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

Hemodynamics following endoscopic thoracic sympathotomy for palmar hyperhidrosis

PURPOSE

We studied patients with palmar hyperhidrosis before and after endoscopic thoracic sympathotomy (ETS) to determine the effect of chronic sympathetic denervation on (1) forearm blood flow (FBF) response to mental stress and (2) exercise tolerance.

METHODS AND RESULTS

Twenty-two healthy patients were evaluated before ETS, and 17 returned after surgery (11 F; 19-32 years). We measured heart rate (HR; 12 lead), blood pressure, and FBF (plethysmography, ml dl(-1) min(-1)). Supine HR tended to decrease after ETS (69 ± 10 vs. 66 ± 6, p = 0.2). Mental stress FBF was recorded during baseline, 3-min Stroop color word test, and 2-min recovery. Mental stress responses were unaffected by ETS. However, during post-mental stress recovery period, ETS resulted in a significant elevation in FBF (2 ± 1 vs. 3 ± 1), FVC (3 ± 1 vs. 4 ± 2), and a decrease in FVR (52 ± 22 vs. 32 ± 16, p < 0.01 for all). ETS resulted in a reduction in pre-exercise seated baseline HR (94 ± 2.5 beats/min preoperatively vs. 84 ± 4.3 beats/min postoperatively, p < 0.05), maximal HR response to cycle exercise, and exercise systolic blood pressure (172 ± 5.2 mmHg pre-op vs. 158 ± 5.9 mmHg post-op, p < 0.05) but not mean or diastolic pressure. VO(2)max and exercise duration determined by cycle ergometry was unchanged.

CONCLUSIONS

Functional evidence of upper limb denervation is observed during the FBF recovery period from mental stress and hemodynamic alterations associated with upright cycle exercise. However, the sustained exercise capacity suggests modest clinical consequences.

Determinants of heart rate recovery following exercise in children

PURPOSE

Heart rate (HR) recovery during the first minute after cessation of exercise is predominantly modulated by reactivation of vagal tone. Attenuated 1-min HR recovery is a cardiovascular risk factor in adults. The purpose of this study was to determine predictors of 1-min HR recovery after a maximum-effort exercise test in healthy children.

METHODS

HR recovery after cessation of a maximal treadmill exercise test (Bruce protocol) was assessed in 485 children (197 girls, 288 boys) who underwent an exercise test during their clinical evaluation to exclude cardiac disease and who were discharged as normal. The first-minute cool-down period (1.5 mph, 0% inclination on treadmill) was consistent for all subjects. Age- and gender-specific 25th, 50th, and 75th percentile values of 1-min HR recovery were generated. Multivariable linear regression analyses were performed to determine predictors of 1-min HR recovery.

RESULTS

One-minute HR recovery was higher in boys and correlated inversely with age and with age-adjusted BMI in both boys and girls. In a multivariable linear regression model, age, gender, BMI, and baseline HR were significant predictors of 1-min HR recovery and explained 39% of variance. Exercise duration and peak HR were also significant predictors when added to the model, but they improved the explained variance by only 2%.

CONCLUSION

One-minute HR recovery after exercise is attenuated with age in children. Children with higher BMI, particularly those who are overweight, and those with lower exercise endurance, have slower 1-min HR recovery.

Is Previous Thoracic Sympathectomy a Risk Factor for Exertional Heat Stroke?

We report the case of a physically fit young man who presented with severe, life-threatening heat stroke after running a 10 km road race. He had previously received bilateral thoracic sympathectomy for axillary hyperhidrosis at another hospital, and was known to have upper body and limb anhidrosis. Thoracic sympathectomy can result in reduced sweating and disturbed peripheral vascular and heart rate responses. Patients should be warned that these mechanisms may play a role in the development of exertional heat stroke.

