Accelerometer-based heart sound detection for autocapture

摘要

An implantable cardiac rhythm management device capable of automatically detecting intrinsic and evoked response of a patient's heart. The device operates in an automatic capture verification mode, wherein a global accelerometer signal is utilized to identify heart sounds (S₁ and S₂) of the patient's heart. The presence or absence of one or more of the heart sounds S₁ and S₂ in the accelerometer signal indicates whether a stimulation pulse evokes a response by the patient's heart. The device may automatically adjust the stimulation output in accordance with a step down stimulation protocol, wherein the presence of a predetermined heart sound indicates capture. Also, the device may suspend the automatic capture verification sequence if the patient's physical activity level exceeds a predetermined threshold.