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![MR Image Quality with the Defibrillator Turned On and Off. bSSFP images were obtained when defibrillator was switched off (a) and switched on (b). Note the reduction in image quality (due to increased noise level) when the defibrillator was switched on (b) compared with when it was switched off (a). The images were used to calculate SNR as previously described [11]. There was an approximate 10% reduction in SNR when the defibrillator was switched on. Bottom: image artifact caused by defibrillator pads (d, arrow) compared with the same image without the pads (c)](publication/334972458/figure/fig3/AS:788584495849473@1565024603813/MR-Image-Quality-with-the-Defibrillator-Turned-On-and-Off-bSSFP-images-were-obtained.png)
MR Image Quality with the Defibrillator Turned On and Off. bSSFP images were obtained when defibrillator was switched off (a) and switched on (b). Note the reduction in image quality (due to increased noise level) when the defibrillator was switched on (b) compared with when it was switched off (a). The images were used to calculate SNR as previously described [11]. There was an approximate 10% reduction in SNR when the defibrillator was switched on. Bottom: image artifact caused by defibrillator pads (d, arrow) compared with the same image without the pads (c)
Source publication
Background:
Rapid application of external defibrillation, a crucial first-line therapy for ventricular fibrillation and cardiac arrest, is currently unavailable in the setting of magnetic resonance imaging (MRI), raising concerns about patient safety during MRI tests and MRI-guided procedures, particularly in patients with cardiovascular diseases....
Citations
... These modify commercial defibrillators with output wire filters designed to (1) suppress defibrillator electrical noise that would corrupt MR images, (2) suppress radio-frequency currents generated during MRI scanning that could lead to heating of patient defibrillator electrode patches, modified for safety, and (3) tolerate high voltages generated by the defibrillator. Safe scanning with acceptable levels of electrode heating and image noise has been demonstrated in human volunteers with connected defibrillator patches and successful defibrillation has been performed in animals with ventricular fibrillation [34,35]. ...
... The ability to defibrillate/cardiovert hemodynamically unstable ventricular arrhythmia is often required. Safe defibrillation inside MRI scanner has been demonstrated in animal models [34,35]. ...
Transcatheter cardiovascular interventions increasingly rely on advanced imaging. X-ray fluoroscopy provides excellent visualization of catheters and devices, but poor visualization of anatomy. In contrast, magnetic resonance imaging (MRI) provides excellent visualization of anatomy and can generate real-time imaging with frame rates similar to X-ray fluoroscopy. Realization of MRI as a primary imaging modality for cardiovascular interventions has been slow, largely because existing guidewires, catheters and other devices create imaging artifacts and can heat dangerously. Nonetheless, numerous clinical centers have started interventional cardiovascular magnetic resonance (iCMR) programs for invasive hemodynamic studies or electrophysiology procedures to leverage the clear advantages of MRI tissue characterization, to quantify cardiac chamber function and flow, and to avoid ionizing radiation exposure. Clinical implementation of more complex cardiovascular interventions has been challenging because catheters and other tools require re-engineering for safety and conspicuity in the iCMR environment. However, recent innovations in scanner and interventional device technology, in particular availability of high performance low-field MRI scanners could be the inflection point, enabling a new generation of iCMR procedures. In this review we review these technical considerations, summarize contemporary clinical iCMR experience, and consider potential future applications.
... The cardiac adverse events associated with hypotension, bradycardia, and asystole owing to vagal hypertonia require oxygenation and intravenous fluid loading in the supine position with elevation of the lower extremities and medication with atropine as a parasympathetic blocker, etilefrine or ephedrine as a vasopressor, steroids for the prevention of neurogenic shock, or transcutaneous external pacing. 17 It is also essential to administer adrenaline early in established cardiac arrest. In addition, taking into account the report that the ventricular fibrillation following prolonged asystole needed defibrillation, 18 it may be important to bear in mind a possible occurrence of ventricular fibrillation secondary to vasovagal syncope under a preparation of defibrillator. ...
