Surgery – Diagnostic testing – Cardiovascular
Reexamination Certificate
2001-03-30
2003-10-14
Sykes, Angela D. (Department: 3762)
Surgery
Diagnostic testing
Cardiovascular
C607S030000, C607S059000
Reexamination Certificate
active
06633776
ABSTRACT:
FIELD OF THE INVENTION
The invention generally relates to implantable cardiac stimulation devices and to external programmers used in connection therewith and in particular to methods and apparatus for processing and displaying event markers and other diagnostic information detected by an implanted device.
BACKGROUND OF THE INVENTION
A wide variety of implantable cardiac stimulation devices are provided for surgical implantation into patients. One common example is the cardiac pacemaker. Another is the internal cardioverter defibrillator (ICD). Implantable devices are often configured to be used in conjunction with an external programmer that allows a physician to display information detected by the implanted device. For example, the external programmer may operate to display electrical cardiac signals detected by the implantable device in the form of intracardiac electrograms (IEGMs). An IEGM is a graphic depiction of electrical signals emitted by active cardiac tissue as detected by electrodes placed in the heart. The electrical signals are digitized and recorded with the implanted device along with an indication of the date and time, then transmitted to the external programmer for display thereon, perhaps during a subsequent follow-up session with the physician. Alternatively, the implanted device is controlled to transmit the IEGM signals in real-time during the follow-up session. The external programmer may also be configured to receive real-time surface electrocardiogram (ECG) signals from an external ECG detector, perhaps for display along with contemporaneous real-time IEGM signals transmitted from the implanted device.
The implanted device may also be configured to detect various events, such as paced and sensed events, and to generate event codes representative of the events for transmission to the external programmer. The event codes are detected and stored in the implanted device along with the corresponding IEGM signals and the date and time for subsequent transmission to the external programmer or are detected and transmitted to the external programmer in real-time along with real-time IEGM signals. The external programmer generates event marker icons based on the code and displays the icons along with either IEGM signals, ECG signals, or both. Exemplary event markers are: P for a sensed event in the atria; R for a sensed event in the ventricles; A for a paced event in the atria, and V for a paced event in the ventricles. Along with the event markers, the programmer may also display variable length horizontal lines representative of the length of atrial and ventricular refractory periods associated with the events along with numerical values indicative of measured intervals between atrial and ventricular events, based on still further information recorded and transmitted by the implantable device. The external programmer may also display additional information received from the implanted device such as numerical information identifying the heart rate and the duration of ventricular and atrial refractory periods. Also, the display may provide other event markers as well, such as event markers indicating mode switching events. The implanted device may also maintain counters for counting various events, such as paced and sensed atrial and ventricular event counters, for subsequent transmission to and display using the external programmer.
An exemplary surface ECG display, along with event markers, is provided in FIG.
1
. More specifically,
FIG. 1
illustrates three ECG complexes (denoted
2
,
4
and
6
), along with P and R event markers indicating that the atrial and ventricular events are both intrinsic events. For both the P and R events, the display also includes horizontal lines adjacent thereto that indicate the length of the corresponding refractory period. Although not shown in
FIG. 1
, the external programmer may display additional information received from the implanted device such as IEGM signals.
Such displays of event markers and counters are helpful in permitting the physician to analyze the operation of the implanted device and to diagnose arrhythmias, if any, within the patient. U.S. Pat. No. 5,431,691 to Snell et al. entitled “Method and System for Recording and Displaying a Sequential Series of Pacing Events” provides a description of the operation of an exemplary pacemaker and external programmer including a detailed description of the generation, transmission and display of IEGM data and event markers. U.S. Pat. No. 5,431,691 to Snell et al. is incorporated by reference herein.
Although the typical event codes and counters maintained by implantable devices and the typical event marker icons displayed by external programmers are quite helpful to the physician, room for improvement remains. In particular, state of the art implantable devices are being developed utilizing multiple sensing/pacing leads for pacing or sensing at multiple locations within the heart. For example, separate leads may be provided to the left and right atria, as well as to left and right ventricles. In other cases, a single atrial lead may be capable of sensing and pacing in both the left and right atria, and a single ventricular lead may be capable of sensing and pacing in the left and right ventricles. Devices are also being developed which permit sensing or pacing at two or more locations within a single chamber. Eventually, highly sophisticated devices may be developed which permit sensing and pacing at a large number of locations within each chamber of the heart. As can be appreciated, when using such systems, the aforementioned conventional event codes, counters and event marker icons, which typically distinguish only between the atria and the ventricles may not be sufficient. Consider again the display of FIG.
1
. The intrinsic events of the ECG complexes
2
and
6
may have been detected only within the right atrium and ventricle whereas the intrinsic events of the ECG complex
4
may have been detected only within the left atrium and ventricle. Yet, the events markers indicate no such distinction been the left and right chamber events. Moreover, because the complexes themselves are derived from a surface ECG, rather than an IEGM, the complexes contain no polarization information that might permit the physician to distinguish between the left and right chamber events.
Accordingly, there is a need to develop enhanced event codes, event marker icons and event counters which accommodate implantable devices capable of separately sensing and pacing in the left or right chambers of the heart, or at multiple locations within a single chamber of the heart. There is also a need to develop improved hardware and software for use within implantable devices and within external programmers for recording, tracking and displaying the enhanced codes and markers. It is to these ends that aspects of the invention are primarily directed.
SUMMARY OF THE INVENTION
In accordance with a first aspect of the invention, a system is provided for use in an implantable cardiac stimulation device for generating diagnostic information using enhanced event codes. The enhanced event codes are representative of events detected using a plurality of leads positioned at different locations within the heart, with at least two leads positioned within the atria or with at least two leads positioned within the ventricles. The system includes means for receiving signals representative of electrical events detected at the respective locations of the leads, means for generating stimulation signals using selected leads, and means for generating location-specific event codes representative of events occurring at the respective locations of the leads. The location-specific event codes correspond to the arrangement of leads and hence include at least two distinct event codes associated the atria or at least two distinct event codes associated with the ventricles. The system also includes means for transmitting the location-specific event codes to an external programmer for display thereon.
In accordance with
Bevan Gregory C.
Levine Paul A.
Pacesetter Inc.
Sykes Angela D.
Yu Jeanne
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