados com pneumonia por COVID-19. Parâmetros clínicos e laboratoriais avaliados na admissão são preditores de FAN durante internação.

Bisifusarium lunatum causing cladode soft rot in pear cactus (Nopalea cochenillifera L. Salm-Dyck) in Brazil.

Cactus pear var. miúda (Nopalea cochenillifera L. Salm-Dyck) is an important crop for the Northeast region of Brazil, composing one of the main sources of animal feed. By April 2021, cladode rot caused death of several cactus pear plants in a production area located in Itaporanga, Paraíba state, Brazil (7°21'55.35" S and 38°11'38.68" W). The infected cladodes showed brown circular necrotic spots, and soft rot with perforations that extended throughout the cladode, followed by tipping over and death of the infected plants. The incidence of the disease ranged from 10 to 30% of the plants. Bisifusarium strains were isolated and cultured on potato dextrose agar (PDA) and syntetic-nutrient-poor-agar (SNA). The colonies showed purple color on PDA. On SNA, macroconidia (n = 100) were abundant, hyaline, slightly falcate, three-septate, measuring 11.0-23.1 x 2.3-4.1 µm. Microconidia (n = 100) were oval, generally aseptate, measuring 4.1-8.7 x 2.3-3.0 µm. Conidiogenic cells formed into short monophialides. Chlamydospores were not observed. According to these morphological features, the pathogen was initially identified as Bisifusarium lunatum (Gryzenhoutm et al. 2017). For further confirmation of the identification, the partial sequences of translation elongation factor 1-alpha (TEF1-α) and the second largest subunit of RNA polymerase II (RPB2) genes were sequenced for a representative isolate (CMA 34: GenBank accession no: TEF1-α: OR536502; and RPB2: OR553509) and compared to other Bisifusarium species from GenBank database. Subsequently, it was subjected to a phylogenetic analysis of maximum likelihood including previously published sequences. According to BLAST searches, the TEF1-α and RPB2 sequences were 99% (637/640 nt) and 100% (312/312 nt) similar to B. lunatum (COUFAL0213: TEF1-α (MK640219), and RPB2 (MK301291)), respectively. The isolate was also clustered in a clade containing the ex-type of B. lunatum with 100% support (SH-aLRT and UFboot), being confidently assigned to this species. The pathogenicity test was performed after Medeiros et al. (2015), by using healthy two months old cactus pear seedlings (n = 10) cultivated in a greenhouse. Sterile toothpicks were distributed over colonies of the representative isolate grown on PDA at 25 ± 2 °C for seven days. Seedling cladodes were stuck with the toothpicks, moistened with sterile water and covered with transparent plastic bags for 24h, thus simulating a humid chamber. Following three months, all control plants (stuck with sterile toothpicks) remained healthy, while those inoculated with the representative isolate exhibited rot symptoms. This test was performed twice. B. lunatum was reisolated from symptomatic cladodes and identified as previously described, thus fulfilling the Koch's postulates. To our best knowledge, this is the first report of B. lunatum causing soft rot on N. cochenillifera in Brazil. Besides N. cochenillifera, this species was also reported on Opuntia ficus-indica in India (Gryzenhoutm et al., 2017), which raises concern regarding its ability to infect other forage sources for cattle feed in Brazilian semiarid regions. The present study highlights that the precise identification of B. lunatum is a key factor to adjust control strategies and management of the disease to prevent the spread of this disease to prevent its spread to other crops.

Predictive Model of All-Cause Death in Patients with Heart Failure using Heart Rate Variability. / Modelo Preditivo de Mortalidade por Todas as Causas em Pacientes com Insuficiência Cardíaca Usando a Variabilidade da Frequência Cardíaca.

BACKGROUND: Central Illustration : Predictive Model of All-Cause Death in Patients with Heart Failure using Heart Rate Variability. BACKGROUND: Short and long-duration heart rate variability (HRV) data from Holter monitoring could identify predictors of all-cause death in heart failure (HF) patients. OBJECTIVES: To build a predictive model of all-cause death in patients with HF using HRV. METHODS: Retrospective study including patients with suspected or confirmed HF who were admitted for decompensated HF or syncope that underwent Holter monitoring. In analysis of augmented sympathetic tonus, we evaluated the lowest HRV in nonoverlapping 10-minutes periods throughout 24h continuous electrocardiographic signal recording (short HRV variables). Variables with p<0.01 were included in a multivariate Cox regression model to determine the occurrence of the all-cause death. Variables with statistical significance in Cox regression were chosen to build the predictive model. P<0.05 was considered significant. RESULTS: A total of 116 patients were included, mean age of 71.9±16.3 years, 45.7% men, mean follow-up of 2.83±1.27 years. Thirty-nine deaths occurred (33.6%). By comparing survivors vs. non-survivors, the variables that showed statistical significance were lowest SDNN, lowest rMSSD, age and left ventricular ejection fraction (LVEF). In Cox regression, independent predictors of all-cause death were: age>69 years (HR 3.95, 95%CI 1.64-9.52); LVEF≤57% (HR 4.70, 95%CI 2.38-9.28) and lowest rMSSD≤12ms (HR 5.54, 95%CI 2.04-15.08). An integer value was assigned to each variable. Score<3 showed AUC=0.802 (95%CI 0.72-0.87). CONCLUSION: In HF patients hospitalized for decompensated HF or syncope, independent long-term predictors of all-cause death were age, LVEF, and 10-minutes rMSSD. These findings indicate that even brief moments of high sympathetic tone can impact survival, specifically in the elderly and patients with HF with reduced ejection fraction.

Predation performance and survival of susceptible and pyrethroid-resistant Eriopis connexa Germar (Coleoptera: Coccinellidae) to insecticides used in brassica crops.

