Complications of pacemakers can range from mild to serious. The most common are seroma or hematoma around the pulse generator,
dislodgment of the pacing lead from the heart, congestive heart failure from concurrent heart disease or subsequent myocardial
failure, tissue reaction sufficient to prevent pacing capture (known as exit block) and malfunctions of the pacing system.
Infections occur infrequently, but can be months after the implantation, from hematogenous spread. System malfunctions include
lead fracture or dislodgement, battery depletion or damage to the pulse generator circuitry from electrical impulses (i.e.,
electrocautery or defibrillation).
One should never attempt venipuncture in the jugular vein that carries the pacing lead. Striking the lead with a hypodermic
needle could damage the insulation around it, or the actual metallic core of the lead, resulting in immediate malfunction
of the system and potential life-threatening complications.
Patients with pacemakers have a distinctive electrocardiogram pattern that shows a pacing spike and typically demonstrate
wide QRS complexes. Knowing the pacemaker rate setting can alert the veterinarian to depletion of battery life in a pulse
generator. Pulse generators will automatically reduce their rate when the battery weakens, indicating it is time to replace
Modern pacemakers are not susceptible to interference from microwave ovens, garage door openers or pet-identification microchip
readers. Patients with pacemakers should remain clear of strong magnetic fields, such as magnetic resonance imaging or children
playing with magnets. Patients with implanted pacemakers cannot wear electric-shock collars like those used with invisible-fencing
Dr. Hoskins is owner of DocuTech Services. He is a diplomate of the American College of Veterinary Internal Medicine with
specialities in small animal pediatrics. He can be reached at (225) 955-3252, fax: (214) 242-2200 or e-mail: firstname.lastname@example.org