Page 2310 - Cote clinical veterinary advisor dogs and cats 4th

1148.e2 Pacemaker: Transthoracic Cardiac Pacing

• Patch electrodes are placed directly over Postprocedure • Only the atria can be paced. No ventricular
cardiac impulse on the left and right hemi- Pacing patch electrodes are removed from skin. pacing is possible. Transesophageal pacing
can be used only in patients with sinus node
VetBooks.ir a small dollop of ECG paste is placed on Alternatives and Their dysfunction and cannot be used in AV block.
thorax. The fur on the chest is shaved, and
Adhesive remover can be used.
the surface of the patch electrode facing the
Relative Merits
skin. Dogs ideally should be placed in lateral
recumbency. Transvenous pacing: SUGGESTED READINGS
DeFrancesco TC, et al: Noninvasive transthoracic
• Ensure accurate ECG sensing of dog’s • Specialized transthoracic pacing system not temporary cardiac pacing in dogs. J Vet Intern
intrinsic cardiac rhythm by adjusting ECG required (expensive) Med 17(5):663-667, 2003.
gain and lead selection. A sensing marker • No skeletal muscle twitching or pain associ- Lee S, et al: The optimal size and placement of
will appear on the animal’s QRS complex, ated with pacing stimulus transdermal electrodes are critical for the efficacy
signaling accurate sensing. • Procedure is more invasive, and implementa- of a transcutaneous pacemaker in dogs. Vet J
183(2):196-200, 2010.
• After setting the pacing rate (range, 40-170 tion requires more time and expertise. Sanchis-Mora S, et al: Anaesthetic management and
beats/min), the pacing current (range, • Can be associated with infection, bleeding, lead complications of pacemaker implantation in dogs.
0-200 mA) is gradually increased until wire displacement, lead wire–induced arrhyth- Vet Rec 175(12):303, 2014.
ventricular capture is confirmed on the ECG mia, cardiac perforation, and thromboembolism
monitor and by palpation of a corresponding Transesophageal pacing: RELATED CLIENT EDUCATION
arterial pulse. Ventricular capture is recog- • Same merits as with transvenous pacing in
nized by a wide QRS complex after a pacing terms of no pain or twitching associated with SHEET
spike on the ECG. The pacing current is pacing stimulus and less expensive pacing Consent to Perform General Anesthesia
maintained just above the capture threshold. system
• Pacing rate and current ranges usually • Less invasive, less expertise needed, and faster AUTHOR: Teresa DeFrancesco, DVM, DACVIM,
are 60-80 beats/min and 50-110 mA, time to pacing compared to transvenous DACVECC
respectively. pacing EDITORS: Leah A. Cohn, DVM, PhD, DACVIM; Mark S.
Thompson, DVM, DABVP

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