Robert N. Vincent

University of Manitoba, Winnipeg, Manitoba, Canada

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Publications (11)46.85 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. 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.
    Pediatric Cardiology 02/1988; 9(3):143-8. · 1.55 Impact Factor
  • Journal of ultrasound in medicine: official journal of the American Institute of Ultrasound in Medicine 06/1987; 6(5):261-4. · 1.53 Impact Factor
  • 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.
    The Canadian journal of cardiology 05/1987; 3(3):111-7. · 3.94 Impact Factor
  • The Canadian journal of cardiology 04/1987; 3(2):52-9. · 3.94 Impact Factor
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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.
    Journal of the American College of Cardiology 06/1986; 7(5):1104-6. · 15.34 Impact Factor
  • Robert N. Vincent, George F. Collins
    The American Journal of Cardiology 03/1986; 57(6):490-2. · 3.43 Impact Factor
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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.
    Pediatric Cardiology 02/1986; 7(4):203-4. · 1.55 Impact Factor
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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.
    The American Journal of Cardiology 10/1985; 56(8):536-9. · 3.43 Impact Factor
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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.
    The American Journal of Cardiology 03/1985; 55(5):526-9. · 3.43 Impact Factor
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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.
    The American Journal of Cardiology 08/1984; 54(1):161-5. · 3.43 Impact Factor
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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.
    Pediatrics 05/1984; 73(4):426-30. · 5.30 Impact Factor