Apparatus and method for detecting, confirming and terminating pacemaker mediated tachycardia

A method of automatically detecting and confirming the presence of pacemaker mediated tachycardia (PMT) comprising the steps of:

• (a) in the event that PMT is suspected, measuring the interval between a generated ventricular pacing pulse and the succeeding sensed atrial beat (VP-to-AS interval), and repeating said interval measurement on at least one subsequent VP-to-AS interval,
• (b) detecting PMT by determining whether the measured intervals are consistent,
• (c) if the measured intervals are consistent, then pacing the patient's heart in a manner expected to preclude retrograde conduction, and
• (d) confirming that PMT is present only if, while step (c) is performed, the pattern of atrial beats sensed is markedly different from the pattern of atrial beats sensed in step (a).

An implantable pacemaker which automatically detects and confirms the presence of, and terminates, pacemaker mediated tachycardia (PMT) comprising:

• (a) means for generating ventricular pacing pulses,
• (b) means for measuring the interval between a generated ventricular pacing pulse and the succeeding sensed atrial beat (VP-to-AS interval), and for repeating said interval measurement on at least one subsequent VP-to-AS interval,
• (c) means for detecting PMT by determining whether the measured intervals are consistent,
• (d) means responsive to the measured intervals being consistent for generating several ventricular pacing pulses approximately simultaneously with atrial contractions,
• (e) means for confirming that PMT is present only if, while said several ventricular pacing pulses are being generated, atrial beats are not sensed at the ends of measured intervals consistent with the intervals measured by said measuring means, and
• (f) means responsive to the presence of PMT being confirmed for extending the pacemaker PVARP to exceed the longest VP-to-AS interval measured by said measuring means.

An implantable pacemaker which automatically detects and confirms the presence of pacemaker mediated tachycardia (PMT) comprising:

• (a) means for generating ventricular pacing pulses,
• (b) means for measuring the interval between a generated ventricular pacing pulse and the succeeding sensed atrial beat (VP-to-AS interval), and for repeating said interval measurement on at least one subsequent VP-to-AS interval,
• (c) means for detecting PMT by determining whether the measured intervals are consistent,
• (d) means responsive to the measured intervals being consistent for pacing the patient's heart in a manner expected to preclude retrograde conduction, and
• (e) means for confirming that PMT is present only if, while said pacing means operates in a manner expected to preclude retrograde conduction, the pattern of atrial beats sensed is markedly different from the pattern of atrial beats operated on by said measuring means.