Figure 1. Transthoracic echocardiogram. Red arrows show a septal bounce sign moving through the cardiac cycle (A to B in yellow). RV is the right ventricle, and LV is the left ventricle. The early diastolic filling of the right ventricle leads to the leftward deviation of the interventricular septum followed by a bounce back towards the right ventricle in late diastole. This results from increases in early diastolic pressure in the right ventricle that exceeds left ventricular diastolic pressures during the cardiac cycle. The septal bounce is explained as a rapid and asymmetric filling of ventricles in early diastole, resulting in an intracardiac fluctuating pressure gradient that manifests as an abrupt shift of the septum.