Shortening patterns of the infundibulum in valvular pulmonary stenosis before and after balloon valvuloplasty.

We analyzed shortening patterns of the infundibulum in 11 patients with valvular pulmonary stenosis (PS) before and immediately after balloon valvuloplasty and at follow-up. The control group consisted of 32 patients with Kawasaki disease. The valvuloplasty was performed at the age of 5.8 +/- 2.9 (mean +/- SD) years and a satisfactory relief of obstruction was achieved in each. The follow-up study was done at 1.1 +/- 0.2 years after the valvuloplasty. With the use of lateral projection of right ventriculograms, transverse diameters of the midinfundibulum were measured over one cardiac cycle from initiation of the pulmonary valve opening. Indices demonstrating shortening patterns of the infundibulum were as follows: time to the beginning of shortening (TBS), time to the shortest diameter (TSD), and shortening fraction (SF). TBS were prolonged before the valvuloplasty, whereas it was comparable with that in the control group, immediately after the procedure and at follow-up. TSD was increased before and immediately after the valvuloplasty, but it was normalized at follow-up. SF was increased at every observation. Thus, shortening patterns of the infundibulum in PS were characterized by increasing TBS, TSD, and SF. At short-term follow-up following the valvuloplasty, TBS and TSD were normalized, which could be a result of a successful relief of pulmonary obstruction. In contrast, SF remained elevated, which indicates that the musculature of the infundibulum remains hypertrophic up to 1 year after the valvuloplasty.