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A L Ribeiro

Publications and source records attributed to A L Ribeiro.

11 recordsLinked to original sources
PubMed2001

Doppler tissue imaging to evaluate early myocardium damage in patients with undetermined form of Chagas' disease and normal echocardiogram.

Chagas' disease can lead to severe and potentially lethal damage of cardiac function. Thus, the identification of contractile abnormalities in asymptomatic patients can be important for risk stratification in those patients. Doppler tissue imaging (DTI) is a new diagnostic modality for the study of regional and longitudinal contractility of the left ventricle. However, DTI has not been used for the assessment of Chagas' cardiopathy. The purpose of this study was to identify abnormalities related to longitudinal contractility by means of DTI in patients with an undetermined form of Chagas' disease and with normal echocardiogram and Doppler studies. Forty patients were studied, including 21 chagasic ones with normal electrocardiographic, radiologic, and echocardiographic studies, and 19 normal control individuals. All of the patients were submitted to DTI to evaluate longitudinal contractility in the various myocardial segments, including assessment of systolic and diastolic velocities and isovolumic contraction time (IVCT). Similar values were observed among the various systolic function rates in both groups, except for the IVCT along the septal wall, which was significantly higher in the chagasic group. DTI enabled the early detection of contractile abnormalities in patients with an undetermined form of Chagas' disease and with normal echocardiogram. Such abnormalities were particularly striking in the interventricular septum. The present study could be useful in risk stratification for those patients.

Adult↗
PubMed2001

Parasympathetic dysautonomia precedes left ventricular systolic dysfunction in Chagas disease.

BACKGROUND: Parasympathetic dysautonomia is an established feature of advanced Chagas cardiomyopathy. However, in the absence of cardiac involvement, the presence of vagal dysfunction remains controversial. In a cross-sectional study, we compared patients with Chagas disease without cardiac involvement and healthy individuals by three different methods to determine whether vagal dysfunction is present in the early phase of Chagas disease. METHODS: Sixty-one patients with Chagas disease without cardiac involvement and 38 controls were submitted to respiratory sinus arrhythmia test and 24-hour Holter monitoring. Vagal heart influences were assessed by the expiratory/inspiratory (E/I) ratio, time-domain indexes of heart rate variability (HRV), and by the quantification of a 3-dimensional return map. RESULTS: The two groups were comparable in terms of left ventricular ejection fraction and left ventricular end-diastolic dimension. Compared with the control group, patients with Chagas disease had significantly lower values of the E/I ratio (mean +/- SD: 1.38 +/- 0.02 and 1.25 +/- 0.02, P <.004) and short-term indexes of HRV (median [interquartile range]-rMSSD: 23 [18-27] and 17 [13-23], P =.00; pNN50: 11 [7-17] and 6 [2-12], P =.00). P(3), a beat-to-beat HRV index derived from the 3-dimensional return map, also was significantly reduced in the Chagas disease group (mean +/- SD: 118 +/- 5 vs 100 +/- 4, P =.00). None of these indexes of vagal heart control were significantly correlated with left ventricular function or to the presence of esophageal radiologic abnormalities. CONCLUSION: Parasympathetic dysautonomia is an independent and early phenomenon in Chagas disease and may precede left ventricular systolic dysfunction.

Adolescent↗
PubMed2001

Tissue Doppler imaging enables the identification of diastolic dysfunction of pseudonormal pattern in Chagas' disease.

The Doppler pseudonormal pattern of left ventricular (LV) diastolic function filling, characterized by apparent normal transmitral flow velocities, indicates advanced diastolic dysfunction with abnormal relaxation and compliance. Left ventricular diastolic dysfunction has been shown to occur in the early stages of the outcome of Chagas cardiopathy, and its identification may potentially contribute to the management of those patients. The aim of this study was to evaluate the usefulness of tissue Doppler imaging (TDI) in identifying LV diastolic dysfunction in patients with Chagas' disease with pseudonormal transmitral flow. For this purpose, 89 patients with Chagas' disease (48 men) who had no other pathology and showed normal (n = 79) or pseudonormal (n = 10) patterns of diastolic function by pulsed wave Doppler were submitted to TDI. A significant LV systolic impairment in terms of the dimensions (P = .00001), ejection fraction (P = .000001), and wall motion score (P = .000002) was observed in patients with diastolic dysfunction when compared with the group with normal LV diastolic function. Tissue Doppler imaging enabled the recognition of a pseudonormal type of transmitral flow velocity with high statistical significance through early (P = .000008) and late (P = .0003) expansion waves. The sensitivity and specificity in detecting LV diastolic dysfunction with TDI in the septal, anterior, inferior, posterior, and lateral walls were 90% and 87.3%, 87.3% and 90%, 87.3% and 90%, 84.8% and 90%, and 84.8 and 90%, respectively. In conclusion, TDI enabled the differentiation of patients with Chagas' disease with normal LV diastolic function and those with the pathologic LV pseudonormal pattern with high statistical significance. Moreover, this article shows the potential in demonstrating the occurrence of major alterations in the LV performance of patients with Chagas' disease with LV diastolic dysfunction, as well as the occurrence of signs of an increased LV filling pressure in those patients.

