(Circulation. 1995;92:1627-1633.)
© 1995 American Heart Association, Inc.
Articles |
Endocardial Carbon-Braid Electrodes
A New Concept for Lower Defibrillation Thresholds
Presented in part at the 66th Scientific Sessions of the American Heart Association, Atlanta, Ga, November 8-11, 1993, and published in abstract form (Circulation. 1993;88[pt 2]:I-593).
From the I. Medizinische Klinik, Technische Universität München, Germany (E.U.A., P.C.F., E.M.); the Departments of Medicine and Pathology, Duke University Medical Center, Durham, NC; the Engineering Research Center for Emerging Cardiovascular Technologies and the Department of Biomedical Engineering of the School of Engineering, Duke University, Durham, NC.
Correspondence to Raymond E. Ideker, MD, PhD, Cardiac Rhythm Management Laboratory, Volker Hall G78A, 1670 University Blvd, Birmingham, AL 35294-0019.
Background In the treatment of patients with life-threatening ventricular arrhythmia, transvenous implantable cardioverter/defibrillators provide significant advantages over devices requiring a thoracotomy. This study tested the hypothesis that a new carbon-fiber electrode, designed at the Technische Universität in Munich, Germany, has a lower defibrillation threshold (DFT) than standard transvenous defibrillation electrodes.
Methods and Results In 8 mongrel dogs (weight, 25.2±0.8 kg; heart weight, 192±19 g), we examined the efficacy and electrical characteristics of a right ventricular endocardial carbon prototype defibrillation electrode (9.5F, 4.4-cm2 surface) compared with a standard CPI 0062 Endotak electrode and a Medtronic 6966 Transvene endocardial right ventricular defibrillation electrode. The new electrode consists of 24 braided, tubular carbon filaments, each containing 1000 highly isotropic carbon fibers of 7-µm diameter, yielding a theoretical electrical surface of 480 cm2. The DFTs were determined in random order between each of the three right ventricular electrodes and a subcutaneous wire array anode placed on the left thorax. A standard step-down/-up DFT protocol of 20-V shock steps was applied. Two different biphasic waveforms with a 1-ms delay between phases were tested: 3.2-ms first phase/2.0-ms second phase, and 6.0-ms first phase/6.0-ms second phase. For the 3.2/2.0-ms waveform, we found a significantly lower DFT for the carbon lead (4.96±1.58 J) compared with the CPI 0062 (6.93±1.67 J) and the Medtronic 6966 (7.49±0.99 J) leads. For the 6.0/6.0-ms waveform, the DFT for the carbon electrode (5.97±2.09 J) was significantly lower than for the Medtronic 6966 lead (8.55±1.93 J) but not for the CPI 0062 lead (6.30±1.41 J). The impedance with carbon was lower than with the other two leads for the 6.0/6.0-ms waveform but not for the 3.2/2.0-ms waveform. For the carbon electrode, the 3.2/2.0-ms waveform had a lower DFT than the 6.0/6.0-ms waveform.
Conclusions The present canine study found a lower DFT for a new carbon electrode compared with DFTs for endocardial defibrillation electrodes made of standard metal. Further long-term animal studies and clinical studies are needed to determine whether carbon materials and braided-lead technology are practical and beneficial in patients.
Key Words: pacemakers • death, sudden • defibrillation
This article has been cited by other articles:
 |
|
 |
|
  R. Gradaus, D. Bocker, A. Dorszewski, B. Lamp, D. Hammel, G. Breithardt, and M. Block Fractally coated defibrillation electrodes: Is an improvement in defibrillation threshold possible? Europace, January 1, 2000; 2(2): 154 - 159. [Abstract] [PDF]
|
|
|
|
 |
|
 M. J. Niebauer, B. Wilkoff, Y. Yamanouchi, T. Mazgalev, K. Mowrey, and P. Tchou Iridium Oxide–Coated Defibrillation Electrode : Reduced Shock Polarization and Improved Defibrillation Efficacy Circulation, November 18, 1997; 96(10): 3732 - 3736. [Abstract] [Full Text]
|
|