Home  About us  Contact
 

Single Ventricle (single + ventricle)

Distribution by Scientific Domains
Medical Sciences100%

Terms modified by Single Ventricle

  • single ventricle physiology
    		•

    Selected Abstracts

    Acute Adaptation to Volume Unloading of the Functional Single Ventricle in Children Undergoing Bidirectional Glenn Anastomosis

    CONGENITAL HEART DISEASE, Issue 2 2009
    Catherine Ikemba MD
    ABSTRACT Objective., Volume unloading of the functional single ventricle after a bidirectional Glenn anastomosis (BDG) prior to 1 year of age leads to improved global ventricular function as measured by the myocardial performance index (MPI), a Doppler-derived measurement of combined systolic and diastolic ventricular function. Systolic function remains unchanged after BDG according to previous studies; however, acute changes in global and diastolic function have not been previously investigated in this cohort. Our objective was to assess the short-term effects of the BDG on global ventricular function in patients with a functional single ventricle. Design., Echocardiograms to obtain MPI, isovolumic contraction time, and isovolumic relaxation time were performed at four time periods: in the operating room, in the operating room prior to BDG, shortly after separation from cardiopulmonary bypass, less than 24 hours postoperatively, and either prior to hospital discharge or at the first clinic follow-up visit. Results., Twenty-six patients were enrolled. There was significant ventricular dysfunction noted shortly after separation from cardiopulmonary bypass, median MPI 0.63 (0.39,0.81), that persisted in the short term postoperatively median MPI 0.50 (0.40,0.63). Isovolumic contraction time did not change, however, isovolumic relaxation time was significantly prolonged following BDG. Conclusion., In the postoperative patient after BDG, systolic function is preserved; however, there is evidence of diastolic and global ventricular dysfunction, at least in the short term. [source]

    Fontan Operation and the Single Ventricle

    CONGENITAL HEART DISEASE, Issue 1 2007
    Jamil A. AboulHosn MD
    ABSTRACT The Fontan operation has gone through multiple incarnations since Fontan and Baudet's initial description in 1971. Through the medical dossier of a patient with a single ventricle, we plot the history of medical, surgical, and percutaneous interventions over the past 40 years, specifically focusing on the Fontan procedure, its development, indications, sequelae, and complications. Cardiac computed tomography with angiography is highlighted as a noninvasive imaging tool for the evaluation of the complex Fontan circulation. [source]

    The Spectrum of Long-term Electrophysiologic Abnormalities in Patients with Univentricular Hearts

    CONGENITAL HEART DISEASE, Issue 5 2009
    Kathryn K. Collins MD
    ABSTRACT Patients with univentricular hearts experience a wide range of electrophysiolgic abnormalities which tend to develop years after cardiovascular surgical interventions. Intra-atrial reentrant tachycardia (atrial flutter) in the Fontan population is the most common arrhythmia and, as such, has the largest body of literature addressing its cause and treatment. However, sinus node dysfunction, other atrial arrhythmias, ventricular arrhythmias, and cardiac dysynchrony also occur in this patient population. The purpose of this article is to review the prevalence, mechanisms, and treatment of these electrophysiologic abnormalities within the single ventricle and Fontan patient. [source]

    Acute Adaptation to Volume Unloading of the Functional Single Ventricle in Children Undergoing Bidirectional Glenn Anastomosis

    CONGENITAL HEART DISEASE, Issue 2 2009
    Catherine Ikemba MD
    ABSTRACT Objective., Volume unloading of the functional single ventricle after a bidirectional Glenn anastomosis (BDG) prior to 1 year of age leads to improved global ventricular function as measured by the myocardial performance index (MPI), a Doppler-derived measurement of combined systolic and diastolic ventricular function. Systolic function remains unchanged after BDG according to previous studies; however, acute changes in global and diastolic function have not been previously investigated in this cohort. Our objective was to assess the short-term effects of the BDG on global ventricular function in patients with a functional single ventricle. Design., Echocardiograms to obtain MPI, isovolumic contraction time, and isovolumic relaxation time were performed at four time periods: in the operating room, in the operating room prior to BDG, shortly after separation from cardiopulmonary bypass, less than 24 hours postoperatively, and either prior to hospital discharge or at the first clinic follow-up visit. Results., Twenty-six patients were enrolled. There was significant ventricular dysfunction noted shortly after separation from cardiopulmonary bypass, median MPI 0.63 (0.39,0.81), that persisted in the short term postoperatively median MPI 0.50 (0.40,0.63). Isovolumic contraction time did not change, however, isovolumic relaxation time was significantly prolonged following BDG. Conclusion., In the postoperative patient after BDG, systolic function is preserved; however, there is evidence of diastolic and global ventricular dysfunction, at least in the short term. [source]

