Infra-stellate upper thoracic sympathectomy results in a relative bradycardia during exercise, irrespective of the operated side

Objective: Removal of accessory fibres coming from the sub-stellar thoracic chain to the heart during infra-stellate surgical upper thoracic sympathectomy (ISS) may be responsible for a decreased heart rate to workload relationship during exercise following surgery. We hypothesised that heart rate would decrease not only following right ISS. Methods: We performed repeated bicycle incremental exercise tests in 11 control subjects (26.9 +/- 9.5 years, 61.4 +/- 12.4 kg, 167 +/- 10 cm), and 11 patients (29.8 +/- 10 years, 59.3 +/- 12.0 kg, 168 +/- 7 cm) referred for bilateral ISS: results are mean standard deviation. Surgery was performed at two distinct times allowing to study the consequences of unilateral and bilateral sympathectomy to confirm whether a significant relative bradycardia was constant and dependent on the operated side. Results: For control subjects, test durations were 13.55 +/- 3.29, 14.09 +/- 4.01 and 13.00 +/- 3.26 min and heart rates were 187 +/- 7, 187 +/- 8 and 186 +/- 7 beats min(-1) at the first, second and third test, respectively. Although time to exhaustion was comparable to controls and unchanged between tests: 12.32 +/- 2.87, 12.3 +/- 2.90, 12.33 +/- 3.76 min, heart rate at maximum exercise decreased significantly from 176 +/- 16 to 164 +/- 15, and 148 +/- 15 beats min(-1), before, following unilateral and bilateral ISS, respectively. The operated side did not allow for the prediction of the effect of unilateral sympathectomy. Conclusions: Patients should be informed of the exercise bradycardia resulting from ISS, although clinical tolerance seems excellent in endurance exercise. Contrary to previous reports at rest, during exercise no right-sided dominance was observed. These findings are consistent with reports of random distribution of sub-stellate cardiac fibres from anatomical studies. (C) 2001 Elsevier Science B.V. All rights reserved.