Therapeutic implications of implantable device-based monitoring of patients with heart failure.

Heart failure is one of the most common medical problems faced by patients and clinicians. It has the potential for high morbidity and mortality, and its overall financial cost to society is enormous. Management of heart failure is often difficult and time consuming, and is sometimes frustrating. The usual signs and symptoms of heart failure may not be obvious early in an exacerbation, which has prompted the development of other methods to identify early and subtle clinical changes to initiate early intervention. Current implantable devices, such as defibrillators and pacemakers, can monitor changes in heart rate and heart rate variability, patient activity, arrhythmia frequency, and thoracic impedance, all of which may be markers of clinical decline. Newer implantable devices can also measure right ventricular pressures, oxygen saturation, and pulmonary artery pressures. Many of these technologies have been shown to be feasible and potentially helpful, but outcomes data showing reductions in morbidity and mortality are currently limited. Importantly, none of these newer technologies should be used in isolation; all must be used in combination with clinical findings to provide effective disease management.