Browse Health
Pediatrician, Pediatric Specialist, Cardiologist (heart)
29 years of experience
Accepting new patients


Education ?

Medical School
McGill University Faculty Of Medicine (1983)
Foreign school

Awards & Distinctions ?

1992, I.W.K. Staff Recognition Award
2010, Department of Pediatrics, Master Clinician Award
1992-95, Dedicated Service Award: Heart and Stroke Foundation, Canada
1981-83, J.W. McConnell Scholarship: Medicine, McGill
2006, Commencement Speaker: Pediatric Resident and Fellow Graduation, CHOP
1991, I.W.K. Resident Teaching Award: Runner-up
2004-11, Faculty Honor Roll: CHOP resident teaching award
1987, Claude Giroud Prize: Pediatric Research, McGill
1981-83, Faculty Scholar: Medicine, McGill
Castle Connolly America's Top Doctors® (2013 - 2015)
Patients' Choice Award (2010 - 2011, 2013)
Compassionate Doctor Recognition (2011, 2013)
American Board of Thoracic Surgery
Cardiothoracic Surgery Network
Pulmonary Hypertension Association
American Board of Pediatrics

Affiliations ?

Dr. Hanna is affiliated with 1 hospitals.

Hospital Affiliations

  • Rush University Medical Center
  • Publications & Research

    Dr. Hanna has contributed to 35 publications.
    Title Impact of Oral Sildenafil on Exercise Performance in Children and Young Adults After the Fontan Operation: a Randomized, Double-blind, Placebo-controlled, Crossover Trial.
    Date May 2011
    Journal Circulation

    Children and young adults with single-ventricle physiology have abnormal exercise capacity after the Fontan operation. A medication capable of decreasing pulmonary vascular resistance should allow improved cardiac filling and improved exercise capacity.

    Title Use of Angiographic Ct Imaging in the Cardiac Catheterization Laboratory for Congenital Heart Disease.
    Date February 2011
    Journal Jacc. Cardiovascular Imaging

    This study sought to retrospectively evaluate our initial experience using angiographic computed tomography (ACT) in a pediatric cardiac catheterization laboratory.

    Title Ventricular Assist Device-associated Anti-human Leukocyte Antigen Antibody Sensitization in Pediatric Patients Bridged to Heart Transplantation.
    Date June 2010
    Journal The Journal of Heart and Lung Transplantation : the Official Publication of the International Society for Heart Transplantation

    Ventricular assist devices (VAD) are associated with the formation of antibodies to anti-human leukocyte antigens (HLA) or sensitization. The incidence and effects of VAD-associated anti-HLA sensitization have not been well studied in the pediatric population.

    Title Clinical Practice. The Impact of Lung Disease on the Heart and Cardiac Disease on the Lungs.
    Date February 2010
    Journal European Journal of Pediatrics

    Pathologies in both the respiratory and cardiovascular systems frequently coexist and impact on each other. This manuscript introduces an approach to the interpretation of this complex relationship. Pulmonary hypertension can be a significant consequence of many respiratory diseases. This in turn can lead to right ventricular dysfunction and cor pulmonale. Many childhood illnesses can result in cor pulmonale and can be conveniently grouped into three categories: idiopathic pulmonary hypertension, neonatal lung diseases, and lung disease beyond the neonatal period. When considering the impact of cardiac disease on the lung, one must consider two main pathologies: compression of the pediatric airway and increased lung water. In conclusion, thorough attention must be given to the interpretation of the complex relationship between cardiac and respiratory diseases. Pulmonary hypertension is a complication to consider in respiratory illness at all ages. In addition, when dealing with the complexities of congenital heart disease, one must always be aware of the risks of pulmonary complications whether parenchymal or airway. Ongoing improvements in ventilation strategies, vasodilator therapy, and surgical interventions continue to improve the outlook for these complex cases.

    Title A Pediatric Case Study of Treprostinil Overdose.
    Date August 2009
    Journal The Journal of Heart and Lung Transplantation : the Official Publication of the International Society for Heart Transplantation

    This case study reports the effects of a treprostinil accidental overdose in a patient with pulmonary hypertension. Treprostinil is labeled for treatment of pulmonary hypertension with New York Heart Association (NYHA) Class II, III and IV symptoms. It is characterized as a long-acting prostacyclin analog that can be delivered by intravenous or subcutaneous continuous infusions. This pediatric case report describes a massive overdose without significant side effects, thus suggesting a beneficial therapeutic index in pediatric patients.

