Congenital Heart And Pediatric Electrophysiology

Multicenter retrospective evaluation of magnetic resonance imaging in pediatric and congenital heart disease patients with cardiac implantable electronic devices. Gakenheimer-Smith L, Ou Z, Kuang J, Moore JP, Burrows A, Kovach J, Dechert B, Beach CM, Ayers M, Tan RB, Mostafavifar M, Mah DY, Conner TM, Turpin S, Avasarala K, Shah MJ, Webster G, Posey J, Etheridge SP, Binka E, Niu M, Asaki SY, Lambert LM, Pilcher TA.Heart Rhythm. 2023 Dec;20(12):1752-1758. doi: 10.1016/j.hrthm.2023.08.034. Epub 2023 Aug 28. PMID: 37648183 Take Home Points: MRI scans (Cardiac and Non-Cardiac) are feasible in Pediatric and ACHD patients with and without non-conditional cardiac electronic implantable devices (CIEDs) including abandoned leads. Patient symptoms, predominately transient warmth and pain occurred in 2.3% of MRI scans. CIED changes, predominately increase in lead impedance, occurred in 3.4% of MRI scans noted after the MRI scan or at follow-up. Overall, 4.9% of MRI scans and 6.1% of patients had symptoms, arrhythmias, or CIED changes Study findings support the 2021 PACES CIED guideline recommendations for MRI in CIEDs: IIA (non-conditional endocardial CIED) and IIB (non-conditional epicardial CIED or abandoned leads) Comment from Dr. Akash Patel (Cleveland), section editor of Congenital Electrophysiology Journal Watch.    Magnetic Resonance Imaging (MRI) scans are an important diagnostic tool used in pediatric and adult congenital heart disease (ACHD) patients. Historically, MRIs were contraindicated in patients with cardiac electronic implantable devices (CIEDs). However, the development of MRI-conditional CIEDs has allowed for the safe use in endocardial systems. Despite reports of no significant adverse events, the use of MRIs in non-conditional CIED systems, including epicardial CIED systems and abandoned endocardial and epicardial leads, remains limited. This limitation is due perceived risks, lack of reimbursement from Centers for Medicare & Medicaid Services (CMS), limited data on pediatric and congenital heart disease patients, and variation in institutional comfort and policies for performing MRIs in this context. The 2021 PACES (Pediatric and Congenital Electrophysiology Society) device guidelines provided a 2A indication for MRI scans in non-conditional endocardial CIED systems and 2B indication for MRI scans in patients with abandoned, epicardial, or fractured leads based on individual risk-benefit ratio.  To address the lack of comprehensive data, this multicenter study was conducted to evaluate adverse events in pediatric and ACHD patients with CIEDs undergoing MRI across U.S. centers. This was a multicenter retrospective cohort study of pediatric and ACHD patients with CIEDs or abandoned leads who underwent an MRI between 2007 and 2022 at 14 participating centers. All MRIs were done on a 1.5 T MRI scanner.  Each center had their own protocol for selecting and monitoring patients and CIEDs before, during, and after the MRI. Protocols generally included a review and approval by an electrophysiologist, informed consent, continuous monitoring during the MRI, and reprogramming of CIEDs as per recommendations. Device interrogations were conducted pre-MRI, post-MRI, and at follow-up. Both conditional CIEDs and non-conditional CIEDs were analyzed. The primary outcome was any patient adverse event (death, symptoms, or arrhythmia) or clinically significant CIED change after MRI, defined as pacing lead capture threshold increase >0.5 V and change in programmed output, P- or R-wave amplitude decrease >50% and change in programmed sensitivity, or impedance change >50%. Patient, CIED, and MRI Characteristics A total of 314 patients (median age 18.8 years) underwent 389 MRIs.  Most patients (82%) had congenital heart disease.  Indications for CIED included sinus node dysfunction (39%), AV block (33%), not paced (16%), other (6%), and atrial arrhythmia (4%). The MRI scans were done in 288 (74%) with pacemakers, 87 (22%) with implantable cardioverter-defibrillators, and 14 (4%) with abandoned leads only. Seventeen percent (n=65) of scans were done in pacemaker-dependent patients. Most scans were done on MRI non-conditional CIEDs (74%) of whom 47% were under the age of 18. Of these, 52% had epicardial leads, 13% had abandoned epicardial leads, 4% had abandoned endocardial leads. The types of MRI scans performed varied: 174 (45%) cardiac, 130 (33%) brain, 71 (18%), upper torso, 87 (22%) lower Torso, 17 (4%) extremity, 2 (1%) lymphangiogram, 2 (1%) other. The median time between MRI Scan and outpatient follow-up CIED interrogation was 36 [IQR: 1–73] days Patient Related Outcomes Overall, 2.3% (9) of patients scanned experienced symptoms (not mutually exclusive) including warmth in 5 (1.3%), pain in 3 (0.8%), tingling sensation in 3 (0.8%), presyncope in 1 (0.3%), and bradycardia when programmed in non-paced mode in 1 (0.3%).  