Cardiology. Named after Antonio M. Valsalva (1666-1723). The Valsalva's maneuver is used to study cardiac function by causing changes in blood pressure and pulse frequency. The subject tries to forcibly exhale against a closed glottis. This causes an increased intrathoracic pressure and a decreased return of venous blood to the heart. The stroke volume of the right ventricle falls. Due to the high intrathoraic pressure the venous blood flow of the lungs to the left ventricle is increased as long as the volume of the lungs is suffient. Then the arterial pressure decreases that may result in dizziness and even fainting.