A nurse is assessing an infant in the cardiology clinic. Which of the following sets of clinical manifestations is consistent with a large ventricular septal defect?

A. A large ventricular septal defect (VSD) is a congenital heart defect characterized by an abnormal opening between the left and right ventricles. In a large VSD, blood flows from the higher-pressure left ventricle to the lower-pressure right ventricle, increasing pulmonary blood flow and causing pulmonary congestion. This leads to tachypnea (rapid breathing) as the infant works harder to oxygenate blood and compensate for inefficient circulation. The increased workload of the heart and lungs can cause fatigue with feeds, since infants expend significant energy trying to eat. A systolic murmur is typically present at the lower left sternal border due to turbulent blood flow across the defect. These clinical manifestations—murmur, tachypnea, and feeding fatigue—are classic indicators of a hemodynamically significant VSD. B. Bradypnea, or abnormally slow breathing, is not associated with VSD. In fact, the pulmonary overcirculation caused by a large VSD leads to tachypnea, not bradypnea. Although a murmur and fatigue with feeds are consistent, the presence of bradypnea makes this option inaccurate. C. Excessive weight gain is unlikely in infants with a large VSD. Due to tachypnea and fatigue during feeding, infants often have poor weight gain or failure to thrive. While murmur and tachypnea are correct, the inclusion of excessive weight gain makes this choice incorrect. D. This option is incorrect for two reasons. Bradypnea is not a feature of VSD, and excessive weight gain does not occur; infants with a large VSD are at risk for growth delays because of increased metabolic demands and feeding difficulties. Fatigue with feeds is correct, but the other two signs do not align with the pathophysiology of a large VSD.