The perioperative cardiac events may be brought about by a relative imbalance of autonomic activities due to excessive psychological and physical stress. The present case study focuses on the asystole that can occur as a serious cardiac adverse event associated with vasovagal reflex likely to be triggered by venipuncture for securing an intravenous line during dental care. In addition, we describe and discuss herein the management of intravenous sedation for a dental phobic patient who experienced the vasovagal reflex involved in an unexpected transient asystole. The patient with vasovagal reflex episodes in daily life, who had no past medical history relevant to cardiovascular disorders, was scheduled for dental extraction under intravenous sedation. Immediately after peripheral intravenous catheterization, she complained of discomfort and nausea, and a II-lead electrocardiogram revealed asystole following bradycardia associated with vasovagal reflex. Oxygenation and intravenous fluid loading in the supine position with elevation of the lower extremities restored sinus rhythm and normal hemodynamics without the intervention of cardiopulmonary resuscitation. With administration of intravenous atropine and betamethasone as premedication, she was uneventfully treated in stress-free psychosomatic conditions under optimal sedation with midazolam without any signs of cardiovascular disorders. After administration of flumazenil, the patient satisfactorily recovered from sedation without re-sedation. The present case suggests that an asystole associated with vasovagal reflex can be triggered by venipuncture for intravenous catheterization during dental anxiety likely to affect the imbalance between sympathetic and parasympathetic activities.
... 2019 Jun 24;21(1):33 [17]Shusterman et al. High-energy external defibrillation and transcutaneous pacing during MRI: feasibility and safety[18] ...
There were 79 articles published in the Journal of Cardiovascular Magnetic Resonance ( JCMR ) in 2019, including 65 original research papers, 2 reviews, 8 technical notes, 1 Society for Cardiovascular Magnetic Resonacne (SCMR) guideline, and 3 corrections. The volume was down slightly from 2018 (n = 89) with a corresponding 5.5% increase in manuscript submissions from 345 to 366. This led to a slight decrease in the acceptance rate from 25 to 22%. The quality of the submissions continues to be high. The 2019 JCMR Impact Factor (which is published in June 2020) increased from 5.07 to 5.36. The 2020 impact factor means that on average, each JCMR published in 2017 and 2018 was cited 5.36 times in 2019. Our 5 year impact factor was 5.2. We are now finishing the 13th year of JCMR as an open-access publication with BMC. As outlined in this report, the Open-Access system has dramatically increased the reading and citation of JCMR publications. I hope that our authors will continue to send their very best, high quality manuscripts for JCMR consideration and that our readers will continue to look to JCMR for the very best/state-of-the-art publications in our field. It takes a village to run a journal. JCMR is blessed to have very dedicated Associate Editors, Guest Editors, and Reviewers. I thank each of them for their efforts to ensure that the review process occurs in a timely and responsible manner. These efforts have allowed the JCMR to continue as the premier journal of our field. My role, and the entire process would not be possible without the dedication and efforts of our managing editor, Diana Gethers (who will leaving the journal in the coming months) and our assistant managing editor, Jennifer Rodriguez, who has agreed to increase her reponsibilities. Finally, I thank you for entrusting me with the editorship of the JCMR. As I begin my 5 th year as your editor-in-chief, please know that I fully recognize we are not perfect in our review process. We try our best to objectively assess every submission in a timely manner, but sometimes don't get it “right.” The editorial process is a tremendously fulfilling experience for me. The opportunity to review manuscripts that reflect the best in our field remains a great joy and a highlight of my week!
The possibilities of cardiovascular magnetic resonance (CMR) imaging for myocardial tissue characterization and catheter ablation guidance are accompanied by some fictional concepts. In this review, we present the available facts about CMR-guided catheter ablation procedures as well as promising, however unproven, theoretical concepts. CMR promises to visualize the respective arrhythmogenic substrate and may thereby make it more localizable for electrophysiology (EP)-based ablation. Robust CMR imaging is challenged by motion of the heart resulting from cardiac and respiratory cycles. In contrast to conventional “passive” tracking of the catheter tip by real-time CMR, novel approaches based on “active” tracking are performed by integrating microcoils into the catheter tip that send a receiver signal. Several experimental and clinical studies were already performed based on real-time CMR for catheter ablation of atrial and ventricular arrhythmias. Importantly, successful ablation of the cavotricuspid isthmus was already performed in patients with typical atrial flutter. However, a complete EP procedure with real-time CMR-guided transseptal puncture and subsequent pulmonary vein isolation has not been shown so far in patients with atrial fibrillation. Moreover, real-time CMR-guided EP for ventricular tachycardia ablation was only performed in animal models using a transseptal, retrograde, or epicardial access—but not in humans. Essential improvements within the next few years regarding basic technical requirements, such as higher spatial and temporal resolution of real-time CMR imaging as well as clinically approved cardiac magnetic resonance–conditional defibrillators, are ultimately required—but can also be expected—and will move this field forward.
