Comparison Between the Valsalva Maneuver and a Newly-Devised Expiratory Valve on Splitting of the Second Heart Sound

The authors have compared the effect on the second heart sound of normal inspiration, the Valsalva maneuver, and a breathing mask with an expiratory obstruction. A comparison of the results in 25 subjects showed that both the Valsalva maneuver and the expiratory valve widened the splitting of the second sound, a fact which permitted a better analysis of its components. However, the response to the valve was superior in 15 out of 25 subjects, inferior in five, and equal in another five. This demonstrates that the new method is both useful and practical. Moreover, it is based on a standard modification of the respiration.