title: Echocardiographic assessment of left ventricular outflow tract diameter in preterm infants.
abstract: Introduction: Left ventricular output (LVO) measurement is an important part of the echocardiographic assessment of cardiac function in preterm infants. The accurate measurement of left ventricular outflow tract diameter (LVOD) is key to the calculation of LVO. Given the lack of an appropriate gold standard, we used right ventricular output (RVO) as the comparator and sought to identify the most accurate method of determining LVO in preterm infants.Methods: We studied stable preterm infants without significant cardiac shunts. LVOD was measured at the aortic valve, the aortic sinus and at the sinotubular junction. LVOs were calculated and the precision and accuracy of each was determined relative to the RVO using the Bland-Altman method.Results: 52 infants were included in this analysis. The mean difference between RVO and LVO was largest when LVOD was measured at the aortic valve and aortic sinus, +106 and -115 ml/kg/min, respectively, and smallest when measured at the sinotubular junction, 9 ml/kg/min. Limits of agreement between RVO and LVO were narrowest when LVOD was measured at the STJ.Conclusion: LVOD measurement at the sinotubular junction provides more precise and accurate measurement of LVO, in comparison to RVO, than measurement at the aortic valve or the aortic sinus.
authors.affiliation: Neonatal Intensive and Special CareThe Royal Women's HospitalParkvilleVictoriaAustralia; Newborn Intensive Care UnitThe Mercy Hospital for WomenHeidelbergVictoriaAustralia.
authors.forename: Friederike
authors.initials: F
authors.lastname: Beker
authors.affiliation: Neonatal Intensive and Special Care The Royal Women's Hospital Parkville Victoria Australia.
authors.forename: Peter G
authors.initials: PG
authors.lastname: Davis
authors.affiliation: Monash Newborn Southern Health Clayton Victoria Australia.
authors.forename: Arvind
authors.initials: A
authors.lastname: Sehgal
authors.affiliation: Neonatal Intensive and Special Care The Royal Women's Hospital Parkville Victoria Australia.
authors.forename: Sheryle
authors.initials: S
authors.lastname: Rogerson
keywords: Bland Altman Plot; cardiac output; left ventricular outflow tract; precision; preterm infant