Influences of bilateral endoscopic transthoracic sympathicotomy on cardiac autonomic nervous activity

Endoscopic transthoracic sympathicotomy (ETS) is a minimal invasive procedure of thoracic sympathetic blockage. The purpose of this study was to evaluate cardiac autonomic nervous activity after ETS in order to confirm the reliability and safety of ETS.

A series of electrophysiological studies were performed before and 1 week after bilateral 2nd and 3rd thoracic sympathicotomy in 13 patients with primary palmar hyperhydrosis. Palmar perspiration was measured under sympathetic stress, and body surface mapping was recorded in a supine position. In the head-up tilt test of 0, 30, 60 and 90 degrees, corrected QT interval (QTc) and T wave amplitude (Twa) were assessed. The power spectral analysis of heart rate variability was processed to attain power values of the low-frequency (0.04-0.15 Hz), the high-frequency (0.15-0.40 Hz) and the low/high frequency ratio.

In all patients, the perspiration response on the palm to sympathetic stimulation was completely inhibited after ETS. Isointegral mapping revealed that ETS altered electroactivity on the heart. In the head-up tilt study, R-R intervals significantly increased after the surgery in the head-up tilt positions (P < 0.05), although there was no significant difference in the supine position. There is no significant difference in QTc and Twa before and after the surgery, both in the supine and the head-up tilt positions. There was no significant difference in the LF or HF before and after surgery, either in the supine position or the head-up tilt positions. In the LF/HF, there was no significant difference before and after surgery in the supine position. However, the LF/HF in the head-up tilt positions was significantly decreased after surgery (P < 0.05). Sympathetic suppression of ETS was recognized more obviously under the steeper head-up tilt positions.

The influences on the cardiac autonomic nerve system of the ETS of upper thoracic sympathetic nerve were seen to be of a lesser degree at rest. However, the response to sympathetic stimulation was suppressed after the surgery.