Left cardiac sympathectomy prevents exercise-induced QTc prolongation in congenital long QT syndrome

Congenital long QT syndrome (LQTS) is a group of ion channel disorders of ventricular myocytes caused by mutations of genes that encode these ion channels. The main clinical features of LQTS are syncope, cardiac arrest and QT prolongation on body surface electrocardiogram. The present study reports on the case of a 42-year-old female patient with a 10-year history of LQTS and syncopal attacks resistant to beta-blocker therapy. Treadmill exercise testing in this patient increased the corrected QT interval (QTc) from 0.48 s to 0.54 s and reduced the amplitude of the T wave. Left cardiac sympathectomy did not affect the resting heart rate or QTc but it prevented exercise-induced T wave reduction and QTc prolongation. Therefore, sympathetic activation plays a key role in exercise-induced QT prolongation and changes in T wave morphology in patients with congenital LQTS.