<prompt> Answer this question truthfullyWhat can effusion echocardiography detect in the pericardial region?  <response>: <reason> In pericardial effusion, large hypoechoic regions are seen surrounding the heart with presence of oscillatory motion of the heart. The echocardiogram below demonstrates swinging motion of the heart in cardiac tamponade. ev:youtubeU4xQ3-VRiNgEchocardiography of heart with loculated pericardial effusion compressing the left ventricle ev:youtubeunnmmlCyyZMCardiac tamponade ev:youtubeYWVI6rRTIzUCardiac tamponade ev:youtube_az8_V6bHE8Left ventricular free wall rupture in patient with cardiac tamponade ev:youtubeg9TdKcFRiLoCollapse of right ventricle in patient with cardiac tamponade ev:youtubedwJkJr00v5c 