If the ventricular lead fell out or failed to capture, you would likely have a slow, underlying heart
rhythm that we call
an escape rhythm. It is possible that there would be no underlying rhythm, but very unlikely. If the lead falls, you will likely become lightheaded, dizzy, and unable to do you normal activity. If you experience these symptoms, you should either call 911, go to an emergency room or call your doctor, depending on how serious your symptoms are.