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Biomedical subjects

O H Teixeira

Publications and source records attributed to O H Teixeira.

At least 19 recordsLinked to original sources
PubMed1999

Cerebral blood flow velocity during tilt table test for pediatric syncope.

BACKGROUND: Brain hypoperfusion during neurocardiogenic syncope develops as a consequence of hypotension and bradycardia. Transcranial Doppler indicates that an increase in cerebral vascular resistance occurs before or during the loss of consciousness. OBJECTIVE: Cerebral blood flow velocity was studied during tilt table testing in pediatric patients with neurocardiogenic syncope. We assessed whether a critical reduction in flow velocity (>40%) was predictive of the presyncopal manifestations during the test. METHODS: A 2-MHz transcranial Doppler measured blood flow velocity in the right middle cerebral artery in 27 pediatric patients (ages, 8 to 18 years) during a three-stage 80 degrees tilt table test protocol. A positive test required development of syncope or presyncope with at least 30% decrease in systolic blood pressure and/or heart rate relative to preceding values. Patients were divided into: group I (isoproterenol-induced positive tests), group II (positive without isoproterenol), and group III (negative tests). RESULTS: Within the first 3 minutes of the upright position mean cerebral blood flow velocity in groups I, II, and III decreased by 18%, 29%, and 17%, respectively, as the systolic and diastolic blood pressures showed only minimal changes. A decreased mean blood flow velocity of 48% and 45% and an increase in resistance index of 42% and 26% from supine values in the absence of hypotension, were detected in groups I and II at 46 seconds (range, 30-120 seconds) and 50 seconds (range, 0-300 seconds) before any clinical symptom (presyncope latency). Mean blood flow velocity during presyncope decreased by 58% and 59%, whereas resistance index was double. A significant correlation (rho = -0.62) was found between presyncope latency and the decreased mean cerebral blood flow velocity. Similar blood flow velocity changes were not detected in group III. CONCLUSION: A sustained reduction >40% in mean cerebral blood flow velocity in the absence of hypotension always resulted in presyncopal or syncopal manifestations. It seems that once this critical threshold is identified during the tilt table testing, supine position may be resumed several seconds before the clinical manifestations of syncope.

Adolescent↗
PubMed1998

Cerebral blood flow velocities monitored by transcranial Doppler during cardiac catheterizations in children.

Transcranial Doppler (TCD) was used to evaluate brain circulation during cardiac catheterizations in 32 children requiring pulmonary (n=10) or aortic balloon dilatations (n=2), ductus arteriosus coil insertions (n=5), or angiography (n=15). Cerebral blood flow velocity (CBFV) in the middle cerebral artery was measured before (baseline), during, and after each procedure (mean+/-95%ci). High-intensity transient signals (HITS) were also detected during these maneuvers. Balloon angioplasty decreased CBFV by 63+/-11% from baseline (P < 0.01). Shorter durations of the inflation cycle resulted in earlier CBFV recovery (r=0.78). During angiography, CBFV increased by 11+/-4% (P < 0.01) in all except one case that showed retrograde diastolic flow. Mean total HITS count was 44 (95%ci.limits: 27,74). These signals were more frequently found in septal defects or systemic arterial manipulations. Pediatric cardiac catheterization may impose transient fluctuations in brain perfusion as indicated by TCD, but their clinical implications are uncertain. CBFV changes during balloon angioplasty emphasize the importance of rapid inflation/deflation cycles. TCD can monitor such changes and evaluate preventive measures.

Adolescent↗
PubMed1994

Radiofrequency catheter ablation of atrioventricular nodal reentrant tachycardia in children.

