Heart failure affects over one million Americans and thousands of new cases are diagnosed each year. This syndrome tends to be progressive and is associated with an increased risk for hospitalizations and possbile death. The CardioMEMS™ HF System is an FDA approved device for individuals with class III heart failure. The system is placed in your heart during a short procedure. Following placement, your doctor is able to monitor the pressures in your heart from the comfort of your own home.The GUIDE-HF study will investigate to determine if the device is effective in individuals with class II, III, or IV heart failure with elevated labs and/or those who have had prior heart failure hospitalizations. During the study, patients will be seen 6 times in our research clinic. During these visits the study staff will ask you to fill out questionnaires, measure your vital signs (blood pressure, heart rate, weight), perform a 6 minute hall walk, draw blood to look at your heart function, and review medications. The device is permanent after implant.