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Mobile Electrocardiogram Monitor for Bottlenose Dolphins in the Marine Environment


RT&L FOCUS AREA(S): Biotechnology TECHNOLOGY AREA(S): Biomedical;Electronics OBJECTIVE: Develop a wearable, wireless electrocardiogram (ECG) unit to analyze and communicate heart rate and rhythm in bottlenose dolphins in the marine environment (i.e., salt water). DESCRIPTION: The U.S. Navy uses bottlenose dolphins (Tursiops truncatus) in the Fleet’s operational Marine Mammal Systems to protect harbors and Navy assets, detect and/or mark underwater mines, and locate and attach recovery hardware to underwater objects. To contribute to maintaining the fitness of these marine mammals for duty and the readiness of the U.S. Navy Marine Mammal Systems, the U.S. Navy is interested in developing a wearable, wireless ECG unit to monitor dolphin cardiac rate and rhythm while the animal is at rest and actively swimming in the marine environment. Synchronized information regarding the swimming depth of the animal is required. With aging populations of marine mammals under professional care, cardiac disease is of increasing clinical concern. Over the years, the U.S. Navy Marine Mammal Program has diagnosed several dolphins with cardiac disease, particularly in geriatric animals. Developing improved cardiac monitoring techniques are vital to identifying and monitoring cardiac disease cases, supporting healthy aging, and enhancing dolphin cardiac medicine. Due to their marine environment home, no clinically viable options for in-water ECG monitoring exist in bottlenose dolphins. Limitations include electrode signal interference from seawater, animal motion artifacts, and lack of wireless systems. Several studies have described ECG evaluation in cetaceans over the last two decades [Ref 1-6]. However, there are no commercially available units that allow for ECG recording while the dolphin is swimming or diving untethered. Electrodes are also very sensitive to interference from motion and seawater. Analyzing not only heart rate, but heart rhythm as well, while dolphins are free swimming will provide valuable data to drive clinical decision making and will be especially valuable in monitoring animals with known dysrhythmias. Examples of cardiac health issues in Navy dolphins leading to dysrhythmias have included dilated cardiomyopathy, valvular disease, and arrhythmias due to a variety of etiologies. This need for “in ocean“ monitoring is significant because, while we are able to obtain ECG data with the animal out of the water, we do not fully understand the physiologic consequences that may be occurring with the animal out of its aquatic habitat, potentially confounding the ECG interpretation. The techniques that would be most reflective of true cardiac health will be best assessed while the animal is in the natural marine environment. This technique would also allow for cardiac event monitoring over longer periods of time, which may identify important dysrhythmias not evident in brief ECGs. As such, proposed concepts should generate a reliable, wireless, mobile ECG device for in-water recording in dolphins that can be used and evaluated by veterinarians to help maintain Navy dolphin health. PHASE I: BASE period: Conceptualize, design, and build a prototype mobile ECG monitor for bottlenose dolphins. The mobile ECG monitor should be cordless and wearable, allowing dolphins to swim safely and freely in enclosures or the open ocean, up to 50m depth and at temperatures between 32-98 degrees F. The device should have 4-leads with 6 vector recordings (i.e., leads I, II, III, AVR, AVL, AVF). The device should be able to transmit ECG data in real time via Bluetooth to a laptop or tablet when worn at the surface or out of water; it should also be able to record and store ECG data when the dolphin is swimming or diving underwater for a minimum of 24 hours, which can then be transmitted or downloaded onto a laptop/tablet once the animal has returned from swimming or diving. Synchronized information on the depth the animal swimming is also required. Battery life should allow for several hours of recording at a time. The wearable design, materials, and lead locations should be refined to create an optimal working prototype and allow for animal safety and comfort. To allow for future testing and refinement of the ECG unit, documentation required by the U.S. Navy to conduct research involving vertebrate animals should be completed and approval obtained. Collaboration with dolphin ECG experts and board-certified veterinary cardiologists is recommended. OPTION period: Test and refine the prototype mobile ECG monitor for bottlenose dolphins. PHASE II: Build an operable mobile ECG monitor with the technology developed in Phase I. Demonstrate/validate the operability and reliability of the system on bottlenose dolphins in the marine environment. Document and report the ECG findings of dolphins wearing the unit, and refine the technology for optimal use in terms of wearability (i.e., lack of physical harm or change in animal’s behavioral or condition) and ECG quality (i.e., interpretable ECG trace with lack of artifacts, repeatability, and comparison to out of water measurements). PHASE III DUAL USE APPLICATIONS: Efforts should lead to development of a product that meets appropriate standardization requirements and focuses on technology transition, preferably commercialization (i.e., marine mammal health management industry for zoos, aquariums, marine mammal parks, marine mammal conservation organizations, etc.; professional or recreational diving industry). REFERENCES: 1. Harms, C.A.; Jensen, E.D.; Townsend, F.I.; Hansen, L.J.; Schwacke, L.H. and Rowles, T.K. "Electrocardiograms of bottlenose dolphins (Tursiops truncatus) out of water: habituated collection versus wild postcapture animals." J Zoo Wildl Med, Vol. 44, December 31, 2013, pp. 972-981. doi:10.1638/2013-0093.1. 2. Yaw, T.J.; Kraus, M.S.; Ginsburg, A.; Clayton, L.A.; Hadfield, C.A. and Gelzer, A.R. "Comparison of a smartphone-based electrocardiogram device with a standard six-lead electrocardiogram in the Atlantic bottlenose dolphin (Tursiops truncatus)." J Zoo Wildl Med, Vol. 49, September 1, 2018, pp. 689-695. doi:10.1638/2017-0140.1. 3. Williams, T.M.; Fuiman, L.A.; Kendall, T.; Berry, P.; Richter, B.; Noren, S.R.; Thometz, N.; Shattock, M.J.; Farrell, E.; Stamper, A.M. and Davis, R.W. "Exercise at depth alters bradycardia and incidence of cardiac anomalies in deep-diving marine mammals." Nat Commun, Vol. 6, article 6055, January 16, 2015. doi:10.1038/ncomms7055. 4. Bickett, N.; Tift, M.; St. Leger, J. and Ponganis, P. "Heart Rate Regulation in the Killer Whale." FASEB J, Vol. 30, April 1, 2016, pp. 1230.9-1230.9. 5. Elmegaard, S.L.; Johnson, M., Madsen, P.T. and, McDonald, B.I. "Cognitive control of heart rate in diving harbor porpoises." Curr Biol, Vol. 26, November 21, 2016, pp. R1175-R1176. doi: 10.1016/j.cub.2016.10.020. 6. Goldbogen, J.A.; Cade, D.E.; Calambokidis, J.; Czapanskiy, M.F.; Fahlbusch, J.; Friedlaender, A.S. et al. "Extreme bradycardia and tachycardia in the world’s largest animal." PNAS, Vol. 116, December 10, 2016, pp. 25329-25. doi:10.1073/pnas.1914273116.
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