Method for low-voltage termination of cardiac arrhythmias by effectively unpinning anatomical reentries
A method for extinguishing a cardiac arrhythmia utilizes destructive interference of the passing of the reentry wave tip of an anatomical reentry through a depolarized region created by a relatively low voltage electric field in such a way as to effectively unpin the anatomical reentry. Preferably, the relatively low voltage electric field is defined by at least one unpinning shock(s) that are lower than an expected lower limit of vulnerability as established, for example, by a defibrillation threshold test. By understanding the physics of the electric field distribution between cardiac cells, the method permits the delivery of an electric field sufficient to unpin the core of the anatomical reentry, whether the precise or estimated location of the reentry is known or unknown and without the risk of inducting ventricular fibrillation. A number of embodiments for performing the method are disclosed.
1. A method for terminating a ventricular tachycardia event in a patient comprising:
establishing a termination window associated with the ventricular tachycardia event that is defined as a time period based on a frequency of the ventricular tachycardia event;
applying one or more unpinning pulses in the termination window to unpin a rotating wave associated with one or more anatomical reentries causing the ventricular tachycardia event; and
applying a plurality of anti-repinning (ARP) pulses following the one or more unpinning pulses and within the termination window and without verification of the ventricular tachycardia event to exterminate any unpinned, functional reentries,
wherein the one or more unpinning pulses have an energy that is higher than conventional anti-tachy pacing pulses and lower than an expected lower limit of vulnerability of the patient and the plurality of ARP pulses have an energy that is less than the one or more unpinning pulses.
2. The method of claim 1 wherein the step of establishing the termination window comprises determining a dominant frequency (DF) for a ventricular tachycardia event based on electrocardiograph (ECG) data and using the DF to establish the termination window.
3. The method of claim 2 wherein the step of using the DF to establish the termination is accomplished by dividing a period defined by 1/DF by an integer less than ten.
4. The method of claim 3 wherein the integer used in the step of dividing is between two and six.
5. The method of claim 1 wherein the step of applying one or more unpinning pulses comprises delivering multiple pulses over a period of 100-150 ms, where all of the pulses are delivered through a same electrode path in order to present alternative wave fronts to the anatomical reentry so as to increase the likelihood of destructively interfering with the wave tip.
6. The method of claim 1 wherein the step of applying one or more unpinning pulses comprises delivering multiple pulses, where at least two of the pulses are delivered through different electrode paths in order to present alternative wave fronts to the anatomical reentry so as to produce an equivalent of a vector rotating field to the anatomical reentry.
7. A method of providing a device for treating cardiac arrhythmias, comprising:
providing a device including programmably-operable circuitry to detect and terminate a ventricular tachycardia event in a heart of a patient; and
providing instructions for operating the device for treating cardiac arrhythmias such that the programmably-operable circuitry:
detects a tachycardia event in the heart of the patient,
establishes a termination window associated with the ventricular tachycardia event that is defined as a time period based on a frequency of the ventricular tachycardia event,
applies one or more unpinning pulses in the termination window to unpin a rotating wave associated with one or more anatomical reentries causing the ventricular tachycardia event, the one or more unpinning pulses having an energy that is higher than conventional anti-tachy pacing pulses and lower than an expected lower limit of vulnerability of the patient, and
applies a plurality of anti-repinning (ARP) pulses following the one or more unpinning pulses and within the termination window and without verification of the ventricular tachycardia event to exterminate any unpinned, functional reentries and terminate the tachycardia event, the plurality of ARP pulses having an energy that is less than the one or more unpinning pulses.
8. The method of claim 7 , wherein providing instructions for operating the device for treating cardiac arrhythmias such that the programmably-operable circuitry establishes a termination window comprises determining a dominant frequency (DF) for a ventricular tachycardia event based on electrocardiograph (ECG) data and using the DF to establish the termination window.
9. The method of claim 8 wherein the using the DF to establish the termination window is accomplished by dividing a period defined by 1/DF by an integer less than ten.
10. The method of claim 9 wherein the integer used in the step of dividing is between two and six.
11. The method of claim 7 wherein providing instructions for operating the device for treating cardiac arrhythmias such that the programmably-operable circuitry applies one or more unpinning pulses comprises delivering multiple pulses over a period of 100-150 ms, where all of the pulses are delivered through a same electrode path in order to present alternative wave fronts to the anatomical reentry so as to increase the likelihood of destructively interfering with the wave tip.
12. The method of claim 7 wherein providing instructions for operating the device for treating cardiac arrhythmias such that the programmably-operable circuitry applies one or more unpinning pulses comprises delivering multiple pulses, where at least two of the pulses are delivered through different electrode paths in order to present alternative wave fronts to the anatomical reentry so as to produce an equivalent of a vector rotating field to the anatomical reentry.