Device and method for ventricular tracking and pacing

Claim 1

A multi-chamber cardiac rhythm management device functioning in a stimulation mode including atrial and ventricular tracking, said device comprising: means for sensing atrial events and transmitting a signal containing information corresponding to sensed atrial events; means for sensing ventricular events and transmitting a signal containing information corresponding to sensed ventricular events; stimulation means for selectively stimulating ventricles of the patient's heart; atrial tracking means for tracking a P-wave included in the signal containing information corresponding to the sensed atrial events; ventricular tracking means for tracking an R-wave included in the signal containing information corresponding to the sensed ventricular events; means for determining a sinus rate from at least one of the sensed atrial and ventricular events; and means for controlling the stimulation means, wherein said means for controlling is coupled to said stimulation means, said atrial tracking means, and said ventricular tracking means, said means for controlling controls said stimulation means in accordance with a predetermined timing sequence having a protocol for stimulating the ventricles, wherein the predetermined timing sequence protocol requires stimulation to the ventricles dependant upon a prior sensed intrinsic ventricular event, and implementation of the predetermined timing sequence protocol avoids a stimulation hysteresis as the sinus rate decreases from a predetermined ventricular maximum tracking rate.

Claim 8

A method for stimulating a ventricle of a patient's heart using a cardiac rhythm management device of the type which senses and tracks independently atrial and ventricular depolarization events and includes a plurality of programmed timing and stimulation intervals, said method comprising the steps of: a) sensing and tracking P-wave intrinsic conduction transmitted from an atrium of the patient's heart; then b) sensing and tracking intrinsic conduction transmitted from a ventricle of the patient's heart; then c) identifying an R-wave from the sensed and tracked intrinsic conduction transmitted from the ventricle of the patient's heart, wherein said identified R-wave corresponds to an immediately preceding tracked P-wave; d) tracking the identified R-wave; e) initiating a pre-selected timing sequence having a protocol for stimulating the ventricles after the identified R-wave, wherein the pre-selected timing sequence protocol requires a stimulation of the ventricles dependant upon said identified R-wave and implementation of the predetermined timing sequence protocol avoids a stimulation hysteresis; and f) controlling a stimulation to the ventricle dependant upon the pre-selected timing sequence protocol.

Claim 9

A method for stimulating a ventricle of a patient's heart using a cardiac rhythm management device of the type which senses and tracks independently atrial and ventricular depolarization events and includes a plurality of programmed timing and stimulation intervals, said method comprising the steps of: a) sensing and tracking P-wave intrinsic conduction transmitted from an atrium of the patient's heart; then b) sensing and tracking intrinsic conduction transmitted from a ventricle of the patient's heart; then c) identifying an R-wave from the sensed and tracked intrinsic conduction transmitted from the ventricle of the patient's heart, wherein said identified R-wave corresponds to an immediately preceding tracked P-wave; d) tracking the identified R-wave; e) initiating a pre-selected timing sequence having a protocol for stimulating the ventricles after the identified R-wave, wherein the pre-selected timing sequence protocol requires a stimulation of the ventricles dependant upon said identified R-wave and implementation of the predetermined timing sequence protocol avoids a stimulation hysteresis; and f) controlling a stimulation to the ventricle dependant upon the pre-selected timing sequence protocol.