Pediatric cardiology
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Pediatric cardiology · Jun 2013
Reference values of aortic flow velocity integral in 1193 healthy infants, children, and adolescents to quickly estimate cardiac stroke volume.
The aortic velocity time integral (VTI) is an echocardiographic tool used to estimate cardiac output (CO) by multiplying it with the aortic valve (AV) area and heart rate (HR). Inaccurate measurement of AV diameter will lead to squared miscalculation of CO. The aortic VTI itself can serve as a left-ventricular (LV) output parameter. ⋯ Aortic VTI ranged from mean 13.8 cm (10.0-18.4 cm 5-95th percentile) in neonates to 25.1 cm (19.6-32.8 cm 5-95th percentile) in children >17 years of age and had a positive correlation with age (r = 0.685, p < 0.001), BSA (r = 0.645, p < 0.001) and a negative correlation with HR (r = -0.710, p < 0.001). Interobserver and intraobserver variability were excellent (3.9 ± 3.1 and 4.6 ± 3.7 %, respectively). Calculated mean values and percentile charts for the different age groups can serve as reference data to easily judge LV output in patients with or without congenital heart disease without enlargement or dysfunction of the AV.
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Pediatric cardiology · Jun 2013
Infant cardiac magnetic resonance imaging using oscillatory ventilation: safe and effective.
Cardiac magnetic resonance imaging (CMR) for infants and young children typically requires sedation. General anesthesia with controlled ventilation can eliminate motion artifact with breath-holds during imaging to limit respiratory artifact, but these may lead to atelectasis or other complications. High-frequency oscillatory ventilation (HFOV) provides ventilation with near-constant mean airway pressure and minimal movement of chest wall and diaphragm, thus obviating the need for breath-holding. ⋯ There were no adverse events in the HFOV group, but scans were terminated early for two patients in the conventional ventilator group. HFOV during CMR is feasible and well tolerated. Image quality is equivalent to that obtained with conventional ventilation with breath-holding technique and allows shorter cine scan times for some sequences.
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The study reported here is a rare case of fetal sinus bradycardia that evolved into symptomatic bradycardia after birth, at which time the implantation of a cardiac pacemaker was indicated. Fetal echocardiography was used to diagnose the type of cardiac rhythm that caused the intra-uterine bradycardia, which enabled the initiation of the appropriate therapy approach and avoided an unnecessary interruption of the pregnancy. However, the details of the sinus bradycardia were impossible to determine in utero in this case due to sinus node dysfunction. After birth, the electrocardiogram results drew attention to a potentially unusual cause of sinus bradycardia, and enabled the diagnosis of this rare disease in this infant.