Isolated infundibular stenosis

Abstract

We have reported three patients with isolated infundibular stenosis who have undergone surgical correction of the lesion. In two patients the pressure gradient has been completely abolished, and in the third the pressure gradient has been halved. All patients are symptomatically improved. Infundibular stenosis comprises 3 per cent of all cases of pulmonary stenosis with intact ventricular septum. Auscultation offers the most reliable aid in differentiating infundibular from pulmonary valvular stenosis. In infundibular stenosis the murmur and thrill are of maximum intensity in the second to third left intercostal spaces parasternally, or lower, and the murmur is always louder in the third left intercostal space than in the first left intercostal space. The quality of the murmur is considered to be more rasping in the infundibular variety. Cardiac catheterization is diagnostic if an infundibular-chamber pressure curve can be demonstrated. In its absence, the finding of a transition zone between the pulmonary arterial pressure curve and the right ventricular pressure curve at a point much below the usual site of the valve should make one suspect infundibular stenosis. It is important to differentiate preoperatively an isolated infundibular stenosis with a patent foramen ovale from the tetralogy of Fallot, because the surgical procedures and the risks involved are quite different. An infundibular stenosis can be successfully corrected by surgery with but a slightly higher risk than that in valvular stenosis.