RESUMO
BACKGROUND: Few trials have examined the efficacy of esmolol to attenuate hemodynamic and respiratory responses during extubation. However, the most appropriate dose of esmolol and an optimal protocol for administering this beta-blocker are uncertain. METHODS: Ninety patients ASA physical status I, II, and III (aged 18...60 years) scheduled to procedures with general anesthesia and tracheal extubation were selected. Patients were randomized into esmolol and placebo group to evaluate the efficacy and safety of a single bolus dose of esmolol (2...mg.kg-1) on cardiorespiratory responses during the peri-extubation period. The primary outcome was the rate of tachycardia during extubation. RESULTS: The rate of tachycardia was significantly lower in esmolol-treated patients compared to placebo-treated patients (2.2% vs. 48.9%, relative risk (RR): 0.04, 95% confidence interval (95% CI)...=...0.01 to 0.32, p...=...0.002). The rate of hypertension was also significantly lower in the esmolol group (4.4% vs. 31.1%, RR: 0.14, 95% CI 0.03 to 0.6, p...=...0.004). Esmolol-treated patients were associated with higher extubation quality compared to patients who received placebo (p...<...0.001), with an approximately two-fold increase in the rate of patients without cough (91.1%) in the esmolol group compared to the placebo group (46.7%). The rate of bucking was approximately 5-fold lower in the esmolol group (8.9% vs. 44.5%, respectively, RR: 0.20 (95% CI, 0.1 to 0.5, p...=...0.002, with an NNT of 2.8). CONCLUSION: A single bolus dose of esmolol is an effective and safe therapeutic strategy to attenuate cardiorespiratory responses during the peri-extubation period.
Assuntos
Hipertensão , Propanolaminas , Humanos , Extubação/efeitos adversos , Hipertensão/tratamento farmacológico , Hipertensão/etiologia , Propanolaminas/farmacologia , Propanolaminas/uso terapêutico , Antagonistas Adrenérgicos beta/farmacologia , Antagonistas Adrenérgicos beta/uso terapêutico , Taquicardia/tratamento farmacológico , Taquicardia/etiologia , Taquicardia/prevenção & controle , Anestesia Geral/efeitos adversos , Método Duplo-Cego , Frequência CardíacaRESUMO
Abstract Background Few trials have examined the efficacy of esmolol to attenuate hemodynamic and respiratory responses during extubation. However, the most appropriate dose of esmolol and an optimal protocol for administering this beta-blocker are uncertain. Methods Ninety patients ASA physical status I, II, and III (aged 18-60 years) scheduled to procedures with general anesthesia and tracheal extubation were selected. Patients were randomized into esmolol and placebo group to evaluate the efficacy and safety of a single bolus dose of esmolol (2 mg.kg-1) on cardiorespiratory responses during the peri-extubation period. The primary outcome was the rate of tachycardia during extubation. Results The rate of tachycardia was significantly lower in esmolol-treated patients compared to placebo-treated patients (2.2% vs. 48.9%, relative risk (RR): 0.04, 95% confidence interval (95% CI) = 0.01 to 0.32, p= 0.002). The rate of hypertension was also significantly lower in the esmolol group (4.4% vs. 31.1%, RR: 0.14, 95% CI 0.03 to 0.6, p= 0.004). Esmolol-treated patients were associated with higher extubation quality compared to patients who received placebo (p< 0.001), with an approximately two-fold increase in the rate of patients without cough (91.1%) in the esmolol group compared to the placebo group (46.7%). The rate of bucking was approximately 5-fold lower in the esmolol group (8.9% vs. 44.5%, respectively, RR: 0.20 (95% CI, 0.1 to 0.5, p= 0.002, with an NNT of 2.8). Conclusion A single bolus dose of esmolol is an effective and safe therapeutic strategy to attenuate cardiorespiratory responses during the peri-extubation period.
