242 resultados para bradycardia
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Ten male Wistar rats, chronically infected with Colombian, São Felipe (12SF) and Y strains of Trypanosoma cruzi and ten non-infected control animals were submitted to the bradycardia responsiveness test, an assessment of heart parasympathetic function, after phenylephrine injection. Six chagasic animals showed heart parasympathetic dysfuntion characterized by reduction in the index of bradycardia baroreflex responsiveness, as compared with the control group. Microscopic examination of the atrial heart ganglia of chagasic rats showed ganglionitis, but no statiscally significant reduction in the number of neurons.
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The autonomic nervous system (ANS) plays a role as a modulator in the pathogenesis of paroxysmal atrial fibrillation (PAF). The clinical pattern of vagally mediated PAF has been observed mainly in young patients. Neurocardiogenic responses during orthostatic stress are related to autonomic reflexes in which the vagal influence predominates. AIM: To evaluate the susceptibility of elderly patients with PAF to activation of vasovagal syncope mechanisms. METHODS: We performed passive head-up tilt testing (HUT) in 34 patients (62% women, aged 72 +/- 7 years), with > or = 1 year of clinical history of PAF--19 without structural heart disease, 11 with hypertensive heart disease and 4 with coronary artery disease (who had no previous myocardial infarction, had undergone myocardial revascularization, and had no documented ischemia) (PAF group), and compared the results with those obtained in a group of 34 age-matched patients (53% women, aged 74 +/- 6 years), who underwent HUT due to recurrent syncope (Sc group). In this group, 21 had no documented heart disease and none had a clinical history of AF. There was no diabetes, congestive heart failure or syncope in the PAF group. After a supine resting period, the subjects were tilted at 70 degrees for 20 minutes while in sinus rhythm. No provocative agents were used to complement the HUT. ECG and blood pressure were continuously monitored (Task Force Monitor, CNSystems). The test was considered positive when syncope or presyncope occurred with bradycardia and/or arterial hypotension. Abnormal responses were classified as cardioinhibitory, vasodepressor or mixed. RESULTS: HUT was positive in seven patients of the PAF group--vasodepressor response in five and mixed in two (20.5% of the total; 26.3% of those without heart disease)--and in eight patients (vasodepressor in six and mixed in two) of the Sc group (p=NS). During HUT, three patients of the PAF group had short periods of self-limited PAF (in one, after vasodepressor syncope). There were no differences in gender distribution, age or heart disease. No cardioinhibitory responses or orthostatic hypotension were observed. CONCLUSION: In elderly patients with PAF, a significant number of false positive results during passive HUT may be expected, suggesting increased vasovagal reactions despite aging. This suggests that ANS imbalances may be observed in this population.
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AIMS: Protocols using sublingual nitrates have been increasingly used to improve diagnostic accuracy of head-up tilt testing (HUT). Nevertheless, exaggerated responses to nitrates have been frequently described, particularly in elderly patients. The aim of this article is to evaluate, in an elderly population with unexplained syncope, whether the impact of sublingual nitroglycerin (NTG) used as a provocative agent is dose-dependent. METHODS AND RESULTS: One hundred and twenty consecutive elderly patients submitted to HUT using NTG after an asymptomatic drug-free phase were studied. Patients were divided into three groups according to the NTG dosage: 500, 375 and 250 microg. The test was considered positive when there was reproduction of symptoms with bradycardia and/or arterial hypotension. A gradual decrease in the blood pressure after NTG was considered an exaggerated response to nitrates. There were no differences in the clinical characteristics of the different subgroups. A positive test was obtained in 50% of the patients in each group. The rate of exaggerated responses was identical in all groups and ranged between 15 and 17%. CONCLUSION: In an elderly population with syncope of unknown origin submitted to HUT, the response to NTG is not dose-dependent, and no difference was found in the rate of exaggerated responses to nitrates with different NTG dosages.
