Techniques are provided for tracking patient respiration based upon intracardiac electrogram signals or other electrical cardiac signals. Briefly, respiration patterns are detected by integrating cardiac electrical signals corresponding to individual paced cardiac cycles. The integrals may be obtained between consecutive pairs of ventricular pacing pulses or between consecutive pairs of atrial pacing pulses. In either case, cyclical changes in the integrals of the individual cardiac cycles are tracked. The cyclical changes are representative of respiration. Once respiration patterns have been identified, episodes of abnormal respiration, such as apnea, hyperpnea, nocturnal asthma, or the like, may be detected and therapy automatically delivered.