Pathophysiology

  Ductus arteriosus connects aorta to the pulmonary artery.

  Since the aortic pressure is more than that of the pulmonary artery,

      the shunt flow is
from aorta to the pulmonary artery .

  This results in increased blood flow through the left atrium and left ventricle.

  The ECG may be completely normal if PDA is small.



ECG changes in PDA

  Left atrial abnormality.

  Left ventricular hypertrophy.

  If PDA is large or if there is aorticopulmonary window, then pulmonary hypertension may develop

      and result in biventricular hypertrophy pattern.

  Prolongation of PR interval (rarely seen in adults).

  Deep S wave in C1 and/or tall R waves in C5 and C6.



References

  Chou's Electrocardiography in Clinical Practice. Adult and Pediatric.

      5th ed. Philadelphia. WB Saunders. 2001.

  Circulation 1962;25:807.





ECG 1. The ECG of patient with restrictive (small) PDA and left to right shunt flow.
Small PDA does not result in right ventricular hypertrophy.

Prof Dr. R Krishna Kumar has donated this ECG to our website.