Hemodynamic performance of a heart may be improved by determining, from a location associated with a diaphragm, an occurrence of a valid cardiac event; and then delivering asymptomatic electrical stimulation therapy directly to the diaphragm at termination of a diaphragmatic stimulation delay period that is timed relative to the occurrence of the valid cardiac event. The diaphragmatic stimulation delay period may be automatically established by sensing a plurality of cardiac events directly from a diaphragm; and for each of the sensed cardia events, determining whether the sensed cardiac event represents a valid cardiac event or a non-valid cardiac event. The diaphragmatic stimulation delay period is then calculated based on a plurality of sensed cardia events that are determined to be valid.