    Title How Possibly Are We to Choose Albumin or Hydroxyethyl Starch?
    Date May 2009
    Journal Critical Care Medicine
    Title Prevalence and Risk Factors for Tricuspid Valve Regurgitation After Pediatric Heart Transplantation.
    Date June 2008
    Journal The Journal of Heart and Lung Transplantation : the Official Publication of the International Society for Heart Transplantation

    BACKGROUND: Risk factors for tricuspid regurgitation (TR) after adult orthotopic heart transplantation (OHT) have been reported, although there are no pediatric data. METHODS: This study was a single-center retrospective analysis of patients <or= 18 years of age who underwent OHT from January 1990 to December 2004. The impact of TR was evaluated with respect to outcomes (graft failure, etc.). RESULTS: Echocardiograms were available for 99 patients (105 grafts with 6 re-transplants) at a median age of 4.5 years (range 18 days to 17.1 years): 51 (49%) were male; 46 (44%) were transplanted for congenital heart disease; and 76 (72%) had a biatrial anastomosis. Significant TR developed in 30 grafts (29.5%) within a median duration after OHT of 1.2 years (range 0 day to 8.2 years); persistent significant TR until last follow-up was present in 21 grafts (20%). Graft failure (death or need for retransplantation) occurred in 41 grafts (39%), including 14 of 21 grafts (67%) with significant TR. By Kaplan-Meier analysis, freedom from significant TR (95% confidence interval [CI]) at 1, 5 and 10 years was 91.0% (83.4% to 95.2%), 70.2% (55.4% to 80.9%) and 61.5% (39.2% to 77.6%), respectively. No risk factors were identified. Development of significant TR was highly associated with graft failure (p = 0.005). CONCLUSIONS: Significant TR occurs with comparable frequency in pediatric and adult OHT populations; risk factors identified in adults were not present in our pediatric population. Development of significant TR in pediatric heart transplant recipients is highly associated with graft failure.

    Title Too Fat or Too Thin? Body Habitus Assessment in Children Listed for Heart Transplant and Impact on Outcome.
    Date June 2008
    Journal The Journal of Heart and Lung Transplantation : the Official Publication of the International Society for Heart Transplantation

    BACKGROUND: Body habitus assessment (BHA), be it wasted or obese, is a useful marker of nutritional status and overall medical condition. Wasting and obesity pre-heart transplant adversely affects outcomes in adults. The utility of BHA as a prognostic factor in children post-transplant is unknown. METHODS: Weight and height at listing and standard growth charts were used to determine the ideal body weight (%IBW) and percentiles for body mass index for age (BMI%) and weight-for-length (W:L%). Wasting was defined as <90%IBW and/or <or=5th percentile for BMI% or W:L%. Obesity was defined as >120%IBW and/or >or=95th percentile BMI% or W:L%. Outcomes of cohorts based on these criteria were compared. RESULTS: From June 1990 to December 2006, 180 children, aged 5.81 +/- 6 years, were listed for transplant. Wasting occurred in 66 (37%) and obesity in 22 (12%) children, without differences between diagnoses of cardiomyopathy or congenital heart disease. %IBW was a prognostic factor for survival post-transplant on multivariate analysis: obese patients had a hazard ratio (HR) of 3.82 (95% confidence interval [CI] 1.81 to 8.06) compared with normal BHA (p < 0.001). Wasting had a survival advantage compared with normal BHA (HR 0.51, 95% CI 0.27 to 0.94, p = 0.032). There were no significant differences between cohorts in incidence of infections, first-year rejections or graft vasculopathy. CONCLUSIONS: Abnormal BHA at listing was a prognostic factor for survival post-transplant. Obese children had increased mortality, but wasting did not adversely affect post-transplant survival in our population. Body habitus assessment may risk-stratify children at listing, potentially providing a complex target for intervention.

    Title Where Do We Go from Here? Cardiac Output Determination in Pediatrics.
    Date April 2008
    Journal Critical Care Medicine
    Title Heart Rate Variability Following Neonatal Heart Surgery for Complex Congenital Heart Disease.
    Date October 2006
    Journal Pacing and Clinical Electrophysiology : Pace

    BACKGROUND: Altered cardiac autonomic control may play a role in the morbidity and mortality suffered by neonates who undergo surgery for complex congenital heart disease (CHD). The purpose of this study was to evaluate cardiac autonomic activity, as measured by spectral indices of heart rate variability (HRV), prior to and early after infant surgery for CHD and attempt to correlate HRV indices with clinical outcome. In addition, we assessed the hypothesis that single-ventricle physiology and surgical interruption of the great arteries negatively affects HRV. METHODS: Sixty neonates prospectively wore 24-hour Holter monitors at three time points: before and early after CHD surgery, and at 3- to 6-month follow-up. Standard spectral indices of HRV were measured. RESULTS: In the early postoperative time point, patients with single-ventricle physiology had lower low-frequency power (LF) compared to patients with two ventricles (P=0.040). Surgical interruption of the great arteries did not affect HRV in this cohort. For the entire cohort, LF (P=0.004) and high-frequency power (HF) (P<0.001) increased over the three time points, while LF/HF (P=0.119) did not significantly change. In the multivariable linear regression model, significant predictors of longer postoperative hospital stay included longer total support time (P=or<0.001), longer duration of inotrope support (P=0.012), elevated mean heart rate at postoperative time point (P=0.002), and lower LF/HF ratio at the postoperative time point (P=0.014). CONCLUSION: Patients with single-ventricle physiology have a significant physiologic reduction in LF in the early postoperative period compared to patients with two ventricles. Diminished cardiac autonomic control is associated with longer hospitalization following neonatal cardiac surgery.

