Patients with implanted cardiac devices and their physicians sometimes defer important electrodiagnostic testing because of anxiety about potential negative effects the testing may have on the device. Good news for these patients and physicians is that according to recent research, electrodiagnostic testing was found to pose minimal or no risk to patients with implanted cardiac devices such as permanent pacemakers and implanted cardiac defibrillators.
Nerve conduction studies (NCSs) are done to detect and evaluate damage to the peripheral nervous system, which includes all the nerves that lead away from the brain and spinal cord and the smaller nerves that branch out from those nerves. Nerve conduction studies are often used to help diagnose nerve disorders, such as carpal tunnel syndrome or Guillain-Barre syndrome, and find the location of abnormal sensations, such as numbness, tingling, or pain.
The prevailing view among electrodiagnostic physicians and cardiac electrophysiologists, is that electrodiagnostic testing on patients with implanted cardiac devices is safe as long as the electrical stimulation is not given in direct proximity to the pulse generator of the cardiac device. Recording from intracardiac sensing electrodes during NCSs, which has not been previously reported, would be the best test to assess safety.
In a recent study, 10 patients with permanent bipolar pacemakers of various makes and 5 patients with implanted cardiac defibrillators (ICD) underwent nerve stimulation at sites commonly used during NCSs. The electrical impulses generated during routine NCSs were never detected by the sensing amplifier of the pacemaker or defibrillators. The NCS did not affect the programmed pacemaker or defibrillator settings and did not cause the defibrillator to discharge. The pacemaker and defibrillator were interrogated before and after NCSs and surface electrocardiogram and atrial and ventricular electrograms were continuously monitored during NCSs.
The research concluded that routine NCSs are safe in patients with implanted cardiac pacemakers and defibrillators with bipolar sensing configurations.