TRANSPOSITION of the great vessels generally results in death within the first eight months of life. It is the leading cause of death from congenital heart disease in the first two months of life.1,2 Survival with complete, simple transposition of the arterial trunks is directly related to the size and/or number of shunts between the separate pulmonary and systemic circulations. Therefore transposition with an intact ventricular septum offers the shortest life expectancy. It has been reported to average 6 to 8 weeks.3,4 In addition to being the most lethal of the various forms of transposition, it has been reported as the single most common type.3-5 In spite of this, a detailed clinical profile of complete, simple transposition of the great vessels with intact ventricular septum has never been reported. Physiologic data on this group only rarely has been presented6-8 and, to our knowledge never within