2017 HRS expert consensus statement on magnetic resonance imaging and radiation exposure in patients with cardiovascular implantable electronic devices

Wideband myocardial perfusion pulse sequence for imaging patients with a cardiac implantable electronic device

PURPOSE

To develop a wideband cardiac perfusion pulse sequence and test whether it is capable of suppressing image artifacts in patients with a cardiac implantable electronic device (CIED), while not exceeding the specific absorption rate (SAR) limit (2.0 W/kg).

METHODS

A wideband perfusion pulse sequence was developed by incorporating a wideband saturation pulse to achieve a good balance between saturation of magnetization and SAR. Clinical standard and wideband perfusion MRI scans were performed back-to-back in a randomized order on 16 patients with a CIED undergoing clinical cardiac MRI. Two expert readers graded the artifact intensity and extent on a segmental basis using a 5-point Likert scale, where significant artifact was defined by a composite score. The variance in myocardial signal prior to tissue-enhancement was analyzed to quantify artifact-intensity. Whole-body SAR values computed by the MR scanner were read from the DICOM header. Either a paired t-test or Wilcoxon signed-rank test was performed to compare two groups.

RESULTS

While the mean whole-body SAR for a single-slice wideband perfusion scan (0.38 ± 0.08W/kg) was significantly (p < 0.05) higher than for a single-slice standard perfusion scan (0.11 ± 0.03W/kg), it was 81% below 2.0 W/kg. The mean variance in myocardial signal prior to tissue-enhancement was significantly (p < 0.001) higher for standard (422.6 ± 306.6 a.u.) than wideband (107.0 ± 60.9 a.u.). Among 105 myocardial segments, standard produced 19 segments (18%) that were deemed to have significant artifacts, whereas wideband produced only 3 segments (3%).

CONCLUSION

A wideband perfusion pulse sequence is capable of suppressing image artifacts induced by a CIED while not exceeding SAR at 2.0 W/kg.

Management of cardiac implantable devices in patients undergoing radiotherapy

The delivery of radiotherapy to patients with a cardiac implantable electronic device (CIED) is not an infrequent event. Consideration of the potential issues for patients is an important part of their care. An overview of CIEDs is provided, including the potential problems encountered and the steps that can be taken to mitigate this risk.

Transvenous Lead Extractions: Current Approaches and Future Trends

The use of cardiac implantable electronic devices (CIEDs) has continued to rise along with indications for their removal. When confronted with challenging clinical scenarios such as device infection, malfunction or vessel occlusion, patients often require the prompt removal of CIED hardware, including associated leads. Recent advancements in percutaneous methods have enabled physicians to face a myriad of complex lead extractions with efficiency and safety. Looking ahead, emerging technologies hold great promise in making extractions safer and more accessible for patients worldwide. This review will provide the most up-to-date indications and procedural approaches for lead extractions and insight on the future trends in this novel field.

State-of-the-art approach towards magnetic resonance imaging of the nervous system structures in patients with cardiac implantable electronic devices

INTRODUCTION

MRI generated forces are the source of potential complications in patients with cardiac implantable electronic devices (CIED). The technological progress, and growing clinical evidence concerning the operation of the contemporary MR non-conditional CIEDs during MRI, have started to significantly change our every-day clinical practice. Nevertheless, a lot of patients who could have an MRI performed safely, still have been refused the examination.

STATE-OF-THE-ART

In many clinical situations, an MRI examination in a patient with a CIED is reasonable, and is linked to a negligible risk of complications if performed under strict precautions. The MagnaSave Registry that evaluated the influence of nonthoracic MRI on the function of MR non-conditional CIEDs, and numerous studies involving thoracic and non-thoracic MRIs in patients with legacy CIEDs, have confirmed the feasibility and safety of such examinations. In this article, practical tips aimed towards improving the safety of MRI in MR conditional and non-conditional CIED patients are largely based on the very recently released (2017) HRS expert consensus statement.

CLINICAL IMPLICATIONS

Clinical data emphasize the necessity of making the MRI more accessible to CIED patients, also in the case of MR non-conditional systems or when the thorax MR imaging is clinically reasonable. This goal should be achieved by increasing the number of centers complying with respective recommendations and applying protocols that would guarantee the highest safety level.

FUTURE DIRECTIONS

Further studies are warranted to assess safety issues related to the main current contraindication to MRI, i.e., the presence of abandoned leads.

Myocardial Viability Testing to Guide Coronary Revascularization

Left ventricular dysfunction remains one of the best prognostic determinants of survival in patients with coronary artery disease. Revascularization has been shown to improve survival compared with medical therapy alone. Viability testing can help direct patients who will benefit the most from revascularization. Single-photon emission computed tomography, dobutamine stress echo, cardiac MRI, and PET imaging with F18-fluorodeoxyglucose are the most common modalities for assessing myocardial viability. Viability testing can help differentiate which patients benefit most from chronic total occlusion interventions.

