Accelerometer-based heart sound detection for autocapture

A cardiac rhythm management device capable of functioning in a preset stimulation and/or autocapture mode having preset stimulation rates and timing intervals, said rhythm management device comprising:

• a pulse generator that generates a stimulation pulse for delivery to at least one of an atrium and a ventricle of a heart;
• an accelerometer that transmits a signal associated with accelerations of the heart;
• a controller electrically coupled to said pulse generator and said accelerometer, said controller identifying heart sounds from the signal of the accelerometer over corresponding cardiac cycles and further determining whether an identified heart sound is associated with delivery of the stimulation pulse to the heart;
• and
• wherein said controller determines a patient activity level and terminates the determination as to whether the identified heart sound is associated with delivery of the stimulation pulse to the heart when the patient activity level exceeds a predetermined amount.

A cardiac rhythm management device capable of functioning in a preset stimulation and/or autocapture mode having preset stimulation rates and timing intervals, said rhythm management device comprising:

• generating means for generating a stimulation pulse for delivery to at least one of an atrium and a ventricle of a heart;
• means for detecting and transmitting a signal associated with accelerations of the heart;
• control means electrically coupled to said generating means and means for detecting, said control means for identifying heart sounds from the signal of the means for detecting occurring during a predefined period and corresponding to a cardiac cycle, and wherein said control means determines whether an identified heart sound is associated with delivery of the stimulation pulse to the heart;
• wherein said control means determines a maximum output of the signal of the means for detecting for at least one cardiac cycle;
• and
• wherein a midpoint of the predefined period is set to correspond with a timing of detection of a determined maximum output of the signal of the means for detecting during a first cardiac cycle.

A cardiac rhythm management device capable of functioning in a preset stimulation and/or autocapture mode having preset stimulation rates and timing intervals, said rhythm management device comprising:

• generating means for generating a stimulation pulse for delivery to at least one of an atrium and a ventricle of a heart;
• means for detecting and transmitting a signal associated with accelerations of the heart;
• control means electrically coupled to said generating means and means for detecting, said control means for identifying heart sounds from the signal of the means for detecting occurring during a predefined period and corresponding to a cardiac cycle, and wherein said control means determines whether an identified heart sound is associated with delivery of the stimulation pulse to the heart;
• and
• wherein said control means determines a patient activity level and terminates the determination whether the identified heart sound is associated with delivery of the stimulation pulse to the heart when the patient activity level exceeds a predetermined amount.

A method of determining whether a stimulation output is sufficient to evoke a response in a patient's heart, said method comprising the steps of:

• positioning an accelerometer adjacent a patient's heart;
• delivering a stimulation pulse having a predetermined output to a patient's heart;
• obtaining from the accelerometer a signal associated with fluid and myocardial accelerations of the heart;
• identifying heart sounds from the signal of the accelerometer over a cardiac cycle corresponding with the stimulation pulse;
• determining whether the identified heart sounds are associated with delivery of the stimulation pulse to the heart;
• and
• determining a patient activity level and terminating the determination of whether the identified heart sound is associated with delivery of the stimulation pulse to the heart when the patient activity level exceeds a predetermined amount.

A cardiac rhythm management device capable of functioning in a preset stimulation and/or autocapture mode having preset stimulation rates and timing intervals, said rhythm management device comprising:

• a pulse generator that generates a stimulation pulse for delivery to at least one of an atrium and a ventricle of a heart;
• an accelerometer positioned near the heart, wherein said accelerometer transmits a global signal associated with fluid and myocardial accelerations of the heart;
• and
• a controller electrically coupled to said pulse generator and said accelerometer, said controller including a device for identifying heart sounds from the signal of the accelerometer over corresponding cardiac cycles and a device for determining whether an identified heart sound is associated with delivery of the stimulation pulse to the heart;
• wherein said controller includes a detection window having a predefined duration;
• wherein said controller determines a maximum output of the accelerometer signal for at least one cardiac cycle;
• and
• wherein a center of the detection window is aligned with a determined maximum output of the accelerometer signal during a first cardiac cycle.

A cardiac rhythm management device capable of functioning in a preset stimulation and/or autocapture mode having preset stimulation rates and timing intervals, said rhythm management device comprising:

• a pulse generator that generates a stimulation pulse for delivery to at least one of an atrium and a ventricle of a heart;
• an accelerometer positioned near the heart, wherein said accelerometer transmits a global signal associated with fluid and myocardial accelerations of the heart;
• and
• a controller electrically coupled to said pulse generator and said accelerometer, said controller including a device for identifying heart sounds from the signal of the accelerometer over corresponding cardiac cycles and a device for determining whether an identified heart sound is associated with delivery of the stimulation pulse to the heart;
• and
• wherein said controller determines a patient activity level and terminates the determination whether the identified heart sound is associated with delivery of the stimulation pulse to the heart when the patient activity level exceeds a predetermined amount.