Abstract 16689: Smartphone-enabled Device for the Monitoring of Blood Volume Variations Using Magnetohydrodynamic Voltages
Background: Blood volume assessment is a valuable clinical metric, which can diagnostically be used to assess tissue health, monitor patient rehabilitation, and track the progression of wound healing. Currently there exists several methods to assess flow (MRI, US), but are either limited in cost or portability, and may require injection of contrast agents. Magnetohydrodynamic voltages (VMHD) are induced through blood flow interactions with an external magnetic field, and have been successfully measured using a modified ECG recorder and software package . We hypothesize that a portable device capable of measuring induced VMHD could be used to rapidly quantify changes in blood flow.
Objectives: Develop a portable device capable of monitoring of variations in blood volumes using induced VMHD.
Methods: A portable smartphone-based ECG monitor was developed to use methods proposed in  to extract a metric proportional to blood flow from acquired ECGs (Fig. 1a). ECGs were acquired in two healthy volunteers, the second being a trained athlete. VMHD was induced in the carotid artery while in the presence of 0.4T static magnetic field generated by a neodymium magnet embedded in the monitor (Fig. 1b). VMHD signal extraction was performed to isolate the voltage induced by the magnet. Integrating over the VMHD yielded a metric proportional to blood volume [1,2]. Trials were performed at rest and at an elevated heart rate (HR) from exercise stress.
Results: Induced VMHD was shown to increase from the baseline during exercise by 59% and 106% for the healthy subject and the athlete, respectively; resulting in a 47% difference in VMHD variations between the trained athlete and the healthy subject (Fig. 1c).
Conclusions: A stand-alone device capable of quickly assessing blood volumes in the field using custom hardware and smartphone technology was developed. The ability of the device to quantify VMHD-derived blood flow was demonstrated.
Ref:  Tse, MRM, 2013.  Gregory, JCMR, 2015.
Author Disclosures: K.J. Wu: None. T. Gregory: None. C. Reeder: None. B. Leitmann: None. A. Huffines: None. S. Donovan: None. L. Mosteller: None. J.R. Murrow: None. Z. Tse: None.
- © 2015 by American Heart Association, Inc.