초록 ▼

Improved methods and apparatus for providing optimal anti-tachycardia pacing (ATP) regimens in response to the return cycle length (RCL) exhibited by an exploratory ATP sequence initially applied upon detection of the tachycardia episode are disclosed. When a tachycardia episode is detected, an expl

Improved methods and apparatus for providing optimal anti-tachycardia pacing (ATP) regimens in response to the return cycle length (RCL) exhibited by an exploratory ATP sequence initially applied upon detection of the tachycardia episode are disclosed. When a tachycardia episode is detected, an exploratory ATP sequence comprising a burst of pacing pulses is delivered, and an exploratory RCL is measured following delivery of the exploratory ATP sequence. A database of successful and unsuccessful ATP regimens associated with stored exploratory RCL values. The measured exploratory RCL and database are utilized to formulate an ATP regimen that is more likely than not to convert the tachycardia episode to NSR.

대표청구항 ▼

What is claimed is: 1. In an implantable medical device (IMD) of the type that detects intrinsic depolarizations of a heart chamber, detects a tachycardia episode, and responds to the detected tachycardia of a heart chamber by delivering at least one anti-tachycardia pacing (ATP) regimen to the hea

What is claimed is: 1. In an implantable medical device (IMD) of the type that detects intrinsic depolarizations of a heart chamber, detects a tachycardia episode, and responds to the detected tachycardia of a heart chamber by delivering at least one anti-tachycardia pacing (ATP) regimen to the heart chamber, a method of delivering the ATP regimens further comprising: (a) upon detection of a tachycardia episode, delivering an exploratory ATP sequence of pacing pulses to the heart chamber to elicit a paced depolarization of the heart chamber upon delivery of at least the last delivered ATP pulse; (b) measuring an exploratory return cycle length (RCL) from the last delivered exploratory ATP sequence pacing pulse to the next detected intrinsic depolarization; (c) formulating an ATP regimen having ATP parameters formulated as a function of the measured exploratory RCL; (d) delivering the ATP regimen to the heart chamber; (e) following delivery of the ATP regimen, determining whether the tachycardia episode is terminated; and (f) if the tachycardia episode is determined to be terminated in step (e), storing the measured exploratory RCL used in formulating the delivered ATP regimen and storing the delivered ATP regimen as a successful ATP regimen, the stored ATP regimen being stored in association with the stored measured exploratory RCL in IMD memory. 2. The method of claim 1, wherein step (c) further comprises: comparing the measured exploratory RCL determined in step (b) with any previously measured, stored exploratory RCLs stored in step (f); and if the exploratory RCL measured in step (b) matches a stored exploratory RCL, retrieving the successful ATP regimen stored in association with the stored exploratory RCL from the IMD memory, the retrieved successful ATP regimen to be delivered in step (d). 3. The method of claim 2, further comprising: (g) if the tachycardia episode is determined to not be terminated in step (e), storing the measured exploratory RCL used in formulating the delivered ATP regimen and storing the delivered ATP regimen as an unsuccessful ATP regimen, the stored ATP regimen being stored in association with the stored measured exploratory RCL in IMD memory, whereby a database is accumulated in IMD memory comprising stored measured exploratory RCLs and stored successful and unsuccessful ATP regimens, each stored ATP regimen stored in association with a-stored exploratory RCL used to formulate the stored ATP regimen. 4. The method of claim 3, wherein: step (a) further comprises determining a pre-ATP rate of the tachycardia prior to delivery of the exploratory ATP sequence; step (e) further comprises: determining a post-ATP rate of the tachycardia following delivery of the ATP regimen; and comparing the post-ATP rate to the pre-ATP rate to determine if the post-ATP rate is faster or slower than the pre-ATP rate; and step (g) further comprises: storing the exploratory RCL used in formulating the delivered ATP regimen and storing the delivered ATP regimen as an unsuccessful, non-accelerating, ATP regimen, the stored ATP regimen being stored in association with the stored exploratory RCL in IMD memory, if the post-ATP rate is slower or substantially the same as the pre-ATP rate; and storing the exploratory RCL used in formulating the delivered ATP regimen and storing the delivered ATP regimen as an unsuccessful, accelerating, ATP regimen, the stored ATP regimen stored in association with the stored exploratory RCL in IMD memory, if the post-ATP rate is faster, by a predetermined amount, than the pre-ATP rate, whereby a database is accumulated in IMD memory comprising stored measured exploratory RCLs and stored successful and unsuccessful ATP regimens, each stored ATP regimen stored in association with a stored exploratory RCL used to formulate the ATP regimen. 