title: Comparing cardiac action potentials recorded with metal and glass microelectrodes.
abstract: Machine-pulled high-impedance glass capillary microelectrode is standard for transmembrane potential (TMP) recordings. However, it is fragile and difficult to impale, especially in beating myocardial tissues. We hypothesize that a high-impedance pure iridium metal electrode can be used as an alternative to the glass microelectrode for TMP recording. The TMPs were simultaneously recorded from isolated perfused swine right ventricles with a metal microelectrode and a standard glass microelectrode during pacing and during ventricular fibrillation. The basic morphology of TMP recorded with these electrodes was comparable. The action potential duration (APD) at 90% repolarization was 241 +/- 29 ms for the metal microelectrode and 236 +/- 31 ms for the glass microelectrode with a good correlation (r = 0.99, P < 0.0001). The maximum slope value of the APD restitution curves during pacing was also significantly correlated. One metal microelectrode and >20 glass microelectrodes were needed per study. We conclude that, in isolated perfused swine right ventricles, the TMP recorded by the metal microelectrode is comparable with that recorded by the glass microelectrode. Because the metal microelectrode is more durable than the glass microelectrode, it can serve as an alternative for APD recording and for restitution analyses.
authors.affiliation: Division of Cardiology, Department of Medicine, Cedars-Sinai Medical Center and University of California Los Angeles School of Medicine, Los Angeles, California 90048, USA.
authors.forename: C
authors.initials: C
authors.lastname: Omichi
authors.forename: M H
authors.initials: MH
authors.lastname: Lee
authors.forename: T
authors.initials: T
authors.lastname: Ohara
authors.forename: A M
authors.initials: AM
authors.lastname: Naik
authors.forename: N C
authors.initials: NC
authors.lastname: Wang
authors.forename: H S
authors.initials: HS
authors.lastname: Karagueuzian
authors.forename: P S
authors.initials: PS
authors.lastname: Chen
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D004594:Electrophysiology / Q000295:instrumentation* / Q000379:methods*; D005260:Female; D005898:Glass; D006352:Heart Ventricles / Q000166:cytology; D066298:In Vitro Techniques; D007495:Iridium; D008297:Male; D008839:Microelectrodes; D018485:Muscle Fibers, Skeletal / Q000502:physiology*; D009206:Myocardium / Q000166:cytology*; D010138:Pacemaker, Artificial; D013552:Swine; D014693:Ventricular Fibrillation / Q000503:physiopathology; D016276:Ventricular Function
chemical_list: D007495:Iridium