Denervation procedure treats genetic VT disorder

8 May 2008

MedWire News: Researchers have demonstrated that left cardiac sympathetic denervation relieves symptoms in patients with the genetic disorder catecholaminergic polymorphic ventricular tachycardia (VT).

They say the approach could avoid patients unresponsive to beta blockade having to be fitted with an implantable cardioverter defibrillator (ICD), which can trigger new arrhythmias.

In their report in the New England Journal of Medicine, Arthur Wilde (University of Amsterdam, The Netherlands) and team explain that catecholaminergic polymorphic VT is caused by mutations in genes involved in calcium homeostasis in cardiac cells. The disorder is characterized by life-threatening ventricular arrhythmias, usually polymorphic VT or ventricular fibrillation, in particular resulting from increased sympathetic activity, such as occurs during physical exercise and emotional stress.

Most patients are protected by beta-blocker therapy, but many continue to have symptoms and/or exercise-induced VT. For these individuals, the only other option currently available is to receive an ICD. However, even modest exercise can initiate fast VTs that trigger ICD shocks in these patients, impairing their quality of life.

Wilde and team now report three cases of catecholaminergic polymorphic VT successfully treated by surgical left cardiac sympathetic denervation. They explain that the procedure largely prevents norepinephrine release in the heart.

The first case was a man who underwent left cardiac sympathetic denervation at the age of 18 years after suffering ventricular fibrillation while on beta-blocker therapy. The patient remained asymptomatic during the next 20 years, apart from developing nonsustained VT induced by exercise stress testing on a bicycle workload of 120 W or more.

The second patient was a woman who underwent the denervation procedure at 17 years of age, having suffered since the age of 10 years with exercise-induced arrhythmias despite full-dose beta blockade. The woman remained asymptomatic for the next 30 months, with ventricular arrythmias occurring only at high work loads. She also had a clearly reduced total arrhythmia burden after surgery.

Finally, Wilde et al describe the third case of a man who remained asymptomatic for 10 years after undergoing the denervation procedure at the age of 16 years. The patient had received an ICD 3 years earlier and received numerous shocks during the intervening period, despite being on high doses of beta blockers.

"Left cardiac sympathetic denervation may be a viable solution for patients with catecholaminergic polymorphic ventricular tachycardia who are not fully protected by beta blockers, such as the patients described here," the authors comment.

N Engl J Med 2008; 358: 2024-2029