Author + information
- Received February 28, 1983
- Revision received May 23, 1983
- Accepted May 25, 1983
- Published online November 1, 1983.
- Richard E. Kerber, MD, FACC*,
- Robert Hoyt, MD,
- Alfred Aronson, MD,
- Robert Kieso, MS and
- Jeffrey Melton, BS
- ↵*Address for reprints: Richard E. Kerber, MD, Department of Medicine, University of Iowa Hospital, Iowa City, Iowa 52242.
The purpose of this study was to determine the efficacy of a tongue-epigastric defibrillation route in anesthetized dogs. Ventricular fibrillation was induced by rectangular pulses passed down a transvenous catheter into the right ventricle. Three groups of dogs were studied. Group I (15 dogs) received shocks from a 12 cm2 tongue electrode, a 50 cm2 circular, gelled self-adhesive electrode pad placed on the epigastrium and standard transthoracic defibrillator paddle electrodes. Shocks were given at energy levels of 50 to 460 joules (delivered energy, 50 ohm resistance). The success of the tongue-epigastric shocks in achieving defibrillation, and the resistance and current flow were determined at each energy level and compared with the same energy shocks from the standard transthoracic electrodes. In Group II (five dogs), comparisons were made between the 12 cm2 tongue electrode used in the first group of dogs and a larger tongue electrode of 40 cm2. In Group III (five dogs), intracardiac current flow (potential gradient) with tongue-epigastric and standard transthoracic electrodes was studied. In Group I, defibrillation success with the tongue-epigastric electrodes ranged from no success at 50 to 100 joules to 83% success at 460 joules. With standard transthoracic electrodes, success rates ranged from 65% at 50 joules to 100% at 300 joules. At all energies tested, the resistance was significantly higher and current significantly lower using tongue-epigastric compared with transthoracic electrodes. The higher tongue-epigastric resistance is probably related to the longer interelectrode distance; the correlation between interelectrode distance (x, in centimeters) and resistance (y, in ohms) in these dogs was y = 2.2x + 29.6, r = 0.78. In Group II dogs, the larger tongue electrode caused only minimal improvement in current flow and success rates. In Group III dogs, lower values for intracardiac current with tongue-epigastric electrode placement were found, reflecting the lower total current flow and increased interelectrode distance, with a lower proportion of net current traversing the heart.
It is concluded that tongue-epigastric defibrillation is feasible in dogs, but the pathway has higher resistance than the transthoracic route and thus more energy is required to defibrillate.
This work was supported in part by Program Project Grant HL-14388 from the National Institutes of Health, Bethesda, Maryland and in part by a grant from the Cardiac Resuscitator Corporation, Wilsonville, Oregon.
- Received February 28, 1983.
- Revision received May 23, 1983.
- Accepted May 25, 1983.
- American College of Cardiology Foundation