Myopotential inhibition of demand pacemakers.
Two patients are described in whom skeletal muscle potentials originating in the shoulder girdle muscles during isometric movement suppressed the discharge of a ventricular demand unipolar pacemaker, resulting in syncope. Converting the pulse generator into a fixed-rate mode with the magnet prevented the inhibition. Improved filters or wider use of bipolar electrodes should prevent this form of interference.
Lazar
A V
AV
Pacemaker Telemetry Center, Texas Heart Institute, St. Luke's Episcopal Hospital, Houston, Texas 77225, USA.
Mihalick
M J
MJ
De Young
S A
SA
Hall
R J
RJ