SUMMARYExisting data on the effect of retained pacemaker leads on right ventricular (RV) and tricuspid valve function is limited.Objective: In this echocardiographic study we investigated the long-term effect of retained ventricular leads on RV and tricuspid valve function in patients with permanent pacemakers.Forty patients, 18 with two (group I) and 22 with one (group II) ventricular lead were assessed echocardiographically at an average of 39 months after the second lead implantation in group I and 80 months after the lead implantation in group II.The sum of the lead body diameter in group I was significantly greater than the body diameter in group II (P < 0.000). There was no significant difference between the groups with respect to chamber diameters and ventricular or valvular functions. The distributions of the different tricuspid regurgitation (TR) grades were similar, with the majority of patients in both groups having mild TR.Retained second pacemaker leads do not have an additional negative effect on right ventricular and tricuspid valve function. (Jpn Heart J 2004; 45: 103-108) Key words: Permanent pacemaker, Tricuspid regurgitation, Echocardiography, Retained leads LEAD dysfunction is one of the major problems/complications of permanent pacemaker therapy. Dysfunction due to mechanical or infective problems or electrical failure leads to replacement. Although lead extraction is done effectively and safely using the new extraction devices in many centers, there still exists a serious complication risk if it is done by inexperienced operators.1,2) Some of the functionless leads can not be removed safely and are left in situ if an absolute indication for extraction does not exist. It has been shown that the retained functionless pacemaker leads in the cardiovascular system are well tolerated unless they are infected and carry a very low complication rate. 3,4) Other possible comFrom the