Abstract: Because a determination of atrial tachycardia can occur too often where the pacemaker maintained true atrial interval value is designed to converge on the shortest A-A intervals, a method and apparatus either extends PVAB to cover inappropriate atrial senses that should not be counted in determining the true atrial interval, primarily where they occur after an atrial pace, or removes other AS events from consideration.

Abstract: A method of and apparatus for telemetering both analog and digital data transcutaneously between an implantable medical device and an external receiver, such as between an external programmer and an implantable cardiac pacer. A damped carrier at 175 kilohertz is pulse position modulated by digital data. The data, along with synchronization and identification codes, are positioned into predefined ranges within predefined frames as measured by individual time periods. The data is uniquely identified by the position of a burst of the carrier within the predefined range. An automatically initiated hand shake protocol maintains the link over slight variations in programmer head position with an indicator notifying the operator when repositioning is required. Analog data may be transferred in digital form or alternatively transferred using phase modulation of the carrier bursts. A cyclic redundancy code is used for link error detection.