What are signs of decreased cardiac output in an infant with congenital heart disease?

The signs of decreased cardiac output in an infant with congenital heart disease typically include symptoms that indicate inadequate blood flow and oxygen delivery to the body's tissues. Poor feeding is a common symptom because infants with decreased cardiac output often have difficulty coordinating sucking and swallowing due to fatigue. Irritability can also occur as a result of reduced oxygenation and energy levels. Bradycardia, or a slower than normal heart rate, may be observed as the body attempts to conserve energy in response to reduced cardiac function.

These signs—poor feeding, irritability, and bradycardia—reflect the infant's compromised state due to their heart's inability to effectively pump blood. This can lead to inadequate perfusion, manifesting as increased fussiness due to discomfort, poor weight gain due to insufficient nutrition intake, and variations in heart rate that signal distress.

In contrast, the other options contain combinations of symptoms that are not typically associated with decreased cardiac output. For example, increased urine output is generally seen with good perfusion and effective kidney function, which is contrary to low cardiac output scenarios. Additionally, fatigue is an expected outcome of inadequate oxygen delivery, but increased heart rate or hypotonia does not align as closely with decreased cardiac output symptoms in this context.