We plan to study a cohort of patients who are clinically indicated to receive a pacemaker and study their RV in detail at the time of implantation. We will use conductance catheters and echocardiography to determine measures of pumping function. We will then follow them up for a period of six month using echocardiography and blood markers of heart dysfunction. In those patients who have a reduction in heart function we will then look for common patterns within their initial measurements.