AUTHORS' SYNOPSIS: During cardiac catheterization in 49 children regurgitant flow through competent and incompetent pulmonary valves was evaluated with electromagnetic flow velocity catheters using the ratio of the separately integrated backward and forward flow velocity signals (υb/υf.) When the pulmonary valve was normal, υb/υf was ≤0.10. After operation for pulmonary valve stenosis or tetralogy of Fallot larger values were often found. In patients with an outflow patch across the pulmonary valve ring υb/υf values of up to 0.54 were found.,
Cardiovascular Research

Rohmer, J. (J.), Mark, F.V.D. (F. Van Der), & Zijlstra, W. (1976). Pulmonary valve incompetence: II. Application of electromagnetic flow velocity catheters in children. Cardiovascular Research (Vol. 10, pp. 46–55). doi:10.1093/cvr/10.1.46