RESUMEN
INTRODUCTION AND OBJECTIVES: Recent studies have demonstrated that adenosine is an endogenous modulator of the cardiac excitatory afferent nerves, and could provoke a vasovagal response during head-up tilt test. Isoproterenol has been the drug of choice to increase the sensitivity of this testing. The aim of the present study was to analyze the role of adenosine in head-up tilt-induced syncope in susceptible patients, and to compare the relative sensitivities of adenosine and isoproterenol. METHODS: Thirty patients with unexplained syncope (16 female and 14 male, mean age 37.1 +/- 18 years), no heart disease and negative baseline head-up tilt test were studied. After the baseline test, patients were randomized to receive adenosine triphosphate (bolus injections of 3, 6 and 9 mg/ 5 min) or isoproterenol (bolus injections of 2, 4 and 6 micrograms/5 min) and underwent a second tilt test. After 15 min at rest, patients received the alternative drug and a third test was performed. Eleven normal control subjects were tested with adenosine in the upright position to determine its effects. RESULTS: A vasovagal response was induced in 7 patients (23.3%) after ATP administration. Nine patients (30%) showed a positive response with isoproterenol. Only 2 patients (6.6%) showed a positive response with both drugs. Of the control subjects, one (9%) had a vasovagal response after ATP administration. CONCLUSIONS: We conclude that adenosine triphosphate seems to be a useful tool to provoke vasovagal reaction in susceptible patients during head-up tilt test.
Asunto(s)
Adenosina Trifosfato , Síncope Vasovagal/diagnóstico , Pruebas de Mesa Inclinada/métodos , Adulto , Cardiotónicos , Femenino , Humanos , Isoproterenol , Masculino , Síncope Vasovagal/etiologíaRESUMEN
This study was designed to evaluate the role of endogenous opioids in neurally-mediated syncope. Head-up tilt test was performed on 35 patients with syncope of unknown origin. Plasma beta-endorphin was measured (1) at baseline, (2) at the end of tilt test or at time of syncope, (3) 15 min before isoproterenol-test, (4) at the end of the isoproterenol-test or at time of syncope. Subjects with a positive tilt testing showed a larger rise in plasma beta-endorphin concentrations at time of syncope (baseline 13.7+/-8.0 vs. syncope 41.4+/-26.4 pmol l(-1); P<0.01). On the contrary, patients with a positive isoproterenol-test showed no rise in plasma beta-endorphin levels (baseline 7.9+/-3.6 vs. syncope 7.4+/-2.7 pmol l(-1); P=ns). Patients with a passive negative tilt test (baseline 6.7+/-2.8 vs. end of test 7.0+/-3.3 pmol l(-1); P=ns) and negative isoproterenol tilt test (baseline 7.4+/-3.8 vs. end of test 8.1+/-3.4 pmol l(-1); P=ns) showed no changes in beta-endorphin concentrations. To further examine the efficacy of i.v. naloxone to prevent syncope, 10 patients were randomized to naloxone (0.02 mg/kg) or placebo. Second head-up tilt testing was negative in 1/5 patients with naloxone and in 2/5 patients with placebo. We conclude that, (1) endogenous opioids seem to be involved in vasovagal syncope induced by baseline head-up tilt test, (2) changes in plasma beta-endorphin concentrations show significant differences between patients who have isoproterenol-dependent and isoproterenol-independent syncope, this finding might occur in the setting of different pathophysiologic mechanisms, and (3) intravenous naloxone at a dose of 0.02 mg/kg was not superior to placebo in order to prevent positive responses to baseline tilt test.
Asunto(s)
Agonistas Adrenérgicos beta/administración & dosificación , Isoproterenol/administración & dosificación , Péptidos Opioides/fisiología , Síncope Vasovagal/fisiopatología , Pruebas de Mesa Inclinada , Adolescente , Adulto , Anciano , Niño , Femenino , Humanos , Masculino , Persona de Mediana Edad , Naloxona/farmacología , Naloxona/uso terapéutico , Antagonistas de Narcóticos/farmacología , Antagonistas de Narcóticos/uso terapéutico , Síncope Vasovagal/inducido químicamente , Síncope Vasovagal/prevención & control , betaendorfina/sangre , betaendorfina/efectos de los fármacosRESUMEN
BACKGROUND: To know the present epidemiological situation of the infective endocarditis in our environment and its evolution in the last few years. RESULTS: The incidence of infective endocarditis was 0.85 per thousand patients admitted to hospital, with a mean age of 43 years. The predisposed factors more frequently found were: drug addiction (32%) and cardiac prosthetic valves (23%). In the greatest number of our patients the cardiac valves involved were: tricuspid (28%), mitral (27%) and prosthetic valves (23%). The causative organism were: S. aureus (19 cases), Streptococcus (15 cases) and S. epidermidis (11 cases). The echocardiography study resulted diagnostic in 90% of the patients, valve replacements were performed in 22% of the cases. The overall mortality rate was 10%. CONCLUSIONS: The current profile of infective endocarditis is characterized by a high incidence of parenterally drug addict patients or prosthetic valves carriers. Increase of the infections of S aureus and a decrease of Streptococcus infections, as well as a less overall mortality.
