Intrathoracic Impedance Is Negatively Correlated with BNP Value in Patients with Implantable Cardioverter Defibrillator: MOMOTARO Study

Introduction: Heart failure is one of the most common causes for hospitalizations. OptiVol alert, which was fluid status algorism calculated from intrathoracic impedance, may detect impending fluid accumulation. Then, we tried to examine the relationship of OptiVol alert or intrathoracic impedance with various parameters. Methods: The patients who were implanted high energy device with OptiVol feature were included in this study. The patients were evaluated various examinations at enrolment and following an OptiVol alert. We examined how various parameters were different between baseline and OptiVol alert, and the relationships among the factors included in OptiVol alert and intrathoracic impedance were evaluated by factor analysis. Results: From April in 2010, 191 patients were eligible for the present study. In all patients, there was no significant difference in all parameters between OptiVol alert and baseline. However, in the patients with ejection fraction less than 35%, BNP value was likely to increase in OptiVol alert compared with that in baseline, but not significantly. In factor analysis, there was no parameter correlated with OptiVol alert. However, intrathoracic impedance was negatively correlated with BNP value. Conclusions: Intrathoracic impedance, but OptiVol alert, seems to represent fluid retention.