Image Number 5 for United States Patent #8131361.
An intrinsic inter-atrial conduction delay is determined by a pacemaker or implantable cardioverter-defibrillator based, at least in part, on far-field atrial events sensed using ventricular pacing/sensing leads. An atrioventricular pacing delay is then set based on the inter-atrial conduction delay. By detecting atrial events using ventricular leads, rather than using atrial leads, a more useful measurement of the intrinsic inter-atrial conduction delay can be obtained. In this regard, since atrial electrodes detect atrial activity locally around the electrodes, a near-field atrial event sensed using an atrial electrode might not properly represent the actual timing of the atrial event across both the right and left atria. Far-field atrial events sensed using ventricular leads thus allow for a more useful measurement of inter-atrial conduction delays for use in setting atrioventricular pacing delays. The delivery of individual V-pulses to the heart of the patient may be timed relative to the ends of individual far-field atrial events.