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AIMS: Systolic blood pressure (SBP) drops recorded by 24-h ambulatory blood pressure (BP) monitoring (ABPM) identify patients with susceptibility to reflex syncope and orthostatic intolerance. We tested the hypothesis that treatments aimed to increase BP (reassurance, education, and lifestyle measures plus pharmacological strategies) can reduce SBP drops. METHODS AND RESULTS: This was a multicentre, observational proof-of-concept study performed in patients with reflex syncope and/or orthostatic intolerance and with SBP drops on a screening ABPM. Among 144 eligible patients, 111 underwent a second ABPM on average 2.5 months after start of treatment. Overall, mean 24-h SBP increased from 114.1 ± 12.1 to 121.4 ± 14.5â mmHg (P < 0.0001). The number of SBP drops <90 and <100â mmHg decreased by 61%, 46% during daytime, and by 48% and 37% during 24-h period, respectively (P < 0.0001 for all). The dose-response relationship between difference in 24-h average SBP increase and reduction in number of SBP drops reached a plateau around â¼15â mmHg increase of 24-h SBP. The reduction in SBP drop rate was consistent and significant in patients who underwent deprescription of hypotensive medications (n = 44) and in patients who received BP-rising drugs (n = 67). CONCLUSION: In patients with reflex syncope and/or orthostatic intolerance, an increase in average 24-h SBP, regardless of the implemented strategy, significantly reduced the number of SBP drops and symptom burden. A 13â mmHg increase in 24-h SBP appears to represent the optimal goal for aborting the maximal number of SBP drops, representing a possible target for future interventions. ClincalTrials.gov identifier: NCT05729724.
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Hipertensão , Hipotensão , Intolerância Ortostática , Síncope Vasovagal , Humanos , Anti-Hipertensivos/uso terapêutico , Pressão Sanguínea , Monitorização Ambulatorial da Pressão Arterial , Hipertensão/tratamento farmacológico , Intolerância Ortostática/diagnóstico , Intolerância Ortostática/tratamento farmacológico , Reflexo , Síncope Vasovagal/diagnóstico , Síncope Vasovagal/prevenção & controle , Estudo de Prova de ConceitoRESUMO
This review addresses tilt-testing methodology by searching the literature which reports timing of asystole and loss of consciousness (LOC). Despite the Italian protocol being the most widely adopted, its stipulations are not always followed to the letter of the European Society of Cardiology guidelines. The discrepancies permit reassessment of the incidence of asystole when tilt-down is early, impending syncope, compared with late, established LOC. Asystole is uncommon with early tilt down and diminishes with increasing age. However, if LOC is established as test-end, asystole is more common, and it is age-independent. Thus, the implications are that asystole is commonly under-diagnosed by early tilt-down. The prevalence of asystolic responses observed using the Italian protocol with a rigorous tilt down time is numerically close to that observed during spontaneous attacks by electrocardiogram loop recorder. Recently, tilt-testing has been questioned as to its validity but, in selection of pacemaker therapy in older highly symptomatic vasovagal syncope patients, the occurrence of asystole has been shown to be an effective guide for treatment. The use of head-up tilt test as an indication for cardiac pacing therapy requires pursuing the test until complete LOC. This review offers explanations for the findings and their applicability to practice. A novel interpretation is offered to explain why pacing induced earlier may combat vasodepression by raising the heart rate when sufficient blood remains in the heart.
