Long QT syndrome: from genetic basis to treatment

The congenital long QT syndrome (LQTS) is a monogenic disorder, not as rare as it was originally estimated to be, mainly caused by mutations in genes encoding for ion channels. Molecular screening in this disease is part of the diagnostic process and this has already been recognized by current guidelines since 2006. However, very recently, two consensus documents have been published, with the recommendations for the use of genetic testing in the clinical evaluation of genetically transmitted arrhythmogenic diseases. Therefore, we devoted a specific section of the present review to the discussion of these two documents in relation to LQTS. The clinical presentation of the disease is typically characterized by a prolongation of the QT interval on the electrocardiogram (ECG) and by the occurrence of syncope or cardiac arrest, mainly precipitated by sympathetic activation. While the diagnosis of typical cases it is quite easy, borderline cases can be quite challenging and therefore the availability of diagnostic criteria is very useful to support the diagnostic process. Very recently, the LQTS diagnostic criteria have been updated and they are presented in the current review. Finally, the clinical management of LQTS patients is presented together with a schematic flow-chart and recent data coming from the LQTS-ICD European registry are illustrated. The last part of the review is dedicated at future perspectives and latest results on modifier genes and stem cells are presented.