“…The Valsalva maneuver was used to evaluate the para sympathetic influences on the sinus node [41]. This test provides in formation regarding the sympathetic division of the autonomic nervous system [41] and the functional reserve of the heart [20,38]. In spite of the observations that sympathetic stimulation contributes to tachycardia of hypotension [16,17,19,31,40] there is no agreement concerning the extent of this mechanism [24,32], the relative contribution of the autonomic components apparently depending upon the balance of tone before the intervention [33,37].…”