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Parada Cardíaca , Síncope Vasovagal , Humanos , Idoso , Síncope Vasovagal/diagnóstico , Síncope Vasovagal/epidemiologia , Prevalência , Teste da Mesa Inclinada/métodos , Síncope , Parada Cardíaca/diagnóstico , Parada Cardíaca/epidemiologia , Parada Cardíaca/terapiaRESUMO
AIMS: Diagnostic criteria for ambulatory blood pressure monitoring (ABPM) in patients with suspected reflex syncope are lacking. The study hypothesis was that patients with reflex syncope have a higher prevalence of systolic blood pressure (SBP) drops on ABPM. METHODS AND RESULTS: ABPM data from reflex syncope patients and controls, matched by average 24â h SBP, age, sex, and hypertension were compared. Patients with constitutional hypotension, orthostatic hypotension, and predominant cardioinhibition during carotid sinus massage or prolonged electrocardiogram monitoring or competing causes of syncope were excluded. Daytime and nighttime SBP drops (<110, 100, 90, 80â mmHg) were assessed. Findings were validated in an independent sample. In the derivation sample, daytime SBP drops were significantly more common in 158 syncope patients than 329 controls. One or more daytime drops <90â mmHg achieved 91% specificity and 32% sensitivity [odds ratio (OR) 4.6, P < 0.001]. Two or more daytime drops <100â mmHg achieved 84% specificity and 40% sensitivity (OR 3.5, P = 0.001). Results were confirmed in the validation sample of 164 syncope patients and 164 controls: one or more daytime SBP drops <90â mmHg achieved 94% specificity and 29% sensitivity (OR 6.2, P < 0.001), while two or more daytime SBP drops <100â mmHg achieved 83% specificity and 35% sensitivity (OR 2.6, P < 0.001). CONCLUSION: SBP drops during ABPM are more common in reflex syncope patients than in controls. Cut-off values that may be applied in clinical practice are defined. This study expands the current indications for ABPM to patients with reflex syncope.
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Hipertensão , Hipotensão , Pressão Sanguínea , Monitorização Ambulatorial da Pressão Arterial , Humanos , Hipertensão/complicações , Hipotensão/diagnóstico , Reflexo , Síncope/etiologiaRESUMO
While the concept of a receptor reserve (spare receptors) is old, their presence on human cells as an adaptive mechanism in cardiovascular disease is a new suggestion. The presence of spare receptors is suspected when the activation of a weak fraction of receptors leads to maximal biological effects, in other words, when the half-maximal effective concentration (EC50) for a biological effect (cAMP production, for example) is lower than the affinity (KD) of the ligand for a receptor. Adenosine is an ATP derivative that strongly impacts the cardiovascular system via its four membrane receptors, named A1R, A2AR, A2BR, and A3R, with the A1R being more particularly involved in heart rhythm, while the A2AR controls vasodilation. After a general description of the tools necessary to explore the presence of spare receptors, this review focuses on the consequences of the presence of spare adenosine receptors in cardiovascular physiopathology. Finally, the role of the adenosinergic system in the long-term potentiation and its possible consequences on the physiopathology are also mentioned.
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Adenosina/metabolismo , Doenças Cardiovasculares/metabolismo , Potenciação de Longa Duração , Receptores Purinérgicos P1/metabolismo , Animais , HumanosRESUMO
Either central or peripheral baroreceptor reflex abnormalities and/or alterations in neurohumoral mechanisms play a pivotal role in the genesis of neurally mediated syncope. Thus, improving our knowledge of the biochemical mechanisms underlying specific forms of neurally mediated syncope (more properly termed 'neurohumoral syncope') might allow the development of new therapies that are effective in this specific subgroup. A low-adenosine phenotype of neurohumoral syncope has recently been identified. Patients who suffer syncope without prodromes and have a normal heart display a purinergic profile which is the opposite of that observed in vasovagal syncope patients and is characterized by very low-adenosine plasma level values, low expression of A2A receptors and the predominance of the TC variant in the single nucleotide c.1364 C>T polymorphism of the A2A receptor gene. The typical mechanism of syncope is an idiopathic paroxysmal atrioventricular block or sinus bradycardia, most often followed by sinus arrest. Since patients with low plasma adenosine levels are highly susceptible to endogenous adenosine, chronic treatment of these patients with theophylline, a non-selective adenosine receptor antagonist, is expected to prevent syncopal recurrences. This hypothesis is supported by results from series of cases and from observational controlled studies.