5. The method of claim 4, wherein step (c) further comprises: comparing the measured exploratory RCL determined in step (b) with the stored exploratory RCLs stored in both step (f) and step (g); and formulating the ATP parameters of the ATP regimen to be delivered as a baseline ATP therapy if the measured exploratory RCL matches a stored exploratory RCL stored in association with an unsuccessful, accelerating, ATP regimen. 6. The method of claim 5, wherein: step (e) further comprises: measuring an ATP regimen RCL from the last delivered ATP regimen pacing pulse to the next detected intrinsic depolarization; and step (g) further comprises storing the ATP regimen RCL in IMD memory in association with the delivered ATP regimen stored as an unsuccessful, non-accelerating, ATP regimen, if the post-ATP rate is slower or substantially the same as the pre-ATP rate. 7. The method of claim 6, wherein step (c) further comprises: comparing the measured exploratory RCL determined in step (b) with the stored exploratory RCLs stored in both step (f) and step (g); and if the measured exploratory RCL matches a stored exploratory RCL stored in association with a stored unsuccessful, non-accelerating, ATP regimen and an associated stored ATP regimen RCL, formulating the ATP parameters of the ATP regimen to be delivered as an iteration of the ATP parameters of the unsuccessful, non-accelerating, ATP regimen and the ATP regimen RCL. 8. The method of claim 7, wherein the ATP parameters comprise an ATP cycle length and a number of ATP pulses, and step (c) further comprises: comparing the stored ATP regimen RCL and the measured exploratory RCL; and adjusting at least one of the ATP cycle length and the number of ATP pulses as a function of the comparison of the ATP regimen RCL to the measured exploratory RCL. 9. The method of claim 8, wherein the adjusting step comprises one of incrementing the number of ATP pulses or decrementing the ATP cycle length if the ATP regimen RCL exceeds the measured exploratory RCL by a predetermined amount. 10. The method of claim 9, wherein the adjusting step comprises the other of incrementing the number of ATP pulses or decrementing the ATP cycle length if the ATP regimen RCL does not exceed the measured exploratory RCL by a predetermined amount. 11. The method of claim 1, wherein step (f) further comprises: if the tachycardia episode is determined to be terminated in step (e): classifying the delivered ATP regimen as successful; incrementing an historical efficacy of the delivered ATP regimen; and storing the delivered ATP regimen as a successful ATP regimen in association with the historical efficacy and in association with the stored exploratory RCL used in formulating the ATP regimen in IMD memory; and wherein step (c) further comprises: comparing the measured exploratory RCL determined in step (b) with previous exploratory RCLs stored in step (f); if the exploratory RCL measured in step (b) matches at least one stored exploratory RCL, retrieving the successful ATP regimen stored in IMD memory in association with the at least one matching stored exploratory RCL from the database, the retrieved successful ATP regimen to be delivered in step (d); and if the exploratory RCL measured in step (b) matches more than one stored exploratory RCL, comparing the stored historical efficacies, and retrieving, from the database, a successful ATP regimen having a highest stored historical efficacy and stored in association with one of the more than one matching stored exploratory RCLs, the retrieved ATP regimen to be delivered in step (d). 12. The method of claim 11, further comprising: (g) if the tachycardia episode is determined to not be terminated in step (e): if the delivered ATP regimen comprises a previously stored successful ATP regimen, decrementing the historical efficacy of the stored successful ATP regimen; and if the delivered ATP regimen does not comprise a previously stored successful ATP regimen, storing the measured exploratory RCL used in formulating the delivered ATP regimen and storing the delivered ATP regimen as an unsuccessful ATP regimen, the delivered ATP regimen stored in association with the stored exploratory RCL in IMD memory, whereby a database is accumulated in IMD memory comprising stored successful and unsuccessful ATP regimens each stored in association with a stored exploratory RCL. 13. In an implantable medical device (IMD), a method of responding to a tachycardia of a heart chamber by providing anti-tachycardia pacing (ATP) therapies to the heart chamber comprising: (a) detecting intrinsic depolarizations of the heart chamber; (b) detecting a tachycardia episode exhibited by a series of detected intrinsic depolarizations; (c) delivering an exploratory ATP sequence of pacing pulses