Optimizing Electrocardiograph Electrode Placement for Cardiac-Gated Magnetic Resonance Imaging

Dimick, Richard N.; Hedlund, Laurence W.; Herfkens, Robert J.; Fram, Evan K.; Utz, Joseph A.

doi:10.1097/00004424-198701000-00002

Cited by 76 publications

(38 citation statements)

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“…The resultant distortion of the surface ECG was predominantly within the T wave and has been attributed to a potential generated by blood flow in the aorta in the presence of the magnetic field. 11 The temporal distribution of the interfering signal component probably would not compromise cardiac rhythm analysis or analysis of p-wave or QRS morphology. Intracardiac recordings with conventional filter settings were qualitatively unaffected by significant distortion in the presence of the magnetic field.…”

Section: Discussionmentioning

confidence: 99%

Novel, Magnetically Guided Catheter for Endocardial Mapping and Radiofrequency Catheter Ablation

et al. 2002

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Background-Ablation of complex arrhythmias would be greatly facilitated by more precise control of ablation catheters.A feasibility study was performed in animals to evaluate a novel magnetic guidance system (MGS) that generates a magnetic field to control the movement and position of a magnetic ablation catheter. Methods and Results-The MGS is composed of a digital biplanar fluoroscope within an array of superconducting electromagnets that surround the torso of the experimental animal and a computer control system that generates a composite magnetic field for directional catheter deflection. Magnetic catheter navigation was performed in dogs and pigs (20 to 30 kg). A 7F magnetic ablation catheter was used for intracardiac navigation and radiofrequency ablation. The performance of a standard 7F deflectable catheter was not affected by the MGS. The magnetic catheter was navigated successfully to 51 predefined targets throughout the heart in 6 animals. In 5 animals, the magnetic catheter, guided by a 3D computed tomogram, was successfully navigated to all pulmonary veins. Navigation accuracy was estimated as Ͻ1 mm displacement from the target. The magnetic catheter was used to ablate the atrioventricular node in 4 animals and to perform linear ablations across the endocardial surface underlying an epicardial multielectrode recording plaque in 4 animals. Conclusions-These results demonstrate that the MGS can navigate and stabilize an ablation catheter at endocardial targets. Linear or focal radiofrequency ablation with the magnetic catheter is not compromised by the magnetic field.

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Section: Discussionmentioning

confidence: 99%

Novel, Magnetically Guided Catheter for Endocardial Mapping and Radiofrequency Catheter Ablation

et al. 2002

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“…According to Faraday's law, a voltage is induced across a column of conducting fluid (in this case blood) flowing through a magnetic field. The changes are maximal when the fluid flow is at 90" to the field, which occurs in a supine patient when blood flows through the transverse aorta, hence the changes are principally in leads I, 11, V, and V, [45]. These superimposed potentials are greatest in the early T waves, and late ST segments and can mimic the ECG changes of conditions such as hyperkalaemia and pericarditis (Fig.…”

Section: Ecgmentioning

confidence: 99%

“…The recommendations of Wendt et al [47] and Dimick et al [45] are summarised here: ( I ) braid or twist the leads to reduce the loops across which potential differences can be generated; (2) place the ECG electrodes as close as possible to the centre of the magnetic field since the gradients should be changing least a t this point; (3) …”

Section: Ecgmentioning

confidence: 99%

Magnetic resonance for the anaesthetist

et al. 1992

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SummaryAnaesthetists are increasingly involved in patient care during magnetic resonance imaging and spectroscopy. This paper describes a system which has been developed for the management of critically ill patients and the conduct of anaesthesia in a magnetic resonance unit with a 1.6 tesla whole body magnet. Dificulties which arise from working in a confined space in a high magnetic field are highlighted. Different approaches to anaesthesia, sedation and the modijication of equipment for use in [his environment ure reviewed. The problems associated with patient monitoring within a magnetic field are discussed and some solutions are suggested. A transport system for critically ill patients is described and a protocol for management is outlined.

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“…Various approaches have been proposed to assess, cancel, correct for, bypass, or extract MHD blood flow potential induced artifacts from the surface ECG. These efforts include the assessment of MHDinduced ECG distortions in the fringe field of an MR magnet (12), optimization of ECG electrode placement (13), R-wave detection algorithms based on the vector cardiogram (14), alternative triggering/gating techniques that are less sensitive or even immune to interference with EMF, including self-gating techniques (11,15,16), and sophisticated ECG signal processing (17,18).…”

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confidence: 99%

Detailing the use of magnetohydrodynamic effects for synchronization of MRI with the cardiac cycle: A feasibility study

Frauenrath

Fuchs

Dieringer

et al. 2012

Magnetic Resonance Imaging

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Purpose: To investigate the feasibility of using magnetohydrodynamic (MHD) effects for synchronization of magnetic resonance imaging (MRI) with the cardiac cycle. Materials and Methods:The MHD effect was scrutinized using a pulsatile flow phantom at B 0 ¼ 7.0 T. MHD effects were examined in vivo in healthy volunteers (n ¼ 10) for B 0 ranging from 0.05-7.0 T. Noncontrast-enhanced MR angiography (MRA) of the carotids was performed using a gated steadystate free-precession (SSFP) imaging technique in conjunction with electrocardiogram (ECG) and MHD synchronization. Results:The MHD potential correlates with flow velocities derived from phase contrast MRI. MHD voltages depend on the orientation between B 0 and the flow of a conductive fluid. An increase in the interelectrode spacing along the flow increases the MHD potential. In vivo measurement of the MHD effect provides peak voltages of 1.5 mV for surface areas close to the common carotid artery at B 0 ¼ 7.0 T. Synchronization of MRI with the cardiac cycle using MHD triggering is feasible. MHD triggered MRA of the carotids at 3.0 T showed an overall image quality and richness of anatomic detail, which is comparable to ECG-triggered MRAs. Conclusion:This feasibility study demonstrates the use of MHD effects for synchronization of MR acquisitions with the cardiac cycle.

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Optimizing Electrocardiograph Electrode Placement for Cardiac-Gated Magnetic Resonance Imaging

Cited by 76 publications

References 0 publications

Novel, Magnetically Guided Catheter for Endocardial Mapping and Radiofrequency Catheter Ablation

Novel, Magnetically Guided Catheter for Endocardial Mapping and Radiofrequency Catheter Ablation

Magnetic resonance for the anaesthetist

Detailing the use of magnetohydrodynamic effects for synchronization of MRI with the cardiac cycle: A feasibility study

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