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Bloqueio Atrioventricular , Síncope Vasovagal , Adenosina , Humanos , Síndrome do Nó Sinusal , Síncope , Síncope Vasovagal/diagnóstico , Síncope Vasovagal/tratamento farmacológicoRESUMO
BACKGROUND: The head-up tilt test (HUT) and other evidence suggest that the vagal effect on the heart decreases with age. OBJECTIVES: The main aim of the study was to assess whether this age effect also affects the rate of asystole in spontaneous reflex syncope (RS). METHOD: We performed an analysis of pooled individual data from 4 studies that recruited patients ≥40 years of age affected by certain or suspected RS who received an implantable loop recorder (ILR) and reported follow-up data on syncope recurrence. We assessed the presence of asystolic syncope of >3 seconds or nonsyncopal asystole of >6 seconds recorded by ILR and compared the findings to tilt test results on the same patients. RESULTS: A total of 1,046 patients received ILR because of unexplained syncope. Of these, 201 (19.2%) had a documentation of an asystolic event of 10-second (Q1-Q3: 6- to 15-second) duration. They were subdivided in 3 age tertiles: ≤60 years (n = 64), 61 to 72 years (n = 72), and ≥73 years (n = 65). The rate of asystolic events was similar in the 3 subgroups (50.1%, 50.1%, and 49.2%, respectively; P = 0.99). Conversely, the rate of asystolic syncope induced during HUT (performed in 169 of 201) was greatly age dependent (31.0%, 12.1%, and 11.1% in increasing age tertiles, respectively; P = 0.009). CONCLUSIONS: The rate of the spontaneous asystolic form of RS documented by ILR is constant at any age >40 years. Conversely, the rate of asystolic syncope induced by HUT is higher in younger patients and decreases with age. The contrasting results between spontaneous and tilt-induced events cast doubt on the concept that asystole in RS is less common in older patients.
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Parada Cardíaca , Síncope Vasovagal , Humanos , Idoso , Pessoa de Meia-Idade , Adulto , Síncope Vasovagal/diagnóstico , Síncope/diagnóstico , Síncope/epidemiologia , Síncope/etiologia , Teste da Mesa Inclinada/efeitos adversos , Parada Cardíaca/complicações , ReflexoRESUMO
BACKGROUND: We aimed to identify the target of deprescribing, i.e. the 24-hour SBP increase needed to achieve the greatest reduction of SBP drops. METHOD: Forty hypertensive patients (mean age 73.6 ± 9.3 years, 26 females) with reflex syncope and SBP drops on a screening ABPM were advised to withdraw or to reduce their therapy. The study objective was the reduction of SBP drops <90 mmHg and <100 mmHg on a second ABPM performed within 3 months. RESULTS: Out of a total of 98 drugs taken during ABPM 1, 44 were withdrawn, 16 had a dose reduction and 38 remained unchanged at the time of ABPM 2. 24-hour SBP increased from 119.7 ± 10.1 mmHg to 129.4 ± 13.2 mmHg during ABPM2. Total disappearance of daytime SBP drops <100 mmHg was achieved in 20 (50 %) patients who had 24-hour SBP of 134±13 mmHg and an increase from ABPM 1 of 12 (IQR 5-20) mmHg. Compared with the 20 patients who had persistence of drops, these patients had a greater reduction of the number of hypotensive drugs (67 % versus 19 %, p = 0.002) and a greater rate of withdrawals (62 % versus 29 %, p = 0.003). CONCLUSION: In hypertensive patients with reflex syncope, an increase of 12 mmHg and an absolute value of 24-hour SBP of 134 mmHg appear to represent the optimal goals aimed to prevent SBP drops. Drugs withdrawal, rather than simply dose reduction, is mostly required to achieve the above target.
