Method and apparatus of determining atrial capture threshold while avoiding pacemaker mediated tachycardia

A dual-chamber implantable stimulation device having means for determining atrial capture threshold while avoiding pacemaker mediated tachycardias, the device comprising:

• a pulse generator configured to generate atrial and ventricular stimulation pulses to a patient's heart;
• detection circuitry, coupled to the pulse generator, configured to detect the absence or presence of P-waves with each atrial stimulation pulse corresponding to loss-of-capture or cardiac contraction, respectively;
• and
• a processor, coupled to the pulse generator and the detection circuitry, programmed to automatically lengthen the AV Delay prior to triggering the pulse generator to initiate an atrial capture threshold test and, in response to a loss of capture, to restore the atrial stimulation pulse amplitude to a value above capture threshold, and further programmed to trigger the pulse generator to deliver a backup atrial stimulation pulse concurrent with the ventricular stimulation pulse.

A dual-chamber implantable stimulation device having means for determining atrial capture threshold while avoiding pacemaker mediated tachycardias, the device comprising:

• pulse generating means for generating atrial and ventricular stimulation pulses to a patient's heart;
• detecting means for detecting the absence or presence of P-waves with each atrial stimulation pulse corresponding to loss-of-capture or cardiac contraction, respectively;
• and
• control means, coupled to the pulse generating means and the detecting means, for automatically lengthening the AV Delay prior to triggering the pulse generating means to initiate an atrial capture threshold test and, in response to a loss of capture, for triggering the pulse generating means to deliver a backup atrial stimulation pulse concurrent with a ventricular stimulation pulse.