Tachycardia detection in implantable antitachycardia devices.

We have developed a microcomputer algorithm for tachycardia identification suitable for use in an implanted antitachycardia pacemaker. The algorithm distinguishes atrial, ventricular, and AV reentrant tachycardia, while ignoring high rates due to sinus tachycardia. A new method whereby the pacemaker delivers an atrial extrastimulus has been developed for distinguishing paroxysmal 1:1 tachycardia from sinus tachycardia, and has undergone preliminary testing in the electrophysiology laboratory. Preliminary results indicate sinus tachycardia can be reliably distinguished from paroxysmal 1:1 tachycardia by a properly timed extrastimulus delivered to the right atrium.