Assuntos
Humanos , Propanolaminas/uso terapêutico , Propanolaminas/farmacologia , Hipertensão/etnologia , Hipertensão/tratamento farmacológico , Taquicardia/etnologia , Taquicardia/prevenção & controle , Taquicardia/tratamento farmacológico , Antagonistas Adrenérgicos beta/uso terapêutico , Antagonistas Adrenérgicos beta/farmacologia , Extubação/efeitos adversos , Frequência Cardíaca , Anestesia Geral/efeitos adversosRESUMO
INTRODUCTION AND OBJECTIVES: Although lidocaine is widely used to prevent cardiovascular changes resulting from laryngoscopy and orotracheal intubation, it is still unclear whether there are more efficacious drugs. This study aimed to compare the beta-blocker esmolol with lidocaine regarding the effects on hemodynamic response after orotracheal intubation. METHODS: The study has a prospective, randomized, double-blind, superiority design, and assessed 69 participants between 18 and 70 years of age, ASA I-II, scheduled for elective or emergency surgery under general anesthesia with orotracheal intubation. Participants were randomly allocated to receive 1.5â¯mg.kg-1 esmolol bolus followed by 0.1â¯mg.kg-1.min-1 esmolol infusion (nâ¯=â¯34) or 1.5â¯mg.kg-1 lidocaine bolus followed by 1.5â¯mg.kg-1.h-1 lidocaine infusion (nâ¯=â¯35). We recorded changes in heart rate, arterial blood pressure and incidence of adverse events. RESULTS: Post-intubation tachycardia episodes were significantly less frequent in the esmolol group (5.9% vs. 34.3%; Relative Risk (RR) 0.17; 95% Confidence Interval (95% CI) 0.04-0.71; Number Needed to Treat (NNT) 3.5; pâ¯=â¯0.015. After orotracheal intubation, mean heart rate was significantly lower in the esmolol group (74.5 vs. 84.5, pâ¯=â¯0.006). Similar results were observed in the subsequent 3 and 6â¯minutes (75.9 vs. 83.9, pâ¯=â¯0.023 and 74.6 vs. 83.0, pâ¯=â¯0.013, respectively). CONCLUSION: Esmolol was a safe and more effective intervention to reduce incidence of tachycardia and control heart rate immediately after tracheal intubation when compared to lidocaine.
Assuntos
Lidocaína , Propanolaminas , Pressão Sanguínea , Método Duplo-Cego , Frequência Cardíaca , Hemodinâmica , Humanos , Intubação Intratraqueal/efeitos adversos , Laringoscopia/efeitos adversos , Lidocaína/farmacologia , Lidocaína/uso terapêutico , Propanolaminas/farmacologia , Propanolaminas/uso terapêutico , Estudos Prospectivos , Taquicardia/tratamento farmacológico , Taquicardia/etiologia , Taquicardia/prevenção & controleRESUMO
Our group has previously shown in pithed rats that the cardiac sympathetic drive, which produces tachycardic responses, is inhibited by 5-HT via the activation of prejunctional 5-HT1B/1D/5 receptors. Interestingly, when 5-HT2 receptors are chronically blocked with sarpogrelate, the additional role of cardiac sympatho-inhibitory 5-HT1F receptors is unmasked. Although 5-HT2 receptors mediate tachycardia in rats, and the chronic blockade of 5-HT2 receptors unmasked 5-HT7 receptors mediating cardiac vagal inhibition, the role of 5-HT7 receptors in the modulation of the cardiac sympathetic tone remains virtually unexplored. On this basis, male Wistar rats were pretreated during 14 days with sarpogrelate (a 5-HT2 receptor antagonist) in drinking water (30 mg/kg/day; sarpogrelate-pretreated group) or equivalent volumes of drinking water (control group). Subsequently, the rats were pithed to produce increases in heart rate by either electrical preganglionic spinal (C7 -T1 ) stimulation of the cardiac sympathetic drive or iv administration of exogenous noradrenaline. The iv continuous infusion of AS-19 (a 5-HT7 receptor agonist; 10 µg/kg/min) (i) inhibited the tachycardic responses to sympathetic stimulation, but not those to exogenous noradrenaline only in sarpogrelate-pretreated rats. This inhibition was completely reversed by SB258719 (a selective 5-HT7 receptor antagonist; 1 mg/kg, iv) or glibenclamide (an ATP-sensitive K+ channel blocker; 20 mg/kg, iv). These results suggest that chronic 5-HT2 receptor blockade uncovers a cardiac sympatho-inhibitory mechanism mediated by 5-HT7 receptors, involving a hyperpolarization due to the opening of ATP-sensitive K+ channels. Thus, these findings support the role of 5-HT7 receptors in the modulation of the cardiac sympathetic neurotransmission.
