In cardiac amyloidosis, the heart muscle becomes thick and stiff, making it difficult to pump enough blood with each beat. The heart also often cannot increase its stroke volume, making patients with cardiac amyloidosis more dependent on having an adequate heart rate. Many develop conduction problems and need a pacemaker. In a related condition, heart failure with preserved ejection fraction, setting a higher pacemaker rate improved patients' quality of life. It is not known if the same benefits apply to amyloidosis. This study will test whether raising the pacemaker rate improves well-being and daily function in affected patients.