to the heart chamber to elicit a paced depolarization of the heart chamber upon delivery of at least the last delivered ATP pulse; (d) measuring the return cycle length (RCL) between the last delivered exploratory ATP sequence pacing pulse and the next detected intrinsic depolarization as a measured exploratory RCL; (e) formulating an ATP regimen having defined ATP parameters; (f) delivering the ATP regimen formulated in step (e) to the heart chamber to elicit a paced depolarization of the heart chamber upon delivery of each ATP pulse; (g) following delivery of the ATP regimen, determining whether the tachycardia episode is terminated; (h) if the tachycardia episode is determined to be terminated in step (g), classifying the delivered ATP regimen as a successful ATP regimen in association with the exploratory RCL measured in step (d); (i) storing the exploratory RCL measured in step (d) and storing the successful ATP regimen, the stored successful ATP regimen stored in association with the stored measured exploratory RCL in IMD memory; and (j) processing steps (a) and (b) and repeating steps (c)-(i) when a tachycardia is detected in step (b) to accumulate a database comprising at least one stored successful ATP regimen stored in IMD memory in association with at least one stored exploratory RCL, wherein repeating step (e) comprises comparing the measured exploratory RCL determined each time step (d) is repeated with each stored exploratory RCL stored in step (i) and retrieving, from the database, a successful ATP regimen stored in association with a stored exploratory RCL matching the measured exploratory RCL determined in step (d). 14. The method of claim 13, wherein: step (h) further comprises, if the tachycardia episode is determined to not be terminated in step (g), decrementing an historical efficacy of the stored successful ATP regimen if the delivered ATP regimen comprises a previously stored successful ATP regimen; and step (i) further comprises, if the delivered ATP regimen does not comprise a previously stored successful ATP regimen, storing the measured exploratory RCL measured in step (d) and storing the delivered ATP regimen as an unsuccessful ATP regimen in association with the stored exploratory RCL in IMD memory, whereby a database is accumulated in IMD memory comprising successful and unsuccessful ATP regimens each stored in association with a stored exploratory RCL. 15. The method of claim 13, wherein: step (h) further comprises, if the tachycardia episode is determined to not be terminated in step (g): decrementing an historical efficacy of the stored successful ATP regimen if the delivered ATP regimen comprises a previously stored successful ATP regimen; determining if the rate of the tachycardia has accelerated; if tachycardia rate acceleration is determined, classifying the delivered ATP regimen as an unsuccessful, accelerating, ATP regimen in association with the measured exploratory RCL determined in step (d); and if tachycardia rate acceleration is not determined and if the delivered ATP regimen does not comprise a previously stored successful ATP regimen, classifying the delivered ATP regimen as an unsuccessful, non-accelerating, ATP regimen in association with the measured exploratory RCL determined in step (d); and step (i) further comprises: storing the exploratory RCL determined in step (d) and storing the unsuccessful, accelerating, ATP regimen, the unsuccessful, accelerating ATP regimen stored in association with the stored measured exploratory RCL in IMD memory; and storing the exploratory RCL determined in step (d) and the unsuccessful, non-accelerating, ATP regimen, the unsuccessful, non-accelerating ATP regimen stored in association with the stored measured exploratory RCL in IMD memory if the delivered ATP regimen does not comprise a previously stored successful ATP regimen. 16. The method of claim 15, wherein: step (j) further comprises processing steps (a) and (b) and repeating steps (c)-(i) when a tachycardia is detected in step (b) to accumulate a database in IMD memory comprising successful and unsuccessful, accelerating and non-accelerating, ATP regimens and associated stored exploratory RCLs, and step (e) further comprises comparing the exploratory RCL measured in step (d) with each stored RCL, and one of: retrieving a successful ATP regimen from the database if the RCL determined in step (d) matches an RCL stored in association with the successful ATP regimen stored in the database; and retrieving an unsuccessful, non-accelerating ATP regimen from the database if the RCL determined in step (d) matches an RCL stored in association with the unsuccessful, non-accelerating, ATP regimen stored in the database. 