Chagas Cardiomyopathy↗
PubMed2001

Enhancing longevity of pacemakers through reprogramming. Underutilization and cost-effectiveness.

OBJECTIVE: This study was performed to observe the number of pacemakers that had never been reprogrammed after implantation, and the effect of optimised output programming on estimated longevity of pulse generators in patients with pacemaker METHODS: Sixty patients with Teletronics Reflex pacemakers were evaluated in a pacemaker clinic, from the time of the beginning of its activities, in June 1998, until March 1999. Telemetry was performed during the first clinic visit, and we observed how many pulse generators retained nominal output settings of the manufactures indicating the absence of reprogramming until that date. After evaluation of the capture threshold, reprogramming of pacemakers was performed with a safety margin of 2 to 2.5:1, and we compared the estimated longevity based on battery current at the manufacturer's settings with that based on settings achieved after reprogramming. RESULTS: In 95% of the cases, the original programmed setting was never reprogrammed before the patients attended the pacemaker clinic. Reprogramming the pacemaker prolonged estimated pulse generator life by 19.7+/-15.6 months (35.5%). CONCLUSION: The majority of the pacemakers evaluated had never been reprogrammed. Estimated pulse generator longevity can be prolonged significantly, using this simple, safe, efficacious, and cost-effective procedure.

Calibration↗
PubMed2000

A narrow QRS does not predict a normal left ventricular function in Chagas' disease.

Left ventricular (LV) systolic dysfunction is a major prognostic determinant in Chagas' disease (ChD), a potentially fatal disorder which affects nearly 20 million individuals in Latin America. Therefore, reliable screening methods are needed to identify patients in need of a detailed evaluation of LV function. Since previous reports have suggested that a prolonged QRS duration may be an accurate predictor of LV dysfunction, the relationship between QRS duration and LV function was evaluated in ChD patients, in order to determine whether a narrow QRS on surface electrocardiogram (ECG) predicts a normal LV function. Ninety-eight patients with ChD and no other cardiac or systemic illness were underwent standard 12-lead ECG and Doppler echocardiogram (echo) examination. An investigator (blinded to the echo data) measured manually the QRS duration. LV dysfunction was defined by the presence of LV dilatation (LV diastolic dimension > 55 mm), depressed LV ejection fraction (LVEF < 0.50), segmental contractile abnormalities (SCA) or LV aneurysm. QRS duration was significantly correlated with LV diastolic dimension (r = 0.44, P = 0.000) and LVEF (r = 0.24, P = 0.016). A significant percentage of patients with QRS < 100 ms had abnormal systolic LV parameters, including LV dilatation (8.1%), reduced EF (10.2%), SCA (42.8%) and LV aneurysm (14.2%). A narrow QRS does not exclude the presence of significant global and segmental LV dysfunction in ChD patients. Since these abnormalities have prognostic and therapeutic implications, further evaluation of LV systolic performance is desirable in such patients.

Adult↗
PubMed1999

Electrocardiographic changes during low-dose, short-term therapy of cutaneous leishmaniasis with the pentavalent antimonial meglumine.

