Methods, systems, and apparatus for identification and characterization of rotors associated with atrial fibrillation

#The invention relates generally to methods, systems, and apparatus for identifying and characterizing rotors associated with heart arrhythmias such as atrial fibrillation. Some methods described herein are suitable for classifying rotors as substrate rotors, which may significantly influence arrhythmias, and non-substrate rotors, which may not strongly influence arrhythmias.

#In the last few years, scientific understanding of atrial fibrillation has discovered that the electrical activity in the heart during atrial fibrillation is not complete chaos as was once accepted under the Moe model of random wavelets of electrical activity causing atrial fibrillation. Rather, there are local organized electrical drivers of atrial fibrillation. Recent research has revealed that electrical patterns in the heart, commonly referred to as rotors, play an important role in many cases of fibrillation, particularly persistent atrial fibrillation. Currently, surgical systems are available that modify cardiac tissue during treatment using RF energy, cryo, laser, direct current (DC), stem-cells, or drugs. In some situations modifying, ablating, or “burning” a rotor can significantly improve cardiac function by returning the patient to normal sinus heartbeat rhythm.

#Known surgical techniques, however, have inconsistent results; ablation of some rotors results in significant changes in heart rhythm, while ablation of other rotors does not have a significant effect. Current medical equipment and techniques cannot identify which rotors will have a significant effect if ablated. A need therefore exists for methods, systems, and apparatus for identifying and characterizing rotors. Furthermore, a targeted approach to treating rotors in atrial fibrillation patients will shorten treatment procedure times, reduce cost of procedures, reduce the need for repeat procedures, preserve heart tissue, and enable patients to live longer and fuller lives.

#FIG. 1 is a flow chart of a method of treating a cardiac arrhythmia, according to an embodiment.

#FIGS. 2A and 2B depict electro-anatomical models of a left atrium showing cardiac electrical conduction patterns in two unique phases, according to an embodiment.

#FIG. 2C depicts an electro-anatomical model of the left atrium of FIGS. 2A and 2B showing a map of the voltage characteristics of the underlying tissue, according to an embodiment.

#In some embodiments, a system includes a near-field instrument to be placed inside a chamber of a heart, a far-field instrument to be placed in a stable position in relation to the heart (e.g., the coronary sinus), and a control unit. The control unit is configured to receive position coordinates of the near-field instrument and electrogram information from the far-field instrument. The control unit is configured to identify a unique pattern in the electrogram information from the far-field instrument. When the unique pattern is detected, the control unit is configured to receive electrogram information from the near-field instrument and store the associated near-field instrument position information with the unique pattern information and near-field instrument electrogram information. Upon moving the near-field instrument within the heart chamber, the control unit is configured to identify the unique pattern in the electrogram information from the far-field instrument again. Upon detecting the unique pattern, the control unit is configured to receive electrogram information from the near-field instrument at the new position and store the associated new near-field instrument position information with the unique pattern information and the near-field instrument electrogram information associated with the new position.

#In some embodiments, a method includes receiving position coordinates of a near-field instrument from within a patient's heart chamber and electrogram information from a far-field instrument that is located at a stable position with respect to the patient's heart. The method further includes identifying a pattern in the far-field electrogram data, capturing electrogram data from the near-field instrument when the pattern is detected in the far-field electrogram data, and associating in memory the position coordinates and electrogram data of the near-field instrument and the identified pattern. The method further includes moving the position of the near-field instrument within the patient's heart chamber and repeating the steps to gather near-field electrogram data at the new position when the pattern is identified in the electrogram data of the far-field instrument.

#In some embodiments, a method including identifying the location of one or more rotors (i.e., spiraling conduction vector patterns) in a patient's heart. Once the locations are identified, determining the stability of each of the rotors, measuring voltage characteristics and complex fractionation characteristics of the heart tissue in and around the rotor location, and using the stability information and characteristic information to identify which rotors are sources of arrhythmia.