17. The method of claim 16 wherein step (e) further comprises: if the exploratory RCL measured in step (d) matches at least one stored exploratory RCL associated with a successful ATP regimen, retrieving the successful ATP regimen associated with the stored exploratory RCL from the database to be delivered in step (f); and if the exploratory RCL measured in step (d) matches more than one stored exploratory RCL associated with a successful ATP regimen, comparing the stored historical efficacies, and retrieving the successful ATP regimen having the highest stored historical efficacy associated with the stored exploratory RCL from the database to be delivered in step (f). 18. The method of claim 15, wherein the ATP regimen comprises a predetermined number of ATP pulses separated by an ATP regimen cycle length and step (e) further comprises, if the measured exploratory RCL matches a stored exploratory RCL associated with an unsuccessful, non-accelerating, ATP regimen, formulating the ATP parameters of the ATP regimen to be delivered as an iteration of the ATP parameters of the unsuccessful, non-accelerating, ATP regimen by one of incrementing the number of ATP pulses or decrementing the ATP cycle length by a predetermined amount. 19. An implantable medical device (IMD) of the type that detects intrinsic depolarizations of a heart chamber, detects a tachycardia episode and responds to the detected tachycardia of a heart chamber by delivering anti-tachycardia pacing (ATP) therapies to the heart chamber comprising: means operable upon detection of a tachycardia for delivering an exploratory ATP sequence of pacing pulses to the heart chamber to elicit a paced depolarization of the heart chamber upon delivery of at least the last delivered ATP pulse; means for measuring the return cycle length (RCL) between the last delivered exploratory ATP sequence pacing pulse and the next detected intrinsic depolarization as a measured exploratory RCL; formulating means for formulating an ATP regimen having ATP parameters formulated as a function of the measured exploratory RCL; means for delivering the ATP regimen; means for determining whether the tachycardia episode is terminated following delivery of the ATP regimen; classifying means for classifying the delivered ATP regimen as a successful ATP regimen in association with the measured exploratory RCL if the tachycardia episode is determined to be terminated; and storing means for storing the measured exploratory RCL used in formulating the ATP regimen and for storing the successful ATP regimen, the successful ATP regimen stored in association with the stored measured exploratory RCL in IMD memory. 20. The implantable medical device of claim 19, wherein: the formulating means further comprises means for comparing the measured exploratory RCL with each stored RCL and for retrieving a successful ATP regimen from the IMD memory when the measured exploratory RCL matches a stored RCL stored in association with the successful ATP regimen. 21. The implantable medical device of claim 20, wherein: the classifying means is operable for classifying the delivered ATP regimen as an unsuccessful ATP regimen in association with the measured exploratory RCL if the tachycardia episode is determined to not be terminated; and the storing means is operable for storing the measured exploratory RCL used in formulating the ATP regimen and for storing the unsuccessful ATP regimen, the unsuccessful ATP regimen stored in association with the stored measured exploratory RCL in IMD memory, whereby a database is accumulated in IMD memory comprising successful and unsuccessful ATP regimens each stored in association with a stored exploratory RCL. 22. The implantable medical device of claim 21, further comprising: means operable upon detection of a tachycardia for determining a pre-ATP rate of the tachycardia prior to delivery of the exploratory ATP sequence; and means operable if the tachycardia episode is determined to not be terminated for determining a post-ATP rate of the tachycardia following delivery of the ATP regimen; and wherein: the classifying means is operable for classifying the delivered ATP regimen as an unsuccessful, accelerating, ATP regimen in association with the measured exploratory RCL used to formulate the ATP regimen if the post-ATP rate is faster than the pre-ATP rate and for classifying the delivered ATP regimen as an unsuccessful, non-accelerating, ATP regimen in association with the measured exploratory RCL used to formulate the ATP regimen if the pre-ATP rate is faster or the same as the post-ATP rate; and the storing means is operable for storing the measured exploratory RCL used to formulate the ATP regimen and for storing the unsuccessful, accelerating, ATP regimen in IMD memory in association with the stored measured exploratory RCL or for storing the unsuccessful, non-accelerating, ATP regimen in IMD memory in association with the stored measured exploratory RCL. 23. The implantable medical device of claim 21, further comprising: means for determining and storing an historical efficacy of each classified successful ATP regimen stored in association with a stored exploratory RCL, the historical efficacy