PubMed Health⌕ Search

Biomedical subjects

R N Vincent

Publications and source records attributed to R N Vincent.

At least 37 records · Page 2Linked to original sources
PubMed1988

Interventricular septal motion and left ventricular function in patients with atrial septal defect.

In order to assess whether the paradoxical motion of the interventricular septum seen in patients with atrial septal defect (ASD) is due to a true abnormality in septal contraction, eight patients with ASD (age, 1.6-17 years) and eight age-matched control patients were studied using qualitative and quantitative two-dimensional (2D) and M-mode echocardiography. 2-D-echocardiographic images recorded from the parasternal short-axis projection at the level of the papillary muscles and 2D-directed M-mode tracings at this level were obtained. Comprehensive wall motion analysis of the left ventricular (LV) endocardial and epicardial borders was performed using both fixed reference and center of mass (floating reference) models. Our results indicate that interventricular septal wall motion and function are normal in patients with ASD. The apparent "paradoxical" motion is due to excessive anterior motion of the entire left ventricle, and is present only when a fixed reference system is used to assess myocardial motion, but is not present when a center of mass (floating reference system) is employed. Left ventricular function assessed by % area and perimeter change, mean radial shortening fraction, and mean radial wall thickening (2D) as well as LV shortening fraction and septal and posterior wall thickening (M-mode) was not significantly different between the two groups. Standard M-mode tracings can therefore be used to assess LV function despite this apparent abnormal septal motion.

Adolescent↗
PubMed1987

Cardiac embryogenesis: a three-dimensional approach.

In order to aid students in the understanding of cardiac embryogenesis, seven three-dimensional fiberglass models depicting stages eleven to eighteen of cardiac embryogenesis, and one model of a mature heart were constructed. The details of these models, and a review of cardiac embryogenesis is presented. The results we have had with these models in the teaching of cardiac embryogenesis to medical students, cardiac technologists, and nurses have been encouraging, and this approach to teaching is highly recommended.

Heart↗
PubMed1986

Severe mitral insufficiency associated with Kawasaki's valvulitis.

A two-month-old male infant with Kawasaki's disease, severe mitral insufficiency, and normal coronary arteries is described. We postulate the mitral insufficiency was secondary to Kawasaki's valvulitis, and that this occurred in the absence of other forms of cardiac involvement characteristic of Kawasaki's disease.

Humans↗
PubMed1986

Evaluation of pulmonary vascular resistance in the presence of a large pulmonary arteriovenous malformation.

A 1 day old infant presented with severe cyanosis and congestive heart failure. Cardiac catheterization confirmed the clinical suspicion of a pulmonary arteriovenous malformation of the right lower lobe. Catheter occlusion of the right lower pulmonary artery allowed evaluation of the integrity of the remaining pulmonary vascular bed as well as improvement of the patient's hemodynamic condition pending more definitive therapy.

Arteriovenous Malformations↗
PubMed1985

Extravascular lung water in children immediately after operative closure of either isolated atrial septal defect or ventricular septal defect.

Extravascular lung water (EVLW) was measured in 16 patients with congenital heart disease by the cold green dye, double indicator dilution technique. Five patients with optimally corrected tetralogy of Fallot served as controls, and EVLW in this group was 4.7 +/- 0.5 ml/kg (111 +/- 13 ml/m2) (mean +/- standard deviation). In 5 asymptomatic patients with atrial septal defect (ASD), normal pulmonary artery (PA) pressure and increased pulmonary blood flow, EVLW was 5.7 +/- 2.8 ml/kg (132 +/- 63 ml/m2), which was not significantly different from the value of control patients. However, in 6 patients with ventricular septal defect, PA hypertension, normal left atrial pressure and an equivalent left-to-right shunt to ASD patients, EVLW was 15.9 +/- 3.8 ml/kg (270 +/- 60 ml/m2). This was significantly different from values in both control and ASD patients (p less than 0.01). It is concluded that in the face of normal pulmonary vascular resistance, PA pressure is transmitted to the microvasculature, causing hydrostatic pulmonary edema. Other factors that may be implicated in the pathogenesis of pulmonary edema, such as increased pulmonary blood flow and relative lymphatic insufficiency in infants, cannot be excluded.

Child↗
PubMed1985

Assessment of hemodynamic status in the intensive care unit immediately after closure of ventricular septal defect.