Visualization and appearance of artifacts of leadless pacemaker systems in cardiac MRI : An experimental ex vivo study

Background

Leadless pacemaker systems are an important upcoming device in clinical rhythmology. Currently two different products are available with the Micra system (Medtronic) being the most used in the clinical setting to date. The possibility to perform magnetic resonance imaging (MRI) is an important feature of modern pacemaker devices. Even though the Micra system is suitable for MRI, little is yet known about its impact on artifacts within the images.

Objective

The aim of our ex vivo study was to perform cardiac MRI to quantify the artifacts and to evaluate if artifacts limit or inhibit the assessment of the surrounding myocardium.

Methods

After ex vivo implantation of the leadless pacemaker (LP) in a porcine model, hearts were filled with saline solution and fixed on wooden sticks on a plastic container. The model was examined at 1.5 T and at 3 T using conventional sequences and T2 mapping sequences. In addition, conventional X‑rays and computed tomography (CT) scans were performed.

Results

Correct implantation of the LP could be performed in all hearts. In almost all MRI sequences the right ventricle and the septal region surrounding the (LP) were altered by an artifact and therefore would sustain limited assessment; however, the rest of the myocardium remained free of artifacts and evaluable for common radiologic diagnoses. A characteristic shamrock-shaped artifact was generated which appeared to be even more intense in magnitude and brightness when using 3 T compared to 1.5 T.

Conclusion

The use of the Micra system in cardiac MRI appeared to be feasible. In our opinion, it will still be possible to make important clinical cardiac MRI diagnoses (the detection of major ischemic areas or inflammatory processes) in patients using the Micra system. We suggest the use of 1.5 T as the preferred method in clinical practice.

Cardiac implanted electronic devices and MRI safety in 2018-the state of play

Traditionally, the presence of cardiac implanted electronic devices (CIEDs) was a contra-indication to magnetic resonance (MR) imaging. Professional groups from around the world are releasing updated guidelines for the imaging of MR-conditional and legacy CIEDs, reflecting increasing evidence that this can be performed safely when strict protocols are followed.

KEY POINTS

• The presence of a pacemaker or automatic implanted cardioverter defibrillator is no longer an absolute contraindication to magnetic resonance imaging. • Strict protocols enable diagnostic quality images to be obtained with minimal risk. • Close collaboration among radiologists, cardiologists and device manufacturer representatives is required.

Management of patients with cardiac implantable electronic devices (CIED) undergoing radiotherapy: A consensus document from Associazione Italiana Aritmologia e Cardiostimolazione (AIAC), Associazione Italiana Radioterapia Oncologica (AIRO), Associazione Italiana Fisica Medica (AIFM)

The management of patients with a cardiac implanted electronic device (CIED) receiving radiotherapy (RT) is challenging and requires a structured multidisciplinary approach. A consensus document is presented as a result of a multidisciplinary working group involving cardiac electrophysiologists, radiation oncologists and physicists in order to stratify the risk of patients with CIED requiring RT and approaching RT sessions appropriately. When high radiation doses and beam energy higher than 6MV are used, CIED malfunctions can occur during treatment. In our document, we reviewed the different types of RT and CIED behavior in the presence of ionizing radiations and electromagnetic interferences, from the cardiologist's, radiation oncologist's and medical physicist's point of view. We also reviewed in vitro and in vivo literature data and other national published guidelines on this issue so far. On the basis of literature data and consensus of experts, a detailed approach based on risk stratification and appropriate management of RT patients with CIEDs is suggested, with important implications for clinical practice.

Radiotherapy for Patients with Cardiovascular Implantable Electronic Devices: A Review

Because cardiovascular implantable electronic devices are increasingly indicated in older patients, and the burden of cancer is rising with the growth and aging of the world population, the management of patients with cardiac devices who require radiotherapy for cancer treatment is a timely concern. Device malfunctions might occur in as high as 3% of radiotherapy courses, posing a substantial issue in clinical practice. A nonsystematic comprehensive review was undertaken. We searched PubMed and the MEDLINE database for randomized controlled trials, meta-analyses, systematic reviews, observational studies, in vitro/in vivo studies, and case reports. Articles were selected by 2 independent reviewers, and emphasis was given to information of interest to a general medical readership. The pathophysiology and predictors of cardiovascular implantable electronic device malfunction due to radiotherapy are reviewed, recommendations for the management of patients with such devices undergoing radiotherapy are summarized, and the clinical significance and future directions of this field are discussed. Radiotherapy-induced device malfunctions are rare, but because of the potential complications, the development of evidence-based guidelines for the management of patients with cardiovascular implantable electronic devices undergoing radiotherapy is a timely concern.

[Pacemaker, defibrillator and co : Perioperative handling of cardiac implantable electronic devices]

The number of patients treated with cardiac implantable electronic devices (CIED) is continously increasing. Knowledge of the medical indications and technical mode of functioning of these devices is a basic prerequisite for the safe perioperative care of this patient cohort. The CIEDs are subjected to a multitude of disturbing influences in the perioperative setting. This can result in potentially dangerous complications, such as exit block and oversensing. The safe performance of interventions is possible as long as some basic rules are followed. An interdisciplinary approach involving all participating disciplines is necessary in order to adequately deal with the high demands placed on the logistics.