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 val vular pulmonary stenosis (PS) before and immediately after balloon valvulop lasty and at follow-up. The control group consisted of 32 patients with Kaw asaki disease. The valvuloplasty was performed at the age of 5.8 +/- 2.9 (m ean +/- 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 valvulopl asty. With the use of lateral projection of right ventriculograms, transver se diameters of the midinfundibulum were measured over one cardiac cycle fr om initiation of the pulmonary valve opening. Indices demonstrating shorten ing patterns of the infundibulum were as follows: time to the beginning of shortening (TBS), time to the shortest diameter (TSD), and shortening fract ion (SF). TBS were prolonged before the valvuloplasty, whereas it was compa rable with that in the control group, immediately after the procedure and a t follow-up. TSD was increased before and immediately after the valvuloplas ty, but it was normalized at follow-up. SF was increased at every observati on. Thus, shortening patterns of the infundibulum in PS were characterized by increasing TBS, TSD, and SF. At short-term follow-up following the valvu loplasty, TBS and TSD were normalized, which could be a result of a success ful relief of pulmonary obstruction. In contrast, SF remained elevated, whi ch indicates that the musculature of the infundibulum remains hypertrophic up to 1 year after the valvuloplasty.