A respiração de Cheyne-Stokes em pacientes com insuficiência cardíaca congestiva: causas e conseqüências

Cheyne-Stokes respiration is a form of periodic breathing in which central apneas and hypopneas alternate with periods of hyperventilation, producing a waxing and waning pattern of tidal volume. This review focuses on the causes and consequences of Cheyne-Stokes respiration in patients with congestive heart failure, in whom the prevalence is strikingly high and ranges from 30% to 50%. Several factors have been implicated in the genesis of Cheyne-Stokes respiration, including low cardiac output and recurrent hypoxia. The key pathophysiological mechanism triggering Cheyne-Stokes respiration is hyperventilation and low arterial CO2 (PaCO2) that when below the apneic threshold triggers a central apnea. Hyperventilation is associated with pulmonary congestion, and Cheyne-Stokes respiration is more prone to occur during sleep, when the respiratory system is mainly dependent on chemical control. It is associated with recurrent dips in oxygen saturation and arousals from sleep, with oscillations in blood pressure and heart rate, sympathetic activation and increased risk of ventricular tachycardia. Cheyne-Stokes respiration is an independent marker of poor prognosis and may participate in a vicious cycle, further stressing the failing heart.A respiração de Cheyne-Stokes é uma forma de respiração periódica na qual apnéias e hipopnéias se alternam com períodos de hiperpnéias que apresentam um padrão crescendo e decrescendo de volume corrente. Esta revisão enfoca as causa e conseqüências da respiração de Cheyne- Stokes em pacientes com insuficiência cardíaca congestiva na qual a prevalência é extremamente alta e varia entre 30 a 50%. Vários fatores foram implicados na gênese da respiração de Cheyne-Stokes, incluindo baixo debito cardíaco e hipoxia recorrente. Hiperventilacão e baixos níveis de CO2 arterial (PaCO2), que quando abaixo do limiar de apnéia desencadeiam apnéia central são os mecanismos fisiopatológicos chave na gênese da respiração de Cheyne-Stokes. Hiperventilação está associada com congestão pulmonar, e a respiração de Cheyne-Stokes tem uma tendência maior de ocorrer durante o sono, quando o centro respiratório é dependente principalmente do controle químico. A respiração de Cheyne-Stokes está associada a quedas recorrentes da saturação de oxigênio e ao despertar do sono, com oscilações recorrentes na freqüência cardíaca, pressão arterial, aumento da atividade simpática e risco aumentado de taquicardia ventricular. A respiração de Cheyne-Stokes é um marcador independente de mau prognostico e provavelmente participa de um ciclo vicioso que contribui para a deterioração cardíaca

Cardiovascular consequences of obstructive sleep apnea syndrome

Uma condição clínica muito comum é SAOS, que está associada a várias doenças cardiovasculares, incluindo hipertensão arterial sistêmica, fibrilação atrial e aterosclerose. A associação entre SAOS e doença cardiovascular não é somente uma consequência da sobreposição de fatores de risco, incluindo obesidade, sedentarismo, ser do sexo masculino e ter idade maior. Existem evidências crescentes de que SAOS contribui de forma independente para o aparecimento e a progressão de várias doenças cardiovasculares. Os mecanismos pelos quais SAOS pode afetar o sistema cardiovascular são múltiplos e incluem a ativação do sistema nervoso simpático, inflamação sistêmica, resistência a insulina e geração de estresse oxidativo. Existem evidências que o tratamento de SAOS com CPAP pode reduzir a pressão arterial, sinais precoces de aterosclerose, risco de recorrência de fibrilação atrial e mortalidade, principalmente por acidente vascular cerebral e infarto agudo do miocárdio, em pacientes com SAOS grave.Obstructive sleep apnea syndrome (OSAS) is a common condition associated with various cardiovascular diseases, including systemic arterial hypertension, atrial fibrillation, and atherosclerosis. The association between OSAS and cardiovascular disease has been related to the overlapping of risk factors, including obesity, having a sedentary lifestyle, being male, and being older. However, there is mounting evidence that OSAS can also independently contribute to the development and progression of various cardiovascular diseases. The mechanisms by which OSAS can affect the cardiovascular system are multiple, including the activation of the sympathetic nervous system, systemic inflammation, insulin resistance, and oxidative stress. There is also evidence that the treatment of OSAS with CPAP can reduce arterial blood pressure, early signs of atherosclerosis, the risk of atrial fibrillation recurrence, and mortality (principally mortality due to stroke or acute myocardial infarction) in patients with severe OSAS