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Introduction: Congenital complete atrioventricular block (AVB) without cardiac malformation is a rare and potentially fatal condition. In most cases it is associated with maternal systemic lupus erythematosus through transplacental passage of antibodies anti-SSA/Ro and/or anti-SSB/La. Antenatal fluorinated-steroids have been successful in reversing first and second degree congenital AVB but inconsistent in third degree block. Case Report:The authors report a case of fetal bradycardia diagnosed at 24 weeks of gestation. The fetal echocardiogram revealed a second/third degree AVB without structural heart disease. Maternal anti-SSA/Ro antibodies were detected. There was no blockage improvement with maternal oral fluorinated-steroids. An elective cesarean section was performed at term with the delivery of a healthy girl that required an epicardical pacemaker on the 8th day of life. Conclusion: In this case, treatment with maternal fluorinated corticosteroids was not effective in preventing progression of the heart block.
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RESUMO: O envelhecimento da população é um fenómeno à escala mundial, com tendência a aumentar, sendo cada vez mais os idosos e mais velhos. Esta propensão é notória nos utentes que recorrem aos cuidados de saúde. À medida que se envelhece maior vai sen-do a vulnerabilidade e riscos para a saúde, bem como a prevalência para doenças croni-cas, que se traduz num aumento de hospitalizações e consumo. As complicações ocorri-das em idosos aquando submetidos a intervenções cirúrgicas estão descritas na literatu-ra, havendo uma escassez de publicações nacionais relacionadas com o tema. O presente estudo teve por objectivo caracterizar idosos submetidos a correcção cirúrgi-ca de hérnias da parede abdominal, os procedimentos e as complicações ocorridas. O estudo, transversal e de natureza quantitativa, foi realizado no Centro Hospitalar de Lisboa Norte – Hospital Pulido Valente, e teve como critério de inclusão os indivíduos com 65 ou mais anos submetidos a correcção cirúrgica de hérnias da parede abdominal, realizadas em 2009-2010, que tiveram um período de recobro na Unidade de Cuidados Anestésicos Pós-operatórios. Para a obtenção dos dados, foram analisados os processos clínicos do Arquivo Clínico da Instituição e registada informação sobre variáveis de caracterização sócio demográfi-ca, de saúde pré, intra e pós-operatória imediata e descritivas da cirurgia. Foram avaliadas as situações de 164 indivíduos, 78.7% eram homens e 21.3% mulheres e a média de idades era de 72.4 anos e desvio padrão 5.46. Em termos de hábitos de Vida, foi possível constatar um predomínio de baixo consumo de tabaco (13.4%) e álcool (6.7%). O valor médio de co-morbilidades foi de 2.6 e desvio padrão de 1.34 sendo a maior prevalência de 3-4 co-morbilidades com 48.8%. Salienta-se que todas as mulheres da amostra apresentaram doenças. As patologias mais prevalentes são as do foro cardiovascular: Hipertensão Arterial (75.0%), Dislipidémia (35.4%) e Insuficiência Venosa Periférica (14.6%), de forma menos expressiva, mas igualmente relevante a Diabetes Mellitus (23.8%). Nos mais idosos [75 ou mais], verificou-se uma expressivi-dade Hipertrofia benigna da próstata (18.2%). Das cirurgias ocorridas predominou a correcção cirúrgica de Hérnia Inguinal.Das complicações identificadas prevaleceu a dor (97.6%). A hipotermia (34.8%), HTA (24.4%) e bradicárdia (14.6%) encontram-se entre as complicações mais determinantes. Verificaram-se diferenças com significado estatístico entre os dois grupos etários consi-derados nas complicações bradicárdia (p=0.021) e a saturação de oxigénio <90% (p = 0.006), hemorragia (p=0.036) e retenção urinária (p = 0.038). Neste estudo constata-se que a cirúrgica de hérnias da parede abdominal em idosos é uma realidade prevalente. Dos factores que possam estar associados a propensão para complicações pós-cirúrgicas, a idade e a presença de co-morbilidade controlada não revelaram ter influência. Também os tempos de cirurgia e de anestesia não revelaram influências no surgimento de complicações. A monitorização dos sinais vitais deve ser constante, desde o período pré-operatório imediato de forma a permitir aos profissionais de saúde identificar uma propensão para vulnerabilidade, com vantagem em ser apre-sentado sob a forma de score. Este manifestou diferenças significativas a nível dos dois grupos etários considerados (p=0.001). Este score, vai possibilitar sinalizar quais os idosos com maior susceptibilidade de ocorrência de complicações.