**Core Concept**
A patent ductus arteriosus (PDA) is a congenital heart defect where the ductus arteriosus, a vascular structure that connects the aorta and pulmonary artery in fetal life, fails to close after birth. In a 1-year-old child with PDA, the body's natural response to maintain pulmonary blood flow is inadequate, leading to excessive flow from the aorta to the pulmonary artery, causing pulmonary overcirculation.

**Why the Correct Answer is Right**
In a 1-year-old child with PDA, the child often presents with failure to thrive, tachypnea, and tachycardia due to pulmonary overcirculation. This leads to increased pulmonary vascular resistance, which can cause left-to-right shunting of blood. The left ventricle may become overloaded, leading to left ventricular hypertrophy and potential complications such as pulmonary edema and heart failure. The child may also experience respiratory symptoms like wheezing and coughing due to pulmonary congestion.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not relevant to the clinical presentation of PDA in a 1-year-old child.
**Option B:** While respiratory distress may be present, it is not the most accurate description of the clinical presentation in this age group.
**Option C:** This option is incorrect as it does not accurately describe the typical presentation of PDA in a 1-year-old child.

**Clinical Pearl / High-Yield Fact**
It is essential to note that PDA in children can lead to pulmonary hypertension and potentially life-threatening complications if left untreated. Early diagnosis and treatment are crucial to prevent long-term consequences.

**Correct Answer:** A.