Identifying heart failure patients suitable for resynchronization therapy using QRS complex width from an intracardiac electrogram

A system comprising:

• a module providing an atrio-ventricular delay of a patient and information for a QRS interval for the patient, the QRS interval occurring between the beginning of the intrinsic ventricular depolarization and the ending of the intrinsic ventricular depolarization, wherein the information for the QRS interval is indicative of whether a wide QRS interval is present in the QRS interval for the patient;
• and
• a heart stimulation device, coupled to the module providing the atrio-ventricular delay for the patient and the information for the QRS interval for the patient, the heart stimulation device configured to set a paced atrio-ventricular delay to be substantially less than an atrio-ventricular delay of the patient when the wide QRS interval is present.