A maneuverable electrophysiology catheter for percutaneous orintraoperative ablation of cardiac arrhythmias
endocardial surface, where electrical circuits known to cause ventricular tachycardia often arise. Intramyocardial unipolar electrograms show not only the time of onset of an electrogram, but also whether the initial activation was traveling towards or away from the intramyo cardial electrode. This information increases the accuracy of mapping and minimizes the myocardial damage necessary to ablate the arrhythmia. The present invention provides the added advantage that this mapping is done percutaneously. In the practice of the present example, intramyocardial electrograms are obtained prior to ablation by advancing a wire with electrodes at its distal end down the central lumen of the outer catheter. When the outer catheter is in the desired position, the wire with its electrodes is advanced into the tissue for recording of the signals. Once this information has been obtained, the wire is removed and exchanged for the diffusion tipped laser fiber optic, which is placed intramyocardially in the same position. Following tissue heating, the wire is readvanced to record changes in the electrograms of the heated tissue. Intramyocardial mapping allows correlation of tissue characteristics (as reflected in the timing, duration, amplitude, direction and frequency analysis of an electrogram) with the success of an ablation attempt. Comparing the electrograms in an area before and after heating may help distinguish between sublethal damage and totally coagulated tissue. Inferences may also be made on the basis of the information so obtained about the tissue characteristics (e.g., viable, nonviable, partly viable with slow conduction). This information may in turn be correlated with the optical properties of the tissue in order to adjust the dose of laser delivered. For example, an electrogram that is very fractionated and of low amplitude would suggest that the intramyocardial probe is near or within an infarcted area, where there is collagenous tissue (which lacks color and may be less absorptive to some laser wavelengths). The laser is then be adjusted according to dosimetries previously determined as most appropriate for that tissue type. 2 * * * While the apparatus and methods of this invention have been described in terms of preferred embodiments, it will be apparent to those of skill in the art that variations may be applied to the apparatus and methods described herein without 10 departing from the concept, spirit and scope of the invention. All such variations and modifications apparent to those skilled in the art are deemed to be within the spirit, scope and concept of the invention as defined by the appended claims. The following references, to the extent that they provide exemplary procedural or other details supplementary to those set forth herein, are specifically incorporated herein by reference. Currie, R.W. and White, F.P., Characterization of the synthesis and accumulation of a 71-kilodalton protein induced in rat tissues after hyperthermia. Currie, R.W., Karmazyn, Μ., Malgorzata, Κ., and Mailer, Κ., Heat-Shock response is associated with enhanced postischemic ventricular recovery, Currie, R.W., Tanguay, R.M., and Kingma, J.G., Heat-Shock response and limitation of tissue necrosis during occlusion/reperfusion in rabbit hearts. 87:963-971. Donnelly, T.J., Sievers, R.E., Vissem, F.L.J., Welch, W.J., and Wolfe, C.L., Heat shock protein induction in rat hearts. A role for improved myocardial salvage after ischemia and reperfusion? Hutter, Μ.Μ., Sievers, R.E., Barbosa, V.B., and Wolfe, C.L., Heat-shock protein induction in rat hearts. A direct correlation between the amount of heat-shock protein induced and the degree of myocardial protection. Vivaldi, Μ.Τ., Kloner, R.A., and Schoen, F.J., Triphenyltetrazolium staining of irreversible ischemic injury following coronary artery occlusion in rats. Walker, D.M., Pas ini, Ε., Kucukoglu, S., Marber, M.S., Iliodromitis, Ε,, Ferrari, R., and Υ℮11οη, D.M., Heat stress limits infarct size in the isolated perfused rabbit heart. Υ℮11οη, D.M., Pasini, Ε., Cargnoni, A., Marber, M.S., Latchman, D.S., and Ferrari, R., The protective role of heat stress in the ischemic and reperfused rabbit myocardium. A catheter capable of both sensing myocardial electrical activity and delivering ablating energy within myocardial tissue is disclosed. The catheter comprises electrodes on the outer sheath and contains a movable fiber optic cable that can be percutaneously advanced beyond the catheter body and into the myocardium for myocardial heating and coagulation, or modification of tissues responsible for cardiac arrhythmias. The fiber optic tip is designed to diffuse ablating energy radially to ablate a larger volume of tissue than is possible with a bare fiber optic tip. In addition, the tip is treated so that energy is not propagated in a forward direction, thus helping to prevent unwanted perforation of the heart tissue. 1. Apparatus for ablation of cardiac tissue comprising: a catheter adapted to access the cardiovascular system, said catheter having a distal end and a proximal end; and a conductor extending along and within said catheter for transmitting energy to said distal end of said catheter, said conductor having a distal end which is extensible beyond the distal end of the catheter and also retractable within the catheter, said distal end of the conductor configured to penetrate cardiac tissue and to direct energy from and radially and axially relative to the conductor when the conductor is extended beyond the distal end of the catheter. 2. The apparatus of claim 1, further comprising one or more electrode pairs positioned proximate said distal end of said catheter. 