------------------ABSTRACT:Population aging has become a worldwide phenomenon with tendency to increase. This is particularly evident due to the amount of elderly that attend the medical services. As one gets older, more vulnerable and more risks to one’s health. Also chronic diseas-es are more likely to exist which lead to more hospitalizations and increase of consuma-bles. The complications after a surgery in older people are well documented in international scientific studies, however national studies are still lacking. The present study aims to characterize elderly patients after abdominal hernia surgical correction, the procedures and complications detected. This transversal and quantitative nature like study, was held in the Centro Hospitalar Lisboa-Norte – Hospital Pulido Valente, and as inclusive criteria where patients with more than 65 or more years old, who undergone abdominal hernia surgical correction surgery in 2009-2010 and had the post-operation on the Unidade de Cuidados Anestésicos Pós-Operatorios. Data from the clinical files from the archive of the hospital where analyzed. Information was taken regarding social demographic variables; before, during and immediately after surgery variables and also descriptive of the surgery itself. Were evaluated 164 individuals, 78, 7% of which were men and 21, 3% women with an average age of 72, 4 years and standard deviation 5.46. Life habits analyzed detected low consumption of tobacco (13, 4%) and alcohol (6, 7%). The average of co-morblity was 2, 6 and standard deviation 1.34. The biggest prevalence of 3-4 co-morbilities was 48, 8%. Important to notice that, all women from the study presented illnesses. The illnesses more frequent were cardiovascular: High Blood Pressure (75%), Dyslipidemia (35, 4%), Deep Venous Insufficiency (14, 6%), less significant but also relevant, Diabetes Melli-tus (23, 8%). In the older (75 or more), was noticed Benign Prostatic (18, 2%). In the surgeries verified, the abdominal hernia correction was more frequent. From all thecomplications identified, pain was 97, 6%, Hypothermia 34, 8%, high Blood Pressure 24, 4% and Bradycardia 14, 6%, were higher prevalence. Was seen differences in the statistic meaning of the two groups in the Bradycardia com-plications (p=0.021), and the oxygen saturation < 90% (p=0.006), bleeding (p=0,036) and urine retention (p=0,038). In the present study it is evident that the abdominal hernia surgical correction in older population is a common procedure. Of all the factors that might be related with post-operatory complications, age and the presence of controlled co-morbility didn’t reveal relevant. Also, surgical times and duration of anesthesia didn´t seem to be related to complications incidence. Monitoring the vital signs must be constant since the immedi-ate post-operatory to ensure that the professionals can identify any possible vulnerabil-ity, presenting it in a score like way. The score has shown meaningful differences be-tween the two age groups analyzed (p=0,001). This score allows identifying which pa-tients are more likely to suffer complications.
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The case of a patient with gastric adenocarcinoma with indication for gastrectomy is reported. The surgery took place without complications. A palliative, subtotal gastrectomy was performed after para-aortic lymph nodes compromised by neoplasm were found, which was confirmed by pathological exam of frozen sections carried out during the intervention. At the end of the gastroenteroanastomosis procedure, the patient began to show intense bradycardia: 38 beats per minute (bpm), arterial hypotension, changes in the electrocardiogram's waveform (upper unlevelling of segment ST), and cardiac arrest. Resuscitation maneuvers were performed with temporary success. Subsequently, the patient had another circulatory breakdown and again was recovered. Finally, the third cardiac arrest proved to be irreversible, and the intra-operative death occurred. Necropsy showed massive pulmonary embolism. The medical literature has recommended heparinization of patients, in an attempt to avoid pulmonary thromboembolism following major surgical interventions. However, in the present case, heparinization would have been insufficient to prevent death. This case indicates that it is necessary to develop preoperative propedeutics for diagnosing the presence of venous thrombi with potential to migrate, causing pulmonary thromboembolism (PTE). If such thrombi could be detected, preventative measures, such as filter installation in the Cava vein could be undertaken.
