Disclosed are apparatus and method for detecting electromagnetic interference (EMI), or noise, that may disrupt the proper operation of medical devices (10) implantable in patients, such as cardiac stimulators. Circuitry of the detector of the invention is independent of other circuitry of the medical device. EMI is magnetically induced on an antenna (40) that may be within the metal housing (252) of the device (10) in a receiver circuit (40), and the EMI signals are output to the noise detector (66, 68). A variety of alert signals may be provided to the medical device circuitry to warn of the presence of EMI so that appropriate responses may be taken to insure the safety of the patient dependent on the device. The detector may share the telemetry antenna of the medical device, or utilize a separate, dedicated antenna to receive EMI. Alternative antennas external to the metal housing of the medical device include leads from the device to the heart of the patient, and a dedicated antenna (260) in the nonmetal header (254) of the device.

Electromagnetic noise detector for implantable medical devices

Apparatuses and methods selectively blank a neurological channel of a medical device system (100) in the treatment of a nervous system disorder.

Channel-selective blanking for a medical device system

A leadless fully automatic folow-up (LFAPF) device that is triggered into operation either locally or remotely is implemented extra-corporeally to access cardiac data such as ECGs stored in one or more implantable medical device (IMDs) implaned in one or more patients. A telemetry unit is used in the LFAPF to transmit and test stored data in the IMDs. The telemetry unit implements a series of adjustable commands depending on the desired level of detail of the follow-up. An alternate embodiment representing intra-corporeal use of an additional device includes cardiac data monitoring and cardioversion pulse synchroniyation in cooperation with another IMD such as a pacer.

Leadless fully automatic pacemaker follow-up

An implantable medical device includes a giant magnetoresistance ratio (GMR) sensor is used to detect the presence of a magnet in order to command the device to enter a predetermined mode of operation. The GMR responds to a modulated magnetic field generated by the programming of a command transmitter apparatus for non-invasive programming or controlling of the implanted device. The implantable medical device also monitors for the presence of a steady magnetic field to place the implanted device in a known, safe mode.

Apparatus and method for the control of an implantable medical device

The blanking periods for an implantable cardiac device, such as a pacemaker, is determined by providing an excitation in a cardiac chamber and monitoring the corresponding cardiac activity For in-channel blanking periods, the response from the same chamber is monitored while for cross-channel blanking period, the other cardiac chamber is monitored The optimal blanking period is then determined based on the cardiac activity This period is programmed directly into the device, or transmitted to an external programmer where it is used to provide guidance to a health care professional The optimal blanking period duration may also be determined using other signals sensed by the programmer, using ECG's or MTE's

Pacemaker with automatic blanking period function

A dual chamber pacemaker with variable V-A delay based on detection of multiple criteria before lengthening the V-A delay period. Before the V-A delay period can be extended, the pacemaker must be stimulating the ventricle at a maximum ventricular rate, and an atrial event must be sensed in a relative atrial refractory period. During this interval the pacemaker would not respond to an atrial event that was sensed, but the occurrence of the event would be detected. To optimize a ventricular blanking period, in each cardiac cycle, the energy level of the atrial output pulse and the sensitivity of the ventricular sense amplifier are sampled. Based on these dynamic parameters, the duration of the ventricle blanking period is adjusted for each cycle so that a minimum ventricular blanking period can be maintained without cross-talk.

Joseph W. Vandegriff

Papers

Dual chamber pacemaker with adjustable blanking and V-A extension