What cardiac effect is caused by a patent ductus arteriosus (PDA)?

A patent ductus arteriosus (PDA) leads to a left volume overload. This condition occurs when there is a persistent connection between the aorta and the pulmonary artery, allowing blood to flow from the aorta (which is under higher pressure) into the pulmonary artery.

As a result, this abnormal blood flow increases the volume of blood returning to the left side of the heart, particularly the left atrium and left ventricle. Over time, this excessive volume can lead to dilation of the left atrium and left ventricle and may ultimately cause complications such as congestive heart failure if not addressed.

The left ventricle not only has to manage the normal volume of blood returning from the lungs but also the additional volume that is shunted from the aorta. This situation can lead to structural changes in the heart, including hypertrophy of the left ventricular muscle as it works harder to pump the increased volume of blood.

Thus, the primary cardiac effect of a patent ductus arteriosus is left volume overload, which can set the stage for further cardiovascular issues if the PDA is not closed, either surgically or via interventional techniques.