Cross-sectional echocardiographic features of "absent" pulmonary valve. Report of two cases.

"Absence" of the pulmonary valve was recognized by cross-sectional echocardiography in two infants having relatively atypical clinical manifestations for this cardiac malformation. Both had associated lesions: tetralogy of Fallot and ventricular septal defect, respectively, which were also detected by this non-invasive technique. The findings which strongly suggested the diagnosis were the presence of a ridge of rudimentary pulmonary valvular tissue at the level of the pulmonary annulus and the aneurysmal dilation of the pulmonary arteries. The short axis view at the level of the great arteries was the best approach for visualization of these anatomical abnormalities. The parasternal long axis and sub-costal four-chamber views were also helpful in detecting the associated lesions. In both cases the diagnoses were confirmed at autopsy.