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INTRODUCTION: Treatment efficacy of reflex syncope is mainly related to the mechanism underlying syncope rather than its etiology or clinical presentation. The predominant mechanism underlying reflex syncope can be assigned to hypotensive or to bradycardic phenotypes. AREAS COVERED: Methodology and diagnostic criteria of the most useful tests for the identification of hypotensive and bradycardic phenotypes are discussed. Diagnostic tests for the hypotensive phenotype include office blood pressure measurement with active standing test, home, and wearable blood pressure monitoring, 24-h ambulatory blood pressure monitoring and tilt table test. Diagnostic tests for the bradycardic phenotype include carotid sinus massage, tilt table test and prolonged ECG monitoring. EXPERT OPINION: In reflex syncope, the documentation of bradycardia/asystole during a syncopal episode does not rule out the possibility that a preceding or parallel hypotensive reflex plays an important role. Similarly, even when a hypotensive mechanism is established, the possibility of an associated cardioinhibitory reflex should be investigated. Investigating the mechanism of reflex syncope is mandatory in patients with severe recurrent episodes, with the final aim to develop a personalized treatment strategy. Recent trials have demonstrated the benefits of personalized mechanism-based therapy, thus highlighting the importance of a comprehensive assessment of the mechanisms underlying syncope.
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Monitorização Ambulatorial da Pressão Arterial , Síncope Vasovagal , Humanos , Monitorização Ambulatorial da Pressão Arterial/efeitos adversos , Síncope Vasovagal/diagnóstico , Síncope Vasovagal/terapia , Síncope , Eletrocardiografia , Reflexo/fisiologia , BradicardiaRESUMO
We assessed the capability of an integrated multisensory patch-type monitor (RootiRx®) in detecting episodes of reflex (pre)syncope induced by tilt table test (TTT). Firstly, we performed an intrapatient comparison of cuffless systolic blood pressure (SBP), R-R interval (RRI) and variability (power spectrum analysis) obtained by means of the RootiRx® with those obtained with conventional methods (CONV) with validated finger pressure devices at baseline in supine position and repeatedly during TTT in 32 patients affected by likely reflex syncope. Secondly, the LF/HF values obtained with RootiRx® during TTT were analyzed in 50 syncope patients. Compared with baseline supine recordings, during TTT a decrement of median SBP was observed with CONV (-53.5 mmHg) but not with RootiRx® ®(-1 mmHg). Conversely, RRI reduction (CONV: 102 ms; RootiRx®: 127 ms) and RRI Low Frequency/High Frequency powers ratio (LF/HF) increase (CONV: 1.6; RootiRx®: 2.5) were similar. The concordance was good for RRI (0.97 [95% CI 0.96-0.98]) and fair for LF/HF ratio (0.69 [95% CI 0.46-0.83]). During the first 5 min of TTT the LF/HF ratio was higher in patients who later developed syncope than in no-syncope patients. This ratio was significantly different among patients with syncope, presyncope or without symptoms at the time of syncope (p value = 0.02). In conclusion, cuffless RootiRx® was unable to detect rapid drops of SBP occurring during impending reflex syncope and thus cannot be used as a diagnostic tool for hypotensive syncope. On the other hand, RRI mean values and LF/HF power ratios obtained with RootiRx® were consistent with those simultaneously obtained using conventional methods.
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Síncope Vasovagal , Humanos , Síncope Vasovagal/diagnóstico , Pressão Sanguínea/fisiologia , Síncope/diagnóstico , Teste da Mesa Inclinada , Reflexo , Frequência Cardíaca/fisiologiaRESUMO
Although very common, the precise mechanisms that explain the symptomatology of neuroendocrine syncope (NES) remain poorly understood. This disease, which can be very incapacitating, manifests itself as a drop in blood pressure secondary to vasodilation and/or extreme slowing of heart rate. As studies continue, the involvement of the adenosinergic system is becoming increasingly evident. Adenosine, which is an ATP derivative, may be involved in a large number of cases. Adenosine acts on G protein-coupled receptors with seven transmembrane domains. A1 and A2A adenosine receptor dysfunction seem to be particularly implicated since the activation leads to severe bradycardia or vasodilation, respectively, two cardinal symptoms of NES. This mini-review aims to shed light on the links between dysfunction of the adenosinergic system and NHS. In particular, signal transduction pathways through the modulation of cAMP production and ion channels in relation to effects on the cardiovascular system are addressed. A better understanding of these mechanisms could guide the pharmacological development of new therapeutic approaches.