BACKGROUND: Selective insecticides and insecticide-resistant natural enemies are components of chemical and biological methods that can be compatible in an integrated pest management (IPM) program. Many insecticides that are labeled for treatment against insects in Brassica crops have lost their efficacy because of the development of resistance. However, natural enemies can provide an important role in regulating the population of these pests. RESULTS: Survival of Eriopis connexa populations was >80% when exposed to insecticides, except for EcFM exposed to indoxacarb and methomyl. Bacillus thuringiensis, cyantraniliprole, chlorfenapyr and spinosad caused high mortality of P. xylostella larvae, but neither affected E. connexa survival nor its predation upon L. pseudobrassicae. Cyantraniliprole, chlorfenapyr, deltamethrin and methomyl caused high mortality of L. pseudobrassicae, but did not affect E. connexa survival nor its predation upon P. xylostella larvae. According to the differential selectivity index and the risk quotient, chlorfenapyr and methomyl were more toxic to P. xylostella larvae than to E. connexa, whereas indoxacarb was more toxic to E. connexa. CONCLUSION: This study demonstrates that the insecticides B. thuringiensis, cyantraniliprole, chlorantraniliprole, deltamethrin, chlorfenapyr, spinosad, azadiracthin and spiromesifen are compatible with insecticide-resistant adult E. connexa within an IPM program in Brassica crops. © 2023 Society of Chemical Industry.

Modelo Preditivo de Mortalidade por Todas as Causas em Pacientes com Insuficiência Cardíaca Usando a Variabilidade da Frequência Cardíaca / Predictive Model of All-Cause Death in Patients with Heart Failure using Heart Rate Variability

Resumo Fundamento Dados de curto e de longo prazo da variabilidade da frequência cardíaca (VFC) poderiam identificar preditores de mortalidade por todas as causas em pacientes com insuficiência cardíaca (IC). Objetivos Construir um modelo preditivo de mortalidade por todas as causas em pacientes com IC usando a VFC. Métodos Estudo retrospectivo incluindo pacientes com suspeita ou diagnóstico confirmado de IC internados por IC descompensada ou síncope e que realizaram exame de Holter 24 horas. Na análise do tônus simpático aumentado, nós avaliamos a VFC mais baixa em períodos de 10 minutos não sobrepostos em um registro contínuo de sinal eletrocardiográfico por 24 horas (VFC de curta duração). As variáveis com p<0,01 foram incluídas no modelo de regressão multivariada de Cox para determinar a ocorrência da mortalidade por todas as causas. As variáveis com significância estatística na regressão de Cox foram escolhidas para construir o modelo preditivo. Um p<0,05 foi considerado estatisticamente significativo. Resultados Um total de 116 pacientes foram incluídos, com idade média de 71,9±16,3 anos, 45,7% eram do sexo masculino. O tempo médio de acompanhamento foi de 2,83 ± 1,27 anos. Trinta e nove (33,6%) óbitos ocorreram. Na comparação de sobreviventes e não sobreviventes, as variáveis que mostraram significância estatística foram menor SDNN, menor rMSSD, idade e fração de ejeção ventricular esquerda (FEVE). Na regressão Cox, os preditores independentes de mortalidade por todas as causas foram: idade > 69 anos (HR 3,95, IC95% 1,64-9,52); FEVE≤57% (HR 4,70, IC95% 2,38-9,28) e menor rMSSD ≤12ms (HR 5,54; IC 95% 2,04-15,08). Um valor inteiro foi atribuído para cada variável. Este escore < 3 apresentou uma área sob a curva de 0,802 (IC95% 0,72-0,87). Conclusão Em pacientes com IC internados por IC descompensada ou síncope, preditores de longo prazo de mortalidade por todas as causas foram idade, FEVE, e rMSSD em 10 minutos. Esses achados indicam que mesmo breves momentos de tônus simpático elevado podem ter impacto na sobrevida, principalmente em idosos e pacientes com IC e fração de ejeção reduzida.

Abstract Background Short and long-duration heart rate variability (HRV) data from Holter monitoring could identify predictors of all-cause death in heart failure (HF) patients. Objectives To build a predictive model of all-cause death in patients with HF using HRV. Methods Retrospective study including patients with suspected or confirmed HF who were admitted for decompensated HF or syncope that underwent Holter monitoring. In analysis of augmented sympathetic tonus, we evaluated the lowest HRV in nonoverlapping 10-minutes periods throughout 24h continuous electrocardiographic signal recording (short HRV variables). Variables with p<0.01 were included in a multivariate Cox regression model to determine the occurrence of the all-cause death. Variables with statistical significance in Cox regression were chosen to build the predictive model. P<0.05 was considered significant. Results A total of 116 patients were included, mean age of 71.9±16.3 years, 45.7% men, mean follow-up of 2.83±1.27 years. Thirty-nine deaths occurred (33.6%). By comparing survivors vs. non-survivors, the variables that showed statistical significance were lowest SDNN, lowest rMSSD, age and left ventricular ejection fraction (LVEF). In Cox regression, independent predictors of all-cause death were: age>69 years (HR 3.95, 95%CI 1.64-9.52); LVEF≤57% (HR 4.70, 95%CI 2.38-9.28) and lowest rMSSD≤12ms (HR 5.54, 95%CI 2.04-15.08). An integer value was assigned to each variable. Score<3 showed AUC=0.802 (95%CI 0.72-0.87). Conclusion In HF patients hospitalized for decompensated HF or syncope, independent long-term predictors of all-cause death were age, LVEF, and 10-minutes rMSSD. These findings indicate that even brief moments of high sympathetic tone can impact survival, specifically in the elderly and patients with HF with reduced ejection fraction.

Fusarium pseudocircinatum causing stunting and malformation of sunflower plants in Brazil.

