Background and Aims Pacemaker implantation for treating bradyarrhythmias typically involves placing a pacing lead through the tricuspid valve (TV) into the right ventricular (RV) apex. It is now known that tricuspid regurgitation (TR) frequently results from this and may lead to increased morbidity or mortality. Recently, left ventricular (LV) pacing through an epicardial vein via the coronary sinus has been widely practiced due to the advent of biventricular pacing. This lead does not cross the TV, potentially reducing the risk of TV dysfunction and may also reduce the risk of LV dysfunction. The investigators hypothesize that LV pacing will prevent the onset of new TR or worsening of pre-existing TR in patients undergoing pacemaker implantation.