    Title Left Atrial Decompression: Is There a Standard During Extracorporeal Support of the Failing Heart?
    Date October 2006
    Journal Critical Care Medicine
    Title Longitudinal Assessment of Cardiovascular Exercise Performance After Pediatric Heart Transplantation.
    Date July 2006
    Journal The Journal of Heart and Lung Transplantation : the Official Publication of the International Society for Heart Transplantation

    BACKGROUND: No existing longitudinal data document exercise performance after pediatric heart transplantation. We report the exercise performance findings from the longitudinal study of pediatric heart transplantation patients and the association of aerobic capacity with echocardiographic measures of graft function. METHODS: We performed a retrospective analysis of 28 children after heart transplantation who underwent 87 exercise tests and echocardiograms. Subjects exercised using graded cycle or treadmill protocols. Maximal oxygen consumption (VO2), physical working capacity, peak heart rate, and anaerobic threshold were evaluated. To measure systolic and diastolic function, shortening fraction and mitral valve pressure half-time (PHT) respectively, were obtained by echocardiography. RESULTS: The average age at transplantation was 10.9 +/- 5.6 years, at initial exercise test was 13.8 +/- 5.0 years, and at final exercise test was 15.8 +/- 5.2 years. Percent-predicted values at the initial exercise test were VO2, 59.3%; physical working capacity, 60.2%; and peak heart rate, 75.8%; these remained similarly decreased at the final exercise test. Shortening fraction and PHT were within normal limits, but PHT was significantly greater at final test (p < 0.05). The relationship of VO2% with time was statistically significant, described by a quadratic equation that included initial VO2% and time from heart transplantation. This relationship remained significant when the shortening fraction (p < .05) but not PHT was added as a covariate in the equation. CONCLUSIONS: Exercise performance after pediatric heart transplantation is impaired and, despite an initial improvement, declines over time. This can be explained by increasing diastolic dysfunction independent of donor graft age. If confirmed, these findings point the direction to further research aimed at limiting this aerobic capacity decline after heart transplantation.

    Title Risk Factors for Mortality in 137 Pediatric Cardiac Intensive Care Unit Patients Managed with Extracorporeal Membrane Oxygenation.
    Date May 2004
    Journal Critical Care Medicine

    OBJECTIVE: To identify factors associated with mortality in children with heart disease managed with extracorporeal membrane oxygenation (ECMO). DESIGN: Retrospective chart review. SETTING: Tertiary care university-affiliated children's hospital. PATIENTS: All pediatric cardiac intensive care unit patients managed with ECMO between January 1, 1995, and June 30, 2001. INTERVENTIONS: None. RESULTS: During the study period, 137 patients were managed with ECMO in the pediatric cardiac intensive care unit. Of the 137 patients, 80 (58%) survived > or =24 hrs after decannulation, and 53 (39%) survived to hospital discharge. Patients managed with ECMO following cardiac surgery were analyzed separately from patients not in the postoperative period. Factors associated with an increased probability of mortality in the postoperative patients were age <1 month, male gender, longer duration of mechanical ventilation before ECMO, and development of renal or hepatic dysfunction while on ECMO. Single ventricle physiology and failure to separate from cardiopulmonary bypass were not associated with an increased risk of mortality. Cardiac physiology and indication for ECMO were not associated with mortality rate. Although longer duration of ECMO was not associated with increased mortality risk, patients with longer duration of ECMO were less likely to survive without heart transplantation. CONCLUSIONS: In a series of 137 patients managed with ECMO in a pediatric cardiac intensive care unit, survival to hospital discharge was 39%. In postoperative patients only, mortality risk was increased in males, patients <1 month old, patients with a longer duration of mechanical ventilation before initiation of ECMO, and patients who developed renal or hepatic failure while on ECMO.

    Title Heart Rate Variability in Preterm Brain-injured and Very-low-birth-weight Infants.
    Date June 2000
    Journal Biology of the Neonate