The pentavalent antimonial (Sb5+) meglumine is the drug of choice for the treatment of cutaneous leishmaniasis (CL) in Brazil. Although the cardiotoxicity of high-dose, long-term Sb5+ therapy is well known, the use of low-dose, short-term meglumine has been considered to be safe and relatively free from significant cardiac effects. In order to investigate the cardiotoxicity of low-dose, short-term therapy with meglumine in cutaneous leishmaniasis, 62 CL patients treated with meglumine were studied. A standard ECG was obtained before and immediately after the first cycle of treatment (15 mg Sb5+ kg-1 day-1). The electrocardiographic interpretation was carried out blindly by two investigators using the Minnesota Code. There were no significant differences in qualitative ECG variables before and after meglumine treatment. However, the corrected QT interval was clearly prolonged after antimonial therapy (420.0 vs 429.3 ms, P < 10(-6)). QTc augmentation exceeded 40 ms in 12 patients, 7 of whom developed marked QTc interval enlargement (500 ms) after meglumine therapy. This previously unrecognized cardiac toxicity induced by short-term, low-dose antimonial therapy has potentially important clinical implications. Since sudden death has been related to QTc prolongation over 500 ms induced by high-dose antimonial therapy, routine electrocardiographic monitoring is probably indicated even in CL patients treated with short-term, low-dose meglumine schedules. Until further studies are conducted to establish the interactions between pentavalent antimonials and other drugs, special care is recommended when using meglumine in combination with other medications, in particular with drugs that also increase the QTc interval.

Adult↗
PubMed1999

Bilateral Pseudomonas corneal ulcer in a disposable contact lens wearer.

PURPOSE: To describe a case of bilateral corneal ulcers caused by Pseudomonas in a disposable soft contact lens wearer. This case study discusses the role of patient examination, contact lens care instruction, and adequate patient supervision in reducing the risk of serious potential complications. METHODS AND RESULTS: A 17 year old student who had been using disposable soft contact lenses on an extended wear basis for 6 months presented complaining of pain in the left eye. When he was examined, a corneal ulcer with surrounding infiltrate was observed in the superior middle periphery of the left eye. Samples were collected for culture, and treatment with fortified cefalotin and gentamicin was started. After 8 hours the patient returned, now complaining of pain in the right eye. Examination of the right eye revealed a diffused keratitis with a mucopurulent discharge. A culture was taken, and the same treatment was instituted. The laboratory tests revealed Pseudomonas in both eyes. The bilateral corneal ulcers responded to therapy after 1 week of treatment. CONCLUSIONS: We discuss the factors involved in the occurrence of infectious keratitis in contact lens wearers, and stress that even disposable contact lens wear can be associated with serious complications. This case also highlights extended wear as one of the main risk factors for complications in disposable soft contact lens wear.

Adolescent↗
PubMedDate not supplied

[Indeterminate form of Chagas disease: considerations about diagnosis and prognosis].

The indeterminate form of Chagas' disease is defined by the absence of clinical, radiological and electrocardiographic manifestations of cardiac or digestive involvement in Trypanosoma cruzi chronic infected persons. When submitted to advanced cardiovascular tests, these patients may present significant abnormalities. However, the indeterminate form concept was reaffirmed as valid, since diagnostic criteria are simple and prognosis is benignant. In clinical practice, diagnostic difficulties are frequent, related to subjectivity and uncertain meaning of clinical, electrocardiographic and radiological findings. Moreover, indeterminate form prognosis is not equally good: after five to 10 years, a third of patients will have cardiopathy. Sudden death, a rare complication, may be the first manifestation of Chagas' disease. It is necessary to reappraise indeterminate form concept, redefining diagnostic criteria and therapeutic management. Clinical and noninvasive evaluation may allow individual risk stratification; therapeutic interventions may be beneficial in high risk groups. Since etiologic treatment may prevent cardiopathy, its role in indeterminate form management must be reassessed.

Chagas Cardiomyopathy↗
PubMedDate not supplied

Experimental American trypanomiasis in rats: sympathetic denervation, parasitism and inflammatory process.

Tissue parasitism, inflammatory process (histologic methods) and sympathetic denervation (glyoxylic acid-induced histofluorescence for demonstration of catecholamines) were studied in the heart (atrium and ventricle) and the submandibular gland of rats infected with the Y strain of Trypanosoma cruzi. In the heart paralleling intense parasitism and inflammatory process, the sympathetic denervation started at day-6 of infection and at the end of the acute phase (day 20) practically no varicose nerve terminals were found in both myocardium and vessels. In the submandibular gland, in spite of the rarity of amastigote pseudocysts and the scarcity of inflammatory foci, slight to moderate (days 13-15 of infection) or moderate to severe denervation (day 20) was found. At day 120 of infection both organs exhibited normal pattern of sympathetic innervation and only the heart showed some inflammatory foci and rare pseudocysts (ventricle). Our data suggest the involvement of circulating factors in the sympathetic denervation phenomena but indicate that local inflammatory process is, at least, an aggravating factor.

Animals↗