Direct factors • Lead dislodgement • A Macro-dislodgement is radiographically visible. • A Micro-dislodgement is a minimal displacement in the lead that is not visible in a chest X-ray, but has the ability to increase the capture threshold and eventually cause a loss of capture. The generator is rotated on its longitudinal axis, which causes traction and results in a lead dislodgement. • With the advances of technology,
Federal Communications Commission (FCC) is making new frequencies available. Cellphones using these new frequencies might make pacemakers less reliable. A group of cellphone companies is studying that possibility. • Extracorporeal shock-wave lithotripsy (ESWL) procedure is safe for most pacemaker patients, with some reprogramming of the pacing. Careful follow-up after the procedure is required. Patients with certain kinds of pacemakers implanted in the abdomen should avoid ESWL. • Diagnostic radiation (such as screening
X-ray) appears to have no effect on pacemaker pulse generators. However,
therapeutic radiation (such as for treating cancerous
tumors) may damage the pacemaker's circuits. The degree of damage is unpredictable and may vary with different systems. However, the risk is significant and builds up as the radiation dose increases. The
American Heart Association recommends that the pacemaker be shielded as much as possible, and moved if it lies directly in the radiation field. • Short-wave or microwave diathermy uses high-frequency, high-intensity signals. These may bypass pacemaker's noise protection and interfere with or permanently damage the pulse generator. ==Prevention==