Effect of Exercise-Based Cardiac Rehabilitation on Cardiorespiratory Fitness in Adults with Congenital Heart Disease

Background:The purpose of this study was to investigate whether patients with adult congenital heart disease(ACHD)benefit from exercise-based cardiac rehabilitation(CR)short-and long-term with regard to improvement of cardiorespiratory fitness.Methods:Cardiopulmonary exercise tests(CPET)completed by ACHD patients between January 2000 and October 2019 were analysed retrospectively.Linear mixed models were performed for peak oxygen consumption(VO_(2))with patients as random effect and age,sex,disease classification,preceding surgery(≤3 months)and preceding CR(≤4 weeks for short term and>4 weeks for long term)as fixed effects.Results:1056 CPETs of 311 ACHD patients with simple(7),moderate(188)or great(116)complexity heart defects were analysed.The 59 patients who completed a CR(median age 27 yrs,38%females)increased peak VO_(2)from before to after CR by a median of 2.7(IQR–0.6 to 5.5)ml/kg/min.However,in the multivariate mixed model,peak VO_(2)was non-significantly increased short-term after CR(β0.8,95%CI–0.7 to 2.4),not maintained long-term after CR(β0.0,95%CI–1.7 to 1.6)but significantly reduced after surgery(β–5.1,95%CI–7.1 to–3.1).The 20 CR patients after surgery increased their peak VO_(2)by 6.2(IQR 3.6–9.5)ml/kg/min,while the 39 CR patients without preceding surgery increased it by 0.9(IQR–1.5 to 3.1)ml/kg/min.Conclusions:The increase in peak VO_(2)with CR was mainly due to recovery from surgical intervention.The small independent benefit from CR was not maintained long-term,highlighting the potential to improve current CR concepts in ACHD populations.

Cardiopulmonary Response to Exercise at High Altitude in Adolescents with Congenital Heart Disease

Objective:To extend our knowledge on tolerance of acute high-altitude exposure and hemodynamic response to exercise in adolescents with congenital heart disease(AscCHD)without meaningful clinical or functional restriction.Methods:A symptom limited cardiopulmonary exercise stress test and a non-invasive cardiac output measurement during steady state exercise were performed at 540 m and at 3454 m a.s.l.Symptoms of acute mountain sickness were noted.Results:We recruited 21 healthy controls and 16 AscCHD(59%male,mean age 14.7±1.1 years).Three subjects(2 controls,1 AscCHD)presented light symptoms of acute mountain sickness(dizziness and headache).During the symptom limited exercise test at lowland,control subjects showed a significantly higher power to weight index(3.5±0.6 W/kg vs.3.0±0.7 W/kg,p<0.001),heart rate(188.8±10.41/min vs.179.4±13.11/min,p<0.050)and ventilation(92.8±22.9 l/min vs.75.4±18.6 l/min,<0.050).At altitude,power to weight index only remained significantly higher in the control group(2.8±0.6 W/kg vs.2.6±0.6 W/kg,p<0.001).Pulmonary blood flow(PBF)at lowland showed no difference between the control and the AscCHD group,neither at rest(5.4±0.8 l/min vs.5.1±0.9 l/min,p=0.308),nor during the steady state test(10.6±2.4 l/min vs.10.5±2.0 l/min,p=0.825).At high altitude,PBF increased by 110%and 112%,respectively(12.8±2.32 l/min vs.12.5±3.0 l/min;intergroup difference:p=0.986).Conclusions:High altitude exposure was well tolerated in an unselected group of AscCHD.No significant difference in the cardio-pulmonary adaptation to a control group was noted during a steady state exercise.Symptoms of minor acute mountain sickness did occur,which should however not be misinterpreted as signs of hemodynamic maladaptation.

Developmental hemostasis in the neonatal period

Background The hemostatic system is complex and evolves continuously since gestation and well into the adult years,in a process known as“developmental hemostasis.”Data sources A comprehensive review was performed after an extensive literature search on PubMed/MEDLINE concerning developmental hemostasis during the neonatal period.Relevant cross references were also included.Results Although part of a system,each component of the hemostatic system evolves differently,with many displaying both quantitative and qualitative age-related differences.This leads to drastic disparities between the coagulation system of neonates and both other children’s and adults’,while still maintaining a generally balanced and physiological hemostasis.The motives behind this process remain to be fully elucidated but may be,at least in part,related to non-hemostatic factors.Conclusions Knowledge regarding“developmental hemostasis”is essential for everyone caring for newborns or even children in general and in this review,we describe each hemostatic system component’s neonatal characteristics and age-related progression as well as explore some of the possible physiological motives behind the process.

Accuracy of three-dimensional quantification of left ventricular function using magnetic sensor acquisition: a dynamic in vitro model

Objective To evaluate the accuracy of a three-dimensional (3D) magnetic position sensor system in the quantification of ventricular stroke volumes in a dynamic model.Methods A latex balloon model of the left ventricle was suspended in a water bath connected to a pump producing 10 different pulsatile stroke volumes (15-65mi/beat). Scanning was performed using a 5.0 mHz transducer mounted with a Flock of Birds (FOB) magnetic receiver (GE System Five). The probe was scanned to sweep continuously across and over the balloon volume over 3 - 7 seconds. Digital loops were stored on magneto-optical disks and reviewed retrospectively using 3D Echopac software (GE)based on Simpson's method and compared with a two-dimensional (2D) biplane area-length method (1/2L x R) measurements at end systole and end diastole. Both 3D and 2D derived stroke volumes were compared with the reference stroke volume calculated by direct measurement of balloon capacity.Results There was an improved correlation between 3D stroke volume and reference stroke volume ( y = 0.91 x + 0.41, r = 0.97, SEE = 2.83 ml, P = 0.0001 ) compared to 2D stroke volume and reference stroke volume (y=0.49x+8.68, r=0.87, SEE=3.87 ml, P=0.0011, difference between 2D and 3D P＜0.003).Conclusion 3D magnetic FOB scanning is practical, accurate and should facilitate assessment of left ventricular function.