Ensure Safer Procedures with Preanesthetic ECGs

Vet, vet tech, and Yorkie patient

As veterinarians, we do all we can to make sure that every patient is as safe as possible for general anesthesia before embarking on such an event. Yet, despite all our precautions, there are still deaths that occur under anesthesia and they are largely unexplained—no predisposing cause, no warning, just an adverse reaction.1

Most veterinarians routinely run preanesthetic blood work to look for metabolic or electrolyte abnormalities that may complicate anesthesia. Best practice dictates that we include a full chemistry panel with electrolytes, a CBC and urinalysis. Running these diagnostics will help inform you of your patient’s ability to handle anesthesia. It’s also a good opportunity to gather baseline diagnostic results for that patient for future comparison and trending.

While these diagnostics are helpful for screening for anesthetic complications, there is more we can do to help ensure safer anesthetic events for all patients. Testing for every possible disease in a seemingly healthy patient is not a best practice, nor is it cost effective. However, there are other quick, easy and affordable screening tests that we can run to learn more about our patients’ underlying health.

An extra level of confidence

One such test that is often overlooked but which can provide more thorough preventive care and an additional level of confidence is the electrocardiogram, or ECG. While the ECG tests only for electrical conduction within the heart and does not screen for heart disease in general, it is surprising how many preoperative ECGs performed reveal abnormal results.

A retrospective review of 211 consecutive preoperative ECGs revealed 27 (13%) abnormal results.2 As a cardiologist, I wanted to know what exactly was abnormal and what that actually meant for these patients. Since cardiac structure and function can be very normal even in cases where the ECG axis is abnormal, I removed the ECG results that were abnormal because of an axis deviation. That left 7.1% of cases deemed abnormal for arrhythmias alone. You might think that these arrhythmias would be noticed on a physical examination; however, in none of these cases was an arrhythmia noted in the history or physical examination.

Here is a section of a report from a case where a serious arrhythmia was documented:

Telemedicine card

This case demonstrates how even in an asymptomatic patient, serious electrical abnormalities can be present. These abnormalities can significantly increase not only the anesthetic risk for this patient, but can also be indicative of underlying cardiac disease that requires further diagnostics and treatment.

View the full report here: IDEXX Telemedicine Consultants Cardiology Report File Icon

The new Cardiopet ECG device helps to facilitate consultation and collaboration with our cardiologists by letting you submit your case at your convenience.

  • You can take the ECG and upload the case to vetmedstat.com immediately, or click ‘submit later’ to save the ECG and submit the case later if you are busy.
  • You can batch your preoperative cases and submit them all at once.
  • The Cardiopet ECG also facilitates creating a full consult case. For example, if you know a patient has preexisting cardiac disease, you can perform an ECG and thoracic radiographs with or without an echocardiogram prior to the day of the anesthetic event to fully assess the cardiac disease. This will allow you to start the patient on medications prior to anesthesia, if these are deemed necessary.

Safeguarding our patients is our first priority. Including an ECG in preoperative diagnostic screening is one more cost-effective measure we can take to ensure their safety during anaesthetic events. Like other diagnostics, the ECG provides information that you may not get from a history or physical examination or even preanesthetic blood work. That ECG may prompt the need for further diagnostics, or treatment and or signal the need to postpone the anesthetic event.

While the ECG tests only for electrical conduction within the heart and does not screen for heart disease in general, it is surprising how many preoperative ECGs performed reveal abnormal results.

Allison Adams, DVM, DACVIM (Cardiology)

Allison Adams, DVM, DACVIM

Dr. Adams received her DVM degree from the University of Tennessee in 2004. She completed a rotating internship in 2005 at the University of Pennsylvania and her cardiology residency in 2008 at North Carolina State University. She began her career in a private specialty practice in Charleston, South Carolina, and later joined the cardiology department at Colorado State University. In 2010, she became the manager of cardiology for IDEXX Telemedicine Consultants.

  1. Gerdin JA et al. Post-mortem findings in 54 cases of anesthetic associated deaths in cats from two spay-neuter programs in New York State. J Feline Med Surg. 2011;13(12):959–66.
  2. Data on file at IDEXX Laboratories. Inc.