Evidence that the degree of obstructive sleep apnea may not increase myocardial ischemia and arrhythmias in patients with stable coronary artery disease

There is controversy regarding whether obstructive sleep apnea is responsible for triggering myocardial ischemia, arrhythmias and heart rate variability in patients with coronary artery disease. OBJETIVE: The objective of this study was to identify relationships between sleep apnea, myocardial ischemia and cardiac arrhythmia in patients with coronary artery disease. METHODS: Fifty-three patients with stable coronary disease underwent simultaneous polysomnography and electrocardiographic Holter recording. The apnea-hypopnea index (AHI) was defined as the number of apneas/hypopneas per hour of sleep. Patients were divided into a Control group (AHI15, n=23 pts) and an Apnea group (AHI>;15, n=30 pts). A subgroup of 13 patients with an AHI>;30 (Severe Apnea group) was also studied. We analyzed ischemic episodes (ST-segment depressions >;1 mm, >; 1 min), heart rate variability and the occurrence of arrhythmias during wakefulness and sleep. RESULTS: Baseline clinical characteristics among the groups were similar except for higher blood pressure in the Apnea groups (

Lack of reliable clinical predictors to identify obstructive sleep apnea in patients with hypertrophic cardiomyopathy

OBJECTIVE: Obstructive sleep apnea is common among patients with hypertrophic cardiomyopathy and may contribute to poor cardiovascular outcomes. However, obstructive sleep apnea is largely unrecognized in this population. We sought to identify the clinical predictors of obstructive sleep apnea among patients with hypertrophic cardiomyopathy. METHODS: Consecutive patients with hypertrophic cardiomyopathy were recruited from a tertiary University Hospital and were evaluated using validated sleep questionnaires (Berlin and Epworth) and overnight portable monitoring. Ninety patients (males, 51%; age, 46±15 years; body mass index, 26.6±4.9 kg/m2) were included, and obstructive sleep apnea (respiratory disturbance index ≥15 events/h) was present in 37 patients (41%). RESULTS: Compared with the patients without obstructive sleep apnea, patients with obstructive sleep apnea were older and had higher body mass index, larger waist circumference, larger neck circumference, and higher prevalence of atrial fibrillation. Excessive daytime sleepiness (Epworth scale) was low and similar in the patients with and without obstructive sleep apnea, respectively. The only predictors of obstructive sleep apnea (using a logistic regression analysis) were age ≥45 years (odds ratio [OR], 4.46; 95% confidence interval [CI 95%], 1.47-13.54; p = 0.008) and the presence of atrial fibrillation [OR, 5.37; CI 95%, 1.43-20.12; p = 0.013]. CONCLUSION: Consistent clinical predictors of obstructive sleep apnea are lacking for patients with hypertrophic cardiomyopathy, which suggests that objective sleep evaluations should be considered in this population, particularly among elderly patients with atrial fibrillation

Sugar feeding in triatomines: a new perspective for controlling the transmission of Chagas disease

Introduction: Triatomines are vectors of Trypanosoma cruzi, the etiological agent of Chagas disease. Currently, there is no vaccine against this disease. Thus, control of the insect vector population is the main strategy available to reduce the number of cases. Triatomines are considered obligate hematophagous, but different alternative feeding behaviors were described, such as haemolymphagy or plant feeding.Methods: To determine the preference for sugar feeding in nymphs and adults of Rhodnius prolixus, the insects were exposed a piece of cotton containing bromophenol blue plus sucrose. In addition, we offered several sugars for different species of triatomines, and tested sugar meals as a route of delivery of insecticides in first-instar nymphs of R. prolixus. The effect of sugar feeding on the physiology of these different species of triatomines was recorded.Results: First instar nymphs ingested sucrose more strongly than other stages, and showed high mortality rates. In different species of triatomines, sucrose induced an ingestion, but engorgement varied according to the species. R. prolixus nymphs showed an indiscriminate intake of various sugars, with very different physiological effects. Furthermore, ingesting different combinations of insecticides + sugar significantly reduced insect survival.Discussion: In summary, we described for the first-time sugar feeding as a widespread behavior in several species of triatomines, and the possibility of the use of toxic sugar baits for the control of these vectors. The knowledge of feeding behavior in these insects can be fundamental for the development of new strategies to control Chagas disease