    Heart rate variability (HRV) reflects the complex interplay of the sympathetic and parasympathetic innervation of the heart. Developmental maturation of the fetus and newborn results in predictable alterations in the neural cardiac control of heart rate. Furthermore, patterns of HRV are closely correlated to clinical outcome in several pathologic situations. The first aim of this study was to characterize the maturational patterns of HRV in a group of developmentally at-risk newborns (those with severe hemorrhagic or ischemic brain injury and extremely immature, low-birth-weight infants). Secondly, we sought to determine whether a correlation exists between HRV and length of hospital stay, diagnosis of cerebral palsy, and neurodevelopmental test scores at 1-year corrected age. Time domain indices of HRV were computed longitudinally from 32 to 37 weeks of corrected gestational age in 19 very low birth weight, preterm infants. Among the 19 infants studied, 7 infants had no evidence of brain injury, 7 infants had periventricular leukomalacia (PVL), 3 infants had grade III/IV intraventricular hemorrhage (IVH), and 2 infants had both IVH and PVL. Neurologic injuries were documented using ultrasound and neurodevelopmental progress was followed through 1 year of corrected gestational age. A multivariate repeated measures analysis was performed to determine the relationship between the type of perinatal brain injury and neurodevelopmental status at 1 year of corrected gestational age. The type of perinatal brain injury was highly correlated to specific patterns of HRV with multivariate regression models producing adjusted r(2) values ranging from 0.63 to 0.99. The type of perinatal brain injury was highly correlated to the developmental outcome measures (p < 0.0000) with PVL patients having the lowest neurodevelopmental scores, IVH patients having the highest scores, and noninjured infants having midrange, grossly normal values. Using ANOVA, HRV was correlated to outcome, but individual comparisons revealed statistical significance only for the noninjured group (p < 0.04). However, multivariate models, which characterized outcome within each brain injury group, were highly significant (adjusted r (2) ranged from 0.23 to 0.89). In summary, the type of perinatal brain injury determined the pattern of HRV and HRV was highly correlated to length of hospital stay and neurodevelopmental function assessed at 1 year of corrected gestational age.

    Title Cardiac Rhythm Disturbances Among Children with Idiopathic Congenital Central Hypoventilation Syndrome.
    Date June 2000
    Journal Pediatric Pulmonology

    The objective of this study was to determine whether subjects with congenital central hypoventilation syndrome (CCHS) had an increased frequency of cardiac arrhythmias and decreased heart rate variability when compared to subjects without a known deficit in control of breathing, and that these abnormalities would be exaggerated by anesthesia. Continuous ambulatory Holter recordings were obtained in patients with CCHS and compared to two otherwise healthy control groups without a deficit in control of breathing: one with an intact airway (n = 11) and a second group with a tracheostomy (n = 6). Holter recordings were obtained before, during (under general anesthesia), and after bronchoscopy. Fourteen children with CCHS (age: 9.3 +/- 4.4 years mean +/- S.D.) were studied, and 7 underwent bronchoscopy. Seventeen control children were studied (age 6.6 +/- 3.6 years): 11 without a tracheostomy, and 6 with a tracheostomy who also underwent bronchoscopy. Maximum heart rate during baseline recording was significantly lower in the CCHS subjects as compared to controls (P = 0.0001). At baseline the difference in the number of arrhythmias/24 hr/subject in all CCHS vs. all control subjects was significant (P = 0.0002); for the subjects who had bronchoscopy, CCHS vs. control, the difference was also significant (P = 0.03). In addition, there was a significant decrease in the number of events/24 hr/subject among the CCHS subjects between baseline and post-bronchoscopy (P = 0.0288). The predominant arrhythmias were sinus bradycardia and transient asystole. The longest asystole in a CCHS subject was 6.50 sec, and in a control subject, 1.42 sec (at baseline the means of the longest asystole were 2.69 +/- 1.4 vs. 1.24 +/- 0.13; P = 0.003 in the CCHS vs. control groups). Other indices of heart rate variability were significantly reduced in the CCHS subjects (P < 0.05). These results substantiate our hypothesis that subjects with CCHS have more arrhythmias than controls, an increased frequency of bradyarrhythmias, and decreased cyclical sinus arrhythmia.

    Title Oops-the Balloon Burst Before the Stent Was Deployed!
    Date February 1998
    Journal Pediatric Cardiology
    Title Ventricular Dysfunction in the Pediatric Population: Evaluation and Intervention.
    Date September 1997
    Journal The Journal of Heart and Lung Transplantation : the Official Publication of the International Society for Heart Transplantation
    Title Transvenous Closure of Patent Ductus Arteriosus in a Sick 2780g Infant.
    Date June 1996
    Journal The Canadian Journal of Cardiology

    A three-and-a-half-month-old 2780 g critically ill infant had successful transvenous coil occlusion of a ductus arteriosus. At six-and-a-half months of age the infant died, and autopsy showed coverage of the coil on the aortic aspect and no lumenal narrowing. It was concluded that transvenous coil occlusion of the patent ductus arteriosus in small infants is possible and that th venous route is preferred to be arterial route.

