Cardiopulmonary functional status assessment via metabolic response detection by implantable cardiac device
First Claim
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1. An implantable medical device, comprising:
- a controller;
a switch matrix operable by the controller for configuring one or more sensing/pacing channels, wherein the controller is programmed to control the delivery of pacing pulses in accordance with a programmed pacing mode;
a minute ventilation sensor interfaced to the controller;
an activity level sensor interfaced to the controller for measuring a parameter related to a patient'"'"'s level of physical activity;
wherein the controller is programmed to construct a historical record of activity level versus minute ventilation, referred to as a minute ventilation response profile;
wherein the controller is further programmed to monitor a patient'"'"'s cardiopulmonary functional status by computing a minute ventilation response slope from the minute ventilation response profile, defined as the ratio of an incremental change in minute ventilation to an incremental change in measured activity level, and compare the minute ventilation response slope to a specified limit value; and
,wherein the controller is further programmed to deliver pacing pulses in an atrial-triggered mode such that a ventricular pace is delivered upon expiration of an escape interval designated as the AV delay interval and to adjust the AV delay interval upon detecting that the patient'"'"'s minute ventilation response slope has changed to a specified extent wherein the controller is further programmed to adjust a pacing parameter upon detecting that the patient'"'"'s minute ventilation response slope has changed to a specified extent.
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Abstract
An implantable cardiac device is configured and programmed to assess a patient'"'"'s cardiopulmonary function by evaluating the patient'"'"'s minute ventilation response. Such evaluation may be performed by computing a minute ventilation response slope, defined as the ratio of an incremental change in minute ventilation to an incremental change in measured activity level. The minute ventilation response slope may then be compared with a normal range to assess the patient'"'"'s functional status.
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Citations
18 Claims
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1. An implantable medical device, comprising:
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a controller; a switch matrix operable by the controller for configuring one or more sensing/pacing channels, wherein the controller is programmed to control the delivery of pacing pulses in accordance with a programmed pacing mode; a minute ventilation sensor interfaced to the controller; an activity level sensor interfaced to the controller for measuring a parameter related to a patient'"'"'s level of physical activity; wherein the controller is programmed to construct a historical record of activity level versus minute ventilation, referred to as a minute ventilation response profile; wherein the controller is further programmed to monitor a patient'"'"'s cardiopulmonary functional status by computing a minute ventilation response slope from the minute ventilation response profile, defined as the ratio of an incremental change in minute ventilation to an incremental change in measured activity level, and compare the minute ventilation response slope to a specified limit value; and
,wherein the controller is further programmed to deliver pacing pulses in an atrial-triggered mode such that a ventricular pace is delivered upon expiration of an escape interval designated as the AV delay interval and to adjust the AV delay interval upon detecting that the patient'"'"'s minute ventilation response slope has changed to a specified extent wherein the controller is further programmed to adjust a pacing parameter upon detecting that the patient'"'"'s minute ventilation response slope has changed to a specified extent. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for operating an implantable medical device, comprising:
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programming a controller to deliver pacing pulses in accordance with a programmed pacing mode; interfacing the controller to a minute ventilation sensor that measures a patient'"'"'s minute ventilation and to an activity level sensor that measures a parameter related to a patient'"'"'s level of physical activity; programming the controller to; construct a historical record of activity level versus minute ventilation, referred to as a minute ventilation response profile; monitor a patient'"'"'s cardiopulmonary functional status by computing a minute ventilation response slope from the minute ventilation response profile, defined as the ratio of an incremental change in minute ventilation to an incremental change in measured activity level, and comparing the minute ventilation response slope to a specified limit value; and
,delivering pacing pulses in an atrial-triggered mode such that a ventricular pace is delivered upon expiration of an escape interval designated as the AV delay interval and adjusting the AV delay interval upon detecting that the patient'"'"'s minute ventilation response slope has changed to a specified extent. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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Specification