A method of identifying a potential cause of pulmonary edema is provided. The method includes obtaining one or more impedance vectors between predetermined combinations of the electrodes positioned proximate the heart. At least one of the impedance vectors is representative of a thoracic fluid level. The method also includes applying a stimulation pulse to the heart and sensing cardiac signals of the heart that are representative of an electrophysiological response to the stimulation pulse. The method further includes monitoring the cardiac signals and at least one of the impedance vectors with respect to time to identify the potential cause of pulmonary edema.
