Hemodynamic monitoring has long formed the cornerstone of heart failure(HF) and pulmonary hypertension diagnosis and management. We review the long history of invasive hemodynamic monitors initially using pulmonary artery(PA) pressure catheters in the hospital setting, to evaluating the utility of a number of implantable devices that can allow for ambulatory determination of intracardiac pressures. Although the use of indwelling PA catheters has fallen out of favor in a number of settings, implantable devices have afforded clinicians an opportunity for objective determination of a patient’s volume status and pulmonary pressures. Some devices, such as the CardioM EMS and thoracic impedance monitors present as part of implantable cardiac defibrillators, are supported by a body of evidence which show the potential to reduce HF related morbidity and have received regulatory approval, whereas other devices have failed to show benefit and, in some cases, harm. Clearly these devices can convey a considerable amount of information and clinicians should start to familiarize themselves with their use and expect further development and refinement in the future. We review the long history of invasive pulmonary motility of capillary (PA) pressure catheters in the hospital setting, to evaluating the utility of a number of the implantable devices that can allow for ambulatory determination of intracardiac pressures. Although the use of indwelling PA catheters has fallen out of favor in a number of settings, implantable devices have afforded clinicians an opportunity for objective determination of a patient’s volume status and pulmonary pressures. Some devices, such as the CardioM EMS and thoracic impedance monitors present as part of implantable cardiac defibrillators, are supported by a body of evidence which show the potential to reduce HF related morbidity and have received regulatory approval, while other devices have failed to show benefit and, in some cases, harm. Clearly these devices can conve y a considerable amount of information and clinicians should start to familiarize themselves with their use and expect further development and refinement in the future.