3. The apparatus of claim 2, wherein one of said electrode pairs is positioned on the distal end of the catheter. 4. The apparatus of claim 2, wherein an electrode is positioned on a retractable probe slidably disposed in the catheter and extendible beyond the end of said catheter for sensing of intramural electrical activity. 5. The apparatus of claim 2, further comprising a physiological recorder switchably connected to at least one of said electrode pairs operable to map local cardiac electrical activity. 6. The apparatus of claim 2, further comprising an electrical stimulating device switchably connected to at least one of said electrode pairs operable to pace the heart. 7. The apparatus of claim 1, further comprising a stabilizer positioned on an outer surface of the catheter to stabilize the catheter within a body organ. 8. The apparatus of claim 7, wherein said stabilizer comprises an inflatable balloon positioned at the exterior of said distal end of said catheter and operable to expand radially relative to the catheter. 9. The apparatus of claim 1, wherein the conductor comprises an electrical conductor. 10. The apparatus of claim 1, wherein the conductor comprises an optical wave guide and the energy is laser energy. 11. A maneuverable catheter for ablation of cardiac tissue, said catheter comprising a retractable tip, wherein said tip is extendible into the myocardium for lateral diffusion of ablating energy into myocardial tissue. 12. The maneuverable catheter of claim 11, wherein said ablating energy is selected from the group consisting of laser, radiofrequency and hot water. 13. The maneuverable catheter of claim 12, wherein said ablating energy is from 400 to 3,000 nm wavelength laser. 14. A method of treating cardiac arrhythmia comprising the steps of: (a) positioning the distal end of the apparatus of claim 1 proximate the endocardium; (b) identifying the tissue involved in the arrhythmia; (c) extending the distal end of the conductor into the tissue; and (d) transmitting ablating energy through the conductor into the tissue. 15. The method of claim 14, wherein the conductor comprises a wave guide and the ablating energy comprises laser energy. 16. A method for myocardial ablation for treatment of cardiac arrhythmias, comprising: provldinp; a catheter comprising mapping electrodes, stimulating electrodes, and a stabilizer, the catheter being insertable into the heart of a patient and a distal end of the catheter being maneuverable from external to the patient; providing an optical fiber slidably disposed within the catheter, a distal end of the optical fiber comprising an ablation probe that is extensible beyond the distal end of the catheter and adapted for penetrating myocardial and endocardial tissue, the ablation probe being diffusive so as to deliver laser energy substantially radially into the tissue in which the probe is positioned; providing electronic stimulating and mapping instruments coupled to the mapping electrodes and to the stimulating electrodes, and providing a laser energy source coupled to the proximal end of the optical fiber; introducing the catheter into the body of a patient and guiding the catheter into the heart of the patient; stimulating the heart into an arrhythmic condition using said stimulating electrodes; mapping electrical signals produced by the heart and locating an arrhythmic site for ablation; placing the distal end of the catheter proximate the arrhythmic site; activating the stabilizer; advancing the optical fiber through the catheter, thus penetrating the ablation probe through the endocardium and into myocardial tissue at the arrhythmic site; ablating tissue at the arrhythmic site by introducing a desired amount of laser energy into a proximal end of the optical fiber, conducting the laser energy through the optical fiber to the ablation probe, and directing sufficient laser energy into the myocardial tissue at the arrhythmic site to ablate the tissue; and deactivating the stabilizer and removing the catheter and optical fiber from the body of the patient. 17. The method of claim 16, further defined as providing an electrode probe slideably disposed within the catheter that is extensible beyond the distal end of the catheter and designed to penetrate myocardial tissue. 18. The method of claim 17, further comprising attempting to stimulate the heart into an arrhythmic condition using said stimulating electrodes after the ablating step and before removing the catheter from the body. 19. A method for myocardial ablation for treatment of cardiac arrhythmias, comprising: providing a catheter comprising mapping electrodes and stimulating electrodes, the catheter being insertable into a heart of a patient and a distal end of the catheter being maneuverable from external to the patient; providing an energy conductor slidably disposed within the catheter, a distal end of the energy conductor comprising an ablation probe that is extensible beyond the distal end of the catheter and adapted for penetrating endocardial and myocardial tissue; providing electronic stimulating and mapping instruments coupled to the mapping electrodes and to the stimulating electrodes, and providing an ablating energy source coupled to the proximal end of the energy conductor; introducing the catheter into the body of a patient and guiding the catheter into the heart of the patient; stimulating the heart into an arrhythmic condition using said stimulating electrodes; mapping electrical signals produced by the heart and locating an arrhythmic site for ablation; placing the distal end of the catheter proximate the arrhythmic site; advancing the energy conductor through the catheter, thus penetrating the ablation probe through the endocardium and into the myocardium at the arrhythmic site; ablating tissue at the arrhythmic site by introducing a desired amount of energy into a proximal end of the energy conductor, conducting the energy through the energy conductor to the ablation probe, and directing sufficient energy into the myocardium at the arrhythmic site to ablate the tissue; and deactivating the stabilizer and removing the catheter and optical fiber from the body of the patient. 