[Functional disorders of chamber demand (VVI) and sequential AV (DDD) pacemakers caused by muscle potentials]

Muscle potentials as a cause of pacemaker malfunction are often unrecognized, because control examinations are usually performed without physical exercise. Two observations are cited to illustrate how malfunctioning of different modes of stimulation can be caused by interference from muscle potentials. In addition to the known suppression of impulse production, fixed-rate stimulation may occur. These observations indicate that pacemaker function should be tested also during physical activity. Any malfunction can almost always be stopped by re-programming amplifier sensitivity.