Assuntos
Fibras Adrenérgicas/fisiologia , Receptores 5-HT2 de Serotonina/fisiologia , Receptores de Serotonina/fisiologia , Antagonistas do Receptor 5-HT2 de Serotonina/uso terapêutico , Succinatos/uso terapêutico , Taquicardia/prevenção & controle , Fibras Adrenérgicas/efeitos dos fármacos , Animais , Relação Dose-Resposta a Droga , Estimulação Elétrica/efeitos adversos , Frequência Cardíaca/efeitos dos fármacos , Frequência Cardíaca/fisiologia , Masculino , Norepinefrina/toxicidade , Ratos , Ratos Wistar , Antagonistas do Receptor 5-HT2 de Serotonina/farmacologia , Succinatos/farmacologia , Simpatomiméticos/toxicidade , Taquicardia/etiologia , Taquicardia/fisiopatologiaRESUMO
Background and objectives: Laryngoscopy and intubation can cause hemodynamic response. Various medications may be employed to control that response. In this study, we aimed to compare the effects of dexmedetomidine, fentanyl and esmolol on hemodynamic response. Methods: Ninety elective surgery patients who needed endotracheal intubation who were in American Society of Anesthesiology I–II group and ages between 21 and 65 years were included in that prospective, randomized, double-blind study. Systolic, diastolic, mean arterial pressures, heart rates at the time of admittance at operation room were recorded as basal measurements. The patients were randomized into three groups: Group I (n = 30) received 1 μg/kg dexmedetomidine with infusion in 10 min, Group II (n = 30) received 2 μg/kg fentanyl, Group III received 2 mg/kg esmolol 2 min before induction. The patients were intubated in 3 min. Systolic, diastolic, mean arterial pressures and heart rates were measured before induction, before intubation and 1, 3, 5, 10 min after intubation. Results: When basal levels were compared with the measurements of the groups, it was found that 5 and 10 min after intubation heart rate in Group I and systolic, diastolic, mean arterial pressures in Group III were lower than other measurements (p < 0.05). Conclusions: Dexmedetomidine was superior in the prevention of tachycardia. Esmolol prevented sytolic, diastolic, mean arterial pressure increases following intubation. We concluded that further studies are needed in order to find a strategy that prevents the increase in systemic blood pressure and heart rate both. .
Justificativa e objetivos: Laringoscopia e intubação podem causar resposta hemodinâmica. Vários medicamentos podem ser usados para controlar essa resposta. Neste estudo, nosso objetivo foi comparar os efeitos de dexmedetomidina, fentanil e esmolol sobre a resposta hemodinâmica. Métodos: Foram incluídos no estudo prospectivo, randômico e duplo-cego 90 pacientes programados para cirurgias eletivas, com intubação endotraqueal, estado físico ASA I-II, entre 21 e 65 anos. Pressões arteriais médias, sistólicas, diastólicas e frequências cardíacas foram medidas ao darem entrada na sala de operações e registradas como valores basais. Os pacientes foram randomizados em três grupos: Grupo I (n = 30) recebeu 1 μg/kg de dexmedetomidina com infusão em 10 min; Grupo II (n = 30) recebeu 2 μg/kg de fentanil; Grupo III (n = 30) recebeu 2 mg/kg de esmolol 2 min antes da indução. Os pacientes foram intubados em 3 min. As pressões médias, sistólicas e diastólicas e as frequências cardíacas foram medidas antes da indução, antes da intubação e nos minutos 1, 3, 5 e 10 após a intubação. Resultados: Quando os níveis basais foram comparados entre os grupos, verificou-se que nos minutos 5 e 10 pós-intubação as frequências cardíacas no Grupo I e as pressões arteriais médias, sistólicas e diastólicas no Grupo III estavam mais baixas do que em outros tempos mensurados (p <0,05 ). Conclusões: Dexmedetomidina foi superior na prevenção de taquicardia. Esmolol preveniu o aumento das pressões arteriais médias, sistólicas e diastólicas após a intubação. Concluímos que estudos adicionais são necessários para descobrir uma estratégia que previna tanto o aumento ...
