Esophageal Countershock: Anthropometric Determinants of Impedance
Article first published online: 29 SEP 2008
© 1995 Society for Academic Emergency Medicine
Academic Emergency Medicine
Volume 2, Issue 1, pages 63–68, January 1995
How to Cite
McKeown, P. P., Croal, S., Allen, J. D., Anderson, J., Khan, M. M. and Adgey, A. A. J. (1995), Esophageal Countershock: Anthropometric Determinants of Impedance. Academic Emergency Medicine, 2: 63–68. doi: 10.1111/j.1553-2712.1995.tb03087.x
- Issue published online: 29 SEP 2008
- Article first published online: 29 SEP 2008
- Received: September 7, 1993 Revision received: December 29, 1993 Accepted: January 6, 1994
Objective: To examine the use of a novel esophageal electrode system for countershock of atrial and ventricular tachyarrhythmias, with particular regard to the measurement of transesophageal and transthoracic impedances and their association with anthropometric variables.
Methods: Transesophageal cardioversion was attempted during 131 episodes of arrhythmia in 105 patients (including 109 episodes of atrial fibrillation). The esophageal system also was used in 29 patients undergoing electrophysiologic studies for investigation of ventricular tachyarrhythmias. Transesophageal and transthoracic impedances were estimated during passage of a high-frequency, low-amplitude current between the respective electrodes. Impedance estimates were associated with anthropometric measurements using linear regression (least-squares method).
Results: In the group of patients undergoing attempted transesophageal cardioversion, the mean estimated transesophageal impedance of 52.6 ± 11.7 Ω was significantly lower than the mean estimated transthoracic impedance of 63.1 ± 16.4 Ω(n = 104, p < 0.01). For all the patients, transesophageal impedance was associated with weight, body mass index, and chest circumference (all r 0.65, p < 0.01). Transthoracic impedance was associated with the same factors (all r 0.55, p < 0.01).
Conclusion: This esophageal electrode system results in lower impedance values for countershock between the esophagus and the cutaneous cardiac apex in comparison with standard transthoracic cutaneous electrode placement. Both techniques are dependent on anthropometric factors.