The heart is a powerful organ, sending blood through thousands of miles of vessels to fuel the body. This intricate system works continuously, rhythmically ~100,000 times per day, to provide us humans with oxygen and nutrients while cleansing our systems of harmful waste. Each cycle is activated by an electrical impulse. This electrical impulse is reflected by the electrocardiogram (ECG or EKG). An ECG signal can disclose a cardiac or neurological disturbance. Acquiring hundreds of these signals permits a clinician to study the traces for variations from the “norm”, or baseline ECG. Analysis of the traces can reveal a disorder via changes in the rate, shape, rhythm, and length of the PQRST interval durations. Numerous human conditions, including multiple sclerosis, diabetes, and Parkinson’s disease, are associated with changes in the ECG.
Millions of mice are used annually to better understand and treat human disorders. And though heart monitoring is routine in humans, ECG monitoring in mice (whose hearts beat ~1 million times each day!) has been hampered by the need for anesthesia and surgery. Though the periodicity of the mouse ECG signal is about 10x faster than that of humans, the PQRST morphology is remarkably similar, reflecting the incredibly fortunate scale model of the heart afforded by mus musculus. Mouse Specifics, Inc. now provides The ECGenie, elegant non-invasive ECG recording instrumentation to support the research community’s increasing sensitivities and adherence to 21st century animal care and use practices. The ECGenie requires no anesthetic or surgery to record the ECG in awake laboratory animals. Alternatives to the ECGenie require anesthesia, surgery, pain, and recovery. The ECGenie, and implantation of radiotelemetric implants, each provide researchers with ECG recordings in awake mice; however the protocols for each are far from similar.
If you have the skill to weigh a mouse on a typical laboratory scale, you also have the technical capability to record its ECG – it’s that easy to use the ECGenie. Telemetry, in contrast, requires extensive approvals, skill as an animal surgeon, access to controlled subtances, and hyper vigilant animal husbandry to prevent post-surgical morbidity and mortality. The protocol requires skilled surgeons to anesthetize and carefully insert the radio transmitter into the animal, with an advised recovery period of ~3 weeks for the subjects to regain their pre-operative metabolic status.
With the ECGenie of Mouse Specifics, Inc., heart monitoring in lab animals becomes much simpler and less expensive. Factoring in the cost of surgery, implantation, and recovery, the ECGenie is ~ 1/10th of the cost of telemetry. The ECGenie provides researchers the ability to monitor large quantities of awake laboratory animals in a short span of time at a more reasonable price. By simply placing the animal on the patented ECGenie instrumented platform, the cardiac signal is detected passively through the plantar surface of the paws, resulting in an Einthoven limb lead ECG. The ECGenie includes hardware and software to mitigate noise associated with detecting the small electrical signals coming from an awake moving subject. The animals are studied under essentially the same conditions, eliminating the possibility that changes in activity and time of day will mask a phenotype as often happens with data from telemetry. With the companion EzCG analysis software, all of the PQRST interval durations, as well as heart rate variability, in the time and frequency domain, are reported by the ECGenie system. Heart failure? Low heart rate variability. Cardiac hypertrophy? Long QRS. Drug induced arrhythmia? QT dispersion changes. Anything desired from telemetry is delivered by the ECGenie.
Protocols for recording the ECG via telemetry and via the ECGenie are presented here in this brief video to help visualize the comparison of the two. To learn more about the ECGenie, click here, and browse through the Mouse Specifics, Inc. website.