Justificación y objetivos: La laringoscopia y la intubación pueden causar una respuesta hemodinámica. Varios medicamentos pueden ser usados para controlar esa respuesta. En este estudio, nuestro objetivo fue comparar los efectos de la dexmedetomidina, el fentanilo y el esmolol sobre la respuesta hemodinámica. Métodos: Noventa pacientes programados para cirugías electivas con intubación endotraqueal, estado físico ASA I-II, y edades entre 21 y 65 años, se incluyeron en el estudio prospectivo, aleatorizado y doble ciego. Las presiones arteriales medias, sistólicas, diastólicas y las frecuencias cardíacas se midieron cuando los pacientes llegaron al quirófano y se registraron como valores basales. Los pacientes fueron aleatorizados en 3 grupos: el grupo i (n = 30) recibió 1 μg/kg de dexmedetomidina con infusión en 10 min; el grupo ii (n = 30) recibió 2 μg/kg de fentanilo; el grupo iii recibió 2 mg/kg de esmolol 2 min antes de la inducción. Los pacientes fueron intubados en 3 min. Las presiones medias, sistólicas y diastólicas y las frecuencias cardíacas fueron medidas antes de la inducción, antes de la intubación y durante los minutos 1, 3, 5 y 10 después de la intubación. Resultados: Cuando los niveles basales fueron comparados entre los grupos, verificamos que en los minutos 5 y 10 la postintubación, las frecuencias cardíacas en el grupo i y las presiones arteriales medias, sistólicas y diastólicas en el grupo iii eran más bajas que en otros tiempos medidos (p < 0,05). Conclusiones: La dexmedetomidina fue superior en la prevención de la taquicardia. El esmolol previno el aumento de las presiones arteriales medias, sistólicas y diastólicas después de la intubación. Concluimos que son necesarios algunos estudios adicionales para descubrir una estrategia ...
Assuntos
Humanos , Adulto , Pessoa de Meia-Idade , Fentanila/farmacologia , Antagonistas Adrenérgicos beta/farmacologia , Dexmedetomidina/farmacologia , Acoplamento Neurovascular/efeitos dos fármacos , Intubação/instrumentação , Laringoscopia/instrumentação , Taquicardia/prevenção & controle , Método Duplo-Cego , Estudos ProspectivosRESUMO
OBJECTIVE: To determine the variability of the vital signs (temperature, heart rate and respiratory frequency), skin coloration and peripheral oxygen saturation in critically ill preterm newborns (CI PTNB) before, during and after sponge bathing as well as to determine the possible presence of secondary complications of this procedure. MATERIAL AND METHODS: We performed a quasi-experimental study (experimental, prospective, comparative and clinical study with intervention) May to December 2008, in a Neonatal Intensive Care Unit. We included CI PTNB of 0 to 28 days of extrauterine life who have practiced in the routine sponge bathing. Area of significance was considered when p < 0.05. RESULTS: During or after the events in any of the patients presented any complications after 12 h of monitoring, but it was necessary to increase the inspired fraction of oxygen and temperature in the incubator or radiant heat cradle temporarily. CONCLUSIONS: We conclude that the sponge bath is not safe for a CI PTNB and this should be performed in the shortest time possible, and the medical must be very alert to the possibility that patients require more support than they had prior to sponge bathing, mainly in the temperature of the incubator or radiant heat cradle and inspired fraction of oxygen for the required time according to the evolution of these variables.
Assuntos
Banhos/efeitos adversos , Temperatura Corporal , Cuidados Críticos/métodos , Estado Terminal , Frequência Cardíaca , Cuidado do Lactente/métodos , Doenças do Prematuro/fisiopatologia , Recém-Nascido Prematuro/fisiologia , Oxigênio/sangue , Respiração , Banhos/métodos , Contraindicações , Feminino , Humanos , Hipotermia/etiologia , Hipotermia/prevenção & controle , Hipóxia/etiologia , Hipóxia/prevenção & controle , Incubadoras para Lactentes , Recém-Nascido , Recém-Nascido Prematuro/sangue , Doenças do Prematuro/sangue , Doenças do Prematuro/prevenção & controle , Unidades de Terapia Intensiva Neonatal , Masculino , Oxigênio/administração & dosagem , Oxigenoterapia , Estudos Prospectivos , Taquicardia/etiologia , Taquicardia/prevenção & controle , Taquipneia/etiologia , Taquipneia/prevenção & controleRESUMO
