Circulation, Vol 58, 1190-1195, Copyright © 1978 by American Heart Association
MJ Lipton, AK Ream and BH Hyndman
A 60 Hz current, as small as 20 microamperemeter (rms) is capable of
causing ventricular fibrillation when directly applied to the heart.
Significant cost and engineering effort has been spent to construct
monitoring equipment which satisfies the safety regulations requiring
maximum leakage currents below this value. Patients undergoing cardiac
catheterization are particularly at risk from electrical hazards, primarily
because catheters are made from nonconductive materials. A conductive
catheter should allow externally applied currents to leak through its walls
before reaching the catheter tip. A new electrically conductive catheter
was compared with a standard nonconductive catheter. Five dogs were
studied, with 81 attempts to cause fibrillation. Sixty-hertz voltage
between the catheter and an external electrode was increased until
fibrillation occurred or 130 V was reached. Eight states were studied in
randomized sequence: conductive or nonconductive catheter, guidewire or
saline-filled and tip touching wall, or free in left ventricle (verified by
fluoroscopy and cineangiography). The saline-filled and conductive catheter
was safer in that fibrillation never occurred, while fibrillation nearly
always occurred with the nonconductive catheter. A conductive guidewire
negates the protection of the conductive catheter. The application of
conductive catheters could reduce instrumentation costs in laboratories and
intensive care units and improve patient safety.
ARTICLES
A conductive catheter to improve patient safety during cardiac catheterization
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