Chapter 27: Alterations of Cardiovascular Function in Children

Congenital heart disease represents a significant clinical challenge, occurring in approximately four to eight of every one thousand live births and ranking as the primary cardiac cause of infant mortality. Multiple etiological factors contribute to congenital anomalies, including intrauterine viral exposures such as rubella and cytomegalovirus, maternal metabolic conditions like diabetes and phenylketonuria, teratogenic medications including alcohol and phenytoin, and genetic abnormalities associated with chromosomal syndromes such as Down syndrome and Turner syndrome. The chapter classifies congenital defects into four functional categories based on their hemodynamic effects: increased pulmonary blood flow lesions including patent ductus arteriosus, atrial septal defect, and ventricular septal defect that create left-to-right shunting; obstructive defects such as coarctation of the aorta and aortic stenosis that impede ventricular outflow; decreased pulmonary blood flow conditions exemplified by tetralogy of Fallot and tricuspid atresia that cause cyanosis; and mixing defects including transposition of the great arteries and hypoplastic left heart syndrome that result in systemic hypoxemia. The chapter details the pathophysiologic mechanisms underlying each category, clinical manifestations ranging from asymptomatic murmurs to life-threatening cyanotic episodes, and contemporary management approaches including pharmacological interventions, catheter-based procedures, and surgical correction strategies. Congestive heart failure frequently complicates congenital disease in infants, presenting with feeding difficulties, tachypnea, and hepatomegaly, managed through diuretics, neurohormonal modulators, and definitive structural repair. Additionally, the chapter addresses acquired cardiovascular disease in children, particularly Kawasaki disease, an acute inflammatory vasculitis with predilection for coronary arteries that requires prompt recognition and immunoglobulin therapy to prevent aneurysm formation, and pediatric hypertension, an increasingly prevalent condition secondary to renal disease in younger children but attributable to lifestyle factors in adolescents.