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OBJECTIVE: Parasympathetic dysfunction is an independent risk factor in individuals with coronary artery disease, and cholinergic stimulation is a potential therapeutical option. We determined the effects of pyridostigmine bromide, a reversible anticholinesterase agent, on electrocardiographic variables of healthy individuals. METHODS: We carried out a cross-sectional, double blind, randomized, placebo-controlled study. We obtained electrocardiographic tracings in 12 simultaneous leads of 10 healthy young individuals at rest before and after oral administration of 45 mg of pyridostigmine or placebo. RESULTS: Pyridostigmine increased RR intervals (before: 886±27 ms vs after: 1054±37 ms) and decreased QTc dispersion (before: 72±9ms vs after: 45±3ms), without changing other electrocardiographic variables (PR segment, QT interval, QTc, and QT dispersion). CONCLUSION: Bradycardia and the reduction in QTc dispersion induced by pyridostigmine may effectively represent a protective mechanism if these results can be reproduced in individuals with cardiovascular diseases.
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OBJECTIVE: To identify the electrocardiographic changes and their associations with metabolic and electrolytic changes in female alcoholics. METHODS: The study comprised 44 female alcoholics with no apparent physical disorder. They underwent the following examinations: conventional electrocardiography; serologic tests for syphilis, Chagas' disease, and hepatitis B and C viruses; urinary pregnancy testing; hematimetric analysis; biochemical measurements of albumin, fibrinogen, fasting and postprandial glycemias, lipids, hepatic enzymes, and markers for tissue necrosis and inflammation. RESULTS: Some type of electrocardiographic change was identified in 33 (75%) patients. In 17 (38.6%) patients, more than one of the following changes were present: prolonged QTc interval in 24 (54.5%), change in ventricular repolarization in 11(25%), left ventricular hypertrophy in 6 (13.6%), sinus bradycardia in 4 (9.1%), sinus tachycardia in 3 (6.8%), and conduction disorder in 3 (6.8%). The patients had elevated mean serum levels of creatine phosphokinase, aspartate aminotransferases, and gamma glutamyl transferase, as well as hypocalcemia and low levels of total cholesterol and LDL-cholesterol. The patients with altered electrocardiograms had a more elevated age, a lower alcohol consumption, hypopotassemia, and significantly elevated levels of triglycerides, postprandial glucose, sodium and gamma glutamyl transferase than those with normal electrocardiograms. The opposite occurred with fasting glycemia, magnesium, and alanine aminotransferase. CONCLUSION: The electrocardiographic changes found were prolonged QTc interval, change in ventricular repolarization, and left ventricular hypertrophy. Patients with normal and abnormal electrocardiograms had different metabolic and electrolytic changes.
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AbstractBackground:One of the most important thyroid hormone targets is the cardiovascular system. Hemodynamic changes, such as decreased resting heart rate (HR), myocardial contractility, and cardiac output, and increased diastolic pressure and systemic vascular resistance, have been observed in hypothyroid patients. Moreover, in these patients, ECG changes include sinus bradycardia and low voltage complexes (P waves or QRS complexes).Objective:This study aimed at evaluating the prophylactic effect of apelin on HR changes and QRS voltage that occur in propylthiouracil (PTU)-induced hypothyroid rats.Method:In this study, 48 adult male Wistar rats weighing 170-235g were randomly divided into 6 groups: Control group (normal saline ip injection + tap water gavage); P group (PTU 0.05%, in drinking water); A group (apelin 200 µg.kg-1.day-1, ip); PA group [co-administration of PTU and apelin]; PT group [co-administration of PTU + T4 (0.2 mg/g per day, gavage)]; and PAT group (co-administration of PTU, apelin and T4). All experiments were performed for 28 consecutive days, and then the animals were anesthetized with an ip injection of ketamine (80 mg/kg) and xylazine (12 mg/kg). Lead II electrocardiogram was recorded to calculate HR and QRS voltage.Results:Heart rate and QRS voltage increased more significantly in the hypothyroid group that consumed both apelin and T4 (201 ± 4 beat/min, 0.71 ± 0.02 mv vs. hypothyroid 145 ± 9 beat/min, 0.563 ± 0.015 mv; respectively).Conclusion:The co-administration of apelin and T4 showed a protective effect on QRS voltage and HR in PTU‑induced hypothyroid rats.
