A Swan-Ganz catheter during cardiac surgery offers peri-operative haemodynamic monitoring, although insertion of these catheters is not without risk. We report a case of Swan-Ganz catheter entrapment within the tricuspid valve during elective off-pump coronary artery bypass surgery. The diagnosis was made immediately by transoesophageal echocardiography, thus preventing forced withdrawal of the catheter. Intra-operatively, the echocardiographically detected findings of complex entrapment was confirmed. The Swan-Ganz catheter was tightly wrapped around the subvalvular apparatus, requiring on-pump open surgical removal. This case illustrates the anatomical complexity of such a catheter entrapment around the tricuspid valve apparatus and the importance of rapid echocardiographic diagnosis to prevent iatrogenic damage.