Evaluation of Left Ventricular Autothreshold, Phase Two

Inclusion Criteria: * Patients who have a COGNIS CRT-D device implanted for at least 24 hours, with or without a right atrial lead * Patients who have an active LV bipolar lead * Patients who have an active right ventricular (RV) defibrillation lead * Patients who are willing and capable of participating in all testing associated with this Clinical Investigation * Patients who are age 18 or above, or of legal age to give informed consent specific to state and national law Exclusion Criteria: * Patients who have a COGNIS CRT-D that has less than or equal to one year of battery life remaining * Patients who are pacemaker-dependent * Patients who will not tolerate a pacing pause of up to 6 seconds * Patients who have a unipolar LV pace/sense lead, unless the patient has any commercially available epicardial leads with at least two electrodes (from one or more leads) * Patients with pre-existing leads other than those specified in this investigational plan * Patients with a pre-existing unipolar pacemaker * Patients who are unable or unwilling to maintain a supine or sitting position for 40-50 minutes * Patients enrolled in any concurrent study, without Boston Scientific written approval * Women who are pregnant