CardioBird

Estimated reading time: 3.64 minutes

As primary care veterinarians, we all know the challenge: a patient who needs an ECG, but is too stressed to cooperate. A fearful or anxious animal can make obtaining a quality ECG tracing difficult, if not impossible. And, the stress itself can alter the ECG, leading to misinterpretations. This article provides a practical, evidence-based approach to performing ECGs on these challenging patients, ensuring accurate results and a better experience for everyone involved.

 

Understanding the Autonomic Nervous System and the ECG

The autonomic nervous system (ANS), comprised of the sympathetic and parasympathetic branches, exerts significant control over cardiac electrophysiology [Shen, M.J. & Zipes, D.P., 2014].

• Sympathetic Activation: In a “fight or flight” response, the sympathetic nervous system increases heart rate by accelerating electrical signal conduction, enhancing the automaticity of pacemaker cells, and boosting the firing rate of the sinoatrial (SA) node. The atrioventricular (AV) node’s conduction velocity also increases.
• Parasympathetic Activation: Conversely, the parasympathetic system slows the heart rate by reducing electrical signal conduction, decreasing pacemaker cell automaticity, and lowering the SA node’s firing rate. AV nodal conduction also slows.

These changes are important to consider in different physiological states:

• Pathological States: Heightened sympathetic activity in heart failure or long QT syndrome (LQTS) can be proarrhythmic. Increased parasympathetic tone can exacerbate arrhythmias related to AV or SA nodal disease.
• Non-Sedated States (Anxiety, Excitement, Pain): Sympathetic activation predominates. The interplay of psychological and pathological factors should be factored into ECG interpretation.
• Sedated/Anesthetized States: Sedation typically suppresses sympathetic tone, leading to relative parasympathetic dominance. This effect must be considered when interpreting the ECG.

 

Low-Stress Handling: The Cornerstone

Before any instrumentation, prioritize a calm environment [Lloyd, J.K.F., 2017]. Recognize canine and feline stress signals (cowering, hiding, dilated pupils, etc.) [Lloyd, J.K.F., 2017].

• Pre-Visit Strategies:
  • Pre-Visit Pharmaceuticals (PVP): These can significantly reduce anxiety [Erickson, A., et al., 2021; Fear Free SM, 2018].
    • Dogs: Trazodone is often effective. Administer 3-10 mg/kg PO the night before and 1-2 hours before the appointment. Note that it may take up to an hour to take effect, especially if given with food.
    • Cats: Gabapentin is a common choice. Give 50-100 mg/cat PO 2-3 hours prior to the visit [Fear Free SM, 2018].
    • Important Note: These dosages are guidelines only. Always perform a test dose beforehand to assess individual response and watch for paradoxical excitement [Fear Free SM, 2018].
  • Client Communication: Instruct owners on carrier and car acclimation [Lloyd, J.K.F., 2017; Fear Free Pets].
• In-Clinic Techniques:
  • Waiting Area: Keep cats and dogs separate, use visual barriers, and elevate cat carriers [Lloyd, J.K.F., 2017].
  • Exam Room: Create a comfortable, inviting space with soft bedding, treats, and toys [Lloyd, J.K.F., 2017].
  • Approach: Avoid looming and direct eye contact. Let the pet approach you [Lloyd, J.K.F., 2017].
  • Handling: Use gentle, confident movements, and secure support [Yin, S.].

 

CardioBird Specific Tips for Low-Stress ECGs

CardioBird’s quick and easy ECG operation can be particularly useful:

• Minimize Restraint: Often, you can get a tracing with minimal restraint, even with the animal sitting or standing. Refer to our previous article on the effect of body position on the recorded ECG.
• Preparation: Have the CardioBird app and device ready, seeing running signals on screen before handling the animal.
• CardioBird ECG Clips: Use CardioBird ECG clips designed for veterinarians veterinary patients for reduced pressure.
• Electrode Paste/Gel-pad: Consider these for sensitive animals.
• Record Deviations: Note any non-standard positioning in the app.

 

Sedation: A Careful Choice

Sedation should be reserved for essential ECGs when low-stress methods fail.

• Considerations:
  • Patient Stability: Stabilize unstable patients first.
  • Drug Selection: Some sedatives alter ECGs [Gurney, M. & Bradbrook, C., 2016].
    • Avoid Alpha-2 Agonists (dexmedetomidine, xylazine) in cardiac patients. These can cause bradycardia and AV block, potentially mimicking or masking underlying disease.
    • Opioids (fentanyl) can also cause bradycardia.
    • Acepromazine can cause vasodilation and hypotension, affecting heart rate.
  • Record Everything: Document the drug, dose, and time in the CardioBird app.

 

Interpreting ECGs with Autonomic Influence

Always consider the patient’s clinical status and medications. A rapid heart rate might be stress-related, while a slow rate could be a drug effect. Repeat the ECG after calming or drug washout, if possible.

 

In summary: By combining low-stress handling, judicious sedation, and careful interpretation, you can obtain accurate CardioBird ECGs, minimize patient anxiety, and improve care.

 

Reference:

• Erickson, A., Harbin, K., MacPherson, J., Rundle, K., & Overall, K. L. (2021). A review of pre-appointment medications to reduce fear and anxiety in dogs and cats at veterinary visits. The Canadian veterinary journal = La revue veterinaire canadienne, 62(9), 952–960.
• Fear Free SM. (2018). Pre-Visit Pharmaceuticals. Retrieved from https://fearfreepets.com/wp-content/uploads/delightful-downloads/2018/07/PVP-Drug-Charts-Updated-3-27-18-1.pdf
• Gurney, M., & Bradbrook, C. (2016). Common ECG changes in the perioperative period. In Practice, 38(5), 219–228.
• Lloyd, J.K.F. (2017). Minimising Stress for Patients in the Veterinary Hospital: Why It Is Important and What Can Be Done about It. Veterinary Sciences, 4(2), 22.
• Lloyd, J.K.F. (n.d.). Fear Free Pets. Retrieved from https://fearfreepets.com/
• Shen, M. J., & Zipes, D. P. (2014). Role of the autonomic nervous system in modulating cardiac arrhythmias. Circulation research, 114(6), 1004–1021.
• Yin, S. Low Stress Handling. Retrieved from https://cattledogpublishing.com/why-and-what-is-low-stress-handling/