Abstract: A method and system for verifying capture in the heart involves the use of pacing artifact templates. One or more pacing artifact templates characterizing a post pace artifact signal associated with a particular pace voltage or range of voltages are provided. A pacing artifact template is canceled from a cardiac signal sensed following a pacing pulse. Capture is detected by comparing the pacing artifact canceled cardiac signal to an evoked response reference. Fusion/pseudofusion detection involves determining a correlation between a captured response template and a sensed cardiac signal.

Abstract: Techniques are provided for allowing Automatic Mode Switching (AMS) to be exploited within dual unipolar systems employing Combipolar sensing. Relative refractory windows are opened within both the atrial and ventricular refractory periods for the purposes of determining the atrial rate using Combipolar sensing logic. In this manner, T-waves occurring during the relative refractory windows are excluded from the atrial rate calculation, whereas any P-waves occurring during the relative refractory windows are counted, thereby achieving a more accurate atrial rate calculation, particularly at high atrial rates, and thus permitting AMS to be enabled along with Combipolar sensing in the dual unipolar lead system. An alternative technique is provided for use in dual unipolar systems not initially set to a Combipolar Sensing mode, which also achieves more accurate atrial rate calculation at high atrial rates. Additional techniques are provided for use in dual bipolar systems.