20. The method of claim 19, further comprising attempting to stimulate the heart into an arrhythmic condition using said stimulating electrodes after the ablating step and before removing the catheter from the body. 21. The method of claim 19, wherein the energy source is a laser source, and the energy conductor comprises an optical fiber. 22. The method of claim 17, wherein the energy source is a radio frequency (RF) source, and the energy conductor comprises a conductive wire. 23. A method of inducing angiogenesis comprising the steps of: (a) positioning the distal end of the apparatus of claim 1 proximate the endocardium; (b) identifying an area of ischemic tissue; (c) extending the distal end of the conductor into the tissue; and (d) transmitting energy through the conductor into the tissue to create hyperthermia in said tissue. 24. The method of claim 23, wherein the conductor comprises a wave guide and the ablating energy comprises laser energy. 25. The method of claim 23, wherein said tissue reaches a temperature of at least about 40°C. 26. The method of claim 23 wherein said energy is conductive energy. 27 A method of inhibiting tissue damage due to ischemia comprising providing radiative or conductive energy to said tissue in an amount effective to induce local hyperthermia. 28. The method of claim 27, wherein said tissue is heart tissue and said energy is applied to the endocardial surface, the epicardial surface or interstitial area of said heart. 29. A method of endocardial mapping of cardiac rhythm comprising: providing an apparatus comprising a catheter adapted to access the cardiovascular system, said catheter having a distal end and a proximal end and an electrode positioned on a retractable probe slidably disposed in the catheter and extendible beyond the end of said catheter and capable of penetrating endocardium and myocardial tissue and said electrode being connected to a means for sensing intramural electrical activity; inserting said catheter into a patient; extending the distal end of said catheter into the heart of said patient; extending the retractable probe into the myocardium; and detecting an electrogram from the electrode. FIG. 1 SUBSTITUTE SHEET (RULE 26) PCT/US96/13396 FIG. 2 PCT/US96/13396 FIG. 3 FIG. 4 FIG. 5 Ε2 (Η) Group □ (C1) Control FIG. 6Α S (Η) Group □ (C1) Control FIG. 6Β 9.6 0 Right Ventricle □ Left Ventricle 5.4 0¾ V 1.451.75 .5 1-6 ΐ¾ 03 zc Experimental Groups FIG. 7 INTERNATIONAL SEARCH REPORT A. CLASSIFICATION OF SUBJECT MATTER IPC(6) :Α61Β S/04, 17/36 US CL : 128/642; 606/15, 41, 49; 607/126 According to International Patent Classification (IPC) or to both national classification and IPC Β. FIELDS SEARCHED Minimum documentation searched (classification system followed by classification symbols) U.S. ; 128/642; 606/15. 41, 49; 607/89, 122, 126 Documentation searched other than minimum documentation to the extent that such documents are included in the fields searched Electronic data base consulted during the international search (name of data base and, where practicable, search terms used) C. DOCUMENTS CONSIDERED TO BE RELEVANT Category1 Citation of document, with indication, where appropriate, of the relevant passages Relevant to claim No, X X Υ Υ, Ε US 4,862,887 A (WEBER et al) 05 September 1989, col. 2, line 58 to col.4, line 4. US 5,403,311 A (ABELE et al) 04 April 1995, Figs. 9, and 10. US 5,431,649 A (MULIER et al) 11 July 1995, col. 1, line 60 to col. 6, line 5. US 5,551,427 A (ALTMAN) 03 September 1996, col. 10, line 43 to col. 11, line 36. 29 1-29 1, 2,4-6, 9, 11, 12, 14, 23, 25-29 3 3 X Further documents are listed in the continuation of Box C. [ | See patent family annex. * Special categories of cited documents: ‘A* document defining the general state of the an which is not considered to be of particular relevance * E* earlier document published on or after the international filing date 'L* document which may throw doubts on priority ciaimfs) or which is cited special reason (as specified) *0* document referring to an oral disclosure, use, exhibition or other means " p* document published prior to the international filing date but Later than the priority date claimed *T* later document published after the international filing date or priority date and not in conflict with the application but cited to understand the principle or theory underlying the invention ·Χ· document of particular relevance; the claimed invention cannot be considered novel or cannot be considered to involve an inventive step when the document is taken alone ·Υ· document of particular relevance; the claimed invention cannot be considered to involve an inventive step when the document is combined with one or more other such documents, such combination beins obvious to a person skilled in the art *&* document member of the same patent family Date of the actual completion of the international search Date of mailing of the international search report Name and mailing address of the ISA/US Commissioner of Patents and Trademarks Box PCT Washington. D.C. 20231 Facsimile No. (703) 305-3590 Authorized officer LEE S. COHEN Telephone No. (703) 308-2998 Form PCT/ISA/210 (second sbeet)(July 1992)* INTERNATIONAL SEARCH REPORT Ini*, uaiional application No. PCT/US96/13396REFERENCES