Due Diligence in Periprocedural Management of Candidates to CIED Therapy

The use of cardiac implantable electronic devices (CIEDs) for patients with cardiovascular diseases has dramatically escalated in the recent years, resulting in substantially improved quality of life and survival (1). Consistent with these observations, more CIED carriers are exposed to diseases in need of surgery or invasive procedures nowadays.

A fearful condition affecting CIED integrity in the setting of surgical and interventional procedures is represented by electromagnetic interference (EMI) (2). EMI is an unwanted noise or interference in an electrical path or circuit caused by an outside source ultimatey causing electronics to consequently operate poorly, malfunction or disactivate. Intra-procedural occurrence of device malfunction may result in severe hemodynamic impairment or life-threatening cardiac arrhythmias as a consequence of oversensing and inappropriate inhibition of pacing.

EMI interference with an implanted device is influenced by several factors, including intensity of the field (power of EMI source), frequency of EMI source, distance to EMI source, type and programming of the PM/ICD, type and position of the leads in the patient body. Noteworthy, EMI may affect an implantable device without direct contact with EMI source.

The American Heart Association (AHA) Scientific Statement on Peri-procedural Management and Multidisciplinary Care Pathways for Patients with Cardiac Implantable Electronic Devices (CIEDs) in this issue of the Journal (3) provides a timely, comprehensive, up-to-date document offering instructions for optimal management strategies at patient and health system level. Commendably, the document is intended for a large bulk of interested parties, including EP practitioners, surgeons, anesthesiologists, referring physicians, nurses, health care providers, corporate representatives and insurance companies.

The document presents a virtuous circle of interactive operations to be activated in CIED carriers at time of surgery or intervention. They include: 1) a CIED home at the cardiology clinic for procedural planning; 2) a pre-procedural screening to optimize the setting and accurately prepare the planned procedure; 3) an intra-procedural phase for monitoring and manegement of intercurring pre-planned emergencies; 4) a post-procedural phase aimed at restoration of pre-procedural setting and, in keeping with the loop concept addressed in the document, referrral to the CIED home for remote and in-house monitoring during follow-up.

In the present AHA Scientific Statement (2), accurate collection of information on patient's hystory, indication, device characteristics (i.e., manufacturer, model and features) and location, medical procedure is strongly encouraged to prevent or limit possible interactions between CIEDs and EMI. In addition, careful pre-operative assessment in search of potential EMI sources and surgical planning, including pre-procedural CIED-reprogramming, are advocated to optimize patients' safety. These features appear of particular relevance in light of the increasing complexity of CIEDs as devices' technology continues to evolve. Concomitantly, a careful check-up of the technical aspects related to the single CIED and the external devices are to be carefully assessed to confirm battery status, and integrity of lead mechanics and function before intervention and confirm magnet response. Dysfunction of any of these elements at time of pre-procedural screeing requires preventive resolution before engaging in the surgical or interventional procedure.

A dedicated paragraph on anticipated procedure and surgical site in the document highlights some fundamental aspects related to the intervention type and location and provides precious instruction as to how to minimize the risk of EMI-associated events. Electrosurgery using unipolar cautery represents the interventional combination at highest risk of EMI. It can be partially obviated with the use of bipolar cautery, which creates a smaller electric field than unipolar cautery, and placement of the grounding pad below the umbilicus, when feasible. In the AHA Scientific Statement text, a dedicated table (Table 1) provides a detailed summary of the different EMI sources with the correspondent possible detrimental effect.

While surgical procedures above the level of ombelicus are at higher risk of EMI, published reports in patients undergoing knee surgey showed EMI detection or ICD inappropriate discharge during knee surgery (4). As adressed in the document, pre-procedural reprogramming in these patients, especially with asynchronous pacing in PM-dependent recipients and deactivation of ATP and shock therapies in ICD recipients, should be considered. Alternatively, magnet positioning over the pulse generator can be adopted to disactivate current program options. Proper magnet placement during surgery is not always simple and stable and the response to magnet may be different with different devices and, in rare cases, detrimental. To obviate for potential intra-procedural inconvenients, effect of magnet application and assessment of underlying rhythm should be tested prior of surgery by an EP specialist with the help of a 12-lead electrocardiogram and continous telemetry monitoring.

When proceding with pre- or intra-procedural interaction with the programming device mode, the document provides a table (Table 2) of practical assistance in which the various responses to magnet activation are reported together with special considerations pertaining to the specific corporate devices. While the present documented is intended for a variety of participants to the procedure, pre- or intra-procedural interaction with the programming device mode should invariably be planned and exercised by EP practioners.

The document continues by addressing complimentary relevant elements of surgical or interventional procedures in CIED recipients. Among them, considerations about the proximity to the device pocket and leads of the surgical or interventional operative field, interaction of explorative or interventional guidewires and tools with standing lead systems, distinction between MRI conditional or compatible and non-conditional or compatible devices, leadless PMs, subcutaneous ICDs and ILRs are provided with pertinent suggestions on how to optimize intra-procedural management and limit unfavorable outcomes.

At the end of the procedure, it is critically inportant that the device is returned to its original setting under coniunuous monitoring. Also critically important is that procedural records are filed for review, when necessary.

Perioperative management of CIED recipients can be challenging because EMI may cause device malfunction. To avoid CIED-related peri- and intra-operative complications, it is of the utmost importance to assess indication to device implantation, evaluate current pacing dependency, check the device's last follow-up chart, and possibly contact patients' electrophysiologist or their device specialist. All this information will help implement the most convenient strategy for a safe surgical approach. The information contained in the present Scientific Statement is highly informative and can be used on large scale as an helpful tool to optimize uneventful conduciton of surgical and interventional procedures in CIED recipients.