Abstract: Techniques are provided for use by implantable medical devices for controlling ventricular pacing. In one example, optimal atrio-ventricular and interventricular pacing delay values are determined for pacing the heart of the patient based, in part, on a measured inter-atrial conduction delay. Atrio-ventricular conduction delays are then measured within the patient. The atrio-ventricular pacing delays are compared with the measured atrio-ventricular conduction delays. If the atrio-ventricular pacing delays are less than the measured atrio-ventricular conduction delays, biventricular pacing is delivered using the atrio-ventricular pacing delay and the interventricular pacing delay.

Abstract: Techniques are provided for use by implantable medical devices for controlling ventricular pacing. In one example, optimal atrio-ventricular and interventricular pacing delay values are determined for pacing the heart of the patient based, in part, on a measured inter-atrial conduction delay. Atrio-ventricular conduction delays are then measured within the patient. The atrio-ventricular pacing delays are compared with the measured atrio-ventricular conduction delays. If the atrio-ventricular pacing delays are less than the measured atrio-ventricular conduction delays, biventricular pacing is delivered using the atrio-ventricular pacing delay and the interventricular pacing delay.

Abstract: An assist device for an implantable cardiac stimulation lead system includes a handle for a steerable guidewire system. An inner conductive guidewire with a distal tip electrode is pre-shaped into a free state curved configuration. An outer sheath is coaxial with the guidewire and relatively slidable between a first position restraining the guidewire to a straight condition and a second position withdrawn from a freed length of the guidewire allowing it to assume its free state curved condition. A collar on the outer sheath is movable along the handle for moving the sheath between the first and second positions. An electrical terminal is in electrical continuity with the tip electrode such that a pacing system analyzer connected between the electrical terminal and a reference electrode in the body is operable for seeking a location at which optimal pacing parameters can be determined prior to final implantation of the lead system.