The MRI was terminated prematurely in 17 (4.4%). This was due to artifact in 13 (3.3%), patient symptoms in 2 (0.5%), claustrophobia in 1 (0.3%), and bradycardia when programmed in nonpaced mode in 1 (0.3%).   One patient with bradycardia was able to have an MRI done with device programmed in VOO mode. Most symptoms occurred MRI non-conditional CIED (89%) and those with epicardial leads (56%).  Of note, only 1 patient with symptoms (pain and warmth) also had CIED parameter changes (impedance increase).  Device Related Outcomes CIED Related Outcomes Ninety-two percent of the cohort had pre- post MRI data for comparison and only 76% had post- follow-up MRI comparison data.   Overall, 1.4% (n=5) scans had a significant change in CIED Post-MRI and 6 (2.0%) had a significant change in CIED at follow-up.  Post-MRI changes were due to increase in atrial or ventricular lead impedance (4, 80%) and increase in atrial lead capture threshold with reprogramming (1, 20%). Follow-up MRI changes were due to increase in atrial or ventricular lead impedance (3, 50%) and increase in atrial lead capture threshold with reprogramming (50%). Post-MRI or follow-up CIED changes occurred predominately in non-conditional CIEDs (7, 64%) due to impedance increase in 6 and atrial lead capture threshold increase in 1.  Of these non-conditional CIEDs, 5 of 7 had epicardial leads. During the follow-up, 5% of CIED generators and 2% of leads required removal. No CIED systems procedures were required due to CIED changes because of the MRI. There was one patient with an atrial lead fracture with not data provided to assess for causality. This is the largest multicenter study to assess the use of MRI scans in pediatric and ACHD patients with CIEDs of whom 17% were pacemaker dependent.  MRI can thus be done safely without patient related adverse outcomes in 97.7% and without device related adverse outcomes in 96.6%.  The adverse patient symptoms, predominately warmth and pain, were all minor and transient.  The device related adverse outcomes did not result in need for subsequent device procedure. The parameters for changes were predominately impedances changes (7 of 11) and pacing thresholds in (4 of 11). There were no changes in sensing.  The study did not assess acute battery depletion due to lack of data and long-term impact of lead changes due to study design. Importantly, the majority of CIEDs in this study were non-conditional (74%) including 52% with epicardial leads and 17% with abandoned leads.  The findings of this study provide additional support for the 2021 Pediatric and Congenital Electrophysiology Society (PACES) CIED MRI guidelines: IIA for nonconditional transvenous CIEDs if there are no fractured, epicardial, or abandoned leads and IIB for epicardial CIEDs or abandoned leads based on an individualized consideration of the risk/benefit ratio. MRI type, acquisition protocols, duration, and technical equipment features were not a focus of this study but may provide additional insights into reducing symptoms and CIED changes, increasing safety, and standardizing practice.   Of note, most MRIs were done as cardiac or upper torso (63%) which would place the CIEDs in the magnetic field. Also mentioned was that “most” of the adverse events occurred in those undergoing brain or cardiac MRI.  No specifics were provided on MRI duration and protocols used that may have impacted these findings.  It is important to note that 3.3% of MRI scans were stopped prematurely due to artifact. Moreover, the study did not address whether the MRI provided additional diagnostic value beyond what could be achieved with other imaging modalities, such as CT.  Additionally, pediatric MRIs often require sedation, which prevents the assessment of symptoms during the scan and may lead to an underreporting of the true incidence.  Investigating these additional aspects would provide valuable information for weighing the benefits and risks when deciding whether to perform an MRI in a patient with a CIED. Despite the mounting evidence that MRIs can be performed safely in the majority of pediatric and ACHD patients with conditional and non-conditional CIEDs, with or without abandoned leads, many institutions have been slow to adopt this service.  This study provides much needed evidence for advancing this process.