The ECG is normal. This indicates that the lesion responsible for the murmur was not hemodynamically significant. The clinical findings and ECG are consistent with a small ventricular septal defect. The intensity of the murmur is due to the turbulence created when the blood is driven from the high pressure left ventricle across a small opening in the interventricular septum to the low pressure right ventricle. This diagnosis was confirmed by echocardiography.