Differential Diagnosis

The patient's history of Tetralogy of Fallot (TOF) repair and current symptoms suggest several possible diagnoses. Here's a categorized differential diagnosis:

• Single most likely diagnosis
  • C. Pulmonary artery regurgitation: This is a common complication after TOF repair, especially if the repair involved a transannular patch. The decrescendo diastolic murmur at the left sternal border is consistent with pulmonary regurgitation. The single S1 can be explained by the potential for aortic or pulmonary valve issues post-repair.
• Other Likely diagnoses
  • B. Ventricular septal defect: Although the patient had a repair, residual or recurrent VSDs can occur. However, the murmur of a VSD is typically a holosystolic or pansystolic murmur, not a decrescendo diastolic murmur.
  • D. Tricuspid regurgitation: This could also present with a diastolic murmur, but it's more commonly associated with a holosystolic murmur and signs of right heart failure. The lack of radiation and specific location at the left sternal border makes it less likely but still possible.
• Do Not Miss
  • A. Aortic stenosis: Although less likely given the description of the murmur, aortic stenosis can be a serious condition. The murmur of aortic stenosis is typically a crescendo-decrescendo systolic murmur, but in the context of TOF repair, any valvular issue should be considered. Missing severe aortic stenosis could have significant implications.
• Rare diagnoses
  • Other rare possibilities could include issues like pulmonary valve stenosis or other congenital heart defects that were not fully addressed or have developed over time. However, these would be less likely given the provided history and physical examination findings.

Each of these diagnoses should be considered in the context of the patient's history of TOF repair and the physical examination findings. Further diagnostic testing, such as echocardiography, would be necessary to confirm the diagnosis.