In the present study, we investigated the involvement of ß-adrenoceptors in the medial amygdaloid nucleus (MeA) in cardiovascular responses evoked in rats submitted to an acute restraint stress. We first pretreated Wistar rats with the nonselective ß-adrenoceptor antagonist propranolol microinjected bilaterally into the MeA (10, 15, and 20 nmol/100 nL) 10 min before exposure to acute restraint. The pretreatment with propranolol did not affect the blood pressure (BP) increase evoked by restraint. However, it increased the tachycardiac response caused by acute restraint when animals were pretreated with a dose of 15 nmol, without a significant effect on the BP response. This result indicates that ß-adrenoceptors in the MeA have an inhibitory influence on restraint-evoked heart rate (HR) changes. Pretreatment with the selective ß(2)-adrenoceptor antagonist ICI 118,551 (10, 15, and 20 nmol/100 nL) significantly increased the restraint-evoked tachycardiac response after doses of 15 and 20 nmol, an effect that was similar to that observed after the pretreatment with propranolol at a dose of 15 nmol, without a significant effect on the BP response. Pretreatment of the MeA with the selective ß(1)-adrenoceptor antagonist CGP 20712 (10, 15, and 20 nmol/100 nL) caused an opposite effect on the HR response, and a significant decrease in the restraint-evoked tachycardia was observed only after the dose of 20 nmol, without a significant effect on the BP response. Because propranolol is an equipotent antagonist of both ß(1) and ß(2)-adrenoceptors, and opposite effects were observed after the treatment with the higher doses of the selective antagonists ICI 118,551 and CGP 20712, the narrow window in the dose-response to propranolol could be explained by a functional antagonism resulting from the simultaneous inhibition of ß(1) and ß(2)-adrenoceptors by the treatment with propranolol. The present results suggest that ß(2)-adrenoceptors have an inhibitory influence on the restraint-evoked tachycardiac response, whereas ß(1)-adrenoceptors have a facilitatory influence on the restraint-evoked tachycardiac response.
Assuntos
Tonsila do Cerebelo/metabolismo , Receptores Adrenérgicos beta/metabolismo , Estresse Psicológico/complicações , Taquicardia/etiologia , Antagonistas Adrenérgicos beta/farmacologia , Tonsila do Cerebelo/efeitos dos fármacos , Análise de Variância , Animais , Pressão Arterial/efeitos dos fármacos , Relação Dose-Resposta a Droga , Esquema de Medicação , Masculino , Ratos , Ratos Wistar , Restrição Física , Taquicardia/prevenção & controle , Fatores de TempoRESUMO
Upper gastrointestinal endoscopy is often accompanied by tachycardia which is known to be an important pathogenic factor in the development of myocardial ischemia. The pathogenesis of tachycardia is unknown but the condition is thought to be due to the endocrine response to endoscopy. The purpose of the present study was to investigate the effects of sedation on the endocrine response and cardiorespiratory function. Forty patients scheduled for diagnostic upper gastrointestinal endoscopy were randomized into 2 groups. While the patients in the first group did not receive sedation during upper gastrointestinal endoscopy, the patients in the second group were sedated with intravenous midazolam at the dose of 5 mg for those under 65 years or 2.5 mg for those aged 65 years or more. Midazolam was administered by slow infusion. In both groups, blood pressure, ECG tracing, heart rate, and peripheral oxygen saturation (SpO2) were monitored during endoscopy. In addition, blood samples for the determination of cortisol, glucose and C-reactive protein levels were obtained from patients in both groups prior to and following endoscopy. Heart rate and systolic arterial pressure changes were within normal limits in both groups. Comparison of the two groups regarding the values of these two parameters did not reveal a significant difference, while a statistically significant reduction in SpO2 was found in the sedation group. No significant differences in serum cortisol, glucose or C-reactive protein levels were observed between the sedated and non-sedated group. Sedation with midazolam did not reduce the endocrine response and the tachycardia developing during upper gastrointestinal endoscopy, but increased the reduction in SpO2.