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Endocarditis Bacteriana/epidemiología , Adolescente , Adulto , Factores de Edad , Anciano , Anciano de 80 o más Años , Niño , Ecocardiografía , Endocarditis Bacteriana/diagnóstico , Femenino , Implantación de Prótesis de Válvulas Cardíacas/efectos adversos , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Factores de Riesgo , Factores Sexuales , España/epidemiología , Abuso de Sustancias por Vía Intravenosa/complicacionesRESUMEN
INTRODUCTION AND OBJECTIVES: Prognosis and therapeutic assessment of patients with syncope and prolonged asystole during head-up tilt test remain unclear. The aim of the present study was to analyze the clinical evolution of patients with syncope of unknown origin, no heart disease and severe cardioinhibitory response induced by head-up tilt. METHODS: A prospective follow-up study was performed in 12 patients (6 male and 6 female, mean age 31 +/- 20 years) with recurrent syncope, no heart disease and affected by severe cardioinhibitory syncope induced by head-up tilt test. This was defined as syncope or near-syncope induced by baseline or isoproterenol tilt with asystole of > or = 3 seconds. All patients were re-tilted twice: with salt and fluid and with metoprolol (25 mg/b.i.d). According to the results of these tests, 5 patients were discharged with dietetic measures (salt & fluid) and 5 with metoprolol. In 2 patients who showed recurrent prolonged asystole a DDD pacemaker was implanted. RESULTS: After follow-up of 34 +/- 20 months all patients ae alive. The number of recurrences was small (2 syncopes and 2 near-syncopes). No relationship was observed between the number of syncopal recurrences and the applied treatment. CONCLUSIONS: We conclude that prolonged asystole induced by head-up tilt test does not confer an adverse prognosis in patients with syncope of unknown origin and no heart disease, thus, the clinical evolution of these patients is benign.
Asunto(s)
Síncope/fisiopatología , Adulto , Femenino , Estudios de Seguimiento , Humanos , Masculino , Postura/fisiología , Pronóstico , Síncope/diagnóstico , Síncope/terapiaRESUMEN
INTRODUCTION AND OBJECTIVES: The underlying mechanism of syncope induced by head-up tilt test is still incompletely understood. It has been proposed a sudden increase in parasympathetic's activity induced by the excessive activation of the cardiac mechanoreceptors. The aim of our study was to evaluate the clinical, electrocardiographic and hemodynamic responses to head-up tilt test before and after treatment with transdermal Scopolamine (anticholinergic agent). METHODS: We studied 17 patients (8 females, 9 males; mean age 43 +/- 19 years) with > or = 2 syncopal episodes of unknown origin and a positive tilt test (a positive response to tilt testing alone or in conjunction with an infusion of isoproterenol was defined as the appearance of syncope or presyncope associated to hypotension and/or bradycardia). Symptoms developed in 12 patients during the baseline tilt (Group I) and in 5 patients after infusion of isoproterenol (Group II). Mean time to symptoms was 8.5 +/- 7.9 minutes in group I. All patients were them treated with transdermal Scopolamine (1.5 mg/24 hours) and 48 hours later tilt test was repeated. RESULTS: In group I, 8 patients (66.6%) became tilt test negative and in the remaining 4 patients mean time before the appearance of symptoms was increased (8.5 +/- 7.9 vs 16.2 +/- 2.5 minutes; p < 0.05). In group II, 3 patients (60%) became tilt test negative and in the remaining 2 patients symptoms developed after an infusion of higher doses of isoproterenol than in the first study. So, with transdermal scopolamine 11 out of 17 patients became tilt test negative and time to symptoms was increased in all of the remaining 6 patients. CONCLUSIONS: Our study suggest that transdermal scopolamine is an usefull treatment in the prevention of neuro-cardiogenic syncope induced by head-up tilt test.