    Title Will a Critical Level of Hyperventilation-induced Hypocapnia Always Induce an Absence Seizure?
    Date June 1996
    Journal Epilepsia

    We wished to determine if the degree of hypocapnia correlates with increased frequency of absence seizures and if there is a critical pCO2 at which absence seizures are reliably provoked. Twelve untreated children with newly diagnosed absence epilepsy were continuously monitored by EEG and end-expiratory CO2 recording during quiet respiration and hyperventilation (to absence seizure or exhaustion) while breathing four gas mixtures: (a) room air, (b) 100% O2, (c) 4% CO2 in room air, or (d) 4% CO2 + 96% O2).In quiet respiration, a reduction in number of spike and wave bursts and total seconds of spike and wave was noted in children breathing supplemental CO2 (gases c and d vs. gases a and b), p < 0.05. Supplemental O2 had no effect. Eight subjects had absence seizures elicited with each trial of hyperventilation. All subjects had their own critical pCO2, ranging from 19 to 28 mmHg. Three children had no seizures, two despite hypocapnia to pCO2 of 19 and 21 and 1 who achieved a pCO2 of only 25. In 1, absence seizures were provoked in only six of nine hyperventilation trials to pCO2 of 17-23. In 67% of subjects, absence seizures were reliably provoked by hypocapnia. Critical pCO2 varied among children with absence. Determination of whether variation in sensitivity to hypocapnia may be helpful in determining response to antiepileptic drugs (AEDs) or remission of seizures will require further study.

    Title Technology Assessment of Nonsurgical Closure of Patent Ductus Arteriosus: an Evaluation of the Clinical Effectiveness and Costs of a New Medical Device.
    Date November 1995
    Journal Pediatrics

    OBJECTIVE. To assess the clinical efficacy and cost impact of a new medical device for the nonsurgical closure of patent ductus arteriosus (PDA). METHODS. This was a before-after study comparing the most recent 20 surgical procedures with the first 20 nonsurgical procedures for PDA using a new medical device. Clinical outcome, hospital stay, device cost, and physician fees were compared. RESULTS. Surgical closure was effective in all 20 patients, with an average cost of $4667. In a similar patient group, nonsurgical closure was achieved in 18 of 20 patients (90%), with an estimated average cost per successful procedure of $4690. A clinically insignificant PDA leak persisted beyond 12 months in four nonsurgically managed patients. CONCLUSION. Nonsurgical closure of PDA can be recommended as an effective new medical technique that is not associated with a measurable increase in direct costs and that provides significant indirect and intangible cost advantages.

    Title Capacity of Intrinsic Cardiac Neurons to Modify the Acutely Autotransplanted Mammalian Heart.
    Date January 1995
    Journal The Journal of Heart and Lung Transplantation : the Official Publication of the International Society for Heart Transplantation

    The capacity of the intrinsic cardiac nervous system to modify the acutely autotransplanted heart was investigated in eight anesthetized open-chest canine preparations in which the adrenal glands had been removed from the circulation. Cardiac effects elicited by isoproterenol and nicotine were also examined before and after heart-lung transplantation. Cardiac augmentation induced by isoproterenol was similar before and immediately after cardiopulmonary transplantation, indicating that the surgery did not obtund cardiac myocyte function significantly. The initial bradycardia induced by nicotine was greater before transplantation. The subsequent augmentation in left atrial systolic pressure, as well as right and left ventricular intramyocardial systolic pressures, induced by nicotine were similar before and after transplantation. When nicotine was administered to transplanted preparations after atropine administration, cardiac augmentation was induced. Cardiac augmentation was not induced by nicotine after subsequent beta-adrenergic blockade. These data indicate that nicotine-sensitive adrenergic neurons which accompany the transplanted heart are capable of inducing considerable cardiac augmentation. Power spectral analysis of heart rate and left ventricular chamber rate of pressure rise variability indicated an almost complete lack of power in these indexes after, as opposed to before, transplantation. Together with intrinsic cardiac cholinergic neurons, intrinsic cardiac adrenergic neurons may be responsible for physiologically and pharmacologically induced alterations in cardiac variables that occur in acutely transplanted hearts.

    Title Barotrauma During Anesthesia for Cardiac Catheterization.
    Date November 1994
    Journal Anesthesiology
    Title Ambulatory Monitoring of the Sudden Death of an Adolescent with Hypertrophic Cardiomyopathy.
    Date July 1994
    Journal The Canadian Journal of Cardiology

    Sudden death is an important cause of mortality in hypertrophic cardiomyopathy. Several mechanisms have been proposed, but ambulatory monitoring of the event has rarely occurred. The case of an adolescent girl with congenital hypertrophic cardiomyopathy and arthrogryposis multiplex congenita is presented. Despite appropriate therapy and severe activity limitation, the patient's condition progressively worsened. The patient died suddenly in her sleep, one month after a myocardial myomectomy for subaortic stenosis. The fortuitous ambulatory electrocardiographic (ECG) monitoring of the event recorded polymorphic ventricular tachycardia degrading into ventricular fibrillation. Retrospective review of previous ambulatory ECG revealed the presence of nonsustained ventricular tachycardia, a predictive determinant for sudden death, and atrioventricular node dysfunction. However, the patient had never reported symptoms during the dysrhythmias. The pathological specimen showed an unexpected old apical infarction scar, suggesting that her preoperative cardiac status was worse than suspected. In summary, the mechanism of sudden death in this patient was revealed by ambulatory ECG monitoring, and the involvement of neural and myocardial factors are proposed.

