The grave prognostic import of congestive heart failure incident to isolated pulmonic stenosis or to aortic or subaortic stenosis is well known to those interested in the field of cardiology. In fact, it is not an extreme rarity for sudden death to occur even in the absence of recognizable evidence of cardiac failure. Awareness of these hazards has resulted in a drastic lowering of the optimal age at which special diagnostic procedures and definitive surgery are undertaken. Because this recent swing of the pendulum has received little attention in the pediatric literature, it is felt that a discussion of this problem may be of value. The following case reports have been selected from the patients seen in our pediatric cardiac clinic to illustrate the importance of early diagnosis and of prompt surgical relief in patients with advanced degrees of obstruction. Report of Cases Case1.—A 15-month-old Caucasian girl was admitted