Hemodynamic values measured 12 to 24 hours postoperatively in the intensive care unit (ICU) were compared with those measured at a later cardiac catheterization in 68 patients after closure of ventricular septal defect (VSD). A pulmonary arterial (PA) saturation of more than 80% or a pulmonary to systemic blood flow ratio (Qp:Qs) greater than 1.5 in the ICU were sensitive indicators for identifying patients at risk of having a hemodynamically significant residual left-to-right shunt (Qp:Qs greater than 1.5) at catheterization. Measurement of PA pressure in the ICU was a useful predictor of PA pressure at catheterization. In the absence of factors known to alter PA pressure, measurement of PA pressure in the ICU overestimates what it will be at a subsequent cardiac catheterization. Early assessment of hemodynamics after closure of VSD is useful in identifying patients at risk of having hemodynamically significant residual VSD and those who may have persistent PA hypertension.

Adolescent↗
PubMed1985

Pulmonary and systemic hemodynamic responses to ketamine in infants with normal and elevated pulmonary vascular resistance.

Avoidance of ketamine has been recommended in children with pulmonary hypertension or with limited right ventricular reserve, despite absence of data about the effects of ketamine on pulmonary vascular resistance (PVR) in children. Ketamine has been associated with increased PVR in studies of adults; in these studies adults were spontaneously breathing through unprotected airways, despite ketamine's known effects of ventilatory depression and partial loss of airway. The authors measured pulmonary and systemic hemodynamic responses to ketamine during spontaneous ventilation in 14 intubated infants who were receiving minimal ventilatory support with an intermittent mandatory ventilation (IMV) of 4 at an FIO2 of 0.3-0.4. No significant changes were found in cardiac index (CI), pulmonary vascular resistance index (PVRI), or systemic vascular resistance index (SVRI) in a group of seven infants with normal PVRI or in another group of seven infants with preexisting increased PVRI. Results did not differ in infants receiving diazepam sedation. The authors conclude that ketamine has little effect on baseline hemodynamics in mildly sedated infants whose airway and ventilation are maintained; in particular, PVRI is little changed by ketamine administration in ventilated infants with either normal or increased baseline PVRI.

Blood Gas Analysis↗
PubMed1984

Measurement of extravascular lung water in infants and children after cardiac surgery.

Extravascular lung water (EVLW) was measured in 17 patients with congenital heart disease by the cold-green-dye, double indicator-dilution technique. In 5 control patients, EVLW was 4.7 +/- 0.5 ml/kg (111 +/- 13 ml/m2) (mean +/- standard deviation). Twelve patients were studied immediately after correction of their heart defects. In 6 patients with normal or decreased pulmonary blood flow preoperatively (Group I), EVLW was 6.2 +/- 1.9 ml/kg (122 +/- 46 ml/m2). This value is not significantly different from that of the control patients. In 6 patients with increased pulmonary blood flow and congestive heart failure preoperatively (Group II), EVLW was 15.7 +/- 3.8 ml/kg (270 +/- 60 ml/m2), which is significantly different from both control and Group I patients (p less than 0.01). There was no correlation of EVLW with pre- or postoperative left atrial pressure, length of cardiopulmonary bypass or deep hypothermic circulatory arrest, postoperative serum protein, albumin, hematocrit or cardiac index. Thus, EVLW in the immediate postoperative period is determined by preoperative pathophysiologic characteristics rather than by intraoperative management, and patients with congestive heart failure resulting from left-to-right shunts have increased EVLW despite normal left atrial pressures.

Blood Pressure↗
PubMed1984

Hemodynamic response to high-frequency ventilation in infants following cardiac surgery.

The hemodynamic response to high-frequency ventilation was compared with conventional ventilation in six infants following cardiac surgery. While undergoing high-frequency ventilation, adequate gas exchange was maintained in all infants. High frequency ventilation allowed a reduction of peak ventilatory pressure at the airway opening by 19%, and peak tracheal pressure by 42%. No clinically important changes in heart rate, systemic and pulmonary arterial pressure, cardiac index, or systemic and pulmonary vascular resistance were noted when high-frequency ventilation was compared with conventional ventilation.

Blood Pressure↗
PubMed1980

Characterization of X-tropic endogenous retrovirus-specific RNA uninfected tissues and lymphosarcoma of BALB/c mice.

