Heart Rate and Rhythm
Electrocardiography (ECG) done before and during anesthesia give the veterinarian important data regarding heart rate, rhythm
and abnormal complexes. Lead2 is used primarily to monitor rate and rhythm in anesthetized patients. Continuous monitoring
of the ECG pattern enables early recognition of electrical changes associated with disorders of conduction.
Electrocardiograms also can be generated using esophageal probes. While the patient is anesthetized, a probe is inserted into
the esophagus until the distal electrode reaches the area dorsal to the heart base. If the ECG tracing appears small, the
probe may not be inserted far enough. If inserted too deep, the tracing may appear inverted.
ECG gives minimal information on cardiac contractility and tissue perfusion. The presence of normal-appearing complexes does
not indicate the patient's tissues are adequately perfused. When evaluating ECG results, first examine the rate and then the
rhythm. If either is abnormal, a treatment decision usually involving the anesthesia machine settings must be made. Note that
the ECG should be used with another form of monitoring (ETCO2 and/or BP) for patient evaluation during anesthesia.
In conclusion, five-parameter monitoring is a highly valuable tool in keeping patients safe during dental procedures, and
it will lead to better short- and long-term outcomes, reduce the stress in the dental suite and make the veterinary operation
Dr. Bellows owns Hometown Animal Hospital and Dental Clinic in Weston, Fla. He is a diplomate of the American Veterinary Dental College
and the American Board of Veterinary Practitioners. He can be reached at (954) 349-5800; e-mail: email@example.com
1. Monk G, Saini V, Weldon BC, et al. Anesthetic Management and One-Year Mortality After Non-Cardiac Surgery. Anesth Analg 2005;100:4-10.