Apparatus and method for cardiac ablation
A system and method for cardiac mapping and ablation include a multi-electrode catheter introduced percutaneously into a subject's heart and deployable adjacent to various endocardial sites. The electrodes are connectable to a mapping unit, an ablation power unit a pacing unit, all of which are under computer control. Intracardiac electrogram signals emanated from a tachycardia site of origin are detectable by the electrodes. Their arrival times are processed to generate various visual maps to provide real-time guidance for steering the catheter to the tachycardia site of origin. In another aspect, the system also include a physical imaging system which is capable of providing different imaged physical views of the catheter and the heart. These physical views are incorporated into the various visual maps to provide a more physical representation. Once the electrodes are on top of the tachycardia site of origin, electrical energy is supplied by the ablation power unit to effect ablation.
1. A cardiac mapping system for locating a tachycardia site of origin in an endocardium of a subject's heart, comprising:
a catheter having a cluster of electrodes at a distal end, said cluster of electrodes deployable to cover a two-dimensional portion of the endocardium for detecting intracardiac electrogram signals emanating from the tachycardia site of origin;
a computer configured to process the intracardiac electrogram signals detected at each electrode, said computer further configured to compute an arrival time of the intracardiac electrogram signals at each electrode and compute a velocity vector from a speed of travel of the electrogram signal along a first direction and along a second direction orthogonal to the first direction and wherein the tachycardia site of origin has a direction relative to the first and second directions given by the velocity vector;
a physical imaging system providing a view of the heart and the cluster of electrodes;
wherein the computer is further configured to generate a map integrating the view from the physical imaging system and said arrival times of the intracardiac electrogram signals, said map including a display of the cluster of electrodes and arrival time associated with each electrode, and the velocity vector; and
a display monitor for interactively displaying said map, whereby those electrodes being closer to the tachycardia site of origin than others will register earlier arrival times than others, and electrodes that are substantially coincident with the tachycardia site of origin will register an earliest possible arrival time, thereby said map providing guidance for moving said catheter in the direction of those electrodes having earlier arrival times.
2. A cardiac mapping system as in claim 1 , further comprising:
a power supply switchably supplying power to at least one electrode of said cluster of electrodes when said at least one of said cluster of electrodes is placed substantially coincident with the tachycardia site of origin to ablate thereat.
3. A cardiac mapping system as in claim 2 , wherein said power supply supplies radio frequency power of different phases to different electrodes among said cluster of electrodes.
4. A cardiac mapping system as in anyone of claims 1 - 3 , wherein said computer further computes contours of equal arrival time or isochrones; and
said map includes isochrones computed from arrival times derived from existing detected sites.
5. A cardiac mapping system as in anyone of claims 1 - 3 , wherein said map further includes an interactive track of said cluster of electrodes as it scans along a path on the endocardium.