Continuous Lv Chamber Volume Measurement Using Rv Shocking Coil

Introduction Many devices currently warn of impending HF events by determining hemodynamic impairment in patients with systolic dysfunction including monitoring right heart pressures through specialized leads, wedge pressure implants, and left atrial pressure leads. All of these devices require additional implants, but a large portion of HF patients already have devices like pacemakers and defibrillators implanted. Hypothesis: EDV can be safely monitored from a standard implanted RV shocking coil with only modifications to the generator. Methods: In an ongoing clinical trial named RECHARGE, n = 14 patients were tested to determine the agreement between a volume measurement using a standard RV lead and 3D Trans-thoracic echo (3D TTE). The RV lead was connected to a test device using only common ICD components, that recorded the 20kHz admittance of the RV lead in real-time. EDV was modulated by overdrive pacing at 10 and 50 bpm above baseline heart rate to reduce filling time, which reduces EDV. This procedure was repeated three times to help define the resolution of echo and the resolution of RV lead volume, which was reported as mean Coefficient of Variation (CV). The RV lead volume was calibrated to baseline TTE on a patient-by-patient basis, to ensure that variation in lead scarring, placement, and brand would not affect the volume calculation. Results: Concordance (CCC) and Individual (ICC) Correlation Coefficient between 3D TTE and RV lead volume measurement was calculated CCC = 0.97, and ICC = 0.96 (1 is perfect) over all EDVs in the study. Volume measurement using the unmodified lead in all patients showed a mean within-subject Coefficient of Variation (wCV) of 5.9% (0% is perfect repeatability), while the echo wCV was 10.2%. This implies that much of the error in volumes in the study is due to high echo variability, and that RV lead volumes are more reliable than echo. Conclusion: Statistics show excellent agreement between volume measurements made using a single RV shocking coil and 3D TTE, and imply that EDV can be measured with higher repeatability using RV shocking coils than echo in patients. Regardless of device brand, new device generators can be modified to implement this technology in new and existing patients with no additional surgery.