Observations based on 10-years' experience of non-invasive cardiovascular reflex testing of autonomic function from a rehabilitation research centre.

Observations on 1,282 measurements of non-invasive cardiovascular reflex testing of autonomic function in 1,023 control subjects and patients with different disorders are presented. It is suggested that the Valsalva manoeuvre be performed three times rather than once and the highest Valsalva ratio should be used instead of the mean or first of the three ratios. The deep breathing test gives equally reliable information when three breathing cycles are used instead of six. Symptoms were detected in up to 15% of the subjects depending on the test, although the majority of these were minor and transient. The frequency of ventricular/supraventricular extrasystoles increased especially during the Valsalva manoeuvre (+67%/+40%) and post-strain (+49%/+25%) phases and early recovery phase of the orthostatic test (+69%/+156%) and to a lesser degree during deep breathing (+18%/+50%) and handgrip (+36%/-11%) phases compared with the resting phase. However, severe cardiac rhythm disturbances were very rare. 1-2% of the younger (less than 50 years) and 10% of the older subjects were not able to perform the tests adequately. The R-R intervals on which the results are based should be selected carefully, and use of a continuous non-invasive method of blood pressure monitoring should provide further useful information.