(val-sal´vah) increase of pressure inside the chest when a person forcibly exhales with the glottis closed; this traps blood in the great veins and prevents it from entering the chest and right atrium. When the breath is released, the pressure inside the chest drops and the trapped blood is quickly propelled through the heart, producing tachycardia (increased heart rate) and a rise in blood pressure that is followed almost immediately by a reflex bradycardia . The happens when a person strains to defecate or urinate, uses the arms and upper trunk muscles to move up in bed, or strains during coughing, gagging, or vomiting. The increased pressure, tachycardia, and reflex bradycardia can cause cardiac arrest in heart patients. increase in the pressure in the eustachian tube and middle ear by forcible exhalation against closed nostrils and mouth.