Radiofrequency (RF) catheter ablation has been widely used in the treatment of cardiac arrhythmias. In atrioventricular nodal reentrant tachycardia (AVNRT), the experience has been predominantly in adults. The cardiac electrophysiological records of 18 consecutive children undergoing RF catheter AV node modification for AVNRT were reviewed. The patients (10 females, 8 males) were 8.2-17.9 years of age (mean 13.6 +/- 3.0), weight 15.2-88.1 kg (mean 52.2 +/- 20.8), and height 103-190 cm (mean 157.1 +/- 21.7). Thirteen were on antiarrhythmic medications (1-3, average 1.5 drugs/day). All drugs were discontinued 48 hours prior to the ablations. The procedures were performed under sedation and local anesthesia. Pre- and post-AV node modification electrophysiological studies were performed in all procedures. The 18 patients underwent a total of 25 procedures (1.39 +/- 0.61 per patient): the anterior approach aimed at the antegrade fast pathway in the first four patients and the posterior approach aimed at the slow pathway in the remainder. The number of energy applications was 8-54 (19.8 +/- 10.7) per procedure. The maximum energy used in each procedure was 30-50 watts (33.8 +/- 8.4). The average energy was 24-50 watts (33.0 +/- 6.8). The fluoroscopy time was 7.1-73.4 minutes (29.9 +/- 20.0) per procedure, for a total catheterization time of 228-480 minutes (300.3 +/- 59.1). Preablation spontaneous or induced AVNRT (cycle length 310.4 +/- 55.0 msec) was seen in all except one who had the arrhythmia (cycle length 270 msec) on surface ECG.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Transcatheter management of pulmonary venous pathway obstruction with atrial baffle leak following Mustard and Senning repair.

Two patients presenting with pulmonary venous baffle obstruction following Mustard or Senning repair of transposition of the great arteries were successfully treated with percutaneous balloon dilatation. At the time of baffle dilatation, a significant systemic to pulmonary venous Mustard baffle leak was successfully closed with a Rashkind ductal occluder device. Specific features pertaining to the morphology of the baffle defect that allowed successful catheter occlusion are discussed and compared to that found in a Senning patient. The important adjunctive role of transoesophageal echocardiography within the catheterization laboratory is emphasized.

Cardiac Catheterization↗
PubMed1990

Atypical hepatic vein leiomyoma extending into the right atrium: an unusual cause of the Budd-Chiari syndrome.

A 14-year-old male presented with a one week history of weakness, lightheadedness and vomiting. Bilateral pleural effusions were evident on chest radiography; electrocardiogram revealed decreased voltages. Echocardiogram, abdominal ultrasound and magnetic resonance imaging revealed a mass in an hepatic vein and the inferior vena cava extending up to and filling the right atrium. Under deep hypothermia and extracorporeal circulation the mass was removed en bloc. It originated from the hepatic vein. Pathology revealed a smooth muscle tumour intermediate between benign and malignant (atypical leiomyoma). This is the first reported pediatric primary leiomyoma of the hepatic vein. It caused the Budd-Chiari syndrome, a rare pediatric entity.

Actins↗
PubMed1990

Initial evaluation of heart murmurs: are laboratory tests necessary?

Heart murmurs, most of them innocent, are the most common reason for referrals to a pediatric cardiologist. In the evaluation of murmurs, the electrocardiogram and echocardiogram are often included. The purpose of this study was to determine the utility of these examinations in the initial assessment of heart murmurs in children and adolescents. In a prospective series of 161 patients, the clinical diagnosis of heart murmurs by a pediatric cardiologist was compared with that obtained after electrocardiogram and echocardiogram (two-dimensional, M-mode, Doppler, and color-Doppler). On the basis of the clinical diagnosis the patients were classified as having "innocent murmur," "pathologic murmur," or "possible pathologic murmur." A total of 161 patients (51% males), aged 1 month to 17 years (median 3.2 years), were studied. After electrocardiogram, no diagnosis was changed. After echocardiogram, the clinical diagnosis of innocent murmur in 109 patients changed in 2 to pathologic (small ventricular septal defect 1, small atrial septal defect 1); pathologic murmur in 46 changed to innocent in 3 and possible pathologic in 2; and possible pathologic in 6 changed to innocent in 3 and to pathologic in 2. The clinical examination by an experienced pediatric cardiologist is an accurate means of assessing newly referred patients with murmurs. The clinical examination had a sensitivity of 96%, specificity of 95%, positive predictive value of 88%, and negative predictive value of 98%. The electrocardiogram, unlikely to disclose any unsuspected heart disease, may assist in reaching the lesion-specific diagnosis when there is underlying pathology. Echocardiography, although diagnostic when heart disease is suspected, is unnecessary in pediatric patients with clinically diagnosed innocent heart murmurs.

