A Technique for Conducting Noninvasive Cardiac Electrophysiology Studies in Conscious Swine

Abstract

A noninvasive method was developed in swine for conducting cardiac electrophysiology (EP) studies without the potential confounding effects of sedatives or anesthetics. Following a 1-week conditioning regimen in the EP laboratory, 3-month-old Hanford miniature swine underwent transvenous pacemaker (PM) implantation under isoflurane anesthesia. Two bipolar screw-in pacing leads were inserted into the left external jugular vein, with one positioned in the right atrial appendage and one in the myocardium at the right ventricular apex. The leads were attached to a multiprogrammable pulse generator, and the pacing system was placed in a subcutaneous pocket. At weekly intervals following implantation, conscious, unsedated swine were restrained in a sling for noninvasive programmed stimulation (NIPS) using a programmable telemetry system. A NIPS protocol to induce arrhythmias was performed separately for the atrium and ventricle. Data for this model are reported. Complications occurred in 6 of 26 animals studied and included one infection of the PM pocket, three cases of dislodgement of the atrial lead, and rotation of the generator within the pocket in two animals, preventing communication with the PM. This technique has been used to perform EP studies successfully in swine and has been utilized in a variety of studies of the cardiac conduction system.

Key Words:

• animal model
• electrophysiology
• swine