The present disclosure relates to a method and a system for validating inspiratory muscle activity of a patient. Left and right electrical activity signals respectively representing activity of a left muscle and of a right muscle synchronized with an inspiratory effort of the patient are acquired from non-invasive sensors. A cardiac activity signal is extracted from the left and right electrical activity signals. A synchrony, a symmetry or a proportionality of the left and right electrical activity signals from which the cardiac activity signal is extracted is verified. A mechanical ventilation system incorporating the system for validating inspiratory muscle activity of the patient is also disclosed.
