Pediatric cardiology
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Pediatric cardiology · Jul 1994
Descending aortic blood flow velocity as a noninvasive measure of cardiac output in children.
In previous work, we postulated that mean aortic flow velocity (MAFV) might be a direct measure of cardiac index. To investigate the assumptions inherent in this relation, we measured body surface area, aortic cross-sectional area (two-dimensional ultrasonography) and MAFV (Doppler ultrasonography) in 70 normal children. For a direct check of the relation, we simultaneously measured cardiac index (Fick technique) and MAFV (Doppler ultrasonography) in 25 children after cardiac surgery. ⋯ The assumptions made when deriving the relation between MAFV and cardiac index appear to be valid whether measured in the ascending or descending aorta. However, the scatter of results limits its clinical value. Mean aortic flow velocity is probably of greater use as a trend indicator and has the potential for continuous display using an esophageal Doppler probe when measured in the descending aorta.
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Propafenone hydrochloride, a class 1C antiarrhythmic agent, combines sodium channel-blocking effects with beta-blocking capacities and a weak calcium antagonism. The drug exerts marked electrophysiologic effects on accessory atrioventricular pathways. In patients with atrioventricular nodal reentry tachycardia, propafenone is able to block conduction in the fast conducting pathway. ⋯ Propafenone is well tolerated in the majority of young patients. Incidence of proarrhythmic events seems to be lower with propafenone than with other class 1C agents. However, the risk of these serious adverse events should be taken into account when therapy with propafenone is considered, particularly in patients with structural heart disease.
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Pediatric cardiology · Jul 1994
Color Doppler imaging of modified Blalock-Taussig shunts during infancy.
To assess the role of color Doppler echocardiography in the early postoperative evaluation of patients with a Blalock-Taussig shunt we examined 13 consecutive infants who underwent insertion of either a modified right (6 patients) or a modified left (7 patients) Blalock-Taussig shunt (age range 7 days to 6 months, mean age 8 weeks). Examination of the patients in a high parasternal right or left long axis was able to determine patency of the shunt in 12 patients. ⋯ From subcostal views we were able to demonstrate patency of the shunt in 75% of the infants and in all patients younger than 4 weeks of age. In our experience color Doppler echocardiography is a highly reliable method for early postoperative evaluation of infants with a Blalock-Taussig shunt.