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Adenosina , Síncope , Animais , Anuros , Pressão Sanguínea , Frequência CardíacaRESUMO
Syncope can be caused by many physiological and pathophysiological conditions. Causes of syncope encompass a wide range of conditions from benign vasovagal syncope to life-threatening arrhythmias. The lack of a standardized method of evaluation and management of this large patient population leads to a wide practice variation which results in broad-based testing, frequent hospital admission and high healthcare cost. The concept of a syncope observational unit was created for inpatients and outpatients in the United States and Europe. Studies have demonstrated that syncope units, staffed by trained health care providers with sufficient resources could expedite and improve diagnostic yield, reduce hospital admission, and result in decreased healthcare cost with favorable clinical outcomes. The implementation of a standardized syncope unit has been challenging because resources and health care systems are variable regionally, nationally, and internationally. In this review, we provide an overview of the evidences that support a standardized syncope unit practice. We provide step-by-step algorithms for the "best syncope units" in the inpatient and outpatient settings by combining the synergistic experiences from the United States and Europe.
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Serviço Hospitalar de Emergência , Síncope , Arritmias Cardíacas , Hospitalização , Humanos , Síncope/diagnóstico , Síncope/terapia , Estados UnidosRESUMO
Background We assessed the reliability and feasibility of blood pressure (BP) measurements by means of a new wearable watch-type BP monitor (HeartGuide) in detecting episodes of hypotensive (pre)syncope induced by tilt table test. Methods and Results An intrapatient comparison between systolic BP (SBP) measured by means of the HeartGuide device and noninvasive finger beat-to-beat BP monitoring was undertaken both at baseline in supine position and repeatedly during tilt table test in patients evaluated for reflex syncope. Intrapatient fall of systolic BP from baseline was measured. Eighty-one patients (mean age, 61±19 years; 46 women) were included. Overall, HeartGuide was able to yield BP values at the time of BP nadir in 58 (72%) patients (average HeartGuide SBP 102±18 mm Hg, versus finger SBP 101±19 mm Hg). Compared with baseline, the maximum SBP decrease was on average -28.5±27.8 and -30.3±33.9 mm Hg respectively (Lin's concordance correlation coefficient=0.78, r=0.79, P=0.001). In the subgroup of 38 patients with tilt table test induced (pre)syncope, the average HeartGuide SBP during symptoms was 97±16 mm Hg, and the finger SBP was 94±18 mm Hg. Compared with baseline, the maximum SBP decrease was on average -35.2±29.3 and -43.3±31.8 mm Hg, respectively (Lin's concordance correlation coefficient=0.83, r=0.87, P=0.001). Conclusions Our data indicate that the HeartGuide BP monitor can detect low BP during presyncope and that its measure of SBP change is consistent with that simultaneously obtained through continuous BP monitoring, despite some intrapatient variability. Thus, this device might be useful in determining the hypotensive nature of spontaneous (pre)syncopal symptoms, a possibility that should be verified by field studies.
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Hipotensão , Síncope Vasovagal , Dispositivos Eletrônicos Vestíveis , Adulto , Idoso , Idoso de 80 Anos ou mais , Pressão Sanguínea/fisiologia , Estudos de Viabilidade , Feminino , Humanos , Pessoa de Meia-Idade , Reprodutibilidade dos TestesRESUMO
Background: Either high or low values of adenosine blood level (ABL) can differentiate some forms of neurally mediated syncope (NMS). A rapid method of measurement has recently been developed. The aim of the present study was: (1) to compare ABLs in an unselected population of consecutive patients referred for evaluation of suspected NMS syncope and in healthy controls; and (2) to assess the relative prevalence of low and high adenosine forms among an unselected syncope population. Method: Whole blood was collected after finger puncture, blood being deposit on a blot paper and adenosine concentration was measured by liquid chromatography/mass spectrometry (LC-MS/MS). Results: Among 89 control subjects, the median ABL value was 0.54 µM (IQR, 0.46-0.65). The lowest 5% and the upper 95% percentile were 0.40 and 0.80 µM, respectively. Compared with healthy subjects, the 146 patients with syncope showed, on average, a higher median ABL value [0.63 (IQR 0.45-0.73, p = 0.04)] and a larger distribution of values. Low ABL values below the 5th percentile were observed in 28 (19%) patients, and, in five controls, p = 0.003 and high ABL values were observed in 26 (18%) patients and five controls, p = 0.009. Conclusions: ABL is different in patients with suspected NMS than in healthy subjects. Patients with low and high adenosine values account for 19% and 18% of the general population. Thus, low and high ABL limits, as defined in this study, may help to define the purinergic profile of unselected subjects with a clinical diagnosis of suspected NMS.
