heart left atrium morphological measurement heart left atrium end-diastolic diameter clinical_measurement_ontology The distance between two specified opposite points on the periphery of the left atrium of the heart at the end of diastole, that is, when the left ventricle is maximally dilated, and usually corresponds to the left atrium's smallest diameter. VT:0010493 jsmith CMO:0001486 2013-01-25T15:50:33Z