Safety of Body Composition Analysis Using Bioimpedance in Heart Failure Patients With Implantable Cardioverter Defibrillators (ICDs)

Up to one half of heart failure (HF) patients are overweight and obese, as measured by body mass index (BMI). Comprehensive body composition assessment utilizing bioimpedance scales wuch as Biospace America InBody 520 scale, can give accurate measurements of fat mass, lean muscle mass, and edematous water weight. Body composition analysis is routinely used in many clinical settings, including the Ahmanson-UCLA Cardiomyopathy Center. However, bioimpedance scales are generally not used in patients with implantable cardioverter-defibrillators (ICDs), a group that represents a majority of our HF patient population. The safety of InBody 520 technology - direct segmental multifrequency (5, 100, 500 KHz) bioimpedance analysis - in patients with ICDs has not been formally evaluated. There is a theoretic concern that the ICD may misinterpret the applied currents for a cardiac arrhythmia and possibly cause a discharge from the ICD. However, there has been no documentation of any adverse events in patients with ICDs using the InBody 520 or other bioimpedance scales. Furthermore, thoracic bioimpedance analysis (BioZ ICG, 70 Khz) has been documented to be successfully utilized without adverse effects in patients with HF and ICDs. This study will define the safety of using the InBody 520 scale for analysis of body composition in patients with ICD devices. Subjects with HF and and ICD will have their ICD interrogated and continually monitored by an electrophysiologist before, during, and after the 30-50 seconds of bioimpedance analysis, which involves standing on the InBody 520 scale. If there is any suggestion of the ICD interpreting applied frequencies as a cardiac arrhythmia, the patient will be removed from the scale and the electrophysiologist will simultaneously temporarily deactivate their ICD device to prevent discharge. Twenty subjects (from the following four ICD companies: Medtronic, St. Jude, Guidant, and Biotronik) will participate in our study.