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AIMS: To describe the proportion of patients with syncope among those affected by hypertrophic cardiomyopathy (HCM) and the relevance of syncope as risk factor for sudden cardiac death and life-threatening arrhythmic events. METHOD AND RESULTS: Systematic review of original articles that assessed syncope in HCM patients. Literature search of PubMed including all English publications from 1973 to 2021.We found 57 articles for a total of 21.791 patients; of these, 14 studies reported on arrhythmic events in the follow-up. Syncope was reported in 15.8% (3.452 of 21.791) patients. It was considered unexplained in 91% of cases. Life-threatening arrhythmic events occurred in 3.6% of non-syncopal patients and in 7.7% of syncopal patients during a mean follow-up of 5.6 years. A relative risk of 1.99 (95%CI 1.39 to 2.86) was estimated for syncope patients by the random effect model using Haldane continuity correction for 0 events. CONCLUSIONS: In the current practice, the cause of syncope remained unexplained in most patients affected by HCM. The management of patients seems mainly driven by risk stratification rather than identification of the aetiology of syncope. There is a need of precise instructions how to apply the recommendations of current guidelines to this disease, which tests are indicated and how to interpret their findings. The protocol was registered in Prospero (ID: 275963).
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Cardiomiopatia Hipertrófica , Cardiomiopatia Hipertrófica/complicações , Cardiomiopatia Hipertrófica/diagnóstico , Cardiomiopatia Hipertrófica/epidemiologia , Morte Súbita Cardíaca/epidemiologia , Morte Súbita Cardíaca/etiologia , Humanos , Medição de Risco/métodos , Fatores de Risco , Síncope/complicações , Síncope/diagnóstico , Síncope/epidemiologiaRESUMO
OBJECTIVES: Amiodarone-induced thyrotoxicosis (AIT) affects up to 3% of treated patients. Type 2 AIT (AIT2) is a destructive thyroiditis and is usually treated with medium-high oral doses of prednisone. As AIT may worsen the underlying heart disease, a rapid control of thyroid function is desirable. We aimed to determine whether a combined intravenous methylprednisolone (IVMP) pulses therapy associated to prednisone in the interpulse period can represent an efficient and safe alternative to urgent total thyroidectomy in patients with AIT2 not responsive to prednisone alone. DESIGN AND METHODS: Patients presenting with a severe AIT2 studied in a tertiary referral Center from August 2018 to April 2019. We included four patients requiring a rapid improvement of thyroid function for their underlying cardiac disorders. The baseline doses of oral prednisone (range: 5-12.5 mg/day) and IVMP (range: 250-500 twice a week) were determined according to the severity of the thyrotoxicosis and were titrated based on clinical response. RESULTS: Combined treatment was effective in all patients in the prompt restoration of euthyroidism and no major adverse events were reported during the follow-up. In all cases, FT4 and FT3 levels normalized at 3-5 weeks of treatment. A permanent hypothyroidism was observed in one patient, 3 months after the discontinuation of treatment. CONCLUSIONS: We report for the first time that the combined intravenous and oral steroid therapy is effective in patients with AIT2. The treatment is well tolerated and leads to a rapid improvement of thyroid function, avoiding urgent total thyroidectomy and favoring a quick functional recovery and rehabilitation of cardiac patients.
