Effect of electrode surface area on thresholds for AC stimulation and ventricular fibrillation.

TitleEffect of electrode surface area on thresholds for AC stimulation and ventricular fibrillation.
Publication TypeJournal Article
Year of Publication2007
AuthorsPatel SG, Malkin RA
JournalIeee Transactions on Bio Medical Engineering
Volume54
Start Page1829
Issue10
Pagination1829 - 1836
Date Published10/2007
Abstract

Unintended, weak AC stimulation (leakage currents) from medical devices can cause blood pressure collapse and ventricular fibrillation (VF), potentially even death. Yet, little is understood about AC cardiac stimulation. The objective of this paper is to establish the relationship between the stimulation and VF thresholds for electrode size and stimulation frequency. Twenty-four retired male breeder guinea pigs were anesthetized with isoflurane, a tracheotomy and thoracotomy were performed, and vitals were monitored using the lead II ECG and an optical plethysmograph. The circular flat ends of eleven stainless steel rods were used as electrodes with areas ranging from 0.1 to 26.79 mm2. In the first study, 60-Hz AC stimuli of 5 s duration were delivered with strengths from 25-3000 microA or until VF was induced. In the second group, the current thresholds at 20, 40, 80, and 160 Hz were determined at electrode areas of 0.2, 2.01, and 16.4 mm2. Reactions were categorized as having no effect, having some effect (EFFECT, typically blood pressure collapse), and inducing VF. On a log-log scale, electrode radii had a piecewise-linear relationship with the current thresholds for EFFECT (p

DOI10.1109/TBME.2007.904528
Short TitleIeee Transactions on Bio Medical Engineering