Implantable medical device and method using integrated t-wave alternans analyzer

Abstract

An implantable medical device includes a sensor and a T-wave analyzer. The sensor is implantable within the body of a patient to sense electrical cardiac activity and provide an indication of T-wave alternans within the heart of the patient. The T-wave analyzer is responsive to the sensor, and evaluates cardiac risk based on comparison of the indication of T-wave alternans to a predetermined criterion. The T-wave analyzer may form part of a microprocessor, a digital signal processor, or combination of both. The device may include a pacing generator that applies increased rate pacing stimuli to the heart to facilitate sensing of the T-wave alternans by the sensor. The device also may incorporate a memory that stores the T-wave alternans indication provided by the sensor, e.g., over a number of heartbeats. In addition, the device may be equipped to provide an alert to the patient or a physician in the event the processor generates the indication of cardiac risk. The results of the T-wave alternans analysis over a period of time can be stored as data in memory for access by a physician, e.g., by telemetry. In response to the alternans data, the physician may prescribe pharmacologic therapy, programmed cardiac electrical stimulation, or modifications to an electrical stimulation program in the existing implanted device. In some cases, the implantable medical device can be programmed to response to the alternans data, e.g., by controlling a pacing generator.