- Auscultation 👂: Continuous “machine like” murmur
- continuous murmur because continuous shunting as the aortic pressure is higher than the pulmonary artery pressure in both systole and diastole
- Physiologically similar to VSD, both are post-tricuspid shunts
- Complications:
- Left heart enlargement
- Pulmonary vascular remodeling
- Infective endarteritis (although not indication for SBE prophylaxis)
Echo
In (A) you see flow going from the proximal descending aorta through the PDA into the proximal left pulmonary artery. In (B) we see spectral doppler showing continuous flow with higher velocities in systole than in diastole.
Figure source