Analysis of endogenous X-tropic BALB/c retrovirus-specific RNAs in a BALB/c mouse tissue containing mostly non-driving cells (liver), in two normal tissues having significant proportions of dividing cells (20-h regenerating liver and 12-day embryo) and in cells of a lymphosarcoma of BALB/c mice were carried out by determining the extent to which the RNAs from these tissues hybridized to the virus 3H-cDNA probe and by their relative sedimentation values in a sucrose gradient. RNAs from 20-h regenerating liver, 12-day embryo and lymphosarcoma, each containing a significant proportion of proliferating cells, showed 8 to 21 % higher hybridization values than normal liver RNA. Differences in the exact size classes of virus-specific RNAs and, in their relative proportions were found to exist in the four different tissue types examined and no correlation between a specific RNA size-profile and the proliferating activity of a tissue could be detected.

Animals↗
PubMed1976

Changes in transcription of endogenous type-C virus genome during mouse liver regeneration.

In the present study the extent of endogenous, type-C virus genome transcription in normal and regenerating mouse liver was analysed by using the technique of nucleic acid hybridization. The RNA preparations from regenerating liver tissues collected at various intervals following partial hepatectomy, and from normal liver samples of BALB/c mice, were hybridized to 3H-DNA complementary to 60 to 70S RNA of an endogenous, N-tropic virus, released spontaneously from BALB/c mouse cells in culture. Although partial transcription of the endogenous virus genome can be clearly detected in normal liver, a significant increase in the level of virus-specific RNA synthesis in the regenerating liver, in comparison to normal liver, is apparent, following partial hepatectomy. This increase in virus-specific RNA synthesis attains its highest level just before the level of DNA synthesis in the regenerating liver reaches its maximum. These observations may indicate a qualitative or quantitative change in the endogenous type-C virus genome transcription pattern in hepatocytes, in response to partial hepatectomy and suggest that this change in the transcription pattern and the initiation of cell proliferation, in regenerating livers, are probably sequential and related events.

Animals↗
PubMedDate not supplied

Follow-up of surgical correction of vascular anomalies causing tracheobronchial compression.

Between January 1977 and January 1990, 44 patients with symptomatic vascular rings/slings required surgical intervention at this center. Nineteen patients had double aortic arch (group I); 13 patients had vascular ring consisting of right aortic arch, anomalous origin of the left subclavian artery, and ligamentum arteriosus (group II); eight patients had innominate artery compression (group III); and four patients had pulmonary artery sling (group IV). Three patients had complex congenital heart defect and died secondary to it and are excluded from the study. Follow-up was obtained on 31 patients (76%). The follow-up period ranged from 0.4 years to 10.9 years, with a mean of 3.6 years. Seventy percent of the overall group were asymptomatic, and 30% of patients continued to have upper and lower respiratory symptoms on late follow-up. One third of patients in groups I and II, who underwent surgical repair, continue to have symptoms. Patients who have persistent symptoms should be further evaluated with PFTs, MRI, and bronchoscopy, and may benefit from aortopexy. Patients with innominate artery compression and pulmonary artery sling do well soon after surgery with relief of most of their symptoms.

Airway Obstruction↗
PubMedDate not supplied

Presentation of atrial septal defect in the pediatric population.

Our recent experience indicates that patients with a hemodynamically significant atrial septal defect secundum (ASD2) do not necessarily present with classic physical and electrocardiographic (ECG) findings. The purpose of the study was to review the records of patients either receiving a catheter device or undergoing surgical repair for the closure of ASD2 to determine their initial physical and ECG findings. Therefore, we did a retrospective review of 47 consecutive patients who had echocardiographic evidence of a hemodynamically significant isolated ASD2 and who underwent ASD2 closure. Of these 47 patients, the presenting complaints were murmur (n = 36), chest pain (n = 6), seizure (n = 1), stroke (n = 1), syncope (n = 1), Kawasaki's disease (n = 1), and cardiomegaly (n = 1). Charts were reviewed for the evaluation of four abnormal physical findings: hyperactive right ventricular impulse, split fixed second heart sound, systolic and diastolic flow murmurs; and three ECG abnormalities: right axis deviation, right atrial enlargement, and evidence of right ventricular hypertrophy. In all, 30% of patients had either one or no typical physical findings, 18% had normal ECG findings, and 7% had no physical or ECG findings. On physical examination and ECG, the abnormalities due to ASD2 may be too subtle to detect. Although it is well known that variations can occur in the clinical signs and symptoms typical of ASD2, dependence on classical physical and or ECG findings may result in the underdiagnosis of a significant number of patients.

Adolescent↗