VN April 2023

Vetnuus | April 2023 16 Introduction The electrical activity of cardiac muscle cells can be monitored by an electrocardiogram (ECG) tracing. 5 , 15 The ECG tracing consists of three primary complexes: P wave, QRS complex, and T wave, which represent atrial depolarization and ventricular depolarization, respectively (Fig 1). Electrocardiography is particularly useful during long-term anesthesia when disturbances in acid-base and electrolyte balance can lead to arrhythmias or during procedures in which disturbances in cardiac function or rhythm can be anticipated, such as thoracic surgery. 5 Veterinary instruments that accurately monitor rapid heart rates and are capable of displaying low-voltage ECG signals are best in small exotic animals (Fig 2). 5,7 Ideally, the ECG should also have freeze capability and recording speeds up to 100 mm/s. 7,8,9 Electrocardiography in Exotic Animal Species Lafferty K, Pollock CG. Electrocardiography in exotic animal species. Date: May 17, 2018 By: Katrina Lafferty, RLAT, VTS (Anesthesia/Analgesia) Second Author:Christal Pollock, DVM, DABVP (Avian Practice) Reviewed by: Barbara Ambros, DrMedVet, MVetSc, DECVAA and Jody Nugent- Deal, RVT , VTS (Anesthesia), VTS (Exotic Companion Animal) Key Points • Electrocardiography monitors the electrical activity of cardiac muscle cells and is particularly useful during long-term anesthesia when disturbances in acid-base and electrolyte balance can lead to arrhythmias. • Alligator clips are generally not attached directly to small patients or in species with delicate skin. Instead clips are attached to the tips of small-gauge hypodermic needles or stainless-steel suture that has been passed through the skin and subcutaneous space. • Adhesive electrocardiogram (ECG) patches or button electrodes can be placed on the foot pads of small mammals or directly onto the skin of mammals or large, smooth reptiles. • The normal ECG tracing in the bird can resemble ventricular tachycardia, primarily because of a large negative S wave. • The normal reptile ECG tracing can include an SV wave, which represents depolarization of the sinus venosus, low amplitude waveforms, and longer ST and QT intervals. • Always use caution when using ECG as an indicator of life in reptiles as the heart can continue to contract for long periods of time following death. Always use an additional monitoring technique to confirmcirculation like capnography or Doppler ultrasound flow. Figure 1: The classic ECG tracing consists of aPwave (atrial depolarization), QRSwave (ventricular depolarization), andTwave (ventricular repolarization). Illustration fromAnatomy&Physiology, ConnexionsWeb site viaWikimediaCommons.