Augmented Pacing for Shock in the Cardiac Intensive Care Unit

The goal of this clinical trial is to learn if backup pacing at an increased rate improves hemodynamics in adults with relative bradycardia, a permanent pacemaker, and cardiogenic shock. The main question it aims to answer is: Does increasing the backup pacing rate to 100 beats per minute lead to improved cardiac index compared to a backup pacing rate of 75 beats per minute Participants who are already hospitalized in the Cardiovascular Intensive Care Unit with a permanent pacemaker and pulmonary artery catheter in place will be enrolled in this study. Participants will be exposed to each pacemaker rate in a randomized order with hemodynamics assessed after 10 minutes at each rate.