Are Transcutaneous Electrical Nerve Stimulation (TENS) units contraindicated in patients with pacemakers?

TENS Units Are Contraindicated in Patients with Pacemakers

TENS units should not be used in patients with cardiac pacemakers due to the risk of electromagnetic interference that can disrupt pacemaker function and potentially lead to serious adverse events.

Mechanism of Interference

• TENS units generate electrical currents that can be interpreted by pacemakers as cardiac signals, potentially causing inappropriate sensing and pacing inhibition 1, 2
• Modern pacemakers have filtering mechanisms, but interference still occurs at clinically significant rates 3, 4
• The electrical signals from TENS can cause various types of interference with cardiac devices:
  • Inhibition of pacing output 1
  • Inappropriate sensing of ventricular activity 3
  • Noise reversion (switching to asynchronous mode) 3
  • Misinterpretation of signals as arrhythmias 5

Evidence from Guidelines

• The European Society of Cardiology (ESC) and European Society of Anaesthesiology (ESA) guidelines specifically mention that electromagnetic interference can inhibit demand pacemakers, which represents a significant risk to pacemaker-dependent patients 6
• Guidelines recommend that electrical devices should be kept away from pacemakers and that only brief bursts of electrical current at the lowest possible amplitude should be used when necessary 6
• The 2024 AHA/ACC guidelines for perioperative cardiovascular management recommend that pacemaker-dependent patients should have their devices reprogrammed to asynchronous mode if electromagnetic interference is anticipated 6

Risk Factors for Interference

• Bilateral electrode placement creates a higher risk of interference (47.1% of tested configurations) compared to unilateral placement 4
• Electrode placement on the chest or near the pacemaker generator increases interference risk 3
• Higher current intensity is associated with greater likelihood of interference 3
• Different pacemaker manufacturers have varying susceptibility to interference 3

Documented Interference Events

• Studies have shown that TENS can cause:
  • Interpretation as premature ventricular beats in 14% of patients 3
  • Noise reversion in 4.6% of patients 3
  • Temporary asynchronous pacing in 2.8% of patients 3
  • Interpretation as ventricular tachycardia/fibrillation in 1.9% of patients 3
• Even if initial testing shows no interference, problems can develop later during regular use 2

Clinical Implications

• For pacemaker-dependent patients, interference could result in:
  • Bradycardia or asystole if pacing is inhibited 1, 2
  • Dizziness and hemodynamic compromise 2
• For patients with ICDs (implantable cardioverter-defibrillators):
  • Inappropriate shock delivery if TENS signals are misinterpreted as arrhythmias 5
  • Failure to deliver appropriate therapy if noise reversion occurs during actual arrhythmias 5

Alternative Approaches

• If pain management is essential, consider:
  • Non-electrical pain management modalities
  • Pharmacological pain management
  • If TENS must be used, extensive cardiac monitoring should be performed during initial application and regular use 1
  • Pacemaker reprogramming to reduce sensitivity may be considered in select cases, but this requires specialized evaluation 1

Special Considerations

• Even if initial testing shows no interference, problems can develop with continued use, as demonstrated in case reports 2
• The 2023 research shows that while modern devices have improved filtering, 15.9% of patients still experienced some form of interference 3
• Due to the potentially serious consequences of interference, most experts do not recommend TENS use in patients with cardiac devices 5