Orientation determination for an implantable medical device

摘要

An implantable medical device (IMD) is provided which is capable of sensing and determining its orientation, and of determining whether the IMD has been displaced over time away from its original or optimal position. Electronic components of the IMD, including a processor, digital memory, signal conditioning components, and a power supply, are preferably hermetically sealed within a biocompatible housing. At least three subcutaneous electrodes have fixed relative spacing for sensing electrical cardiac activity for various combinations of two electrodes, forming sensing vectors. Amplitude ratios and sign indicators associated with the sensing vectors are compared with a reference to determine an orientation of the device. In one embodiment, a telemetry unit transmits orientation data as a function of time to a remote device, and the remote device compares different stored orientations to detect displacement over time.

主权项

1. An implantable medical device (IMD), comprising:
a hermetically sealed, biocompatible housing; at least three electrodes having fixed relative spacing, the electrodes being capable of subcutaneous detection of electrical signals; a power supply installed within the housing; electronic components installed within the housing and energized by the power supply, including:
signal conditioning components, wherein each signal conditioning component is connected between a pair of electrodes to sense amplitudes of electrical activity, so as to form a set of at least three sensing vectors;a digital memory;a processor in communication with the digital memory and the signal conditioning components, the processor implemented to receive sensing vectors, compute amplitude ratios between different sensing vectors, and store in the digital memory the amplitude ratios corresponding to at least one orientation of the IMD.