Sunflower (Helianthus annuus L.) is among the main oleaginous crops used in Brazil. During January, 2017, at CCA/UFPB laboratory and greenhouses (Areia/Brazil, 6°58'12″ S; 35°42'15″ W), we observed various sunflower seeds (cultivar Olisun 3, 2017-2018 crop) highly infested with Fusarium. Those seeds were from crops in the municipality of Alagoinha -PB/Brazil (06º57'00'' S; 35º32'42'' W), supplied by Empresa Brasileira de Pesquisa Agropecuária/EMBRAPA. The emerged seedlings from these seeds were also contaminated, with 5% to 26% of them exhibiting stunting and malformation. Fusarium strains were isolated from symptomatic plants, and a single spore was used to grow pure colonies on potato-dextrose-agar (PDA) and synthetic-nutrient-poor-agar (SNA) media. Mycelia of PDA colonies were floccous and dense varying from yellow to orange. Fungal colonies developed aerial mycelium, producing orange pigments. On SNA, hyaline macroconidia, measuring 2.9-4.1 x 32.4-65.0 µm, slightly falcate with three to six septa. Oval microconidia, measuring 2.4-3.6 x 5.1-9.0 µm, were abundant in false heads forming on monophyalides. Chlamydospores were absent. Sterile hyphae were rarely formed. Colectively, the morphological features corresponded to species that belong to the Fusarium fujikuroi species complex (Leslie & Summerell, 2006). To assure the species identity, we sequenced the elongation factor 1α region of two representative isolates (i.e., F2 and F3, GenBank access numbers: MZ666934 and MZ666935, respectively) and compared them to the other Fusarium species found at Fusarium-ID and GenBank databases. Subsequently, we performed a maximum likelihood phylogenetic analysis including previously published sequences (Nicolli et al., 2020). Both isolates exhibited 100% similarity with Fusarium pseudocircinatum (MN386745), and clustered with its ex-type at 100% bootstrap values. The isolates were then grown on PDA amended with manitol to adjust the osmotic pressure to -1.0 Mpa, at 25 ± 2 ° C, for seven days (Sousa et al., 2008). A total of 100 disinfested sunflower seeds (cultivar Olisun 3, 2018-2019 crop) were distributed over the colonies and 48h later they were sown on sterile substrate maintained inside a greenhouse. About 30 days after inoculation, the emerged plants exhibited symptoms of stunting and malformation (60%) compared to controls, which were healthy. F. pseudocircinatum was reisolated from the symptomatic plants, completing Koch's postulates and identified based on above morphological and molecular biological methods. This test was performed twice. Fusarium pseudocircinatum is a broadly distributed and ecologicaly diverse species that infects several wild and cultivated plants. For instance, it was reported on seeds of the wild 'Peroba Rosa' (Aspidosperma polyneuron Muell. Arg.) in Brazil (Mazarotto et al. 2020). Infection of sunflowers may cause plant stand failures, thus resulting in yield and economic losses for Brazilian growers. The correct identification of any pathogen, especialy a generalist one such as F. pseudocircinatum, is crucial to develop eficient management strategies. To our best knowledge, this is the first report of F. pseudocircinatum causing stunting and malformation of sunflower plants in Brazil.

Multiple factors mediate insecticide toxicity to a key predator for cotton insect pest management.

Mortality of agricultural pests caused by arthropod predators is a valuable ecosystem service for crop production. The earwig, Euborellia annulipes (Lucas), attacks different pest species in various crop ecosystems, including larvae and pupae of the boll weevil, Anthonomus grandis grandis (Boh.). In this study, multiple factors were assessed to measure the selectivity of insecticides used against sap-sucking and chewing cotton pests for two E. annulipes populations. Nymphs and adults of E. annulipes were exposed to the insecticides in two ways: ingestion of contaminated prey, and contact with dried residues on either inert surfaces or treated plants bearing prey. Pymetrozine, chlorantraniliprole, and spinetoram had little effect on the predator regardless the tested earwig population, life stage with developmental time and survival, or the route of exposure (ingestion and residual). Cyantraniliprole dried-residue impeded nymph to complete development and only 27% of adults survived until 20 days after exposure. Pyriproxyfen was harmless through acute toxicity to nymphs and adult earwigs (70-100% survival 72 h after exposure), but prevented normal development of nymphs to adults causing chronic toxicity. Chlorfenapyr, indoxacarb, lambda-cyhalothrin, chlorpyrifos, dimethoate, and malathion were harmful to the predator regardless life stage or method of exposure. The negative impact of thiamethoxam, lambda-cyhalothrin and indoxacarb was diminished when exposure occurred on plants with predator allowed to shelter in the soil. The results indicate that insecticide selectivity outcome varies by the insecticide, predator life stage and the predator's behavior. Therefore, testing different predator life stages via several routes of exposure, without denying the insect the opportunity to engage in its normal behavior can provide better estimates of insecticide selectivity.

Experiência de um Centro Brasileiro com Crioablação para Isolamento Elétrico das Veias Pulmonares na Fibrilação Atrial Paroxística e Persistente - Resultados Preliminares no Brasil / Experience in a Brazilian Center with Cryoablation for Electric Isolation of the Pulmonary Veins in Paroxysmal and Persistent Atrial Fibrillation - Preliminary Results in Brazil

Resumo Fundamento O isolamento elétrico das veias pulmonares é reconhecidamente base fundamental para o tratamento não farmacológico da fibrilação atrial (FA) e, portanto, tem sido recomendado como passo inicial na ablação de FA em todas as diretrizes. A técnica com balão de crioenergia, embora amplamente utilizada na América do Norte e Europa, ainda se encontra em fase inicial em muitos países em desenvolvimento, como o Brasil. Objetivo Avaliar o sucesso e a segurança da técnica de crioablação em nosso serviço, em pacientes com FA paroxística e persistente. Métodos Cento e oito pacientes consecutivos com FA sintomática e refratária ao tratamento farmacológico foram submetidos à crioablação para isolamento das veias pulmonares. Os pacientes foram separados em dois grupos, de acordo com a classificação convencional da FA paroxística (duração de até sete dias) e persistente (FA por mais de sete dias). Dados de recorrência e segurança do procedimento foram analisados respectivamente como desfechos primário e secundário. O nível de significância adotado foi de 5%. Resultados Cento e oito pacientes, com idade média de 58±13 anos, 84 do sexo masculino (77,8%), foram submetidos ao procedimento de crioablação de FA. Sessenta e cinco pacientes apresentavam FA paroxística (60,2%) e 43, FA persistente (39,2%). O tempo médio do procedimento foi de 96,5±29,3 minutos e o tempo médio de fluoroscopia foi de 29,6±11,1 minutos. Foram observadas cinco (4,6%) complicações, nenhuma fatal. Considerando a evolução após os 3 meses iniciais, foram observadas 21 recorrências (19,4%) em período de um ano de seguimento. As taxas de sobrevivência livre de recorrência nos grupos paroxístico e persistente foram de 89,2% e 67,4%, respectivamente. Conclusão A crioablação para isolamento elétrico das veias pulmonares é um método seguro e eficaz para tratamento da FA. Nossos resultados estão consoantes com demais estudos, que sugerem que a tecnologia pode ser utilizada como abordagem inicial, mesmo nos casos de FA persistente. (Arq Bras Cardiol. 2020; [online].ahead print, PP.0-0)