Assuntos
Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Anestésicos Intravenosos/uso terapêutico , Pressão Sanguínea/efeitos dos fármacos , Gastroscopia/efeitos adversos , Frequência Cardíaca/efeitos dos fármacos , Midazolam/uso terapêutico , Taquicardia/etiologia , Proteína C-Reativa/análise , Eletrocardiografia , Glucose/análise , Hidrocortisona/sangue , Oxigênio/sangue , Taquicardia/prevenção & controleRESUMO
Upper gastrointestinal endoscopy is often accompanied by tachycardia which is known to be an important pathogenic factor in the development of myocardial ischemia. The pathogenesis of tachycardia is unknown but the condition is thought to be due to the endocrine response to endoscopy. The purpose of the present study was to investigate the effects of sedation on the endocrine response and cardiorespiratory function. Forty patients scheduled for diagnostic upper gastrointestinal endoscopy were randomized into 2 groups. While the patients in the first group did not receive sedation during upper gastrointestinal endoscopy, the patients in the second group were sedated with intravenous midazolam at the dose of 5 mg for those under 65 years or 2.5 mg for those aged 65 years or more. Midazolam was administered by slow infusion. In both groups, blood pressure, ECG tracing, heart rate, and peripheral oxygen saturation (SpO2) were monitored during endoscopy. In addition, blood samples for the determination of cortisol, glucose and C-reactive protein levels were obtained from patients in both groups prior to and following endoscopy. Heart rate and systolic arterial pressure changes were within normal limits in both groups. Comparison of the two groups regarding the values of these two parameters did not reveal a significant difference, while a statistically significant reduction in SpO2 was found in the sedation group. No significant differences in serum cortisol, glucose or C-reactive protein levels were observed between the sedated and non-sedated group. Sedation with midazolam did not reduce the endocrine response and the tachycardia developing during upper gastrointestinal endoscopy, but increased the reduction in SpO2.
Assuntos
Anestésicos Intravenosos/uso terapêutico , Pressão Sanguínea/efeitos dos fármacos , Gastroscopia/efeitos adversos , Frequência Cardíaca/efeitos dos fármacos , Midazolam/uso terapêutico , Taquicardia/etiologia , Adulto , Idoso , Proteína C-Reativa/análise , Eletrocardiografia , Feminino , Glucose/análise , Humanos , Hidrocortisona/sangue , Masculino , Pessoa de Meia-Idade , Oxigênio/sangue , Taquicardia/prevenção & controleRESUMO
Atualmente os cardioversores desfibriladores implantáveis, em função de sua eficácia e segurança, tornaram se a primeira opção de tratamento na profilaxia secundária de morte súbita e, em algumas situações, na profilaxia primária. No entanto, o emprego desta prótese comumente está associado ao uso de drogas antiarrítmicas em pacientes de alto risco para morte súbita. Os antiarrítmicos frequentemente são julgados como responsáveis por alterações dos limiares de desfibrilação ventricular, especialmente a amiodarona. Portanto um conhecimento básico sobre a a interação entre estas drogas e limiares de desfibrilação é fundamental, no momento da seleção de um determinado agente.
Assuntos
Humanos , Desfibriladores Implantáveis , Amiodarona , Taquicardia/prevenção & controleRESUMO
The crustacean nervous system is an important source of substances with diverse biological activities, particularly affecting invertebrate cardiocirculatory physiology. However, the effects of these substances on the cardiovascular system of higher vertebrates are not very well documented. The purpose of this study was to evaluate the effects of a cardioexcitatory substance (CES) isolated from the eyestalk of the shrimp Peneaus vanameii on rat cardiovascular function. The administration of a purified fraction of this substance raised mean arterial pressure by 37.33 +/- 5.00 mm Hg, pulse pressure 35.00 +/- 4.93 mm Hg and heart rate 80.00 +/- 12.83 beats/min over basal values (p < 0.01). Evaluation of the possible underlying mechanisms of this hypertensive and tachycardic effect reveled that dihydroergotamine pretreatment (20 microg/0.2 mL) reduced the effect of CES on mean blood pressure, but not on heart rate. Propranolol pretreatment (4 microg/0.2 mL) reduced the tachycardia, but not the hypertensive response. Enalapril pretreatment (5 microg/0.2 mL) did not modify the effects induced by CES on heart rate or blood pressure, and the verapamil pretreatment (1 microg/0.2 mL) reduced both cardiovascular changes by 85% (p < 0.01). These results indicate that CES isolated from the shrimp eyestalk produces hypertension and tachycardia mediated by adrenergic receptors in association to calcium channels activation.