representing the ratio of the number of successful terminations of a tachycardia by the ATP regimen to the number of unsuccessful, non-accelerating, terminations by the same ATP regimen; and wherein: the formulating means further comprises means for selecting a successful ATP regimen having the highest historical efficacy among stored successful ATP regimens that are stored in association with the same stored exploratory RCL that matches the measured exploratory RCL. 24. The implantable medical device of claim 19, further comprising: storing means for storing the delivered ATP regimen as an unsuccessful ATP regimen in IMD memory in association with the stored measured exploratory RCL if the tachycardia episode is determined to not be terminated by the termination determining means; whereby a database is accumulated in IMD memory comprising successful and unsuccessful ATP regimens each stored in association with a stored exploratory RCL. 25. The implantable medical device of claim 24, further comprising: tachycardia rate determining means for determining a pre-ATP rate of the tachycardia prior to delivery of the exploratory ATP sequence and a post-ATP rate of the tachycardia following delivery of the ATP regimen; and wherein the storing means is operable to store the delivered ATP regimen as an unsuccessful, non-accelerating, ATP regimen in IMD memory in association with the stored measured exploratory RCL used in formulating the ATP regimen, if the post-ATP rate is slower or substantially the same as the pre-ATP rate and is operable to store the delivered ATP regimen as an unsuccessful, accelerating, ATP regimen in IMD memory in association with the stored measured exploratory RCL used in formulating the ATP regimen, if the post-ATP rate is faster, by a predetermined amount, than the pre-ATP rate, whereby a database is accumulated in IMD memory comprising successful and unsuccessful ATP regimens each stored in association with a stored exploratory RCL. 26. The implantable medical device of claim 25, wherein the formulating means further comprises: means for comparing the measured exploratory RCL with the stored exploratory RCLs stored in IMD memory; and means for formulating the ATP parameters of the ATP regimen to be delivered as a baseline ATP therapy if the measured exploratory RCL matches a stored exploratory RCL stored in association with an unsuccessful, accelerating, ATP regimen. 27. The implantable medical device of claim 24, further comprising: means for measuring an ATP regimen RCL from the last delivered ATP regimen pacing pulse to the next detected intrinsic depolarization; tachycardia rate determining means for determining a pre-ATP rate of the tachycardia prior to delivery of the exploratory ATP sequence and a post-ATP rate of the tachycardia following delivery of the ATP regimen; and wherein the storing means is operable to store the delivered ATP regimen as an unsuccessful, non-accelerating, ATP regimen stored in IMD memory in association with the stored measured exploratory RCL and store the ATP regimen RCL in IMD memory in association with the stored delivered ATP regimen, if the post-ATP rate is slower or substantially the same as the pre-ATP rate. 28. The implantable medical device of claim 27, wherein the formulating means further comprises means operable if the measured exploratory RCL matches a stored exploratory RCL stored in association with an unsuccessful, non-accelerating, ATP regimen for formulating the ATP parameters of the ATP regimen to be delivered as an iteration of the ATP parameters of the unsuccessful, non-accelerating, ATP regimen and its associated stored ATP regimen RCL. 29. The implantable medical device of claim 28, wherein the ATP parameters comprise an ATP cycle length and a number of ATP pulses, and the formulating means further comprises means for adjusting at least one of the ATP cycle length and the number of ATP pulses as a function of the comparison of the stored ATP regimen RCL to the measured exploratory RCL. 30. The implantable medical device of claim 29, wherein the adjusting comprises one of incrementing the number of ATP pulses or decrementing the ATP cycle length if the ATP regimen RCL exceeds the measured exploratory RCL by a predetermined amount. 31. The implantable medical device of claim 30, wherein the adjusting comprises the other of incrementing the number of ATP pulses or decrementing the ATP cycle length if the ATP regimen RCL does not exceed the measured exploratory RCL by a predetermined amount. 