Pacing guidewire
Guidewires and methods for transmitting electrical stimuli to a heart and for guiding and supporting the delivery of elongate treatment devices within the heart are disclosed. A guidewire can comprise an elongate body, including first and second elongate conductors, and at least first and second electrodes. A distal end portion of the elongate body can include a preformed bias shape, such as a pigtail-shaped region, on which the first and second electrodes can be located. The preformed bias shape can optionally be non-coplanar relative to an intermediate portion of the elongate body. The first and second elongate conductors can be formed of a single structure or two or more electrically connected structures. The conductors can extend from proximal end portions to distal end portions that electrically connect to the first and second electrodes. A corewire can extend the length of the elongate body, can at least partially form the first conductor, and can be at least partially surrounded by the second conductor.
1. A method, comprising:
advancing a guidewire that includes a first insulated conductor and a second insulated conductor into a left ventricle of a patient's heart;
positioning a pre-formed region of the guidewire against or spaced from a ventricular apex or ventricular wall of the patient's heart;
transmitting electrical stimuli through the first insulated conductor and the second insulated conductor to a distal region of the guidewire to induce and maintain cardiac ventricular tachycardia; and
delivering a treatment device to the heart while the heart is maintained in a state of ventricular tachycardia.
2. The method of claim 1 , wherein the first insulated conductor and the second insulated conductor are electrically coupled to a first electrode and a second electrode, respectively, and each electrode is located in the distal region of the guidewire.
3. The method of claim 2 , wherein a distance between the first electrode and the second electrode can be varied.
4. The method of claim 2 , wherein the first electrode is an anode and the second electrode is a cathode.
5. The method of claim 2 , further comprising removably coupling a connector body to a proximal end portion of the guidewire, including electrically coupling first and second terminals of the connector body to the first insulated conductor and the second insulated conductor.
6. The method of claim 5 , wherein removably coupling the connector body to the proximal end portion of the guidewire includes preventing shorting between the first insulated conductor and the second insulated conductor.
7. The method of claim 1 , wherein positioning the pre-formed region of the guidewire includes advancing a pre-formed curved shape into the left ventricle.
8. The method of claim 7 , wherein the pre-formed curved shape includes a pigtail-shaped region that turns through 540 degrees or more.
9. The method of claim 1 , wherein positioning the pre-formed region of the guidewire includes advancing a V-shaped region that is configured to conform to the ventricular apex.
10. The method of claim 1 , wherein transmitting electrical stimuli through the first insulated conductor includes transmitting electrical stimuli through a corewire and a helical coil.
11. The method of claim 1 , wherein transmitting electrical stimuli through the second insulated conductor includes transmitting electrical stimuli through a hypotube or a braid and a helical coil.
12. The method of claim 1 , wherein transmitting electrical stimuli includes generating a current flow of 4.0 mA or less.
13. The method of claim 12 , wherein transmitting electrical stimuli includes generating a current flow of 3.0 mA or less.
14. The method of claim 1 , wherein inducing and maintaining cardiac ventricular tachycardia includes inducing ventricular rates of 120-220 bpm and lowering the patient's blood pressure.
15. The method of claim 1 , wherein delivering the treatment device includes delivering a balloon catheter over the guidewire until the balloon portion of the catheter is positioned within a native aortic valve.
16. The method of claim 15 , further comprising radially expanding the balloon into contact with a native heart valve annulus.
17. The method of claim 16 , further comprising adjusting the electrical stimuli transmitted through the guidewire.
18. The method of claim 17 , wherein sensing the electrophysiological response includes sensing if less than a 1:1 capture of the left ventricle exists.
19. The method of claim 17 , wherein sensing the electrophysiological response includes sensing the patient's systolic blood pressure or pulse pressure.
20. The method of claim 1 , further comprising:
sensing an electrophysiological response to the electrical stimuli transmitted through the guidewire; and
adjusting the transmitted electrical stimuli through the guidewire based on the electrophysiological response.