Abstract Background Electrical isolation of the pulmonary veins is recognized as the cornerstone of non-pharmacological treatment of Atrial Fibrillation (AF), and therefore, has been recommended as the first step in AF ablation according to all guidelines. Even though the cryoballoon technology is widely used in North America and Europe, this experience is still incipient in many developing countries such as Brazil. Objective To evaluate initial results regarding success and safety of the new technology in patients with persistent and paroxysmal AF. Methods One hundred and eight consecutive patients with symptomatic AF refractory to pharmacological treatment were submitted to cryoablation for isolation of the pulmonary veins. Patients were separated into two groups according to AF classification: persistent (AF for over one week); or paroxysmal (shorter episodes). Recurrence and procedural safety data were analyzed respectively as primary and secondary outcomes. The level of significance was 5%. Results One hundred and eight patients, with mean age 58±13 years, 84 males (77.8%), underwent cryoablation. Sixty-five patients had paroxysmal AF (60.2%) and 43 had persistent AF (39.2%). The mean time of the procedure was 96.5±29.3 minutes and the mean fluoroscopy time was 29.6±11.1 minutes. Five (4.6%) complications were observed, none fatal. Considering a blanking period of 3 months, 21 recurrences (19.4%) were observed in a one-year follow-up period. The recurrence-free survival rates of AF in the paroxysmal and persistent groups were 89.2% and 67.4%, respectively. Conclusion Cryoablation for electrical isolation of the pulmonary veins is a safe and effective method for the treatment of AF. Our results are consistent with other studies suggesting that this technology can be used as an initial technique even in cases of persistent AF.

Experience in a Brazilian Center with Cryoablation for Electric Isolation of the Pulmonary Veins in Paroxysmal and Persistent Atrial Fibrillation - Preliminary Results in Brazil. / Experiência de um Centro Brasileiro com Crioablação para Isolamento Elétrico das Veias Pulmonares na Fibrilação Atrial Paroxística e Persistente ­ Resultados Preliminares no Brasil.

BACKGROUND: Electrical isolation of the pulmonary veins is recognized as the cornerstone of non-pharmacological treatment of Atrial Fibrillation (AF), and therefore, has been recommended as the first step in AF ablation according to all guidelines. Even though the cryoballoon technology is widely used in North America and Europe, this experience is still incipient in many developing countries such as Brazil. OBJECTIVE: To evaluate initial results regarding success and safety of the new technology in patients with persistent and paroxysmal AF. METHODS: One hundred and eight consecutive patients with symptomatic AF refractory to pharmacological treatment were submitted to cryoablation for isolation of the pulmonary veins. Patients were separated into two groups according to AF classification: persistent (AF for over one week); or paroxysmal (shorter episodes). Recurrence and procedural safety data were analyzed respectively as primary and secondary outcomes. The level of significance was 5%. RESULTS: One hundred and eight patients, with mean age 58±13 years, 84 males (77.8%), underwent cryoablation. Sixty-five patients had paroxysmal AF (60.2%) and 43 had persistent AF (39.2%). The mean time of the procedure was 96.5±29.3 minutes and the mean fluoroscopy time was 29.6±11.1 minutes. Five (4.6%) complications were observed, none fatal. Considering a blanking period of 3 months, 21 recurrences (19.4%) were observed in a one-year follow-up period. The recurrence-free survival rates of AF in the paroxysmal and persistent groups were 89.2% and 67.4%, respectively. CONCLUSION: Cryoablation for electrical isolation of the pulmonary veins is a safe and effective method for the treatment of AF. Our results are consistent with other studies suggesting that this technology can be used as an initial technique even in cases of persistent AF.

FUNDAMENTO: O isolamento elétrico das veias pulmonares é reconhecidamente base fundamental para o tratamento não farmacológico da fibrilação atrial (FA) e, portanto, tem sido recomendado como passo inicial na ablação de FA em todas as diretrizes. A técnica com balão de crioenergia, embora amplamente utilizada na América do Norte e Europa, ainda se encontra em fase inicial em muitos países em desenvolvimento, como o Brasil. OBJETIVO: Avaliar o sucesso e a segurança da técnica de crioablação em nosso serviço, em pacientes com FA paroxística e persistente. MÉTODOS: Cento e oito pacientes consecutivos com FA sintomática e refratária ao tratamento farmacológico foram submetidos à crioablação para isolamento das veias pulmonares. Os pacientes foram separados em dois grupos, de acordo com a classificação convencional da FA paroxística (duração de até sete dias) e persistente (FA por mais de sete dias). Dados de recorrência e segurança do procedimento foram analisados respectivamente como desfechos primário e secundário. O nível de significância adotado foi de 5%. RESULTADOS: Cento e oito pacientes, com idade média de 58±13 anos, 84 do sexo masculino (77,8%), foram submetidos ao procedimento de crioablação de FA. Sessenta e cinco pacientes apresentavam FA paroxística (60,2%) e 43, FA persistente (39,2%). O tempo médio do procedimento foi de 96,5±29,3 minutos e o tempo médio de fluoroscopia foi de 29,6±11,1 minutos. Foram observadas cinco (4,6%) complicações, nenhuma fatal. Considerando a evolução após os 3 meses iniciais, foram observadas 21 recorrências (19,4%) em período de um ano de seguimento. As taxas de sobrevivência livre de recorrência nos grupos paroxístico e persistente foram de 89,2% e 67,4%, respectivamente. CONCLUSÃO: A crioablação para isolamento elétrico das veias pulmonares é um método seguro e eficaz para tratamento da FA. Nossos resultados estão consoantes com demais estudos, que sugerem que a tecnologia pode ser utilizada como abordagem inicial, mesmo nos casos de FA persistente. (Arq Bras Cardiol. 2020; [online].ahead print, PP.0-0).