32. The implantable medical device of claim 19, further comprising: means for determining whether the tachycardia episode is terminated following delivery of the ATP regimen; and means operable if the tachycardia episode is determined to be terminated for classifying the delivered ATP regimen as successful for incrementing an historical efficacy of the delivered ATP regimen, and storing the delivered ATP regimen as a successful ATP regimen in association with the historical efficacy and the stored measured exploratory RCL in IMD memory; and wherein the formulating means further comprises: means for comparing the measured exploratory RCL with stored exploratory RCLs; means operable if the measured exploratory RCL matches at least one stored exploratory RCL for retrieving a successful ATP regimen stored in association with the matching stored exploratory RCL from the IMD memory to be delivered to the heart; and means operable if the measured exploratory RCL matches more than one stored exploratory RCL for comparing the stored historical efficacies and for retrieving a successful ATP regimen having the highest stored historical efficacy and stored in association with the matching stored exploratory RCL from the IMD memory to be delivered to the heart. 33. The implantable medical device of claim 32, further comprising: means for decrementing the historical efficacy of the stored successful ATP regimen if the delivered ATP regimen comprises a previously stored successful ATP regimen and has not terminated the tachycardia episode; and means for storing the delivered ATP regimen as an unsuccessful ATP regimen in IMD memory in association with the stored measured exploratory RCL, if the delivered ATP regimen does not comprise a previously stored successful ATP regimen whereby a database is accumulated in IMD memory comprising successful and unsuccessful ATP regimens each stored in association with a stored exploratory RCL. 34. In an implantable medical device (IMD), apparatus that responds to a tachycardia of a heart chamber by providing anti-tachycardia pacing (ATP) therapies to the heart chamber comprising: detecting means for detecting intrinsic depolarizations of the heart chamber; tachycardia detecting means for detecting a tachycardia episode exhibited by a series of detected intrinsic depolarizations; pacing pulse delivery means for delivering pacing pulses to the heart chamber; means for operating the pacing pulse delivery means to deliver an exploratory ATP sequence of pacing pulses to the heart chamber to elicit a paced depolarization of the heart chamber upon delivery of at least the last delivered ATP pulse; return cycle length (RCL) determining means for measuring an exploratory RCL between the last delivered exploratory ATP sequence pacing pulse and the next detected intrinsic depolarization; ATP regimen formulating means for formulating an ATP regimen having defined ATP parameters; means for operating the pacing pulse delivery means to deliver the formulated ATP regimen of ATP pulses to the heart chamber; termination determining means for determining whether the tachycardia episode is terminated or not terminated following delivery of the ATP regimen; classifying means for classifying the delivered ATP regimen as a successful ATP regimen in association with the measured exploratory RCL if the tachycardia episode is determined to be terminated; and storing means for storing the measured exploratory RCL and for storing the successful ATP regimen in IMD memory in association with the stored measured exploratory RCL, and wherein the ATP regimen formulating means comprises means for comparing each subsequently measured exploratory RCL with each stored RCL stored in IMD memory in association with a stored successful ATP regimen, and means for retrieving a stored successful ATP regimen if the measured exploratory RCL matches a RCL stored in IMD memory in association with the successful ATP regimen. 35. The implantable medical device of claim 34, wherein: the classifying means further comprises means for classifying the delivered ATP regimen as an unsuccessful ATP regimen in association with the measured exploratory RCL if the tachycardia episode is determined to not be terminated; and the storing means further comprises means for storing the measured exploratory RCL and for storing the unsuccessful ATP regimen in IMD memory in association with the stored measured exploratory RCL. 36. The implantable medical device of claim 35, wherein the classifying means further comprises: tachycardia acceleration determining means for determining if the rate of the tachycardia has accelerated if the tachycardia episode is determined to not be terminated, means for classifying the delivered ATP regimen as an unsuccessful, accelerating, ATP regimen in association with the measured exploratory RCL if acceleration is determined; and means for classifying the delivered ATP regimen as an unsuccessful, non-accelerating, ATP regimen in association with the measured exploratory RCL if acceleration is not determined. 37. The implantable medical device of claim 36, wherein the storing means further comprises means for storing the unsuccessful, accelerating, ATP regimen in IMD memory in association with the stored measured exploratory RCL or the unsuccessful, non-accelerating, ATP regimen in IMD memory in association with the stored measured exploratory RCL.