The directional analysis of contrast echographic flow lines is routinely used for tricuspid insufficiency diagnosis. The value of this noninvasive technique for the assessment of pulmonic regurgitation is not yet established. Therefore we evaluated the contrast M-mode echocardiograms at the pulmonary valve in 55 patients. Echographic contrast was obtained by injection of 6-8 ml of indocyanin-saline solution into an antecubital vein. In all 5 patients with documented pulmonic insufficiency (3 patients after repair of tetralogy of Fallot, one with pulmonic endocarditis, one posttraumatic) typical diastolic retrograde directed flow lines crossing the pulmonary valve were recorded. In addition, 6 of 18 patients with primary or secondary pulmonary hypertension exhibited early to middiastolic retrograde flow lines at the pulmonary valve. In contrast, none of the normals (N = 13), and none of 19 patients with various cardiac diseases but unaffected pulmonary valve and normal pulmonary artery pressure, had contrast echographic evidence of pulmonary insufficiency. There were distinctive differences between the contrast flow patterns of the patients with organic pulmonary insufficiency and patients with functional pulmonic regurgitation due to pulmonary hypertension. It is concluded that the directional analysis of contrast echographic flow lines at the pulmonary valve allows a sensitive assessment of pulmonary regurgitation using standard echocardiographic equipment.