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This article presents a critical review of the literature about the potential benefit of cardiac pacing in patients suffering from vasovagal or neurocardiogenic syncope. The manifestation of vasovagal syncope comprises some reflex bradycardia and vasoplegia resulting in cerebral hypoperfusion that ultimately leads to a loss of consciousness. The literature reports conflicting results of the potential benefit of cardiac pacing on the prevention of recurrence of vasovagal events. A detailed analysis of the inclusion criteria of these studies permits to clarify the discrepancy. Only patients older than 50 years with prolonged sinus pause at time of syncope benefit of the implantation of a cardiac pacemaker.
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Human Chagas' disease, caused by the protozoan Trypanosoma cruzi, is associated with pathological processes whose mechanisms are not known. To address this question, T cell lines were developed from chronic chagasic patients peripheral blood mononuclear cells (PBMC) and cloned. These T cell clones (TCC) were analyzed phenotypically with monoclonal antibodies by the use of a fluorescence microscope. The surface phenotype of the TCC from the asymptomatic patient were predominantly CD4 positive (86%). On the contrary, the surface phenotype CD8 was predominant in the TCC from the patients suffering from cardiomegaly with right bundle branch block (83%), bradycardia with megacolon (75 %) and bradycardia (75%). Future studies will be developed in order to identify the antigens eliciting these T cell subpopulations.
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BACKGROUND AND PURPOSE: Carotid artery stenting (CAS) is associated with a higher risk of both hemodynamic depression and new ischemic brain lesions on diffusion-weighted imaging than carotid endarterectomy (CEA). We assessed whether the occurrence of hemodynamic depression is associated with these lesions in patients with symptomatic carotid stenosis treated by CAS or CEA in the randomized International Carotid Stenting Study (ICSS)-MRI substudy. METHODS: The number and total volume of new ischemic lesions on diffusion-weighted imaging 1 to 3 days after CAS or CEA was measured in the ICSS-MRI substudy. Hemodynamic depression was defined as periprocedural bradycardia, asystole, or hypotension requiring treatment. The number of new ischemic lesions was the primary outcome measure. We calculated risk ratios and 95% confidence intervals per treatment with Poisson regression comparing the number of lesions in patients with or without hemodynamic depression. RESULTS: A total of 229 patients were included (122 allocated CAS; 107 CEA). After CAS, patients with hemodynamic depression had a mean of 13 new diffusion-weighted imaging lesions, compared with a mean of 4 in those without hemodynamic depression (risk ratio, 3.36; 95% confidence interval, 1.73-6.50). The number of lesions after CEA was too small for reliable analysis. Lesion volumes did not differ between patients with or without hemodynamic depression. CONCLUSIONS: In patients treated by CAS, periprocedural hemodynamic depression is associated with an excess of new ischemic lesions on diffusion-weighted imaging. The findings support the hypothesis that hypoperfusion increases the susceptibility of the brain to embolism. CLINICAL TRIAL REGISTRATION URL: http://www.controlled-trials.com. Unique identifier: ISRCTN25337470.