Avaliação da Dinâmica do Acoplamento da Condução Atrioventricular à Variação dos Intervalos RR em Atletas e Indivíduos Sedentários / Assessing Dynamic Atrioventricular Conduction Time to RR-interval Coupling in Athletes and Sedentary Subjects

Resumo Fundamento O tempo de condução atrioventricular (TCAV) é influenciado pelo estímulo autonômico e sujeito a remodelação fisiológica. Objetivo Avaliar a variabilidade da TCAV batimento-a-batimento e o intervalo RR em atletas e indivíduos sedentários saudáveis. Métodos Vinte adultos, incluindo 10 indivíduos sedentários saudáveis (controles) e 10 corredores de elite de longa distância (atletas), com idade, peso e altura ajustados foram submetidos à avaliação do equivalente metabólico máximo (MET) e registro de ECG em repouso supino de 15 minutos sete dias depois. O intervalo entre os picos da onda P e da onda R definiu o TCAV. Foram calculadas a média (M) e o desvio padrão (DP) de intervalos RR consecutivos (RR) e TCAV acoplados, bem como as linhas de regressão de RR vs. TCAV (RR-TCAV). A condução AV concordante foi definida como o slope RR-AVCT positivo e, caso contrário, discordante. Um modelo de regressão linear multivariada foi desenvolvido para explicar o MET com base nos parâmetros de variabilidade do TCAV e intervalo RR. Nível de significância: 5%. Resultados Nos atletas, os valores de M-RR e DP-RR foram maiores que nos controles, enquanto M-TCAV e DP-TCAV não foram. Os slopes RR-TCAV foram, respectivamente, 0,038 ± 0,022 e 0,0034 ± 0,017 (p < 0,05). Utilizando um valor de corte de 0,0044 (AUC 0,92 ± 0,07; p < 0,001), o slope RR-TCAV mostrou 100% de especificidade e 80% de sensibilidade. Em um modelo multivariado, o slope DP-RR e RR-TCAV foram variáveis explicativas independentes do MET (razão F: 17,2; p < 0,001), apresentando especificidade de 100% e sensibilidade de 90% (AUC: 0,99 ± 0,02; p < 0,001). Conclusão Em corredores de elite, o acoplamento dinâmico de TCAV para intervalo RR apresenta condução AV discordante espontânea, caracterizada por slope na linha de regressão TCAV negativa vs. intervalo RR. O desvio padrão dos intervalos RR e o slope da linha de regressão do TCAV vs. intervalo RR são variáveis explicativas independentes do MET. (Arq Bras Cardiol. 2020; [online].ahead print, PP.0-0)

Abstract Background Atrioventricular conduction time ( AVCT ) is influenced by autonomic input and subject to physiological remodeling. Objective To evaluate beat-by-beat AVCT and RR-interval variability in athletes and healthy sedentary subjects. Methods Twenty adults, including 10 healthy sedentary (Controls) and 10 elite long-distance runners (Athletes), age, weight and height-adjusted, underwent maximal metabolic equivalent (MET) assessment, and 15-min supine resting ECG recording seven days later. The interval between P-wave and R-wave peaks defined the AVCT . Mean (M) and standard deviation (SD) of consecutive RR-intervals (RR) and coupled AVCT were calculated, as well as regression lines of RR vs. AVCT (RR-AVCT) . Concordant AV conduction was defined as positive RR-AVCT slope and discordant otherwise. A multivariate linear regression model was developed to explain MET based on AVCT and RR-interval variability parameters. Significance-level: 5 %. Results In Athletes, M-RR and SD-RR values were higher than in Controls, whereas M-AVCT and SD-AVCT were not. RR-AVCT slopes were, respectively, 0.038 ± 0.022 and 0.0034 ± 0.017 (p < 0.05). Using a cut-off value of 0.0044 (AUC 0.92 ± 0.07; p < 0.001), RR-AVCT slope showed 100% specificity and 80% sensitivity. In a multivariate model, SD-RR and RR-AVCT slope were independent explanatory variables of MET (F-ratio: 17.2; p < 0.001), showing 100% specificity and 90% sensitivity (AUC 0.99 ± 0.02; p < 0.001). Conclusion In elite runners, AVCT to RR -interval dynamic coupling shows spontaneous discordant AV conduction, characterized by negative AVCT vs. RR -interval regression line slope. RR -intervals standard deviation and AVCT vs. RR -interval regression line slope are independent explanatory variables of MET (Arq Bras Cardiol. 2020; [online].ahead print, PP.0-0)

Assessing Dynamic Atrioventricular Conduction Time to RR-interval Coupling in Athletes and Sedentary Subjects. / Avaliação da Dinâmica do Acoplamento da Condução Atrioventricular à Variação dos Intervalos RR em Atletas e Indivíduos Sedentários.