    Title Functional Capacity of Nicotine-sensitive Canine Intrinsic Cardiac Neurons to Modify the Heart.
    Date June 1994
    Journal The American Journal of Physiology

    The capacity of intrinsic cardiac efferent parasympathetic and sympathetic neurons to modify the heart was investigated in nine anesthetized open-chest dogs with adrenal glands removed from the circulation. The effects elicited by intravenously administered isoproterenol, tyramine, and nicotine on cardiac variables were examined before and after acute decentralization of the heart. Major vessels, as well as other tissues at the base of the heart, were denuded by means of an ultrasonic aspirator that removed neural elements without damaging muscles or blood vessels. The efficacy of the acute decentralization was assured by testing cardiac responses elicited by right and left stellate ganglia and cervical vagosympathetic complex stimulations after surgery. Heart rate, atrial force, and both right and left ventricular intramyocardial systolic pressures were augmented similarly by isoproterenol and tyramine before and after acute decentralization, indicating that the surgery necessary to decentralize the heart did not obtund cardiac myocyte function. Power spectral analysis of heart rate and left ventricular chamber pressure rate of change indicated an almost complete lack of variability of these indexes after, but not before, acute decentralization. Despite these changes, similar cardiac augmentation was elicited by nicotine before and after acute decentralization. Cardiac augmentation was elicited by nicotine in acutely decentralized preparations after atropine administration but not after beta-adrenergic blockade. These data indicate that the canine intrinsic cardiac nervous system contains a significant population of nicotine-sensitive adrenergic neurons that modulate the heart. Furthermore, the intrinsic cardiac nervous system does not appear to be primarily responsible for the heart rate and ventricular pressure variability found in intact hearts.

    Title Postnatal Maturation of Baroreflex Heart Rate Control in Neonatal Swine.
    Date May 1994
    Journal The Canadian Journal of Cardiology

    OBJECTIVE: Despite extensive knowledge about basic baroreceptor function, there continues to be controversy as to whether there is postnatal maturation of the cardiovascular baroreflex. DESIGN/ANIMALS: Acutely studied postnatal developmental changes in baroreflex sensitivity with a neonatal porcine model in 28 chloralose-anesthetized piglets from birth to six weeks of age. INTERVENTIONS: Steady-state heart rate versus blood pressure response curves were generated by altering blood pressure with increasing doses of phenylephrine or nitroprusside. Data were fitted to the Hill equation for sigmoidal curves, and the maximum heart rate, maximum slope (sensitivity) and blood pressure at 50% maximal heart rate (P50) were calculated. MAIN RESULTS: Baroreflex sensitivity was found to increase from birth to six weeks of age (P < 0.0001), with the most rapid changes occurring after two weeks of age. Increasing age was accompanied by shift of the baroresponse curve to an increased range of heart rate changes at higher blood pressures. Maximal heart rates did not differ with advancing postnatal age. CONCLUSIONS: Swine baroreflex sensitivity increases from birth to six weeks of age, with higher blood pressures causing greater bradycardia in older piglets. These findings are consistent with postnatal maturation of the cardiovascular autonomic nervous system.

    Title Massive Pericardial Effusion As a Cause for Sudden Deterioration of a Very Low Birthweight Infant.
    Date January 1994
    Journal American Journal of Perinatology

    We describe the successful resuscitation of a very low birthweight infant after sudden deterioration caused by a massive pericardial effusion. The neonatal course of this 740 gm, 26-week gestational age infant had been complicated by moderate respiratory distress syndrome, apnea, and bronchopulmonary dysplasia. A Silastic catheter was placed percutaneously in the right axillary vein on day 6 of life and documented to be in the superior vena cava prior to continuous parenteral nutrition. On day 38, her cardiorespiratory status abruptly deteriorated, blood return could not be obtained from the central line, and it was removed. Chest radiograph and subsequent echocardiogram confirmed a massive pericardial effusion. Under echocardiographic guidance, an emergency percutaneous pericardiocentesis allowed aspiration of 23 ml of straw-colored fluid. Her vital signs immediately returned to normal and reaccumulation of the effusion did not occur. Despite the high mortality of premature infants from pericardial effusion as a complication of central venous catheterization, early diagnosis and prompt therapy can assure a good outcome. As a cause of sudden deterioration of very low birthweight infants, tamponade must not be forgotten, since it is now a rapidly treatable complication of central venous cannulation.