Effects of bilateral T2-sympathectomy on static and dynamic heart rate responses to exercise in hyperhidrosis patients

The static/dynamic changes of gas exchange, heart rate (HR) and blood pressure in terms of work rate (WR) and WR changes in ramp exercise were investigated by cardio-pulmonary exercise tests (CPETs) in hyperhidrosis patients before (W0), one week (W1) and four weeks (W4) after bilateral T2-sympathectomy. Accompanied by constant oxygen consumption and WR at peak exercise and similar oxygen debt in recovery, the HR significantly (p<0.05) decreased statically in all stages of CPET, but was not altered dynamically, i.e., similar slope but significantly diminished intercept in HR changes versus WR changes (70+/-6.0 vs. 82+/-19 beats/min, p<0.01), in W1 (n=11), compared to W0 (n=13). However, this surgical effect on static HR changes seemed to have disappeared in W4 (n=8), albeit at that time the static blood pressure decreased significantly during exercise. These findings suggest that bilateral T2-sympathectomy will reduce static HR without causing cardiovascular insufficiency in one week, and would then recover by one month in hyperhidrosis patients.

Exercise assessment in infants after cardiac transplantation

BACKGROUND

Few data describe exercise performance after cardiac transplantation during infancy. The aim of this study was to compare the cardiorespiratory response to exercise in healthy subjects with that of subjects who had undergone heart transplantation during infancy to treat hypoplastic left heart syndrome.

METHODS

Subjects (24 heart transplant recipients and 25 healthy controls) exercised on a treadmill using pediatric ramp protocols. We measured heart rate (HR), blood pressure, and metabolic data. Median age at transplantation was 20 days (range, 4 to 97 days). Age of recipients at exercise testing was 9.7 +/- 2.3 years and in healthy subjects was 10.5 +/- 1.4 years (p=not significant [NS]).

RESULTS

Exercise duration was similar in both groups (10.3 +/- 2.0 minutes in recipients vs 11.1 +/- 1.5 minutes in healthy subjects, (p=NS). Heart rate at rest was greater in recipients (94 +/- 15 beats per minute [bpm] vs 85 +/- 11 bpm, p=0.02). Peak HR also was less in the recipient group (158 +/- 15 bpm vs 189 +/- 12 bpm, p <0.001). Peak oxygen consumption was 14% less in the recipients (32.3 +/- 5.6 ml/kg/min vs 36.8 +/- 5.5 ml/kg/min, p <0.01). Ventilatory anaerobic threshold was decreased in recipients, 27.6 +/- 9.6 vs 32.8 +/- 6.0, p <0.05. Respiratory exchange ratio at peak exercise was equal in both groups (1.06 +/- 0.06 vs 1.06 +/- 0.08). Oxygen pulse index did not differ significantly, 5.5 +/- 1.1 ml/beat/m2 in recipients and 6.1 +/- 1.7 ml/beat/m2 in healthy subjects (p=NS).

CONCLUSIONS

Overall, children who undergo cardiac transplantation in infancy have exercise capacities within the normal range. These recipients have a decreased heart rate reserve that may account for the differences in peak oxygen consumption when compared with healthy subjects.

Holter changes resulting from right-sided and bilateral infrastellate upper thoracic sympathectomy

BACKGROUND

We tested the hypothesis that no right-sided dominance exists after infrastellate surgical upper-thoracic sympathectomy. We aimed to confirm whether a significant bradycardia was constant and only dependent on the right side.

METHODS

We performed 24-hour Holter electrocardiographic recordings in 12 patients referred for bilateral sympathectomy. Surgery was performed at two distinct times allowing for the study of the consequences of unilateral right and bilateral sympathectomy.

RESULTS

Heart rate was 77 +/- 8 beats per minute before surgery on the 24-hour recording and significantly decreased after bilateral (67.8 +/- 6.5 beats per minute; p < 0.05) but not after unilateral right sympathectomy. Consistently spectral analysis variables significantly changed after bilateral surgery but showed no right-sided dominance. Little effect of sympathectomy was found on the QT interval, which tended to decrease after bilateral sympathectomy.

CONCLUSIONS

Patients should be informed of the bradycardia resulting from sympathectomy. No right-sided dominance can be found consistently with the random distribution of substellate cardiac fibers reported in anatomic studies.