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Septal His‐Purkinje Ventricular Pacing in Canines: A New Endocardial Electrode Approach
Author(s) -
KARPAWICH PETER P.,
GATES JAMES,
STOKES KENNETH B.
Publication year - 1992
Publication title -
pacing and clinical electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.686
H-Index - 101
eISSN - 1540-8159
pISSN - 0147-8389
DOI - 10.1111/j.1540-8159.1992.tb03012.x
Subject(s) - medicine , cardiology , purkinje fibers , cardiac pacing , ventricular pacing , electrophysiology , heart failure
Ventricular activation sequences and cardiac performance are influenced by pacing sites. Stimulation of or close to the specialized a trioventricular (AV) conduction system optimizes paced ventricular function compared to alternative epi‐ or endocardial muscle conduction sites. This study reports a new endocardial electrode implant approach to approximate septal His‐Purkinje ventricular pacing. Five 6‐month‐old beagles were used, A custom, platinum‐iridium, exposed helical screw electrode (Medtronic, Inc.), 4.5‐mm long, with a 17.8‐mm 2 surface area, was designed with a polyurethane covered 4 filar MP35N nickle conductor lead. An 8 French sheath (USCI, Inc.) was modified as introducer to permit simultaneous implant intracardiac pressure and electrogram recordings. Following a thoracotomy, the introducer was inserted through the right atrial appendage and advanced to record optimal His‐bundle electrogram while maintaining atrial pressure along the septal tricuspid valve annulus. After electrode implant, ECG demonstrated narrow paced QRS morphology. Mean implant values showed sensed R wave 6,3 mV, slew rate 0.65 V/sec, pacing impedance 319 ohms, and threshold 0.9 V/3.3 mA at 0.5‐msec output. Necropsy showed implant above the tricuspid annulus with electrode extension into and contained within the proximal ventricular septum. This study demonstrates that an endocardial septal approach to His‐Purkinje ventricular pacing to optimize paced ventricular function is feasible with a new electrode design and precise septal implant technique. Alternative introducer designs may permit tranvenous application of this approach.