This invention relates generally to electrophysiological (EP) mapping systems and catheter devices, and more specifically to a radio frequency (RF) adapter for providing wireless communication between a catheter and an electrophysiological mapping system.
Catheters are flexible, tubular devices that are widely used by physicians performing medical procedures to gain access into interior regions of the body. For diagnostic purposes, a catheter is usually connected by a cable to an EP mapping system. The catheter includes a plurality of electrodes on its distal area. The catheter electrodes detect signals from the tissue surrounding the distal area of the catheter and send the detected signals to the EP mapping system. The EP mapping system uses the detected signals to generate a map of the tissue surrounding the catheter distal region.
Currently, a catheter cannot communicate wirelessly with an EP mapping system.
One embodiment of the present invention is a catheter system for wireless communication with an electrophysiological (EP) mapping system. The catheter system comprises a catheter, a catheter adapter, and a radio frequency receiver module. The catheter includes an elongated body having a distal end, and a proximal end, a plurality of mapping electrodes including a tip electrode being disposed on a distal portion of the elongated body, the plurality of mapping electrodes detecting electrocardiograph (ECG) signals; and a reference electrode being disposed on the elongated body at a distance from the plurality of mapping electrodes such that the reference electrode substantially does not detect electrocardiograph (ECG) signals. The catheter includes a handle. The catheter adapter is attached to the handle. The catheter adapter includes an RF transmitter module for receiving, processing, and transmitting the detected ECG signals. The reference electrode provides a reference signal to the radio frequency (RF) transmitter module. The RF receiver module receives the transmitted ECG signals. The RF receiver module is coupled to the EP mapping system.
The catheter RF adapter of the present invention allows a diagnostic catheter to communicate wirelessly with an EP mapping system. Without a cable attaching the diagnostic catheter to an EP mapping system, a physician will be able to manipulate and control the catheter with greater ease.
The catheter RF adapter of the present invention comprises an RF transmitter module and a RF receiver module. The RF transmitter module is adapted to be securely attached to the handle of the catheter. The RF receiver module is coupled to the front end of the EP mapping system.
The catheter 110 comprises a distal region. The catheter distal region includes bands of electrodes positioned spaced apart in different longitudinal sections of the distal region. The tip of the catheter may also include an electrode. The catheter tip electrode and the catheter bands of electrodes send electrocardiograph (ECG) signals to the RF transmitter module 120. The tip electrode and the number of bands of electrodes determine the number of signals being outputted to the RF transmitter module 120, which in turn determine the number of RF channels used for wireless transmission. In one embodiment of the invention, the catheter 110 outputs 20 signals to the RF transmitter module 120 which processes the 20 signals and transmits the processed signals in 20 corresponding RF channels. The catheter 110 also includes a reference band electrode located at a large distance from the last band of electrode that senses an ECG signal, i.e., the furthest band electrode from the catheter distal end.
The multiplexer 210 receives, at its 20 inputs, 20 ECG analog signals in parallel from the catheter 110, and outputs a single ECG analog signal.
The amplifier 230 receives at its inputs the single ECG analog signal and the signal from the reference electrode. The amplifier 230 amplifies the difference between the ECG analog signal and the signal from the reference electrode to a level suitable for wireless transmission and outputs the amplified analog signal to the A/D converter 240.
The A/D converter 240 converts the amplified analog signal to a digital signal and outputs the digital signal to the microcontroller 250.
The microcontroller 250 codes the digital signal into a format suitable for wireless transmission. In one embodiment, an error correcting code is also employed in coding the digital signal. The microcontroller 250 output the coded digital signal to the RF transmitter 260. The microcontroller 250 also outputs a multiplexer control interface signal 252 to control the operation of the multiplexer 210.
The RF transmitter 260 receives the coded digital signal and transmits it over the air medium as an RF signal in a corresponding RF channel.
The RF receiver 310 receives the RF signal over the air medium from the corresponding RF channel and outputs the digital signal to the microcontroller 320.
The microcontroller 320 decodes the digital signal and outputs the decoded digital signal to the multi-channel D/A converter 330.
The multi-channel D/A converter 330 converts the digital signal into an analog signal. The multi-channel D/A converter 330 also demultiplexes the analog signal into 20 analog signals which are then outputted to the EP mapping system.
In order to measure the ECG signals, a reference signal is needed. In an existing catheter system where a catheter is connected to an EP system by a cable, a signal measured from a body surface of a patient via a patch connected directly to the EP system by a cable is used as a reference signal. In the present invention, where the communication to the EP system is wireless, a novel self-creating reference scheme is employed to provide a reference signal.
Due to the buffer 270 driving the DC voltage Vbias out to the reference electrode, the signal from the reference electrode is practically equal to the DC voltage Vbias, and serves as a virtual reference.
The multiplexer 210 receives, at its 20 inputs, 20 ECG analog signals in parallel from the catheter 110, and outputs a single ECG analog signal.
The amplifier 230 comprises a differential amplifier. The differential amplifier receives the single ECG analog signal at its positive input and the signal from the reference electrode at its negative input. The amplifier 230 amplifies the difference between the 2 signals and outputs an amplified ECG analog signal that substantially does not have a DC component.
While the invention has been described in terms of several embodiments, those of ordinary skill in the art will recognize that the invention is not limited to the embodiments described, but can be practiced with modification and alteration within the spirit and scope of the appended claims. The description is thus to be regarded as illustrative instead of limiting.
This application claims the benefit of U.S. Provisional Application Ser. No. 61/135,837, filed on Jul. 23, 2008, entitled “Catheter radio frequency adapter”, which is hereby incorporated by reference in its entirety.
Number | Date | Country | |
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61135837 | Jul 2008 | US |