References:

Left atrial volume in children without heart disease and in those with ventricular septal defect or patent ductus arteriosus or hypertrophic cardiomyopathy.
Taggart NW, Cetta F, O'Leary PW, Seward JB, Eidem BW. Am J Cardiol. 2010 Nov 15;106(10):1500-4. Epub 2010 Sep 21. PubMed PMID: 21059443.