The utility of thoracic impedance monitoring in a patient with biventricular defibrillator

The severity of pulmonary congestion can be assessed by monitoring thoracic impedance (TI). In patients with congestive heart failure (CHF), TI monitoring provides a unique opportunity to foresee decompensation before clinical signs and symptoms ensue. Some biventricular defibrillators (BiV-ICD) have TI monitoring capability, providing hemodynamic data as well as treatment of CHF and arrhythmias. We present an 80-year-old male patient in whom TI monitoring by BiV-ICD was utilized for clinical decision making. He had undergone coronary artery bypass graft surgery and BiV-ICD implantation, and had decompensated CHF on admission. Interrogation of BiV-ICD revealed a substantial decrease in TI compatible with volume overload. Shortly after treatment for CHF, a steady increase was noted in TI parallel to effective diuresis. However, after discharge, a decrease in TI was again noted without any signs and symptoms of decompensation. Treatment was tailored and TI values became normal. No need for hospitalization occurred and he showed a steady decrease in the ventricular rate in parallel to increases in TI and heart rate variability.