Assuntos
Cardiotônicos/farmacologia , Hemodinâmica/efeitos dos fármacos , Neuropeptídeos/farmacologia , Penaeidae/química , Extratos de Tecidos/farmacologia , Estruturas Animais/química , Animais , Antiarrítmicos/farmacologia , Antiarrítmicos/uso terapêutico , Anti-Hipertensivos/farmacologia , Anti-Hipertensivos/uso terapêutico , Pressão Sanguínea/efeitos dos fármacos , Canais de Cálcio/efeitos dos fármacos , Cardiotônicos/isolamento & purificação , Di-Hidroergotamina/farmacologia , Di-Hidroergotamina/uso terapêutico , Avaliação Pré-Clínica de Medicamentos , Enalapril/farmacologia , Enalapril/uso terapêutico , Gânglios dos Invertebrados/efeitos dos fármacos , Frequência Cardíaca/efeitos dos fármacos , Hipertensão/induzido quimicamente , Hipertensão/prevenção & controle , Masculino , Neurônios Motores/efeitos dos fármacos , Neuropeptídeos/isolamento & purificação , Pré-Medicação , Propranolol/farmacologia , Propranolol/uso terapêutico , Ratos , Ratos Sprague-Dawley , Receptores Adrenérgicos beta/efeitos dos fármacos , Taquicardia/induzido quimicamente , Taquicardia/prevenção & controle , Extratos de Tecidos/isolamento & purificação , Verapamil/farmacologia , Verapamil/uso terapêuticoRESUMO
Diversos algoritmos foram incorporados aos cardioversores-desfibriladores automáticos implantáveis (CDis) para identificar os distúrbios do ritmo ventricular e, sobretudo, para os diferenciar de taquicardias supraventriculares que não necessitam terapia. Esses benefícios também são encontrados nos CDis bicamerias que têm como benefício a detecção atrial acoplada à detecção do ventrículo. O objetivo dos algoritmos é de identificar todas as arritmias ventriculares (sensibilidade de 100 por cento), para que sejam tratadas corretamente. Devem ainda evitar erros de identificação de arritmias supraventriculares (especificidade máxima). Infelizmente, não é possível alcançar 100 por cento de sensibilidade e especificidade. Além disso, todo aumento da especificidade será acompanhado por uma diminuição da sensibilidade. Essa diminuição de especificidade pode conduzir a falha na detecção dos distúrbios do ritmo ventricular, e como consequência, isto é pior que o tratamento inadequado de uma taquicardia sinusal ou supraventricular
Assuntos
Humanos , Fibrilação Ventricular/diagnóstico , Fibrilação Ventricular/prevenção & controle , Taquicardia/diagnóstico , Taquicardia/prevenção & controle , AlgoritmosAssuntos
Humanos , Arritmias Cardíacas , Desfibriladores Implantáveis , Marca-Passo Artificial/normas , Próteses e Implantes , Bloqueio Cardíaco/terapia , Cardiomiopatia Hipertrófica , Cardiopatias Congênitas/terapia , Eletrodos Implantados/normas , Estimulação Cardíaca Artificial/métodos , Estimulação Cardíaca Artificial/tendências , Infarto do Miocárdio/prevenção & controle , Síndrome do Nó Sinusal , Taquicardia/prevenção & controleRESUMO
O marcapasso que é capaz de detectar a atividade atrial e deflagrar estímulos sincronizados em ventrículo, funciona como uma via acessória de conduçäo entre átrios e ventrículos, estabelecendo condiçöes para a existência de um circuito de reentrada. Assim, diversas formas de taquicardia podem ser mediadas pelos marcapassos de dupla câmara. Neste artigo é feito uma revisäo de todos estes tipos de taquicardias
Assuntos
Humanos , Masculino , Feminino , Adulto , Pessoa de Meia-Idade , Marca-Passo Artificial/efeitos adversos , Taquicardia/etiologia , Taquicardia/diagnóstico , Taquicardia/prevenção & controleRESUMO
Left ventricular reconstruction was used to control recurrent ventricular tachycardia in 19 patients (16 male), mean age of 56 years, with postinfarction anteroseptal aneurysms. The "origin" of recurrent ventricular tachycardia was not determined because the ventricular tachycardia induced by programmed stimulation produced hemodynamic deterioration in all patients. The average ejection fraction was 30.7% +/- 10.1%. In the left ventricular reconstruction technique, the plication of the aneurysmal septum and the reduction of the orifice of the left ventricular cavity after aneurysmal resection with a purse-string suture appear important to prevent the functioning of the reentry circuits. There was one death in the immediate postoperative period. The mean ejection fraction was 47.8% +/- 8.1% (p less than 0.001). The postoperative programmed stimulation induced ventricular tachycardia in only one patient. There were two late deaths. The other 16 patients are asymptomatic (five with antiarrhythmic drugs) in functional class I and without recurrence of ventricular tachycardia. Left ventricular reconstruction is an acceptable technique that changes the spatial orientation in eventual tachycardia circuits. Hence this technique is an alternative for long-term control of the right ventricular tachycardia associated with postinfarction anteroseptal aneurysm without previous electrophysiologic mapping.