Background Atrioventricular conduction time ( AVCT ) is influenced by autonomic input and subject to physiological remodeling. Objective To evaluate beat-by-beat AVCT and RR-interval variability in athletes and healthy sedentary subjects. Methods Twenty adults, including 10 healthy sedentary (Controls) and 10 elite long-distance runners (Athletes), age, weight and height-adjusted, underwent maximal metabolic equivalent (MET) assessment, and 15-min supine resting ECG recording seven days later. The interval between P-wave and R-wave peaks defined the AVCT . Mean (M) and standard deviation (SD) of consecutive RR-intervals (RR) and coupled AVCT were calculated, as well as regression lines of RR vs. AVCT (RR-AVCT) . Concordant AV conduction was defined as positive RR-AVCT slope and discordant otherwise. A multivariate linear regression model was developed to explain MET based on AVCT and RR-interval variability parameters. Significance-level: 5 %. Results In Athletes, M-RR and SD-RR values were higher than in Controls, whereas M-AVCT and SD-AVCT were not. RR-AVCT slopes were, respectively, 0.038 ± 0.022 and 0.0034 ± 0.017 (p < 0.05). Using a cut-off value of 0.0044 (AUC 0.92 ± 0.07; p < 0.001), RR-AVCT slope showed 100% specificity and 80% sensitivity. In a multivariate model, SD-RR and RR-AVCT slope were independent explanatory variables of MET (F-ratio: 17.2; p < 0.001), showing 100% specificity and 90% sensitivity (AUC 0.99 ± 0.02; p < 0.001). Conclusion In elite runners, AVCT to RR -interval dynamic coupling shows spontaneous discordant AV conduction, characterized by negative AVCT vs. RR -interval regression line slope. RR -intervals standard deviation and AVCT vs. RR -interval regression line slope are independent explanatory variables of MET (Arq Bras Cardiol. 2020; [online].ahead print, PP.0-0).

Prognostic Value of a New Marker of Ventricular Repolarization in Cirrhotic Patients / Valor Prognóstico de um Novo Marcador da Repolarização Ventricular em Pacientes Cirróticos

Abstract Background: There is still debate about the relationship between changes in ventricular repolarization on the surface electrocardiogram and cirrhosis severity. Objective: To study the relationship between variables related to ventricular repolarization and the clinical severity of the cirrhotic disease. Methods: We selected 79 individuals with hepatic cirrhosis, classified according to the Child-Pugh-Turcotte criteria (Child A, B, and C). We measured the QT and corrected QT (QTc) intervals, and the interval between the peak and the end of the T wave (TpTe), and we identified their minimum, maximum, and mean values in the 12-lead electrocardiogram. We also calculated the dispersion of the QT (DQT) and QTc (DQTc) intervals. Results: In 12 months of clinical follow-up, nine subjects underwent hepatic transplantation (Child A: 0 [0%]; Child B: 6 [23.1%]; Child C: 3 [18.8%]; p = 0.04) and 12 died (Child A: 3 [12.0%]; Child B: 4 [15.4%]; Child C: 5 [31.3%]; p = 0.002). No significant differences were observed between the cirrhotic groups related to the minimum, maximum, and mean values for the QT, QTc, TpTe, DQT, and DQTc intervals. A minimum TpTe interval ≤ 50 ms was a predictor for the composite endpoints of death or liver transplantation with a sensitivity of 90% and a specificity of 57% (p = 0.005). In the Cox multivariate analysis, the Child groups and a minimum TpTe of ≤ 50 ms were independent predictors of the composite endpoints. Conclusion: The intervals QT, QTc, DQT, DQTc, and TpTe have similar distributions between different severity stages in cirrhotic disease. The TpTe interval proved to be a prognostic marker in subjects with cirrhosis, regardless of disease severity (NCT01433848).

Resumo Fundamento: Ainda há debate sobre a relação de alterações da repolarização ventricular ao eletrocardiograma de superfície e a gravidade da cirrose. Objetivo: Estudar a relação entre variáveis relacionadas à repolarização ventricular e a gravidade clínica da doença cirrótica. Métodos: Foram selecionados 79 sujeitos com cirrose hepática, classificados segundo os critérios Child-Pugh-Turcotte (Child A, B e C). Foram medidos intervalos QT e QT corrigido (QTc), o intervalo entre o ápice e o final da onda T (TpTe) e identificados os respectivos valores mínimos, máximos e médios nas 12 derivações do eletrocardiograma. Foram calculados também as dispersões dos intervalos QT (DQT) e QTc (DQTc). Resultados: Em 12 meses de acompanhamento clínico, nove sujeitos foram submetidos a transplante hepático (Child A: 0 (0%); Child B: 6 (23,1%); Child C: 3 (18,8%); p=0,04) e 12 faleceram (Child A: 3 (12,0%); Child B: 4 (15,4%); Child C: 5 (31,3%); p=0,002). Não foram observadas diferenças significativas entre os grupos cirróticos relacionadas aos valores mínimos, máximos e médios dos intervalos QT, QTc, TpTe, DQT e DQTc. O intervalo TpTe mínimo ≤50ms foi preditor de desfecho composto de óbito ou transplante hepático com sensibilidade de 90% e especificidade de 57% (p=0,005). Na análise multivariada de Cox, grupos Child e TpTe mínimo ≤50ms foram preditores independentes de desfechos compostos. Conclusão: Os intervalos QT, QTc, DQT, DQTc e TpTe apresentam distribuições semelhantes entre diferentes estágios de gravidade da doença cirrótica. O intervalo TpTe mostra-se marcador prognóstico em sujeitos cirróticos, independente da gravidade da doença. (NCT01433848).

Prognostic Value of a New Marker of Ventricular Repolarization in Cirrhotic Patients.

BACKGROUND: There is still debate about the relationship between changes in ventricular repolarization on the surface electrocardiogram and cirrhosis severity. OBJECTIVE: To study the relationship between variables related to ventricular repolarization and the clinical severity of the cirrhotic disease. METHODS: We selected 79 individuals with hepatic cirrhosis, classified according to the Child-Pugh-Turcotte criteria (Child A, B, and C). We measured the QT and corrected QT (QTc) intervals, and the interval between the peak and the end of the T wave (TpTe), and we identified their minimum, maximum, and mean values in the 12-lead electrocardiogram. We also calculated the dispersion of the QT (DQT) and QTc (DQTc) intervals. RESULTS: In 12 months of clinical follow-up, nine subjects underwent hepatic transplantation (Child A: 0 [0%]; Child B: 6 [23.1%]; Child C: 3 [18.8%]; p = 0.04) and 12 died (Child A: 3 [12.0%]; Child B: 4 [15.4%]; Child C: 5 [31.3%]; p = 0.002). No significant differences were observed between the cirrhotic groups related to the minimum, maximum, and mean values for the QT, QTc, TpTe, DQT, and DQTc intervals. A minimum TpTe interval ≤ 50 ms was a predictor for the composite endpoints of death or liver transplantation with a sensitivity of 90% and a specificity of 57% (p = 0.005). In the Cox multivariate analysis, the Child groups and a minimum TpTe of ≤ 50 ms were independent predictors of the composite endpoints. CONCLUSION: The intervals QT, QTc, DQT, DQTc, and TpTe have similar distributions between different severity stages in cirrhotic disease. The TpTe interval proved to be a prognostic marker in subjects with cirrhosis, regardless of disease severity (NCT01433848).

