Abstract 4563: Left Atrial Volume in Children: Normative Data and Impact of Increased Left Ventricular Preload in Congenital Heart Disease
In adults, left atrial volume (LAV) has been shown to strongly correlate with diastolic dysfunction and is a powerful predictor of cardiac morbidity and mortality. Normative data regarding LAV in children as well as the impact of loading conditions on LAV in congenital heart disease are lacking. (1) establish normal values for LAV in healthy children (group 1) and (2) assess the impact of increased left ventricular (LV) preload on LAV in congenital heart disease (group 2). We conducted a retrospective review of all echocardiograms performed on children <18 years of age at Mayo Clinic between 01/2004 and 12/2006 in whom LAV was documented. Group 1 comprised a large cohort of children with normal echocardiograms. Group 2 included children with isolated ventricular septal defect (VSD) or patent ductus arteriosus (PDA). LAV was calculated using a modified biplane area-length method and was indexed to body surface area (LAVI). VSDs and PDAs were graded by the degree of left-to-right shunt. Data were analyzed to establish LAVI in healthy children. In group 2, the relationship of LAVI to shunt size and to LV end-diastolic dimension (LV EDD) was assessed. Patients in both groups had normal traditional echocardiographic parameters of systolic and diastolic function.
Results: 522 healthy children, 50 with isolated VSD, and 21 with isolated PDA were identified. Among children >3 months of age, LAVI was consistent and independent of age (linear regression = 20.6 + Age × 0.11). LA enlargement was more common in patients with VSD or PDA than in controls (23.7% vs. 4.4%, p<0.0001) and more common in children with moderate or large shunts than smaller shunts (50.0% vs. 8.3%, p=0.0009). In group 2 patients LAVI correlated closely with increasing LV EDD (p<0.0001) independent of age and shunt size. This study is the first to establish normal values for left atrial volume in children. LA volume index is an accurate, age-independent measure of left atrial size in children >3 months of age. As expected, LAVI correlates with chronic increases in LV preload. Left atrial volume increases relative to shunt size and correlates with similar increases in LV EDD. LAVI may be a useful measure of diastolic function in children and deserves ongoing assessment.