Pii: S1010-7940(01)01002-8

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 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, 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. q 2001 Elsevier Science B.V. All rights reserved.