LV threshold measurement and capture management

An apparatus for determining in a non-tracking pacing mode (e.g., DDI/R, VVI/R) whether a ventricular pacing stimulus is capturing a paced ventricle, comprising:

• means for increasing a ventricular pacing rate a nominal amount to an overdrive pacing rate higher than a most recent heart rate;
• means for evaluating a conduction interval from a first pacing ventricle to a second sensing ventricle to ensure that a threshold testing pacing rate will not exceed a predetermined minimum interval;
• and
• means for providing pacing stimulation at the overdrive pacing rate to the first ventricle and sensing the second ventricle to determine whether the pacing stimulation to the first ventricle was one of sub-threshold and supra-threshold.

A computer readable medium for storing executable instructions for determining in a non-tracking pacing mode (e.g., DDI/R, VVI/R) whether a ventricular pacing stimulus is capturing a paced ventricle, comprising:

• instructions for increasing a ventricular pacing rate a nominal amount to an overdrive pacing rate higher than a most recent heart rate;
• instructions for evaluating a conduction interval from a first pacing ventricle to a second sensing ventricle to ensure that a threshold testing pacing rate will not exceed a predetermined minimum interval;
• instructions for monitoring an underlying rate for a predetermined number of cardiac cycles;
• and
• instructions for providing pacing stimulation at a rate that provides a temporal capture window prior to expected timing of an underlying rhythm beat and sensing the second ventricle to determine whether the pacing stimulation to the first ventricle was one of sub-threshold and supra-threshold.

A method of determining in an atrial-tracking pacing mode whether a ventricular pacing stimulus is capturing a paced ventricle, comprising:

• increasing a ventricular pacing rate a nominal amount to an overdrive pacing rate higher than a most recent heart rate;
• evaluating a conduction interval from a first pacing ventricle to a second sensing ventricle (V-V conduction interval);
• monitoring the underlying rate for a predetermined number of cardiac cycles to ensure that a threshold testing pacing rate will not exceed a predetermined minimum interval;
• measuring an atrio-ventricular (AV) conduction time to ensure that it is at least as long as the sum of fifty milliseconds added to an operating AV interval longer than longest V-V conduction interval;
• providing pacing stimulation to the first ventricle at a rate that provides a capture window prior to the expected timing of an underlying rhythm beat and sensing the second ventricle to determine whether the pacing stimulation to the first ventricle was one of sub-threshold and supra-threshold;
• providing at least a pair of pacing stimuli for a given magnitude of pacing energy;
• employing N or M logic criteria to determine whether the pacing stimulation to the first ventricle was one of sub-threshold and supra-threshold, wherein the N of M logic criteria comprises 2 of 3 assessment criteria and the at least a pair of pacing stimuli are provided by at least two monitored cardiac cycles and wherein the N of M criteria depends on whether one of a prior at least a pair of pacing stimuli was of greater or lesser magnitude than a present pacing stimuli.