Detection of heart failure decompensation using intrathoracic impedance monitoring by a triple-chamber implantable defibrillator

Decompensated heart failure is the leading cause of hospital admissions for US Medicare patients.(1) Early detection of intrathoracic fluid accumulation may reduce the morbidity and mortality associated with cardiac decompensation, but appropriate tools for monitoring patients with chronic heart failure are lacking. Intrathoracic impedance measurement recently has been integrated in a triple-chamber implantable defibrillator (InSync Sentry (TM), Medtronic Inc., Minneapolis, MN, USA). The system can alert the patient with an audible signal if a decrease in intrathoracic impedance indicates pulmonary fluid accumulation due to cardiac decompensation. However, the clinical value of this monitoring function has not been evaluated. This is the first case report to describe detection of heart failure decompensation using intrathoracic impedance monitoring by an implantable device.