Fig. 3From: Reliability of intra-atrial ECG method of insertion of central venous line through right internal jugular vein when compared to formula and radiological landmark method: a prospective randomized studya Normal intra-atrial ECG when catheter tip is in upper third of SVC. b P wave increases in amplitude denoting proximity to Sino-Atrial node. c P wave equals R wave when catheter tip in right atrium. d P wave comes back to normal size once the catheter is retrievedBack to article page