Pacesetter, Inc.

Siemens-pacesetter, Inc.

Raymond J Wilson

Jonathan A Kleks

Gene A Bornzin

John W Poore

Brian M Mann

Laurence S Sloman

Alan B Vogel

Ali Enayat Zadeh

Stuart W Buchanan

The system of the present invention records and stores, in long-term memory and in form of data snapshots, medical data acquired prior to and subsequent to an occurrence of cardiac episodes and implantable device functions defined as important by the medical practitioner. The system provides the medical practitioner with the ability to specify trigger criteria representative of important cardiac episodes and implantable device functions. The system of the present invention allows the medical practitioner to control the amount of medical data stored in the data snapshots. The system allows the medical practitioner to specify a mode of storing data snapshots when the maximum storage capacity of long-term memory has been reached. In a first mode, the system stores data snapshots in a circular buffer manner, overwriting the older data snapshots. In a second mode, the system stops storing new data snapshots after the maximum storage capacity of long-term memory has been reached.

System and method for recording and storing medical data in response to

Methods and apparatus are provided for classifying cardiac events with an implantable cardiac device. Cardiac signals are stored in a buffer. When a significant cardiac event is confirmed, a corresponding segment of the stored cardiac signals is processed to generate a set of feature values. The set of feature values is compared to various sets of reference values. Each set of reference values preferably corresponds to a separate type of cardiac event, so that the cardiac device may classify the significant cardiac event by matching its set of feature values to a set of reference values. Feature values include the maximum positive and negative slew rates exhibited by the cardiac signal during the segment, the maximum positive and negative signal amplitudes, the times to reach the maximum positive and negative signal amplitudes, the area under the cardiac signal curve, the area under the cardiac signal curve above zero as compared to the area below zero, and the number of zero crossings made by the cardiac signal. Additional feature values are generated by simultaneously processing the cardiac signals measured along two different vector directions in the heart.

Methods and apparatus for classifying cardiac events with an implantable

An autocapture system within an implantable pulse generator automatically maintains the energy of a stimulation pulse at a level just above that which is needed to effectuate capture. The electrical post-stimulus signal of the heart following delivery of a stimulation pulse is compared to a polarization template, determined during a capture verification test. A prescribed difference between the polarization template and the post-stimulus signal indicates capture has occurred. Otherwise, loss of capture is presumed, and a loss-of-capture routine is invoked that increases the energy a prescribed amount to obtain capture. Periodically, and/or at programmed intervals or events, the capture verification test is performed. During the capture verification test, the pulse generator determines a polarization template for a particular stimulation energy and for each of a plurality of sensitivity or threshold settings. A determination is also made as to which sensitivity settings yield capture. An autocapture routine extends the capture verification test data to a wide range of stimulation energies. An autothreshold routine automatically sets the energy of the stimulation pulse a specified level above the energy at which capture is first lost.

Autocapture system for implantable pulse generator

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Parker, CO, United States of America

Raymond J Wilson