The exercise test that indicates a low risk of events. Differences in prognostic significance between patients with chronic stable angina and patients with unstable angina.

OBJECTIVES: The objective of this prospective study was to determine the differences in the prognostic significance of an exercise test (ET) that indicates a low risk of events (low-risk exercise test [LRET]) between patients with unstable angina (UA) and those with chronic stable angina (CSA). BACKGROUND: It is not known whether the prognostic significance of an LRET is influenced by the disease; that is the reason for performing exercise testing. METHODS: All patients not presenting with high-risk criteria were submitted to a prognostic ET. The ET was performed by patients with CSA and patients with primary UA stabilized with medical therapy. Medical therapy was planned for all patients. A combined end point was defined as cardiac death, nonfatal acute myocardial infarction or hospital admission for UA. Multivariate analysis was performed to determine the independent predictors of events. RESULTS: Low-risk criteria were fulfilled by 105 patients with UA and 86 patients with CSA. The mean follow-up time was 347 +/- 229 days. The event rate was higher in the UA group than in the CSA group (28% vs. 9%, p = 0.001). The CSA group showed worse ET results. Performance of ET by patients with UA was the principal predictor of events (odds ratio 4.2, p = 0.0005). CONCLUSIONS: Among patients who underwent an LRET, those with UA had a rate of events significantly higher than that of patients with CSA, despite the worse results of ET in patients with CSA.

Effects of early use of atenolol or captopril on infarct size and ventricular volume: A double-blind comparison in patients with anterior acute myocardial infarction.

BACKGROUND: beta-Blockers and ACE inhibitors reduce early mortality when either one is started in the first hours after myocardial infarction (MI). Considering the close correlation between morphological changes and prognosis, we aimed to investigate whether the benefit of both beta-blockers and ACE inhibitors might reside in a similar protective effect on infarct size or ventricular volume. METHODS AND RESULTS: In a randomized, double-blind comparison between early treatment with captopril or atenolol in 121 patients with acute anterior MI, both drugs showed a similar reduction in mean blood pressure. However, only the atenolol-treated patients showed a significant early reduction in heart rate. Infarct size, obtained from the perfusion defect in resting single photon emission imaging, was higher in captopril-treated patients than in atenolol-treated patients: 29.8+/-12% versus 20.8+/-12% (P:<0.01) by polar map and 28.3+/-13% versus 20.0+/-13% (P:<0.01) by tomography. Changes from baseline to 1 week and to 3 months in ventricular end-diastolic volume, assessed by echocardiography, were as follows: 58+/-14 versus 64+/-19 (P<0.05) and 65+/-21 mL/m(2) (P<0.05), respectively, with captopril, and 58+/-18 versus 64+/-18 (P<0.05) and 69+/-30 mL/m(2) (P<0.05), respectively, with atenolol. Neither group showed significant changes in end-systolic volume. Among patients with perfusion defect >18% (n=51), those treated with atenolol showed a significant increase of end-systolic and end-diastolic ventricular volumes, whereas captopril-treated patients did not. CONCLUSIONS: Although early treatment with atenolol or captopril results in similar overall short- and medium-term preservation of ventricular function and volumes, in patients with larger infarctions, a beta-blocker alone does not adequately protect myocardium from ventricular dilatation.

Head-up tilt test in patients with high pretest likelihood of neurally mediated syncope: an approximation to the "real sensitivity" of this testing.

UNLABELLED: This study was designed to examine the "true sensitivity" of a specific head-up tilt (HUT) testing protocol using clinical findings. The HUT protocol used 45 minutes at 60 degrees for the baseline portion and intermittent boluses of 2, 4, and 6 micrograms of isoproterenol in the second phase. Eighty-eight patients (40 men and 48 women; mean age of 33.8 +/- 16 years) with recurrent syncope and high pretest likelihood of neurally mediated syncope were included. The following were considerated as high pretest likelihood criteria: (1) at least two syncopal episodes; (2) no structural heart disease and normal baseline ECG; (3) age < 65 years; (4) a typical history of neurally mediated syncope, triggering factors plus premonitory signs; and (5) short duration of symptoms and fast recovery without neurological sequelae. Fifty-four patients (61%) had a positive tilt test (34/88 baseline [39%] and 20/50 with isoproterenol [40%]). The shorter time interval between the last syncopal episode and baseline HUT test was the only predictor for a positive response (P < 0.003). Conversely, this time interval was not predictor of positive responses during isoproterenol-tilt testing. IN CONCLUSION: (1) we claim a "sensitivity" for this combined protocol of 61%; and (2) our results indicate that patients with syncope of unknown origin must be tilted nearest as possible to the last syncope to increase the positive responses of HUT test.

[Role of adenosine triphosphate (ATP) in head-up tilt-induced syncope]. / Papel del adenosín trifosfato (ATP) en la inducción de síncope mediante test de basculación.

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.

Role of endogenous opioids in syncope induced by head-up tilt test and its relationship with isoproterenol-dependent and isoproterenol-independent neurally-mediated syncope.

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.

[Epidemiological changes in infectious endocarditis. A prospective study, 1992-96]. / Cambios epidemiológicos en la endocarditis infecciosa. Estudio prospectivo 1992-96.

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.

[Long-term prognosis of patients with syncope of unknown origin in prolonged asystole induced by the head-up tilt test]. / Pronóstico a largo plazo de pacientes con síncope de origen desconocido y asistolia prolongada inducida mediante test de basculación.

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.

[Use of transdermal scopolamine in the prevention of neuro-cardiogenic syncope induced by the tilt test]. / Uso de la escopolamina transdérmica en la prevención del síncope neurocardiogénico inducido mediante test de basculación.

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.