    Protein-Losing Enteropathy after Fontan Operation

    CONGENITAL HEART DISEASE, Issue 5 2007
    Jack Rychik MD
    ABSTRACT Protein-losing enteropathy (PLE) is a poorly understood and enigmatic disease process affecting patients with single ventricle after Fontan operation. In those afflicted, PLE after Fontan operation results in significant morbidity and mortality. The pathophysiology of the disease is unknown; however, a proposed mechanism incorporates a combination of phenomena including: (1) altered hemodynamics, specifically low cardiac output; (2) increased mesenteric vascular resistance; (3) systemic inflammation; and (4) altered enterocyte basal membrane glycosaminoglycan make-up. A paradigm for the clinical management of PLE after Fontan operation is proposed. [source]

    Fontan Operation and the Single Ventricle

    CONGENITAL HEART DISEASE, Issue 1 2007
    Jamil A. AboulHosn MD
    ABSTRACT The Fontan operation has gone through multiple incarnations since Fontan and Baudet's initial description in 1971. Through the medical dossier of a patient with a single ventricle, we plot the history of medical, surgical, and percutaneous interventions over the past 40 years, specifically focusing on the Fontan procedure, its development, indications, sequelae, and complications. Cardiac computed tomography with angiography is highlighted as a noninvasive imaging tool for the evaluation of the complex Fontan circulation. [source]

    Low Energy Biphasic Waveform Cardioversion of Atrial Arrhythmias in Pediatric Patients and Young Adults

    PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 12 2006
    LEONARDO LIBERMAN M.D.
    Background: Low-dose biphasic waveform cardioversion has been used for the termination of atrial arrhythmias in adult patients. The energy required for termination of atrial arrhythmias in pediatric patients is not known. The objective of this study is to determine the minimum energy required for successful external cardioversion of atrial arrhythmias in pediatric patients using biphasic waveform current. Methods: Prospective study of all patients less than 24 years of age with and without congenital heart disease undergoing synchronized cardioversion for atrial arrhythmias. Patients were assigned to receive an initial biphasic energy shock of 0.2,0.5 J/kg and if unsuccessful in terminating the arrhythmia, subsequent sequential shocks of 1 and 2 J/kg would be administered until cardioversion was achieved. The end point of the cardioversion protocol was successful cardioversion or delivery of three shocks. Results: Between June 2005 and June 2006, 16 patients underwent biphasic cardioversion for atrial flutter or fibrillation. The mean age was 14.7 ± 6.4 years (range: 2 weeks to 24 years). The mean weight was 51 ± 21 kg (range: 3.8,82 kg). Seven patients had normal cardiac anatomy, three had a single ventricle (Fontan), two had a Senning operation; the remaining four patients had varied forms of congenital heart disease. The median length of time that the patients were in tachycardia was 12 hours (range: 5 minutes to 2 months). Using either transthoracic echocardiography (TTE) or transesophageal echocardiography (TEE), no thrombi were identified in any patient. All patients were successfully cardioverted with biphasic waveform energy. The successful energy shock was 0.35 ± 0.19 J/kg (range: 0.2,0.9 J/kg). All but one patient were successfully cardioverted with less than 0.5 J/kg. The transthoracic impedance range was between 41 and 144 ,; one patient had an impedance of 506 , (2-week-old infant with a weight of 3.8 kg). The mean current delivered was 5.4 ± 2.2 A (range: 1,11 A). Conclusion: Low-dose energy using biphasic waveform shocks can be used for successful termination of atrial arrhythmias in pediatric patients with and without congenital heart disease. [source]

    A noninvasive estimation of mixed venous oxygen saturation using near-infrared spectroscopy by cerebral oximetry in pediatric cardiac surgery patients

    PEDIATRIC ANESTHESIA, Issue 6 2005
    TIA A. TORTORIELLO MD FAAP
    Summary Background :,Near-infrared spectroscopy (NIRS) is a noninvasive optical monitor of regional cerebral oxygen saturation (rSO2). The aim of this study was to validate the use of NIRS by cerebral oximetry in estimating invasively measured mixed venous oxygen saturation (SvO2) in pediatric postoperative cardiac surgery patients. Methods :,Twenty patients were enrolled following cardiac surgery with intraoperative placement of a pulmonary artery (PA) or superior vena cava (SVC) catheter. Five patients underwent complete biventricular repair , complete atrioventricular canal (n = 3) and other (n = 2). Fifteen patients with functional single ventricle underwent palliative procedures , bidirectional Glenn (n = 11) and Fontan (n = 4). Cerebral rSO2 was monitored via NIRS (INVOS 5100) during cardiac surgery and 6 h postoperatively. SvO2 was measured from blood samples obtained via an indwelling PA or SVC catheter and simultaneously correlated with rSO2 by NIRS at five time periods: in the operating room after weaning from cardiopulmonary bypass, after sternal closure, and in the CICU at 2, 4, and 6 h after admission. Results :,Each patient had five measurements (total = 100 comparisons). SvO2 obtained via an indwelling PA or SVC catheter for all patients correlated with rSO2 obtained via NIRS: Pearson's correlation coefficient of 0.67 (P < 0.0001) and linear regression of r2 = 0.45 (P < 0.0001). Separate linear regression of the complete biventricular repairs demonstrated an r = 0.71, r2 = 0.50 (P < 0.0001). Bland,Altman analysis showed a bias of +3.3% with a precision of 16.6% for rSO2 as a predictor of SvO2 for all patients. Cerebral rSO2 was a more accurate predictor of SvO2 in the biventricular repair patients (bias ,0.3, precision 11.8%), compared with the bidirectional Glenn and Fontan patients. Conclusions :,Regional cerebral oximetry via NIRS correlates with SvO2 obtained via invasive monitoring. However, the wide limits of agreement suggest that it may not be possible to predict absolute values of SvO2 for any given patient based solely on the noninvasive measurement of rSO2. Near-infrared spectroscopy, using the INVOS 5100 cerebral oximeter, could potentially be used to indicate trends in SVO2, but more studies needs to be performed under varying clinical conditions. [source]

