Pediatric cardiology and cardiovascular surgery: 1950-2000.

For those caring for the patient with congenital heart disease, the last 50 years of the 20th century was witness to staggering advances in virtually all aspects of pediatric cardiovascular medicine and surgery. The first half of the 20th century was not dormant in this regard. Dr Maude Abbott of Montreal had published her wonderful atlas in 1936 under the auspices of the American Heart Association, a unique compilation of 1000 cases of congenital heart disease.1 Dr Helen Taussig of Baltimore had founded her cardiac clinic at Johns Hopkins and had begun in the 1930s to characterize the clinical and fluoroscopic findings of a wide variety of congenital heart malformations; this material matured into her 2-volume compendium on congenital heart disease published in 1960.2 Dr Robert E. Gross of the Children’s Hospital in Boston successfully ligated the patent arterial duct in 1938, and that signal accomplishment ushered in the era of surgery for congenital heart disease.3 On the basis of her clinical observations that some children with cyanotic congenital heart disease became progressively more cyanotic coincidently with closure of the arterial duct and cognizant of Gross’s benchmark contribution, Dr Taussig traveled to Boston to attempt to persuade him to construct an arterial duct. When he refused, she broached the subject to Dr Blalock at Johns Hopkins. Some years earlier, when in Vanderbilt and with the technical assistance of Vivien Thomas, in an attempt to produce pulmonary hypertension and using the dog as the experimental animal, Dr Blalock constructed an end-to-end surgical anastomosis between the subclavian artery and the pulmonary artery. With Dr Alfred Blalock as the surgeon and the wisdom of his assistant Vivien Thomas, Taussig and Blalock revolutionized the care of the cyanotic child with the construction of the subclavian artery– to–pulmonary artery end-to-side anastomosis, thus augmenting pulmonary blood flow, and published their early experience in 1945.4 Coarctation of the aorta was successfully repaired in 1945 by Crafoord and Nylin of Stockholm5; Brock, using a “closed” technique, performed a pulmonary valvotomy6; and in 1950, Blalock and Hanlon performed an atrial septectomy using the surgical clamp designed by Vivien Thomas.7 And then came the last half of the 20th century. Perinatal Cardiac Physiology An understanding of the physiology of the unique aspects of the circulation of the fetus and neonate, as well as the concept of the transitional circulation, had a profound impact on the development of treatment modalities in pediatric cardiology.8–10 Basic understanding of developmental cardiovascular physiology allowed a number of medical and surgical advances in the care of infants with heart disease. Research regarding the distribution of blood flow in the fetus and the changes in flow and in vascular channels at the time of birth led to the concept of the persistent fetal circulation (or persistent transitional circulation). These babies were often mistaken for babies with significant structural cardiac malformations, and attempts at definitive diagnosis or intervention could be disastrous. The relative contribution of changes in stroke volume and heart rate in the potential for providing cardiac output reserve of the neonate compared with the adult led to insights of profound importance in neonatal cardiac care. Research that led to an understanding of myocardial perfusion in the developing heart and the unique metabolic aspects of the neonatal heart opened the way for efficient cardioplegia and myocardial protection, pharmacological circulatory support, and neonatal cardiac resuscitation. Rudolph and his colleagues, among many others, have fully characterized the fetal circulation, demonstrating flow patterns of the great veins; the fetal channels, including the ductus venosus and the arterial duct; and the obligatory right-to-left shunting at the level of the foramen ovale occurring in the fetus.8–10 The nature of the combined ventricular output in the fetal lamb has been determined, and the relative distributions of flow to the collapsed and unaerated lungs, as well as to the various components of the aortic arch, the transverse aortic arch, and the isthmus. Those complex overlapping changes responsible for the normal functional and anatomic closure of the arterial duct have also been elucidated. In part, the understanding of the pharmacological and physiological manipulation of the arterial duct led to the development of prostanoid therapy and to biological manipulation of the arterial duct. Many have shown that the contractility or force generated by fetal myocardium is less than that generated by adult myocardium. There is evidence