Sudden cardiac death in individuals with structurally normal hearts accounts for 
approximately 20% of sudden cardiac death cases. Patients in this subgroup 
suffer from what has been named "electrical diseases" which are gradually coming 
into focus as inherited ion channelopathies, diseases of anchoring proteins or 
of intracellular calcium regulating proteins. From 1993, the Short QT Syndrome 
(SQTS) came to our attention, as a new inherited "electrical disease" associated 
with increased risk of sudden cardiac death and atrial fibrillation. Mutations 
of Ikr, Iks, Ikl channels cause dysfunctional Iks, Ikr, Ikl channels with an 
increase in the net outward K current leading to shortening of repolarization. 
This in turn leads to a shorter QT interval on the ECG and shorter atrial and 
ventricular refractory periods with increased susceptibility to VF and AF. There 
seems to be an autosomal dominant mode of inheritance. The clinical profile of 
SQTS consists of: family history of sudden cardiac death, personal history of 
palpitations, syncope, dizziness, resuscitated SCD, history of AF and documented 
VF. It is important to emphasize that SQTS is symptomatic from early age 
(new-born) to old age. Therefore, it is possible that SQTS accounts for some of 
the sudden infant death syndrome cases and for some cases of AF, especially lone 
AF. The only efficient treatment for ventricular arrhythmias is ICD, associated 
with drugs (Quinidine or Propaphenone) for AF prophylaxis and for reducing the 
number of ventricular arrhythmic events (and ICD discharges).