    Combining low inspired oxygen and carbon dioxide during mechanical ventilation for the Norwood procedure

    PEDIATRIC ANESTHESIA, Issue 1 2003
    Ilan Keidan MD
    Summary Background: Staged reconstruction has become the preferred approach for treating neonates with hypoplastic left heart syndrome (HLHS). The haemodynamic instability of a single ventricle providing blood flow in parallel to the systemic and the pulmonary circulation, combined with the effects of cardiopulmonary bypass (CPB), results in precarious perioperative conditions. The two ventilatory manoeuvres commonly used for increasing pulmonary vascular resistance are (i) decreasing the fraction of inspired oxygen to <,0.21 and (ii) adding carbon dioxide (CO2) to the ventilatory circuit. Whether molecular nitrogen (N2) or CO2 is used in these situations is a matter of physician and institutional preference. The effect of the two modalities in combination has not been studied in depth. Methods: This prospective observational study was designed to look at the effects of adding inhaled CO2 to children with HLHS who were already on a hypoxic mixture during the immediate perioperative period. Results: Twelve suitable neonates were enrolled in the study. Combining the two ventilatory modalities had an additive effect. The effect was more significant in the prebypass (83% of patients) compared with the postbypass period (25% of patients). Conclusions: Low inspired oxygen and CO2 have an additive vasoconstrictive effect on the pulmonary vessels. The use of both of these ventilatory manoeuveres is less effective postoperatively compared with the prebypass period. [source]

    Development of a Closed Air Loop Electropneumatic Actuator for Driving a Pneumatic Blood Pump

    ARTIFICIAL ORGANS, Issue 8 2009
    Gi Seok Jeong
    Abstract In this study, we developed a small pneumatic actuator that can be used as an extracorporeal biventricular assist device. It incorporated a bellows-transforming mechanism to generate blood-pumping pressure. The cylindrical unit is 88 ± 0.1 mm high, has a diameter of 150 ± 0.1 mm, and weighs 2.4 ± 0.01 kg. In vitro, maximal outflow at the highest pumping rate (PR) exceeded 8 L/min when two 55 mL blood sacs were used under an afterload pressure of 100 mm Hg. At a pumping rate of 100 beats per minute (bpm), maximal hydraulic efficiency was 9.34% when the unit supported a single ventricle and 13.8% when it supported both ventricles. Moreover, pneumatic efficiencies of the actuator were 17.3% and 33.1% for LVAD and BVAD applications, respectively. The energy equivalent pressure was 62.78,208.10 mm Hg at a PR of 60,100 bpm, and the maximal value of dP/dt during systole was 1269 mm Hg/s at a PR of 60 bpm and 979 mm Hg/s at a PR of 100 bpm. When the unit was applied to 15 calves, it stably pumped 3,4 L/min of blood at 60 bpm, and no mechanical malfunction was experienced over 125 days of operation. We conclude that the presently developed pneumatic actuator can be utilized as an extracorporeal biventricular assist device. [source]

    Design of a Protective Cage for an Intravascular Axial Flow Blood Pump to Mechanically Assist the Failing Fontan

    ARTIFICIAL ORGANS, Issue 8 2009
    Amy L. Throckmorton
    Abstract Currently, no long-term mechanical bridge-to-transplant or bridge-to-recovery therapeutic alternative exists for failing single ventricles. A blood pump that would augment pressure in the cavopulmonary circulation is needed, and would lead to a reduction in elevated systemic venous pressure, and improve cardiac output. Thus, we are developing a collapsible, percutaneously inserted, axial flow blood pump to support the cavopulmonary circulation in adult patients with a failing single ventricle physiology. This collapsible axial flow pump is designed for percutaneous positioning. The outer protective cage will be designed with radially arranged filaments as touchdown surfaces to protect the vessel wall from the rotating components. This study examined the geometric characteristics of the protective cage of filaments and the impeller through the development and numerical analysis of 13 models. A blood damage analysis was also performed on selected geometric models to assess the probability of blood trauma. All models demonstrated an acceptable hydraulic performance by delivering 2,6 L/min at a rotational speed of 6000,10 000 rpm and generating pressure rise of 5,20 mm Hg. Expected trends in the hydraulic performance of the pump models were found. This study represents the initial first design phase of the impeller and protective cage of filaments. Validation of these flow and performance predictions will be completed in the next round of experimental testing with blood bag evaluation. [source]