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Introduction: Rotenone is a botanical pesticide derived from extracts of Derris roots, which is traditionally used as piscicide, but also as an industrial insecticide for home gardens. Its mechanism of action is potent inhibition of mitochondrial respiratory chain by uncoupling oxidative phosphorylation by blocking electron transport at complex-I. Despite its classification as mild to moderately toxic to humans (estimated LD50, 300-500 mg/kg), there is a striking variety of acute toxicity of rotenone depending on the formulation (solvents). Human fatalities with rotenone-containing insecticides have been rarely reported, and a rapid deterioration within a few hours of the ingestion has been described previously in one case. Case report: A 49-year-old Tamil man with a history of asthma, ingested 250 mL of an insecticide containing 1.24% of rotenone (3.125 g, 52.1-62.5 mg/kg) in a suicide attempt at home. The product was not labeled as toxic. One hour later, he vomited repeatedly and emergency services were alerted. He was found unconscious with irregular respiration and was intubated. On arrival at the emergency department, he was comatose (GCS 3) with fixed and dilated pupils, and absent corneal reflexes. Physical examination revealed hemodynamic instability with hypotension (55/30 mmHg) and bradycardia (52 bpm). Significant laboratory findings were lactic acidosis (pH 6.97, lactate 17 mmol/L) and hypokalemia (2 mmol/L). Cranial computed tomography (CT) showed early cerebral edema. A single dose of activated charcoal was given. Intravenous hydration, ephedrine, repeated boli of dobutamine, and a perfusor with 90 micrograms/h norepinephine stabilized blood pressure temporarily. Atropine had a minimal effect on heart rate (58 bpm). Intravenous lipid emulsion was considered (log Pow 4.1), but there was a rapid deterioration with refractory hypotension and acute circulatory failure. The patient died 5h after ingestion of the insecticide. No autopsy was performed. Quantitative analysis of serum performed by high-resolution/accurate mass-mass spectrometry and liquid chromatography (LC-HR/AM-MS): 560 ng/mL rotenone. Other substances were excluded by gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS/MS). Conclusion: The clinical course was characterized by early severe symptoms and a rapidly fatal evolution, compatible with inhibition of mitochondrial energy supply. Although rotenone is classified as mild to moderately toxic, physicians must be aware that suicidal ingestion of emulsified concentrates may be rapidly fatal. (n=3): stridor, cyanosis, cough (one each). Local swelling after chewing or swallowing soap developed at the earliest after 20 minutes and persisted beyond 24 hours in some cases. Treatment with antihistamines and/or steroids relieved the symptoms in 9 cases. Conclusion: Bar soap ingestion by seniors carries a risk of severe local reactions. Half the patients developed symptoms, predominantly swellings of tongue and/or lips (38%). Cognitive impairment, particularly in the cases of dementia (37%), may increase the risk of unintentional ingestion. Chewing and intraoral retention of soap leads to prolonged contact with the mucosal membranes. Age-associated physiological changes of oral mucosa probably promote the irritant effects of the surfactants. Medical treatment with antihistamines and corticosteroids usually leads to rapid decline of symptoms. Without treatment, there may be a risk of airway obstruction.
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Introduction: Electroconvulsive therapy (ECT) may be used to treat severe depression and needs a specific general anaesthesia. Important cardiovascular changes occur during the ECT with a parasympathetic induced bradycardia followed by a sympathetic response. A dedicated protocol was designed 6 years ago. The goal of this study was to analyse the management of anaesthesia for ECT in our institution, the adherence to the protocol and the occurrence of adverse events during anaesthesia. Methods: After Institutional Ethics Committee approval, we conducted a retrospective analysis of our anaesthesia protocol for patients scheduled for electroshock therapy during a five years period (2004- 2008). The protocol includes administration of atropine subcutaneously 30 minutes before the procedure, followed by general anaesthesia induced with etomidate (0.2 mg/kg). Suxamethonium (1 mg/kg) is administered after the inflation of a pneumatic tourniquet on the opposite arm, in order to observe the electroshocks convulsive effects. The psychiatrist initiates the convulsive crisis once curarisation is achieved. Face mask ventilation is then applied during the post-ictal phase with closed blood pressure monitoring. : 228 ECT were performed in 25 patients. The median dosage of etomidate was 0.37 mg/kg and suxamethonium 1.20 mg/kg. Hypertension during the ECT procedure was present in 62.7% of cases, tachycardia 23.2% and bradycardia 10.5%. Esmolol was administered in 73.4% of hypertensive patients in a range of 0 to 30 mg. The protocol was followed in half of the cases in regards to atropine administration (50.4%). We observed a significant increase of hypertension (73.9%, p = 0.001) after atropine administration, without effect on heart rate. Conclusions: The management of anaesthesia for ECT is specific and follows a predefined protocol in our institution. Adherence to our protocol was poor. Adverse events are frequent and significant association between the administration of atropine and the incidence of hypertension as well as poor protocol adherence implies reconsideration of our anaesthesia protocol for electroconvulsive therapy and better quality control of the clinical practice.