The Effect of Left Cardiac Sympathetic Denervation on Exercise in Patients With Long QT Syndrome.
OBJECTIVES
This study evaluated the effect of left cardiac sympathetic denervation (LCSD) on heart rate, cardiac contractility, and cardiopulmonary fitness in human subjects.


BACKGROUND
The primary treatment for long QT syndrome (LQTS) is beta-blocker (BB) therapy, but some patients experience breakthrough cardiac events or intolerable side effects. LCSD provides a significant antifibrillatory, protective effect in LQTS. However, the effect of LCSD on cardiopulmonary fitness in humans has not been previously described.


METHODS
A retrospective analysis of patients with LQTS and LCSD (2006 to 2017) who had both pre- and post-LCSD exercise stress tests (N = 55; 39 females; mean age at LCSD 22 ± 12 years; mean follow-up 5.1 ± 2.5 years; 36 patients with LQT1; 15 patients with LQT2). Forty patients (73%) were receiving BBs pre-LCSD.


RESULTS
Mean peak heart rate before LCSD was 143 ± 23 beats/min, mean peak oxygen consumption (VO2) was 32 ± 10 ml/kg/min, and mean peak respiratory exchange ratio was 1.14 ± 0.12. There was no difference in peak heart rate, peak VO2, peak QTc, or respiratory exchange ratio pre- and post-LCSD. To evaluate the isolated effect of LCSD, the study performed a subset analysis of patients with LCSD monotherapy (n = 10) or no change in BB dose (n = 12). Patient-matched pre- and post-LCSD exercise testing showed no difference in heart rate, VO2, or left ventricular function following LCSD.


CONCLUSIONS
LCSD provides increased protection from an LQTS-triggered event without negatively affecting peak heart rate, cardiopulmonary fitness, or cardiac contractility, as assessed by both treadmill exercise stress testing and echocardiography.
['Anderson|Heather N|HN|', 'Bos|J Martijn|JM|', 'Rohatgi|Ram K|RK|', 'Ackerman|Michael J|MJ|']
D000293:Adolescent D000328:Adult D002648:Child D004452:Echocardiography D015444:Exercise D005080:Exercise Test D005260:Female D006321:Heart D006339:Heart Rate D006801:Humans D008133:Long QT Syndrome D008297:Male D012189:Retrospective Studies D013562:Sympathectomy D055815:Young Adult
left cardiac sympathetic denervation long QT syndrome cardiac contractility cardiopulmonary fitness exercise testing