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Amiodarona/efeitos adversos , Antiarrítmicos/efeitos adversos , Anti-Inflamatórios/administração & dosagem , Anti-Inflamatórios/uso terapêutico , Metilprednisolona/administração & dosagem , Metilprednisolona/uso terapêutico , Tireotoxicose/induzido quimicamente , Tireotoxicose/tratamento farmacológico , Administração Intravenosa , Idoso , Humanos , Iodo/urina , Masculino , Pessoa de Meia-Idade , Tireoglobulina/sangue , Testes de Função Tireóidea , Tireotropina/sangue , Tiroxina/sangue , Tri-Iodotironina/sangueRESUMO
OBJECTIVE: This study aimed at verifying the accuracy of three automated electronic oscillometric blood pressure measuring devices, namely Omron M5-I (home use upper arm monitor), R5-I (home use wrist monitor) and HEM-907 (professional use upper arm monitor) according to the European Society of Hypertension International Protocol in elderly individuals. METHODS: Sequential measurements of systolic and diastolic blood pressure were obtained in 33 participants (aged >or=75 years) using the mercury sphygmomanometer (two observers) and each of the tested devices (one supervisor). A standard adult cuff was always employed during the study because all participants had an arm circumference compatible with such a cuff. According to the European Society of Hypertension validation protocol 99 couples (three pairs per patient) of test device and reference blood pressure measurements were obtained during phase 1 (15 participants studied) and phase 2 (a further 18 participants) for each electronic monitor. RESULTS: All devices successfully passed the validation study with a mean (+/-SD) device-observer difference for systolic and diastolic blood pressure of 0.2+/-3.6/0.2+/-3.9 mmHg (Omron M5-I), -1.5+/-6.2/-0.7+/-3.7 mmHg (Omron R5-I), and 0.1+/-5.1/-1.9+/-4.2 mmHg (Omron HEM-907). SD of the mean difference was lower and thus the precision was better for diastolic than for systolic blood pressure, and for the Omron M5-I than for the other two devices. CONCLUSIONS: According to the results of the validation study based on the European Society of Hypertension International Protocol the Omron M5-I, R5-I, and HEM-907 may be recommended for clinical use in elderly individuals, without atrial fibrillation or frequent ectopic beats.
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Determinação da Pressão Arterial/instrumentação , Monitores de Pressão Arterial/normas , Hipertensão/diagnóstico , Idoso , Idoso de 80 Anos ou mais , Braço/irrigação sanguínea , Determinação da Pressão Arterial/métodos , Monitorização Ambulatorial da Pressão Arterial/instrumentação , Monitorização Ambulatorial da Pressão Arterial/métodos , Europa (Continente) , Feminino , Humanos , Hipertensão/fisiopatologia , Masculino , Oscilometria/instrumentação , Oscilometria/métodos , Reprodutibilidade dos Testes , Punho/irrigação sanguíneaRESUMO
BACKGROUND Twenty-four-hour finger arterial pressure (FAP) recordings show a negative bias against intrabrachial artery pressure (BAP) and the bias is greater during the night, thereby overestimating the nocturnal blood pressure dip. We have available a methodology with which to reconstruct BAP from FAP by waveform filtering (transfer function) and generalized level (bias) correction that reduces the bias for short-term blood pressure records. OBJECTIVE To investigate if this methodology also decreases the extra bias during the night, thereby yielding a better estimate of the nocturnal dip. METHODS Twenty-four-hour FAP and BAP blood pressure recordings were simultaneously obtained in eight healthy normotensive volunteers and 14 patients with hypertension (ages 19-60 years), during standardized scheduled activities. The data were analysed off-line, applying the brachial reconstruction technique (reBAP) consisting of a waveform filter and level correction. Simultaneous beats yielded systolic, diastolic and mean pressures that were averaged per 30 min, per day, per night, per activity, over the 24-h period, and for volunteers and patients separately. RESULTS Over the full 24 h, FAP systolic, diastolic and mean values for the total group differed from BAP by +1 +/- 10, -8 +/- 7 and -10 +/- 8 mmHg (mean +/- SD), respectively. Similarly, reBAPs differed by +1 +/- 11, -2 +/- 7 and -2 +/- 7 mmHg. BAPs dipped by 20 +/- 8, 13 +/- 6 and 15 +/- 6 mmHg, respectively, during the night. These dips were overestimated by +8, +4 and +4 mmHg by FAP, but not by reBAP: -1, +1 and +1 mmHg. The volunteer and the patient groups showed slight differences in results, but these were not statistically significant. CONCLUSIONS The generalized reconstruction technique to obtain near-brachial pressure from non-invasive FAP almost completely removed bias over the full 24-h day-night period and improved tracking of diurnal changes for all three blood pressure values.