    Title Effects of Transient Coronary Artery Occlusion on Canine Intrinsic Cardiac Neuronal Activity.
    Date May 1993
    Journal Integrative Physiological and Behavioral Science : the Official Journal of the Pavlovian Society

    In order to further elucidate the regulatory function of canine epicardial neurons, the effects of transient coronary artery occlusion on their spontaneous activity was studied. Fifty-eight individual, spontaneously active units were identified by means of their action potential configurations in specific loci of atrial and ventricular epicardial fat of 10 anesthetized dogs. The activity of 49 of the units was modified by one minute of coronary artery occlusion. Twenty-four of the 49 responding units exhibited increased activity and 37 decreased activity during coronary artery occlusions. Activity changes were sometimes, but not always, associated with decreased left ventricular intramyocardial systolic pressure. During reperfusion, the activity of 6 units was increased compared to control levels, even though ventricular pressures remained the same. Following acute decentralization, 48% of previously active units generated spontaneous activity; the activity of 89% of these was altered during coronary artery occlusion despite the fact that overall cardiodynamics were unchanged. Following hexamethonium administration, the activity generated by 9 of 10 spontaneously active units was modified by coronary artery occlusion. It is concluded that transient coronary artery occlusion can modify the activity generated by intrinsic cardiac neurons, such modification involving central and peripheral neuronal interactions.

    Title Tranexamic Acid in the Treatment of Kasabach-merritt Syndrome in Infants.
    Date August 1989
    Journal The American Journal of Pediatric Hematology/oncology

    Kasabach-Merritt syndrome (thrombocytopenia, consumption coagulopathy, and, occasionally, microangiopathic hemolysis) is an infrequent but often lethal complication of giant capillary hemangiomas in the infant. We report the clinical course of an infant who came to us with this syndrome shortly after birth. She was successfully treated with transfusions of blood products, high-dose oral prednisone, and a fibrinolytic inhibitor, tranexamic acid. No complications of the treatment occurred. The hematological abnormalities resolved completely by 2 years of age. Although prednisone may have been necessary for stabilization and involution of the hemangioma, the addition of tranexamic acid allowed earlier tapering of the steroid therapy and fewer transfusions. Tranexamic acid was extremely well tolerated in this newborn.

    Title Role of Carotid and Central Chemoreceptors in the Co2 Response of Sympathetic Preganglionic Neurons.
    Date November 1981
    Journal Journal of the Autonomic Nervous System

    In anesthetized, vagotomized, paralyzed, artificially ventilated cats with aortic nerves cut, we recorded the response of 28 sympathetic preganglionic neurons (SPNs) of the cervical sympathetic trunk of changes in arterial pCO2. We observed the effects on these responses of: (i) surgical denervation of carotid sinus chemoreceptors in normoxia (paO2 110 mm Hg); and (ii) hyperoxia (paO2 greater than 350 mm Hg) which is known to depress peripheral chemoreceptor sensitivity to CO2. Stimulus-response curves, obtained by rebreathing at constant paO2, were used to detect the effects of these manoeuvres. The present experiments have confirmed previous observations demonstrating the CO2-sensitivity of this neuron population. The population average firing rate, as a function of paCO2, describes a sigmoid curve, increasing continuously between 20 and 90 mm Hg and asymptotically approaching plateaus at the highest and lowest paCO2 values. Carotid sinus nerve section caused a decrease of the average response of the population at all paCO2 values, resulting in a displacement to the right of the response curve, in a decrease in slope and maximum values. On the assumption that the CO2 response curve after carotid sinus nerve section is due to central chemoreceptor input, and that there is a simple addition between the effects of central and carotid chemoreceptors, the difference between CO2 response curves ("difference curves") before and after denervation represents the contribution of the carotid chemoreceptors. A comparison of this "difference curve" with the curve obtained after denervation reveals that the contribution of the carotid chemoreceptors is of the same magnitude as that of the central chemoreceptors up to a paCO2 value of 60-70 mm Hg. Beyond this value, the carotid contribution declines and becomes a smaller component of the total response, whereas the contribution of the central chemoreceptors continues to increase. Similar results were obtained with rebreathing in hyperoxia, after correction for the central excitatory effect of hyperoxia. Hyperoxia never caused a depression of the CO2 response of units after section of the carotid sinus nerve. Observation of the effects of the two manoeuvres on individual SPNs leads to the conclusion that in approximately half of the CO2-sensitive units there is an overlap of central and peripheral chemoreceptor input. The remainder of the CO2-sensitive units receive input only from the central chemoreceptors.

    Title Cardiovascular Control by Medullary Surface Chemoreceptors.
    Date October 1981
    Journal Journal of the Autonomic Nervous System

    The cardiovascular and respiratory effects of superfusion of the ventral surface of the medulla with acid hypercapnic or alkaline hypocapnic solutions have been studied in anaesthetized, paralyzed, artificially ventilated cats. Peripheral chemoreceptor and baroreceptor denervation was achieved by section of carotid sinus, aortic and cervical vagus nerves. Systemic arterial and central venous pressure, hindquarters blood flow, heart rate and phrenic nerve activity were recorded. Acid hypercapnic (pH 6.8, pCO2 85 mm Hg) superfusion caused increases in systemic arterial pressure, phrenic nerve activity and heart rate, and a decrease in hindquarters blood flow. Alkaline hypocapnic (pH u.i, pCO2 less than 10 mmHg) superfusion caused opposite effects. These experiments indicate a significant role of the chemoreceptors of the ventral surface of the medulla in cardiovascular control.