Assessment of Autonomic Function by Phase Rectification of RRInterval Histogram Analysis in Chagas Disease.

BACKGROUND: In chronic Chagas disease (ChD), impairment of cardiac autonomic function bears prognostic implications. Phase­rectification of RR-interval series isolates the sympathetic, acceleration phase (AC) and parasympathetic, deceleration phase (DC) influences on cardiac autonomic modulation. OBJECTIVE: This study investigated heart rate variability (HRV) as a function of RR-interval to assess autonomic function in healthy and ChD subjects. METHODS: Control (n = 20) and ChD (n = 20) groups were studied. All underwent 60-min head-up tilt table test under ECG recording. Histogram of RR-interval series was calculated, with 100 ms class, ranging from 600-1100 ms. In each class, mean RR-intervals (MNN) and root-mean-squared difference (RMSNN) of consecutive normal RR-intervals that suited a particular class were calculated. Average of all RMSNN values in each class was analyzed as function of MNN, in the whole series (RMSNNT), and in AC (RMSNNAC) and DC (RMSNNDC) phases. Slopes of linear regression lines were compared between groups using Student t-test. Correlation coefficients were tested before comparisons. RMSNN was log-transformed. (α < 0.05). RESULTS: Correlation coefficient was significant in all regressions (p < 0.05). In the control group, RMSNNT, RMSNNAC, and RMSNNDC significantly increased linearly with MNN (p < 0.05). In ChD, only RMSNNAC showed significant increase as a function of MNN, whereas RMSNNT and RMSNNDC did not. CONCLUSION: HRV increases in proportion with the RR-interval in healthy subjects. This behavior is lost in ChD, particularly in the DC phase, indicating cardiac vagal incompetence.

Assessment of Autonomic Function by Phase Rectification of RRInterval Histogram Analysis in Chagas Disease / Avaliação da Função Autonômica na Doença de Chagas Através da Análise de Histogramas de Intervalos RR com Retificação de Fase

Background: In chronic Chagas disease (ChD), impairment of cardiac autonomic function bears prognostic implications. Phase‑rectification of RR-interval series isolates the sympathetic, acceleration phase (AC) and parasympathetic, deceleration phase (DC) influences on cardiac autonomic modulation. Objective: This study investigated heart rate variability (HRV) as a function of RR-interval to assess autonomic function in healthy and ChD subjects. Methods: Control (n = 20) and ChD (n = 20) groups were studied. All underwent 60-min head-up tilt table test under ECG recording. Histogram of RR-interval series was calculated, with 100 ms class, ranging from 600–1100 ms. In each class, mean RR-intervals (MNN) and root-mean-squared difference (RMSNN) of consecutive normal RR-intervals that suited a particular class were calculated. Average of all RMSNN values in each class was analyzed as function of MNN, in the whole series (RMSNNT), and in AC (RMSNNAC) and DC (RMSNNDC) phases. Slopes of linear regression lines were compared between groups using Student t-test. Correlation coefficients were tested before comparisons. RMSNN was log-transformed. (α < 0.05). Results: Correlation coefficient was significant in all regressions (p < 0.05). In the control group, RMSNNT, RMSNNAC, and RMSNNDC significantly increased linearly with MNN (p < 0.05). In ChD, only RMSNNAC showed significant increase as a function of MNN, whereas RMSNNT and RMSNNDC did not. Conclusion: HRV increases in proportion with the RR-interval in healthy subjects. This behavior is lost in ChD, particularly in the DC phase, indicating cardiac vagal incompetence. .

Fundamento: Na doença de Chagas (DCh) crônica, a função autonômica cardíaca está frequentemente comprometida e traz implicações quanto ao prognóstico. A retificação de fase da série de intervalos RR isola as influências simpática (fase de aceleração – AC) e parassimpática (fase de desaceleração – DC) na modulação autonômica cardíaca. Objetivo: Este estudo investigou a variabilidade da frequência cardíaca (VRR) como função dos intervalos RR, para avaliar a função autonômica em indivíduos saudáveis e com DCh. Métodos: Os grupos controle (n = 20) e com DCh (n = 20) foram estudados. Todos fizeram o teste de inclinação ortostática de 60 minutos, com o registro do ECG. O histograma da série de intervalos RR dividido em classes de 100 ms, variando de 600 a 1100 ms foi calculado. Para cada classe, foram calculados os intervalos RR médios (MNN) e a diferença média quadrática (RMS) entre os intervalos RR normais que se encaixavam naquela classe. A média de todos os valores de RMS foi analisada como uma função dos MNN na série inteira (RMST) e nas fases de aceleração (RMSAC) e desaceleração (RMSDC). A inclinação das linhas de regressão linear foi comparada entre grupos através do teste t de Student. Os coeficientes de correlação foram testados antes das comparações. A RMS sofreu transformação logarítmica (α < 0,05). Resultados: O coeficiente de correlação foi significativo em todas as regressões (p < 0,05). No grupo controle, a RMST, a RMSAC e a RMSDC aumentaram de forma significativa proporcionalmente ao MNN (p < 0,05). No grupo com DCh, apenas a RMSAC mostrou um aumento significativo como função do MNN, enquanto a RMST e a RMSDC não aumentaram significativamente. Conclusão: A VRR aumenta proporcionalmente ao intervalo RR em indivíduos saudáveis. Este comportamento é perdido na DCh, especialmente na DC, indicando incompetência vagal cardíaca. .