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Pressão Sanguínea/fisiologia , Artéria Braquial/fisiologia , Artéria Braquial/cirurgia , Ritmo Circadiano/fisiologia , Dedos/irrigação sanguínea , Adulto , Viés , Diástole/fisiologia , Humanos , Hipertensão/epidemiologia , Hipertensão/fisiopatologia , Pessoa de Meia-Idade , Sístole/fisiologiaRESUMO
Blood pressure (BP) is characterized by continuous fluctuations, including fast changes lasting only a few seconds as well as slower and more prolonged variations, with a time constant of minutes or hours. Assessing the relative contribution of these different components to overall blood pressure variance is now possible through a number of mathematical approaches, either in the time or in the frequency domain (spectral analysis). Due to its complex nature, a precise and detailed assessment of blood pressure variability can be obtained only from the analysis of continuous, beat-by-beat, blood pressure recordings. Some information, however, can also be derived from analysis of discontinuous blood pressure tracings, such as those commonly performed in a clinical setting. This would require that attention is paid both to the quality of the recordings and to the selection of suitable analysis methods that should cope with the discontinuous nature of the measurements to be processed and to their intrinsic low sampling frequency.
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Pressão Sanguínea/fisiologia , Monitorização Ambulatorial da Pressão Arterial , Ritmo Circadiano , Humanos , Modelos Teóricos , Periodicidade , Pulso ArterialRESUMO
BACKGROUND: Conventional calculation of mean 24-h ambulatory blood pressure (BP), SBP and DBP based on the average of all BP readings disregards the fact that a larger number of measurements is usually scheduled during the daytime than at night, an imbalance possibly leading to an overestimation of 24-h average BP. The aim of our study was to quantify this possible bias and to explore its determinants. METHODS: Four hundred and fifty untreated individuals were subdivided into three groups (150 individuals each) with three different ambulatory blood pressure measurement schedules for day/night: group I, four (day)/two (night) readings/h; group II, four (day)/three (night) readings/h; and group III, with BP readings every 30 min throughout 24 h. Hourly and 24-h averages were computed. The conventional 24-h averages of all SBP and DBP values were compared with the averages of hourly SBP and DBP mean values (time-weighted quantification). The difference between 24-h conventional and 24-h time-weighted BP was computed in each group and related to the degree of nocturnal BP dip and to the ratio between the number of readings of day and night. RESULT: In the three groups, 24-h conventional and 24-h time-weighted BP values were highly correlated (r > 0.99), 24-h conventional SBP and DBP being significantly higher (P < 0.01) than the corresponding 24-h time-weighted values in groups I and II but not in group III (Bland-Altman analysis). The bias magnitude was related to the day/night ratio in number of readings and to nocturnal BP dip in groups I and II (P < 0.01) but not in group III. CONCLUSION: The higher number of readings/h during daytime leads to an overestimation of conventional 24-h average BP, particularly in individuals with preserved nocturnal BP dipping. This can be avoided either by scheduling the same number of readings/h throughout 24 h or by performing a time-weighted quantification of 24-h BP. The clinical implications of these different approaches deserve further investigation.