    Title The Effect of Cold Blockade of the Medullary Chemoreceptors on the Co2 Modulation of Vascular Tone and Heart Rate.
    Date October 1979
    Journal Canadian Journal of Physiology and Pharmacology
    Title Evaluation of a Screen Oxygenator Suitable for Small Animal Organ Perfusion.
    Date September 1979
    Journal The American Journal of Physiology

    A small vertical screen oxygenator was built using a stainless steel screen enclosed in a Plexiglas box as the oxygenating surface. The unit was primed with 35 ml dextran-diluted blood (Hct 25.1 +/- 0.6%. mean +/- SE) and tested in cats with a partial cardiopulmonary bypass circuit. An oxygen saturation of more than 95% was always obtained, even when the incoming venous saturation was as low as 15%. The O2 exchange capacity was minimally affected by changes in blood flow (1.5 to 70 ml/min) through the unit. CO2 extraction was not flow limited over the range tested. Output PCO2 was 33.3 +/- 0.6 mmHg and pH was 7.29 +/- 0.02. These results were obtained when 3% CO2 in O2 was passed through the oxygenator chamber at 1.0 to 5.0 l/min. The performance of the unit was stable for periods up to 4 h. The small priming volume and reliable performance make this oxygenator suitable for organ perfusion in small experimental animals.

    Title Co2-dependent Component of the Neurogenic Vascular Tone in the Cat.
    Date August 1978
    Journal Pflügers Archiv : European Journal of Physiology

    Complete vascular isolation of the hindlimbs was performed in vagotomized cats under Sodium Pentobarbital anesthesia. The hindlimbs were perfused at constant flow with blood kept at a constant and physiological PO2, PCO2, and pH values by means of a specially designed pump-oxygenator system. The animals were hyperventilated with different CO2 mixtures (0%, 5%, 7% and 10% in O2) thereby changing blood gases and pH levels in the upper body but not in the hindlimb vascular bed. At body PaCO2 (mm Hg) of 13.7 +/- 1.0 (means +/- SE), 30.6 +/- 1.05, 40,4 +/- 0,9 and 58.4 +/- 2.9 the hindlimb perfusion pressure (mm Hg) was, respectively 124 +/- 7.6, 138 +/- 7.4, 156 +/- 11.9 and 187 +/- 15.1. These changes in perfusion pressure were still present after complete peripheral chemoreceptor denervation but were abolished after section of the spinal cord at the T5 level. Since hindlimb perfusion pressure fell when body PaCO2 was lowered below physiological levels it is concluded that part of the neurogenic vascular tone of the hindlimbs is maintained by a CO2 mediated stimulation of supraspinal structures.

    Title Nerve Entrapment at the Elbow in Rheumatoid Arthritis.
    Date February 1976
    Journal Rheumatology and Rehabilitation

    Although there was some delay in the posterior interosseous branch of the radial nerve conduction time in six of the 152 rheumatoid elbows, in no case were there clinical signs attributable to entrapment of this nerve. Some delay in ulnar nerve conduction was recorded in 27 of the 152 elbows; this was marked in 12. These patients tended to be older and to have more severe disease of the elbow.

    Title Contemporary Management of Congenital Malformations of the Heart in Infants with Ellis - Van Creveld Syndrome: a Report of Nine Cases.
    Journal Cardiology in the Young

    IntroductionEllis - van Creveld syndrome is an autosomal recessive disorder manifest by short-limb dwarfism, thoracic dystrophy, postaxial polydactyly, dysplastic nails and teeth, and an approximately 60% incidence of congenital malformations of the heart. Despite patients with Ellis - van Creveld syndrome being regarded as having a high surgical risk, few data are available regarding their outcomes following surgery for congenital malformations of the heart in the current era.Materials and methodsIn this retrospective report, we summarise the clinical observations and outcomes of nine infants with Ellis - van Creveld syndrome who underwent surgery for congenital malformations of the heart between 2004 and 2009. RESULTS: We identified 15 patients with Ellis - van Creveld syndrome during the study period; 11 (73%) had haemodynamically significant congenital malformations of the heart warranting surgery. In two of these patients, surgery was not performed. Of the nine patients who underwent surgery, all of whom were infants, eight (89%) had various forms of an atrioventricular septal defect and one patient (11%) had hypoplastic left heart syndrome (mitral and aortic atresia). Among the nine patients who underwent surgery, four (44%) died at a median of 102 days with a range of 25-149 days post-operatively, mostly from respiratory failure. Respiratory morbidity was seen in all surviving patients, of whom three underwent tracheostomy. CONCLUSIONS: Surgery for congenital malformations of the heart can be successful in infants with Ellis - van Creveld syndrome, but mortality is high and post-operative respiratory morbidity should be expected.

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