Endocardial lead–induced tricuspid regurgitation has not been well recognized, either clinically or echocardiographically, and yet it is likely a preventable iatrogenic disease. In severe cases, it can lead to right ventricular failure and require tricuspid valve surgery. This complication will become increasingly important, because the numbers of permanent pacemakers and implantable cardioverter-defibrillators are expected to increase because of the aging population and the expanding capabilities of these devices. Published studies are largely retrospective, and serial studies to assess the time course of the development of tricuspid regurgitation are lacking. The mechanisms and severity of tricuspid regurgitation may not be well evaluated by two-dimensional echocardiography. Real-time three-dimensional echocardiography appears to be a promising technique to evaluate the mechanism of tricuspid regurgitation and may allow the early detection of patients who will develop severe lead-induced tricuspid regurgitation. A better understanding of the mechanism of lead-induced tricuspid regurgitation will be essential to the development of preventive strategies, which can then be tested in future clinical trials.