BALLOON CATHETER AND RELATED IMPEDANCE-BASED METHODS FOR DETECTING OCCLUSION
A system for assessing occlusion of a region to blood flow includes a catheter with an inflatable member, a first electrode configured for placement upstream of the inflatable member and the second electrodes configured for placement downstream of the inflatable member, the inflatable member configured for inflation to occlude the blood flow through the region. The system further includes a current/voltage source, a resistor and a voltmeter, wherein these components along with the first and second electrodes are configured to form an impedance measuring circuit configured to detect a change in impedance for indicating occlusion of the region to the blood flow.
1 . An electrophysiology catheter comprising:
an inflatable member configured for placement in blood flow through a region, the member configured to adopt an inflated configuration in the region;
a first electrode distal of the inflatable member and configured for placement in the blood flow upstream of the inflatable member, a second electrode proximal of the inflatable member and configured for placement in the blood flow downstream of the inflatable member, the first and second electrodes configured to define a conduction pathway; and
a first lead wire connected to the first electrode and a second lead wire connected to the second electrode, the first and second lead wires configured to pass an electrical current between the first and second electrodes for measuring impedance of the conduction pathway.
2 . The catheter of claim 1 , further comprising a shaft extending through the inflatable member, wherein the first electrode is mounted on the shaft distal of the inflatable member and the second electrode is mounted on the shaft proximal of the inflatable member.
3 . The catheter of claim 1 , wherein the inflatable member in the inflated configuration is configured to fully occlude the region from blood flow.
4 . The catheter of claim 1 , wherein the inflatable member has an outer surface and a plurality of ablation electrodes are affixed to the outer surface, the plurality of ablation electrodes configured for circumferential contact with tissue wall of the region when the inflatable member is in the inflated configuration.
5 . An electrophysiology system for detecting occlusion, comprising
a catheter of claim 1 ;
an impedance measuring unit electrically connected to the first and second lead wires, the unit configured to provide an output signal representative of a measured impedance of the conduction pathway;
an impedance controller configured to receive the output signal; and
an alarm responsive to the impedance controller configured to provide an indication to a user.
6 . The system of claim 5 , wherein the impedance measuring unit includes a current/voltage source, a resistor, and a voltmeter.
7 . The system of claim 5 , wherein the impedance controller is configured to determine an occurrence of a measured impedance exceeding a threshold impedance value.
8 . The system of claim 5 , wherein the impedance controller is configured to determine a rate of change of measured impedance.
9 . The system of claim 5 , wherein the impedance controller is configured to determine an occurrence of a rate of change of measured impedance exceeding a threshold rate of change of impedance.
10 . The system of claim 5 , wherein the impedance controller includes an A/D converter, an impedance processor, a memory and a clock.
11 . An electrophysiology catheter for use in or near a tubular region of a patient's heart, comprising:
an inflatable member configured for placement in blood flow through the tubular region, the inflatable member configured to adopt an inflated configuration in or near the tubular region;
a first electrode distal of the inflatable member and configured for placement in the blood flow upstream of the inflatable member, a second electrode proximal of the inflatable member and configured for placement in the blood flow downstream of the inflatable member, the first and second electrodes configured to define a conduction pathway; and
a first lead wire connected to the first electrode and a second lead wire connected to the second electrode, the first and second lead wires configured to pass an electrical current between the first and second electrodes for measuring impedance of the conduction pathway.
12 . The catheter of claim 11 , further comprising a shaft extending through the inflatable member, wherein the first electrode is mounted on the shaft distal of the inflatable member and the second electrode is mounted on the shaft proximal of the inflatable member.
13 . The catheter of claim 11 , wherein the inflatable member in the inflated configuration is configured to provide circumferential contact of an outer surface of the inflatable member with tissue wall of the tubular region to occlude the tubular region from blood flow.
14 . The catheter of claim 13 , wherein a plurality of ablation electrodes are affixed to the outer surface.
15 . An electrophysiology system for detecting occlusion, comprising:
a catheter having:
an inflatable member configured for placement in blood flow from a pulmonary vein into a left atrium through an ostium, the inflatable member configured to adopt an inflated configuration in or near the ostium;
a first electrode distal of the inflatable member and configured for placement in the pulmonary vein, a second electrode proximal of the inflatable member and configured for placement in the left atrium, the first and second electrodes configured to define a conduction pathway between the pulmonary vein and the left atrium; and
a first lead wire connected to the first electrode and a second lead wire connected to the second electrode, the first and second lead wires configured to pass an electrical current between the first and second electrodes for measuring impedance of the conduction pathway;
an impedance measuring unit electrically connected to the first and second lead wires, the unit configured to provide an output signal representative of a measured impedance of the conduction pathway;
an impedance controller configured to receive the output signal; and
an alarm responsive to the impedance controller configured to provide an indication to a user.
16 . The system of claim 15 , wherein the impedance measuring unit includes a current/voltage source, a resistor, and a voltmeter.
17 . The system of claim 15 , wherein the impedance controller is configured to determine an occurrence of a measured impedance exceeding a threshold impedance value.
18 . The system of claim 15 , wherein the impedance controller is configured to determine a rate of change of measured impedance.
19 . The system of claim 15 , wherein the impedance controller is configured to determine an occurrence of a rate of change of measured impedance exceeding a threshold rate of change of impedance.
20 . The system of claim 15 , wherein the impedance controller includes an A/D converter, an impedance processor, a memory and a clock.