Abstract 16397: HRV Analysis for Estimating Cardiac Function During Continuous-Flow LVAD Assistance
Objective: We have been looking into the potential of heart rate variability (HRV), a well-known prognosis factor of heart disease, as a non-invasive assessment tool of cardiac function for heart failure patients. In this study, we focused on the alteration of HRV and its correlation with the left ventricular (LV) volume and pressure under left ventricular assist device (LVAD) support in a chronic heart failure animal study.
Methods: A chronic heart failure animal was created using an adult goat by coronary artery micro-embolization to the LAD and subsequent rapid ventricular pacing for 5 weeks. A continuous-flow LVAD (EVAHEART, Sun Medical Technology Research Corp.) was implanted and circulatory support was started. One month after LVAD implantation, we examined the alteration of HRV by changing the LVAD’s driving condition in two ways; 1) raising rotational speed (RS) by 100 rpm every 10 minutes from minimum to maximum assistance, 2) maintained 75% and 100% bypass for 24 hours each. Low (LF) and High frequency (HF) power of HRV which represent cardiac autonomic activity were analyzed and the correlations with the LV end-diastolic volume (LVEDV) and pressure (LVEDP) were evaluated.
Results: In the first study, the LF and HF increased gradually as the LVEDV and LVEDP decreased until just before full bypass. However, further rise of RS made sharp fall of LVEDV and rapid increase of LF. A strong correlation was observed between log of LVEDV and log of LF (r = -0.95, P < 0.01), log of LVEDV and log of HF (r = -0.71, P < 0.01), log of LVEDP and log of LF (r = -0.80, P < 0.01), and log of LVEDP and log of HF (r = -0.80, P < 0.01). The second study revealed the decreased LVEDV and LVEDP increased the HRV indexes likewise in the longer time range.
Conclusions: These findings indicate that the HRV indexes substantially reflect the LV volume and pressure. We conclude that the HRV monitoring has a great potential to be a non-invasive method for estimating LV condition under LVAD assistance.
- © 2013 by American Heart Association, Inc.