Robert N. Vincent

Health Sciences Centre Winnipeg, Winnipeg, Manitoba, Canada

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Publications (13)52.54 Total impact

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    ABSTRACT: 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. 2D-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.
    No preview · Article · Feb 1988 · Pediatric Cardiology
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    ABSTRACT: Hypoplastic left heart syndrome, as its name implies, is not a distinct anatomic entity, but describes a spectrum of malformations of the left heart. In its most severe form it consists of mitral atresia, a diminutive hypoplastic left ventricle, aortic atresia, and hypoplasia of the ascending aorta. The echocardiographic features of this lesion are well known, and increasingly the diagnosis of this lesion is being made prenatally. To date, all reports of the intrauterine recognition of hypoplastic left heart syndrome have been of the classic variety with a diminutive left ventricle. We now report the fetal echocardiographic appearance of aortic atresia with intact ventricular septum and an unusually large left ventricle, a very unusual form of hypoplastic left heart syndrome.
    No preview · Article · Jun 1987 · Journal of ultrasound in medicine: official journal of the American Institute of Ultrasound in Medicine
  • J Butler · R N Vincent · M Reed · G F Collins
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    ABSTRACT: 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.
    No preview · Article · May 1987 · The Canadian journal of cardiology
  • R N Vincent · L E Hawkins · A N Pelech · G F Collins

    No preview · Article · Apr 1987 · The Canadian journal of cardiology
  • Robert N. Vincent · George F. Collins

    No preview · Article · Aug 1986 · Critical care nursing quarterly
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    ABSTRACT: 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.
    Preview · Article · Jun 1986 · Journal of the American College of Cardiology
  • Robert N. Vincent · George F. Collins
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    ABSTRACT: Demonstration of aortic arch anatomy in neonates with aortic arch abnormalities, including interruption of the aortic arch, severe coarctation of the aorta and hypoplastic left heart syndrome, is essential before surgical intervention. Left ventricular angiograms are often inadequate in patients with interruption of the aortic arch or coarctation of the aorta. Most infants have an associated ventricular septal defect so that contrast material injected into the left ventricle will opacify most of the heart and both great arteries, making visualization of the transverse aortic arch difficult. Now that surgical palliation and physiologic correction are possible for infants with hypoplastic left heart syndrome,1 demonstration of the arch anatomy and identification of a potential coarctation are of vital importance. We describe 2 patients with aortic arch abnormalities in whom the aortic arch anatomy was demonstrated using a new angiographic technique.
    No preview · Article · Mar 1986 · The American Journal of Cardiology
  • Robert N. Vincent · Murray S. Kesselman · George F. N. Collins
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    ABSTRACT: 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.
    No preview · Article · Feb 1986 · Pediatric Cardiology
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    ABSTRACT: 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.
    No preview · Article · Oct 1985 · The American Journal of Cardiology
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    ABSTRACT: 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.
    No preview · Article · Apr 1985 · Anesthesiology
  • Robert N. Vincent · Peter Lang · Carl W. Chipman · Aldo R. Castaneda
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    ABSTRACT: 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.
    No preview · Article · Mar 1985 · The American Journal of Cardiology
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    ABSTRACT: 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.
    No preview · Article · Aug 1984 · The American Journal of Cardiology
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    ABSTRACT: 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.
    No preview · Article · May 1984 · Pediatrics

Publication Stats

128 Citations
52.54 Total Impact Points


  • 1986
    • Health Sciences Centre Winnipeg
      Winnipeg, Manitoba, Canada
    • University of Manitoba
      Winnipeg, Manitoba, Canada
  • 1985
    • Harvard University
      Cambridge, Massachusetts, United States
    • Harvard Medical School
      • Department of Anesthesia
      Boston, Massachusetts, United States
  • 1984
    • Boston Children's Hospital
      • Department of Pediatric Surgery
      Boston, Massachusetts, United States