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The Effect of Electrode Design on the Efficiency of Delivery of Radiofrequency Energy to Cardiac Tissue In Vitro
Author(s) -
BLOUIN LEONARD T.,
MARCUS FRANK I.
Publication year - 1989
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.1540-8159.1989.tb02640.x
Subject(s) - electrode , biomedical engineering , power density , medicine , joule (programming language) , materials science , power (physics) , electrical engineering , efficient energy use , chemistry , physics , quantum mechanics , engineering
Four types of electrodes were studied with respect to efficiency of delivery of radiofrequency energy (HFE) and characteristics of the lesions produced in dog ventricular muscle in vitro. An imbeddable needle electrode was found to be the most efficient of the four types studied, with a lesion volume/energy‐delivered ratio of 1.10 mm 3 joule at an optimum power level of 2.8 watts and power density at the electrode surface of 0.45 watt/mm 2 . Lesion volume was linearly related to energy delivered at all power levels used below a power density of 0.64 watt/mm 2 , at and above which tissue impedance increased abruptly. The electrode catheter typically used for RFE ablations was the least efficient at 0.15 mm 3/ joule and a power density at the electrode surface of 0.50 watt/mm 2 at 6.27 watts. Masking 2/3 of the electrode surface with electrically insulating epoxy caused the RFE current to be directed into the tissue, resulting in a threefold increase in efficiency (0.46 mm 3 /joule) at less than half the power (2.79 watts). A flat, thermally insulated electrode with larger (10 mm 2 ) contact area approached the efficiency of the imbedded electrode with a ratio of 0.69 mm 3 /joule at a low power density of 0.19 watt/mm 2 and 1.85 watt power level. Characteristics of an “ideal” electrode for RFE lesion production in cardiac tissue are discussed.