Left Cardiac Sympathetic Denervation
Arthur Moss performed the first left cardiac sympathetic denervation (LCSD) in a patient with the long QT syndrome in 1971.
As opposed to beta blockers which simply block the ability of adrenaline to bond to beta receptors in the heart, LCSD removes the ganglia which supply adrenaline to the heart. This numbs the body’s natural fight or flight response in dangerous situations.
In the same way beta blockers limit the heart's reaction to adrenaline, LCSD reduces the QTc by minimising the QT stunning and stretching.
Catecholamines are a group of chemical messengers that help the body respond to stress. They include:
• Adrenaline (epinephrine)
• Noradrenaline (norepinephrine)
• Dopamine
These are released by the adrenal glands and nerve endings during physical or emotional stress — think of them as the body’s “emergency broadcast system.”
Between LQTS1 and LQTS2, LQTS1 is generally more susceptible to catecholamines, especially adrenaline surges during physical exertion.
LQTS1 involves mutations in the KCNQ1 gene, affecting the IKs potassium channel — which is crucial during sympathetic stimulation (like exercise or stress). When catecholamines flood the system, a healthy heart shortens its QT interval to keep up. But in LQTS1, the IKs channel can’t respond properly, so the QT interval prolongs instead, increasing arrhythmia risk.
LQTS2 (KCNH2 gene, IKr channel) is more reactive to emotional stress and sudden auditory stimuli — like alarms, phone rings, or unexpected fright. Catecholamines still play a role, but the trigger profile is more startle-based than exertion-based.
A comparative study showed that during exercise stress, QT adaptation was less effective in LQTS1 than in LQTS2, suggesting a stronger catecholamine-linked vulnerability in LQTS1. This means Long QT 1 patients who still love to exercise are ideal candidates for LCSD surgery.
For people who still had breakthrough events while on beta blockers, the annual risk of recurrent cardiac events fell by about 86% after LCSD compared to their pre-treatment period.
LCSD surgery is usually only recommended for people with long QT syndrome and persistent rhythm problems who can't take or tolerate beta blockers.
It doesn't cure long QT syndrome, but it does help reduce the risk of sudden death.
LCSD helps bridge the gap between beta blockers and implanting an ICD which should be reserved for the highest risk patients.
If your physician recommends LCSD surgery I would suggest you join some support groups and speak to patients who have had the procedure to fully inform yourself of the risks and benefits.