Patent ID: 6512951
Filing Date: 2003-01-28
Classification: A61N

Abstract:
An apparatus for delivering atrial defibrillation therapy, comprising:an atrial sensing channel; a ventricular sensing channel; a shock pulse generator for generating atrial defibrillation shock pulses; a controller for controlling operation of the shock pulse generator in response to sensed events and for measuring R-R intervals with each sensed R wave; and, wherein, after detecting an episode of atrial defibrillation, the controller is programmed to deliver an atrial defibrillation shock pulse synchronously with a sensed R wave if a shockable R-R interval is measured, where a shockable current R-R interval is defined as an interval that is longer than a preceding QT interval by a specified therapy margin; and, wherein the controller is programmed such that the preceding QT interval is estimated as a function of a measured preceding R-R interval according to the following formula: QT(previous RR)=K ln(Râˆ’Rprev)âˆ’C where QT(previous RR) is the estimate of the preceding QT interval, K and C are defined constants, and Râˆ’Rprev is the measured preceding R-R interval.