Method and apparatus for avoiding unwanted sensing in a cardiac rhythm management device

A multi-chamber cardiac rhythm management device functioning in a pre-selected stimulation mode and capable of atrial and ventricular tracking, said device comprising:

• sensing means for sensing at least one of atrial and ventricular events and transmitting signals containing information corresponding to sensed events;
• stimulation means for selectively stimulating pre-selected chambers of the patient's heart;
• and
• a controller coupled to said means for sensing and said stimulation means, wherein during a cardiac cycle said controller manipulates the means for sensing to thereby create a first and second refractory period of sensed events for pre-selected chambers during the cardiac cycle.

A cardiac rhythm management device capable of uni-polar or bipolar atrial and ventricular stimulation, said cardiac rhythm management device including:

• (a) a controller;
• (b) means for stimulating at least one of an atrium or ventricle of a heart, said means electrically coupled to said controller;
• (c) sensing means for sensing a cardiac electrogram, said sensing means electrically coupled to the controller;
• (d) an atrial lead having an atrial electrode electrically coupled to the controller;
• (e) a ventricular lead having a ventricular electrode electrically coupled to the controller;
• and
• (f) said controller having means for defining a refractory period and a floating refractory period for a predetermined cardiac cycle for a predetermined chamber of the heart.

A method for stimulating a pre-selected chamber of a patient's heart using a cardiac rhythm management device of the type which senses and determines independently atrial and ventricular depolarization events and includes a plurality of programmed timing and stimulation intervals, said method comprising the steps of:

• a) sensing cardiac electrograms and detecting an intrinsic event occurring in pre-selected chambers of the patient's heart;
• then
• b) identifying a time at which the intrinsic event is sensed;
• c) initiating a first interval for blanking detected events for a predetermined cardiac cycle;
• d) initiating a second interval for blanking detected events for the predetermined cardiac cycle;
• and
• e) stimulating pre-selected chambers in accordance with a predetermined stimulation protocol so long as an intrinsic cardiac event having an amplitude exceeding a predetermined amount is not sensed between the first and second intervals.

A method for programming a cardiac rhythm management device to enhance its ability to sense intrinsic depolarization events while avoiding detection of artifacts and after-potentials comprising the steps of:

• (a) examining cardiac electrogram data originating from different sites in a heart to identify unwanted potentials;
• (b) determining a temporal relationship between the unwanted potentials and a known, repeatable, intrinsic or paced event;
• (c) programming the known, repeatable, intrinsic or paced event as a trigger event that initiates a blanking or refractory period in a sensing channel exhibiting the unwanted potential;
• (d) programming a delay value that starts with the trigger event and extends to a point in time before which the unwanted potential is predicted not to occur;
• and
• (e) programming a duration of the blanking or refractory period that begins with the end of the delay and extends to cover a period of time during which the unwanted potential is predicted to occur.