System and method for magnetic-resonance-guided electrophysiologic and ablation procedures
First Claim
1. A method for performing an electrophysiological procedure on a mammalian patient having a heart, comprising:
- placing the patient such that the heart is in a main magnetic field of an MRI scanner;
introducing an MR-compatible catheter into the heart;
attenuating a frequency induced in the catheter by the MRI scanner, wherein the attenuated frequency corresponds to a radio frequency emitted by the scanner;
acquiring a magnetic resonance image of the heart;
using the magnetic resonance image to determine a location of said MR-compatible electrode catheter in the heart, andat substantially the same time that the image is acquired, using said MR-compatible electrode catheter to acquire electrical signals of the heart.
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Accused Products
Abstract
A system and method for using magnetic resonance imaging to increase the accuracy of electrophysiologic procedures is disclosed. The system in its preferred embodiment provides an invasive combined electrophysiology and imaging antenna catheter which includes an RF antenna for receiving magnetic resonance signals and diagnostic electrodes for receiving electrical potentials. The combined electrophysiology and imaging antenna catheter is used in combination with a magnetic resonance imaging scanner to guide and provide visualization during electrophysiologic diagnostic or therapeutic procedures. The invention is particularly applicable to catheter ablation, e.g., ablation of atrial fibrillation. In embodiments which are useful for catheter ablation, the combined electrophysiology and imaging antenna catheter may further include an ablation tip, and such embodiment may be used as an intracardiac device to both deliver energy to selected areas of tissue and visualize the resulting ablation lesions, thereby greatly simplifying production of continuous linear lesions. The invention further includes embodiments useful for guiding electrophysiologic diagnostic and therapeutic procedures other than ablation. Imaging of ablation lesions may be further enhanced by use of MR contrast agents. The antenna utilized in the combined electrophysiology and imaging catheter for receiving MR signals is preferably of the coaxial or “loopless” type. High-resolution images from the antenna may be combined with low-resolution images from surface coils of the MR scanner to produce a composite image. The invention further provides a system for eliminating the pickup of RF energy in which intracardiac wires are detuned by filtering so that they become very inefficient antennas. An RF filtering system is provided for suppressing the MR imaging signal while not attenuating the RF ablative current. Steering means may be provided for steering the invasive catheter under MR guidance. Other ablative methods can be used such as laser, ultrasound, and low temperatures.
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Citations
37 Claims
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1. A method for performing an electrophysiological procedure on a mammalian patient having a heart, comprising:
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placing the patient such that the heart is in a main magnetic field of an MRI scanner; introducing an MR-compatible catheter into the heart; attenuating a frequency induced in the catheter by the MRI scanner, wherein the attenuated frequency corresponds to a radio frequency emitted by the scanner; acquiring a magnetic resonance image of the heart; using the magnetic resonance image to determine a location of said MR-compatible electrode catheter in the heart, and at substantially the same time that the image is acquired, using said MR-compatible electrode catheter to acquire electrical signals of the heart. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for treating cardiac arrhythmias in a mammalian patient having a heart, comprising:
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positioning the patient such that the heart is in a main magnetic field of an MRI magnetic scanner; attenuating a frequency induced in the catheter by the MRI scanner, wherein the attenuated frequency correspond to a radio frequency emitted by the scanner; acquiring a magnetic resonance image of the heart; introducing an ablation catheter into the patient and the heart and applying the catheter to create ablation lesions in the heart; using said catheter to acquire electrical signals indicative of an electrophysiological state of the heart and, using the magnetic resonance image to visualize the ablation lesions while the said ablation catheter is proximate said lesions.
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8. A magnetic resonance imaging compatible cardiac catheter, comprising:
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an electrode for applying an RF ablation current to a heart, and an attenuation device adapted to attenuate in the catheter a radio frequency (RF) signal corresponding to an RF magnetic resonance imaging signal generated by an MR system for a magnetic resonance imaging-guided catheter ablation operation of the heart in a mammalian patient. - View Dependent Claims (9, 10, 11, 12, 13)
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14. A method for treating cardiac arrhythmia in a heart of a mammalian comprising:
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positioning the heart of the patient in a main magnetic field of an MRI system; acquiring a magnetic resonance image of the heart; introducing a catheter into the patient and the heart; attenuating a frequency induced in the catheter by the MRI scanner, wherein the attenuated frequency correspond to a radio frequency emitted by the scanner; acquiring electrical heart signals using said catheter that are indicative of an electrophysiological state of the heart; detecting an area of abnormal electric activity in the heart based on the signals; ablating the area of abnormal activity with the catheter, and using the magnetic resonance image to visualize ablation lesions caused by the ablation while the catheter is proximate the lesions. - View Dependent Claims (15)
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16. An ablation system to perform an electrophysiological procedure on a beating heart of a patient in an MRI scanner, comprising:
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an MR-compatible catheter including an ablation circuit and an intracardiac electrogram measuring circuit; an RF filter adapted to suppress a radio frequency (RF) imaging signal in said intracardiac electrogram measuring circuit; and a electronic filter adapted to suppress noise induced by gradient fields of the MRI scanner. - View Dependent Claims (17, 18, 19)
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20. An ablation system to perform an electrophysiological procedure on a beating heart of a patient in an MRI, comprising:
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MR-compatible catheter equipped with an ablation circuit and an intracardiac electrogram measuring circuit; an RF filter designed to suppress a radio frequency (RF) imaging signal and pass without attenuation the cardiac electrical signal from an ablation catheter between 30 and 300 Hz in the said ablation circuit; and an active gradient induced noise filter in the said intracardiac electrogram measuring circuit.
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21. A method for performing an electrophysiological procedure on a mammalian patient having a heart, comprising:
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positioning a the patient such that the heart is in a main magnetic field of an MRI scanner; introducing an MR-compatible catheter into the heart; attenuating a frequency induced in the catheter by the MRI scanner, wherein the attenuated frequency correspond to a radio frequency emitted by the scanner; acquiring a magnetic resonance image of the heart by applying static and gradient magnetic fields to the patient and sensing radio frequency (RF) emissions from precession of protons in the heart excited by the magnetic fields; using the magnetic resonance image to position said MR-compatible electrode catheter in the heart while continuing to acquire additional magnetic resonance images of the heart; and establishing a conductive connection between the catheter and the heart and monitoring electrical signals in the heart. - View Dependent Claims (22, 23, 24, 25, 26)
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27. A method for treating cardiac arrhythmia in a heart of a mammalian comprising:
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positioning the heart of the patient in a main magnetic field of an MRI system; introducing a catheter into the heart of the patient; ablating an area of the heart with the catheter; using magnetic resonance (MR) imaging to visualize an ablation lesion caused by the ablation; identifying a region of the visualized ablation lesions requiring further ablation, and ablating the identified region. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34, 35, 36, 37)
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Specification