Adolescent↗
PubMed1984

Long-term prostaglandin E1 therapy in congenital heart defects.

Seventeen neonates received an intravenous infusion of prostaglandin E1 for an average of 39 days (range 8 to 104). Seven (group 1) had transposition of the great arteries with no ventricular septal defect or a small one; eight (group 2) had ductus-dependent pulmonary flow (pulmonary atresia or stenosis in six and tricuspid atresia in two); and two (group 3) had aortic coarctation, one with no ventricular septal defect, the other with ventricular septal defect, isthmus hypoplasia and descending aortic flow supplied mainly by the ductus. An increase in the arterial partial pressure of oxygen (PO2) was seen in groups 1 and 2. Six patients from group 1 and two from group 2 developed heart failure; cortical hyperostosis of long bones was seen in three patients from group 1 and three from group 2; one from group 1 had refractory diarrhea. Other side effects seen at the beginning improved as the rate of infusion diminished. In group 3, the patient with complex coarctation had a decrease in blood pressure in the arms, an increase in pressure in the legs and restoration of renal function; in the patient with no ventricular septal defect, heart failure worsened during therapy. Histologic changes seen in three ductus were attributed to the closing process. When delaying surgery in selected ill infants with heart defects is deemed advantageous, long-term infusions of prostaglandin E1 are feasible.

Alprostadil↗
PubMed1983

Cardiovascular anomalies with imperforate anus.

In 68 patients with anorectal malformations cardiovascular anomalies (CVA) were seen in 15 and genitourinary (GU) anomalies in 30. CVA were more frequent (33%) whenever there was a GU anomaly. Ventricular septal defect was the most frequent lesion. All but 1 CVA occurred with type III anorectal malformation. The complexity of the cardiac lesion did not parallel that of the GU anomaly.

Abnormalities, Multiple↗
PubMed1982

Unmet need for pediatric cardiology services and correlates of referral in Ontario, 1975-1977.

We collected data on 930 neonates with structural congenital heart disease seen during 1975-1977 at the existing pediatric cardiac referral and treatment centers in Ontario. Estimates were made of unmet need for pediatric cardiology services in Ontario. The data showed that a number of counties had significantly low referral rates and that at least 25% of the newborns with severe structural heart disease (that is, 75 newborns each year) were not seen by pediatric cardiologists, although the children would benefit from prompt assessment and rapid treatment under specialist supervision.

Cardiac Care Facilities↗
PubMed1980

Kawasaki disease, or mucocutaneous lymph node syndrome: report of seven cases in North America.

The clinical and laboratory findings in seven children with Kawasaki disease are reviewed. Four of the patients had the more complicated course that has characterized the cases diagnosed in North America. This suggests that the benign forms are often mistaken for other febrile illnesses. The patients were two girls and five boys ranging in age from 4 months to 7 years; six were Caucasian and one was a North American Indian. Fever, redness of the oral mucosa, an erythematous or scarlatiniform rash and cervical adenopathy were seen in all; six patients had the characteristic fingertip desquamation and nonexudative conjunctivitis. Cardiac involvement occurred in four patients, two of whom had coronary artery aneurysm or thrombosis. Arthritis or arthralgia was seen in six patients, and aseptic meningitis occurred in four. Of the three patients with jaundice two underwent laparotomy and excision of a hydropic gallbladder; one of them died from Klebsiella pneumoniae sepsis and disseminated intravascular coagulopathy.

Aspirin↗