What is the role of a pacemaker after aortic valve replacement surgery?

If needed. A small percentage of patients require post op pacemakers after aortic valve surgery. It usually does not cause any problems.
Support heart rate. Occasionally after aortic valve replacement and possibly, more commonly, with mitral valve replacement, the conduction system of the heart gets damaged and the electrical communication between the upper and the lower chambers of the heart is lost (the pathway passes by the annulus of these valves). The heart rate then, has to be supported with a pacemaker.