Patent ID: 7706879

Claim:
A method of determining a pre-excitation interval (PEI) for optimized delivery of a bi-ventricular, fusion-pacing therapy to a non-synchronous pair of ventricles, including delivery of a single ventricular pre-excitation pacing pulse to a relatively late activated ventricular chamber to promote mechanical synchrony between the late activated ventricular chamber and a relatively more rapid, intrinsically-conducting ventricular chamber, comprising: measuring an intrinsic atrio-ventricular delay interval for a first-to-depolarize ventricular (V1) chamber for at least one prior cardiac cycle; delivering a pacing stimulus to the V1 chamber upon expiration of an atrio-ventricular (A-V) delay interval and sensing the resulting evoked depolarization in a last-to-depolarize ventricular (V2) chamber, wherein the AV delay interval is shorter than the intrinsic atrio-ventricular delay interval and wherein the; and calculating a PEI using upon at least one of the following and based upon the relative temporal length of the interval between the V1 pacing stimulus delivery and the V2 sensing of the evoked depolarization: PEI=k×(V2p→V1s) or PEI=k×(V1p→V2s) or PEI=k×(V1s→V2s), or PEI=k×[(V1s→V2s)−(V2p→V1s)], and wherein the value of the constant k is about zero-point-five (0.5).