[Detection of coronary sinus by parasternal two-dimensional echocardiography and the clinical significance]

To investigate the potential of a new method for detecting coronary sinus (CS), two-dimensional (2-D) echocardiography was satisfactorily performed on 80 consecutive cases, of which the coronary sinus was detected in 74 by adopting parasternal three-chamber approach. These 74 cases were classified into four groups; 25 normal individuals, 7 patients with atrial septal defect (ASD) but without tricuspid insufficiency (TI), 13 with TI and 29 with other cardiac diseases. We measured diastolic maximum diameter of CS on 2-D echocardiograms. The mean diameter of the CS was significantly increased in ASD (9.0 mm) and TI (12.4 mm) comparing with normal control (6.7 mm). The enlargement of CS seemed to correlate with right-sided volume overload. Although there were three exceptional cases, we could observe the CS during the whole cardiac cycle only in patients with TI. We conclude that CS is excellently detected in over 90% of cases by a new parasternal approach and that the diameter of CS would be a new screening index of right-sided volume overload.