Insomnia symptoms during the covid-19 pandemic: a case-control study

OBJECTIVE: To identify lifestyle-related, sociodemographic, and mental health characteristics of people with insomnia symptoms and people without insomnia during the pandemic. METHODS: A case-control study was conducted with data collected by snowball sampling using an online questionnaire. From November 2020 to April 2021, 6,360 people with a mean age of 43.5 years (SD = 14.3) participated in the survey. For this study, we considered 158 cases of insomnia disorder and 476 controls (three controls per case) randomly selected from the participants without sleep problems. RESULTS: The results of the comparative analysis between cases and controls showed that sleeping less than six hours daily (OR = 3.89; 95%CI 2.50-6.05), feeling sadness frequently (OR = 2.95; 95%CI 1.69-5.17), residing in metropolitan areas (OR = 1.71; 95%CI 1.04-2.84), being 40 years or older (OR = 1.93; 95%CI 1.22-3.06), and the interaction between occupation and poorer education (OR = 2.12; 95%CI 1.22-3.69) were predictors for symptoms of insomnia disorder during the pandemic. CONCLUSIONS: In addition to confirming the hypothesis that mental health problems are associated with insomnia symptoms, the results point to insomnia as an important outcome for studies on the effects of unemployment, vulnerability and low education of the population, especially in large cities, highlighting that the effects of the crisis on health and the economy are extremely unequally distributed.OBJETIVO: Identificar características relacionadas ao estilo de vida, sociodemográficas e saúde mental de pessoas com sintomas de insônia e pessoas sem insônia durante a pandemia. MÉTODOS: A partir de dados coletados por amostragem em bola de neve, por meio de um questionário online foi realizado um estudo caso-controle. Durante o período de novembro de 2020 a abril de 2021, 6.360 pessoas com idade média de 43,5 anos (DP = 14,3) participaram da pesquisa. No presente estudo, foram considerados 158 casos de transtorno de insônia e 476 controles (três controles por caso) selecionados aleatoriamente dentre os participantes sem problemas de sono. RESULTADOS: Os resultados da análise comparativa entre casos e controles mostraram que dormir menos de seis horas diárias (OR = 3,89; IC95% 2,50–6,05), sentir tristeza frequentemente (OR = 2,95; IC95% 1,69–5,17), residir em metrópoles (OR = 1,71; IC95% 1,04–2,84), estar com 40 anos ou mais (OR = 1,93; IC95% 1,22–3,06) e a interação entre ocupação e escolaridade mais precária (OR = 2,12; IC95% 1,22–3,69) foram fatores preditores para sintomas de transtorno de insônia durante a pandemia. CONCLUSÕES: Além da confirmação da hipótese de que problemas de saúde mental estão associados a sintomas de insônia, os resultados apontam para a insônia como um desfecho importante para estudos sobre efeitos do desemprego, vulnerabilidade e baixa escolaridade da população, sobretudo nas grandes metrópoles, ressaltando que os efeitos da crise sobre a saúde e a economia são distribuídos de forma extremamente desiguais

Obstructive sleep apnea is common among patients referred for coronary artery bypass grafting and can be diagnosed by portable monitoring

Background Obstructive sleep apnea (OSA) is common among patients with coronary artery disease. However, OSA remains largely under recognized. The lack of clinical suspicion and difficulties to access full polysomnography (PSG) are limiting factors. The aim of this study was to evaluate, among patients referred to coronary artery bypass grafting (CABG): (i) the prevalence of OSA, (ii) the association of OSA with clinical symptoms, (iii) the performance of overnight unattended portable monitoring (PM) as an alternative method for the diagnosis of OSA. Methods Consecutive patients referred for CABG were evaluated by standard physical evaluation and validated questionnaires (Berlin questionnaire and Epworth Sleepiness Scale) and underwent full PSG and PM (Stardust II). Results We studied 70 consecutive patients (76% men), age 58 +/- 7 years (mean +/- SD), BMI [median (interquartile range)] 27.6 kg/m(2) (25.8-31.1). The prevalence of OSA (full PSG) using an apnea-hypopnea index of at least 5 events/h was 87%. Commonly used clinical traits for the screening of OSA such as the Epworth Sleepiness Scale and neck circumference had low sensitivities to detect OSA. In contrast, the Berlin questionnaire showed a good sensitivity (72%) to detect OSA. PM showed good sensitivity (92%) and specificity (67%) for the diagnosis of OSA. Conclusion OSA is strikingly common among patients referred for CABG. The Berlin questionnaire, but not symptom of excessive daytime sleepiness is a useful tool to screen OSA. PM is useful for the diagnosis of OSA and therefore is an attractive tool for widespread use among patients with coronary artery disease. Coron Artery Dis 23:31-38 (C) 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins.FAPESPFAPES