A NEW AUTOMODE SWITCH ALGORITHM FOR SUPRAVENTRICULAR TACHYCARDIAS

Patients with complete heart block on a spontaneous, or iatrogenic bas is who also have recurrent supraventricular tachycardias, particularly atrial fibrillation and flutter, are often difficult to manage. Vario us techniques include: independently programmable maximum tracking and maximum sensor rates, limiting the maximum atrial tracking rate to th e sensor response of the pacemaker, or automatically switching from DD DR to VVIR based upon the sensed atrial rate. This article will descri be a mode switch algorithm that allows for an independently programmab le atrial tachycardia detection rate (ATDR). This allows mode switchin g to occur only in response to the patient's pathological tachyarrhyth mia, and not during normal upper rate response. The ATDR is based upon a filtered atrial rate, which will prevent an isolated premature beat from initiating the algorithm. In addition, the unit can be programme d to switch to either DDI, DDIR, VVI, or VVIR. Extensive event counter s in the pulse generator allows the system to record and store the num ber of algorithm activations, the average atrial rate which triggered each mode switch, and the duration of the mode switch. These reports a re accessible at each follow-up visit.