Electrophysiological assessment of the autonomic nervous system in male patients with acromegaly.

Background/aims: We aimed to electrophysiologically evaluate the autonomic function in acromegalic patients using sympathetic skin response (SSR) as a reflection of the sympathetic sudomotor activity and RR interval variation (RRIV) as an indicator of the cardiovagal autonomic function.

Methods: The study group consisted of 18 male acromegalics, and the control group was composed of 18 age- and sex-matched healthy subjects. Participants underwent SSR and RRIV tests. Beginning latencies and amplitudes of the median and tibial SSRs were compared among the groups. The RRIV values recorded at rest and during hyperventilation were compared among the patients and controls.

Results: Latencies of SSRs recorded from the palms (median) and soles (tibial) of acromegalics were significantly longer than in healthy subjects (p = 0.004, p < 0.001). The amplitude of SSR recorded from the sole (tibial) was significantly decreased (p = 0.028). The RRIVs obtained from acromegalics at rest and during hyperventilation were significantly decreased compared with those of controls (p < 0.001). The RRIVs obtained from controls prolonged significantly during hyperventilation (p < 0.001); however, in the acromegaly group, hyperventilation did not cause a significant change in RRIV (p = 0.983).

Conclusions: The present study suggests that an autonomic dysfunction exists in patients with acromegaly. Dysautonomia in acromegalics may be documented by means of SSR and RRIV.