In a December “Dear Doctor” letter, Marlborough, Mass.-based Boston Scientific said it received reports of “intermittent oversensing of the Minute Ventilation (MV) sensor signal with certain Boston Scientific pacemaker and cardiac resynchronization therapy pacemaker systems.” The problem can occur with any company’s pacing leads, but an internal investigation showed that it was most likely to happen with right atrium or right ventricle leads made by Abbott (NYSE:ABT) or Medtronic (NYSE:MDT).
“Although all leads evaluated in simulated testing environments comply with appropriate connector standards, we have discovered subtle differences amongst lead manufacturers in the surface finish of the lead terminal ring and amount of axial and radial terminal ring motion within the pacemaker header. These factors may result in intermittent increases in impedance leading to oversensing of the MV sensor signal or changes in daily impedance test measurements,” the company said. “Boston Scientific investigation has shown that the probability of harm associated with MV sensor signal oversensing behavior is significantly greater when affected pacemakers are connected to Medtronic or Abbott pacing leads.
The most common outcome is an inappropriate mode switch; in the worst case, pacing inhibition led to “syncope with associated injury in some pacemaker-dependent patients,” according to the letter.
Boston Scientific said it’s working on a software update to detect and resolve the problem that it expects to submit for regulatory approval in March and to release in October if approved. In the meantime, the MV sensor should be turned off for pacemaker-dependent patients or patients for whom the risks of MV sensing outweigh the benefits. The company also recommended enrolling pacemaker patients in its Latitude NXT remote monitoring program.
“Boston Scientific recognizes the impact of communications on both you and your patients, and wants to reassure you that patient safety remains our highest priority. If you have additional questions regarding this information or would like to report clinical events, please contact your Boston Scientific representative or Technical Services,” the company wrote in the letter.