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Esophageal Countershock: Anthropometric Determinants of Impedance
Author(s) -
McKeown Pascal P.,
Croal Simon,
Allen J. Desmond,
Anderson John,
Khan Mazhar M.,
Adgey A. A. Jennifer
Publication year - 1995
Publication title -
academic emergency medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.221
H-Index - 124
eISSN - 1553-2712
pISSN - 1069-6563
DOI - 10.1111/j.1553-2712.1995.tb03087.x
Subject(s) - medicine , cardioversion , cardiology , atrial fibrillation , esophagus , anesthesia
ABSTRACT 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.