Which modality is typically avoided in patients with pacemakers?

• A. Cryotherapy
• B. Ultrasound
• C. Hydrotherapy
• D. Electrical stimulation modalities (TENS/NMES/IFC)

Answer: (D)

External electrical stimulation can interfere with pacemakers because these devices rely on sensing the heart’s electrical activity to decide when to pace. Modalities that deliver electrical currents—such as TENS, NMES, and IFC—can be picked up by the pacemaker as heart signals or as electrical noise, which can cause inappropriate pacing inhibition or triggering. The risk is higher when the stimulation is applied near the chest or over the generator, so these electrical stimulation approaches are typically avoided or used with caution in patients with pacemakers, often requiring device interrogation and careful planning of pad placement and stimulation settings if they are ever considered.

Other commonly used modalities do not emit electrical energy that interacts with the pacemaker’s sensing circuitry, so they are generally considered safe with standard precautions. Cryotherapy, ultrasound, and hydrotherapy provide mechanical or thermal energy rather than electrical energy, making interference unlikely under normal use.