Refining the deceleration capacity index in phase-rectified signal averaging to assess physical conditioning level.

BACKGROUND: Deceleration capacity (DC) of heart rate is a measure of cardiac vagal modulation. This study introduced a DC adaptation (Modified Index) that measured the velocity of change in the phase-rectified signal averaging curve, and assessed its ability to discriminate athletes from controls. MATERIALS AND METHODS: The Modified Index was compared to Standard DC approach in a prospective case-control study. Subjects were classified according to maximal metabolic equivalents as the control group (CG) and athlete group (AG). The Modified Index was compared to Standard DC and classical approaches (RMSSD and HF) by the area under receiver operating characteristic curve (AUC) using 10,000 bootstraps. RESULTS: In Standard DC and Modified Index bootstrap median values were (ms), respectively, 11.80 and 17.94 (p<0.01) in CG, and 25.98 and 45.62 in AG (p<0.01). AUC (mean±SD) was 0.70±0.12 for Standard DC and 0.96±0.04 for Modified Index (p<0.01). CONCLUSIONS: Modified Index appropriately discriminates athletes from healthy sedentary subjects.

Efeitos da idade e da aptidão aeróbica na recuperação da frequência cardíaca em homens adultos / Effects of age and aerobic fitness on heart rate recovery in adult men

FUNDAMENTO: O envelhecimento fisiológico leva a uma disfunção autonômica cardíaca que está associada ao surgimento e ao agravamento de doenças cardiovasculares e a um maior risco de morte. Atualmente, o exercício físico é apontado como uma estratégia cardioprotetora, sendo necessários mais estudos do seu benefício na função autonômica cardíaca. OBJETIVO: Avaliar o controle autonômico da frequência cardíaca em voluntários jovens e de meia-idade com diferentes níveis de aptidão aeróbica. MÉTODOS: Participaram do estudo 68 voluntários, estratificados quanto à idade e ao nível de aptidão aeróbica. Com base na aptidão aeróbica avaliada pelo teste de esforço submáximo, os sujeitos foram separados em dois grupos, aptidão boa e aptidão deficiente. A avaliação do controle autonômico cardíaco se deu a partir de medidas da variabilidade da frequência cardíaca em repouso e a recuperação da frequência cardíaca pós-esforço. Para comparação das variáveis investigadas, utilizou-se a análise de variância bifatorial. RESULTADOS: A variabilidade da frequência cardíaca é significativamente menor nos voluntários de meia-idade do que nos jovens, independentemente do nível de aptidão aeróbica (p < 0,01). Melhores níveis de aptidão aeróbica nos voluntários de meia-idade estão associados à reentrada vagal pós-esforço mais precoce - taxa de declínio da FC após 1min30s: 39,6% aptidão aeróbica boa vs. 28,4% deficiente (p < 0,01). CONCLUSÃO: Melhores níveis de aptidão aeróbica atuam beneficamente no controle autonômico da frequência cardíaca pós-esforço, preservando a velocidade de reentrada vagal em voluntários de meia-idade. No entanto, não atenua a redução da variabilidade da frequência cardíaca decorrente do processo natural de envelhecimento.

BACKGROUND: Physiological aging leads to cardiac autonomic dysfunction, which is associated with the onset and worsening of cardiovascular disease and an increased risk of death. Currently, physical exercise is considered a cardioprotective strategy and more research is needed on its benefit on cardiac autonomic function. OBJECTIVE: To evaluate the autonomic control of heart rate in healthy young and middle-aged volunteers with different levels of aerobic fitness. METHODS: The study included 68 volunteers, stratified for age and level of aerobic fitness. Based on aerobic fitness assessed by the submaximal exercise test, subjects were separated into two groups, good fitness and poor fitness. Assessment of cardiac autonomic control was performed based on measurements of heart rate variability at rest and heart rate recovery post-exercise. Analysis of variance with two factors was used to compare the variables investigated. RESULTS: The heart rate variability is significantly lower in middle-aged volunteers than in young individuals, regardless of the aerobic fitness level (p <0.01). Higher levels of aerobic fitness in middle-aged volunteers are associated with earlier post-effort vagal reentry - rate of HR decline after 1min30s: 39.6% good aerobic fitness vs. poor 28.4% (p < 0.01). CONCLUSION: Better levels of aerobic fitness act beneficially on the autonomic control of post-exercise heart rate, preserving the vagal reentry velocity in healthy middle-aged volunteers. However, it does not attenuate the decrease in heart rate variability due to the natural aging process.

Effects of age and aerobic fitness on heart rate recovery in adult men.

BACKGROUND: Physiological aging leads to cardiac autonomic dysfunction, which is associated with the onset and worsening of cardiovascular disease and an increased risk of death. Currently, physical exercise is considered a cardioprotective strategy and more research is needed on its benefit on cardiac autonomic function. OBJECTIVE: To evaluate the autonomic control of heart rate in healthy young and middle-aged volunteers with different levels of aerobic fitness. METHODS: The study included 68 volunteers, stratified for age and level of aerobic fitness. Based on aerobic fitness assessed by the submaximal exercise test, subjects were separated into two groups, good fitness and poor fitness. Assessment of cardiac autonomic control was performed based on measurements of heart rate variability at rest and heart rate recovery post-exercise. Analysis of variance with two factors was used to compare the variables investigated. RESULTS: The heart rate variability is significantly lower in middle-aged volunteers than in young individuals, regardless of the aerobic fitness level (p <0.01). Higher levels of aerobic fitness in middle-aged volunteers are associated with earlier post-effort vagal reentry - rate of HR decline after 1min30s: 39.6% good aerobic fitness vs. poor 28.4% (p < 0.01). CONCLUSION: Better levels of aerobic fitness act beneficially on the autonomic control of post-exercise heart rate, preserving the vagal reentry velocity in healthy middle-aged volunteers. However, it does not attenuate the decrease in heart rate variability due to the natural aging process.