An electrocardiogram (EKG), which measures the electrical activity of the heart, chest x-rays, and other medical tests may also be used to make the diagnosis.
[cdc.gov]
In addition, too much blood flow to the lungs may increase the pressure in the lung's blood vessels, leading to a condition called pulmonary hypertension.
[uwhealth.org]
On examination, there is a systolic murmur at the lower left sternal border (LLSB), and a systolic thrill may be present if there is a large shunt.
[ahcmedia.com]