Präder-Willi syndrome fails to alter cardiac autonomic modulation

Twenty-six healthy subjects with a diagnosis of Präder-Willi syndrome were compared with 26 age-, gender-, and body mass index-matched controls for autonomic modulation and baroreflex sensitivity. Electrocardiograms, beat-to-beat finger blood pressures, and respiration were recorded for several minutes in the following sequence: (1) supine, (2) after transition from supine to standing, (3) sitting, (4) during a Valsalva maneuver, (5) while performing moderate exercise, and (6) during recovery from exercise while seated. All recordings were channeled and stored in a computer; analyses were carried out at a later date. Power spectral analysis (fast-Fourier transform) of heart period variability was used to assess cardiac autonomic modulation. The slope of the regression equation between heart period and blood pressure rise after the Valsalva maneuver was used as an index of baroreflex sensitivity. Analysis of variance failed to reveal significant differences in any of the autonomic and baroreflex sensitivity variables between the two groups. Because breathing patterns entrain autonomic modulation, we verified respiration and found no differences between the two groups. Therefore, findings in the current investigation indicate that cardiac autonomic modulation in patients with Präder-Willi syndrome does not differ from age and body mass index-matched subjects.